U.S. patent application number 14/343171 was filed with the patent office on 2014-07-17 for outdoor unit, air-conditioning apparatus, and method for manufacturing outdoor units.
This patent application is currently assigned to MITSUBISHI ELECTRIC CORPORATION. The applicant listed for this patent is Keisuke Hokazono, Nobuaki Miyake, Akio Murata, Hiroki Okazawa, Wataru Suzuki. Invention is credited to Keisuke Hokazono, Nobuaki Miyake, Akio Murata, Hiroki Okazawa, Wataru Suzuki.
Application Number | 20140196874 14/343171 |
Document ID | / |
Family ID | 48696448 |
Filed Date | 2014-07-17 |
United States Patent
Application |
20140196874 |
Kind Code |
A1 |
Miyake; Nobuaki ; et
al. |
July 17, 2014 |
OUTDOOR UNIT, AIR-CONDITIONING APPARATUS, AND METHOD FOR
MANUFACTURING OUTDOOR UNITS
Abstract
Heat exchanger assemblies included in an outdoor unit each
include fins each having notches provided without fin collars or
notches provided with fin collars that are shorter than stacking
intervals between the fins. At least some of the stacking intervals
between the fins in a facing surface are larger than the stacking
intervals between the fins in surfaces excluding the facing
surface.
Inventors: |
Miyake; Nobuaki; (Tokyo,
JP) ; Murata; Akio; (Tokyo, JP) ; Okazawa;
Hiroki; (Tokyo, JP) ; Hokazono; Keisuke;
(Tokyo, JP) ; Suzuki; Wataru; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Miyake; Nobuaki
Murata; Akio
Okazawa; Hiroki
Hokazono; Keisuke
Suzuki; Wataru |
Tokyo
Tokyo
Tokyo
Tokyo
Tokyo |
|
JP
JP
JP
JP
JP |
|
|
Assignee: |
MITSUBISHI ELECTRIC
CORPORATION
Tokyo
JP
|
Family ID: |
48696448 |
Appl. No.: |
14/343171 |
Filed: |
December 26, 2011 |
PCT Filed: |
December 26, 2011 |
PCT NO: |
PCT/JP2011/007260 |
371 Date: |
March 6, 2014 |
Current U.S.
Class: |
165/121 ;
29/890.049 |
Current CPC
Class: |
F28F 2215/04 20130101;
Y10T 29/49384 20150115; F24F 1/46 20130101; F28D 1/0426 20130101;
F28F 3/08 20130101; F28D 2001/0273 20130101; F24F 1/50 20130101;
B21D 53/02 20130101; F24F 1/16 20130101; F28F 1/24 20130101 |
Class at
Publication: |
165/121 ;
29/890.049 |
International
Class: |
F28F 3/08 20060101
F28F003/08; B21D 53/02 20060101 B21D053/02 |
Claims
1. An outdoor unit comprising: a housing; at least two plate
fin-tube heat exchanger assemblies arranged side by side in the
housing and each being bent in an inward direction of the housing
such that the heat exchanger assembly has a facing surface that
faces a surface of another heat exchanger assembly in the housing;
and a fan provided above the housing and causes air taken in from
surfaces of the housing to be exhausted from an upper portion of
the housing, wherein each of the heat exchanger assemblies includes
fins each having notches provided without fin collars or notches
provided with fin collars that are shorter than stacking intervals
between the fins, and wherein at least some of the stacking
intervals between the fins in a portion forming the facing surface
are larger than the stacking intervals between the fins in portions
forming surfaces excluding the facing surface.
2. The outdoor unit of claim 1, wherein, in a case where the heat
exchanger assemblies are each bent substantially perpendicularly at
least once, the stacking intervals between the fins in a portion of
the facing surface that is nearer to an end are larger than the
stacking intervals between the fins in another portion of the
facing surface that is nearer to a bent portion.
3. The outdoor unit of claim 2, wherein each of the heat exchanger
assemblies is bent along surfaces of the housing excluding one
surface.
4. The outdoor unit of claim 1, wherein each of the heat exchanger
assemblies includes flat tubes each having a flat cross-sectional
shape are fitted in the notches provided in the fins, the flat
cross-sectional shape being a shape in which long side thereof is
linear while short side thereof is curved in a semicircular
manner.
5. The outdoor unit of claim 4, wherein the fins each include a
plurality of bridge-type cut-raised portions provided between the
notches.
6. The outdoor unit of claim 4, wherein the fins are fixed to the
flat tubes, which are fitted in the notches, by brazing or
bonding.
7. An air-conditioning apparatus comprising: the outdoor unit of
claim 1; and an indoor unit connected to the outdoor unit.
8. A method for manufacturing an outdoor unit including at least
two fin-tube heat exchanger assemblies each being bent and having a
facing surface that faces a surface of another heat exchanger
assembly, the method comprising the steps of: in each of the at
least two fin-tube heat exchanger assemblies, fitting fins onto a
plurality of flat tubes from an open side of notches, the plurality
of flat tubes being arranged side by side and capable of moving and
positioning altogether in a long-axis direction, the fitting fins
each having notches provided without fin collars or notches
provided with fin collars that are shorter than stacking intervals
between the fins; adjusting at least some of the stacking intervals
between the fins in a portion forming the facing surface so as to
have larger stacking intervals than the stacking intervals between
the fins in portions forming surfaces excluding the facing surface;
and assembling the at least two fin-tube heat exchanger assemblies
by bending thereof.
Description
TECHNICAL FIELD
[0001] The present invention relates to an outdoor unit and an
air-conditioning apparatus including the outdoor unit.
BACKGROUND ART
[0002] Known industrial-use air-conditioning apparatuses intended
for office buildings, factories, and so forth include those having
relatively high power with outdoor units thereof each configured to
exhaust air from two positions in an upper portion in external
view. A known outdoor unit having such a configuration includes, in
its housing, devices such as a heat exchanger assembly, a
compressor, pipe components, and so forth, with two propeller fans
and two bell mouths that guide the flow of air provided in the
upper portion of the housing (see Patent Literature 1, for
example). In such an outdoor unit, when outdoor air sucked into the
housing by an effect of the propeller fans is made to flow through
the heat exchanger assembly, the outdoor air exchanges heat with a
refrigerant, and the resulting air is guided by the bell mouths and
is exhausted from the upper portion of the housing.
[0003] In general, the heat exchanger assembly included in such an
outdoor unit has a two-layer configuration including two heat
exchangers. Many of the known heat exchangers employ a plate
fin-tube structure obtained as follows: a plurality of strip-like
aluminum fins each having circular holes are stacked, a plurality
of copper or aluminum heat transfer tubes each having a circular
cross-sectional shape are inserted into the fins in a direction
substantially vertical to the fins, and the bores of the heat
transfer tubes are expanded by using a hydraulic or mechanical tube
expander, whereby the closeness between the fins and the heat
transfer tubes that is required for providing heat transferability
of the heat exchanger is guaranteed (see Patent Literature 2, for
example).
[0004] The edges of the circular holes provided in each of the fins
are burred and thus form cylindrical collars so that the area of
the fin that is in close contact with each of the heat transfer
tubes is increased. Furthermore, flat portions of the fin between
the circular holes have slits that improve the heat exchangeability
with draft air. In a disclosed technique (see Patent Literature 3,
for example), the circular holes, the collars, and the slits of the
fin are sequentially formed as follows: a progressive die including
a plurality of manufacturing step sections is placed on a pressing
machine, and the pressing machine is operated consecutively while a
strip-like aluminum hoop is fed thereto.
[0005] In a typical method of manufacturing a plate fin-tube heat
exchanger, after pressing is performed, a desired number of fins
obtained by cutting and each having a desired strip length are
sequentially stacked in a collar section. Subsequently, a plurality
of long heat transfer tubes called hair pins and each including a
U-shaped portion are inserted into the fins, and the tubes are
expanded. Since the stacking of the fins and the insertion of the
heat transfer tubes are performed with reference to collars, the
fins are consequently stacked and fixed at regular intervals
corresponding to the height of the collars (see Patent Literature
4, for example).
[0006] In such a plate fin-tube heat exchanger, a plurality of heat
transfer tubes are brazed to U-bends, which are heat transfer tubes
for pipe connection each having a circular cross-sectional shape
and being bent in a U shape at an end, and to other components such
as a distributor, whereby a continuous refrigerant passage that is
folded many times while passing through the stack of fins is
provided.
[0007] In another disclosed plate fin-tube heat exchanger (see
Patent Literature 5, for example), a stack of fins through which
heat transfer tubes extend is bent in an L shape a plurality of
times (twice, for example). In such a plate fin-tube heat
exchanger, the stack of fins is bent a plurality of times.
Ultimately, the plate fin-tube heat exchanger is used as a
substantially U-shaped heat exchanger in which the fins are stacked
and the heat transfer tubes extending therethrough extend in a
direction of a contour line (see Patent Literature 5, for example).
In the substantially U-shaped heat exchanger having three outer
surfaces obtained as a result of bending the stack of fins, all of
the fins are at regular intervals corresponding to the height of
fin collars and determined in a state prior to bending.
[0008] In addition, in view of recent circumstances concerning
enthusiastic discussions about energy problems and so forth, highly
competitive energy-saving and cost-reduction strategies are
underway. Accordingly, various measures have been sought for
further improvements in the shape, the pitch (the stacking
intervals between the fins and the intervals between adjacent heat
transfer tubes), the materials (the material of the fins and the
material of the heat transfer tubes), and other factors of the heat
transfer tubes and the fins. Other measures have also been proposed
in which the pitch of the fins is changed in accordance with the
internal configuration of the outdoor unit (see Patent Literature 6
to 8, for example).
CITATION LIST
Patent Literature
[0009] Patent Literature 1: Japanese Unexamined Patent Application
Publication No. 2008-138951 (FIGS. 1 to 3 and others) [0010] Patent
Literature 2: Japanese Examined Patent Application Publication No.
58-13249 (FIGS. 1 to 3 and others) [0011] Patent Literature 3:
Japanese Examined Patent Application Publication No. 58-9358 (FIGS.
1 to 5 and others) [0012] Patent Literature 4: Japanese Examined
Patent Application Publication No. 3-80571 (FIGS. 1 and 2 and
others) [0013] Patent Literature 5: Japanese Patent No. 4417620
(FIG. 20 and others) [0014] Patent Literature 6: Japanese
Unexamined Patent Application Publication No. 63-233296 (FIGS. 1
and 2 and others) [0015] Patent Literature 7: Japanese Unexamined
Patent Application Publication No. 2004-245531 (FIGS. 1 and 2 and
others) [0016] Patent Literature 8: Japanese Unexamined Patent
Application Publication No. 2008-8541 (FIG. 3 and others)
SUMMARY OF INVENTION
Technical Problem
[0017] As described above, in an air-conditioning apparatus
employing a heat exchanger that is manufactured by a method
including stacking of fins having circular holes, insertion of
circular tubes, and expansion of the tubes, the pitch of the fins
is a constant value determined by the height of collars formed by
burring. Therefore, in such a known air-conditioning apparatus, it
is difficult to change the pitch of the fins, for performance
improvement, in accordance with the internal configuration of an
outdoor unit.
[0018] Particularly, in an air-conditioning apparatus including a
plurality of substantially U-shaped heat exchangers that are
arranged side by side, the cross-sectional area of openings as air
inlets provided between surfaces of substantially U-shaped heat
exchangers that are adjacent to each other is smaller than the
cross-sectional area of openings as air inlets provided in the
other four surfaces (two surfaces of each of two heat exchangers
excluding the foregoing surfaces that are adjacent to each other),
and the wind speed is therefore lower in the surfaces that are
adjacent to each other. To improve cost performance with
consideration for such a fact, a measure of changing the stacking
intervals between the fins in accordance with the position (the
position in the outdoor unit) may be taken. Practically, however,
it is difficult to change the pitch of the fins in accordance with
the internal configuration of the outdoor unit, as described
above.
[0019] In other proposed configurations, the pitch of the fins is
changed in some portions by dividing the heat exchanger, by
changing the setting for the height of the collars, and by using
other techniques. In such a case, different kinds of progressive
dies for forming fins need to be prepared, or a die including a
mechanism that can alone change the setting for the height of
burring needs to be prepared. Moreover, troublesome assembling work
including setting for different groups of fins is required.
Therefore, the die may become complicated or large, or the pressing
machine may become large. Consequently, the costs of the die, the
pressing machine, and the assembling work may become too high to
realize any of the above configurations. Moreover, the variations
in the height of collars that are determinable by the die are
limited to two to three at most because the size of the die is
limited. Such a limitation also makes the realization of the above
configurations more difficult.
[0020] To avoid the above problems, another measure may be taken in
which the height of the collars is made smaller than the stacking
intervals between the fins, and the fins are not stacked with
reference to the height of the collars. In such a case, however,
each heat transfer tube cannot be inserted into a group of fins
that are in a stacked state, that is, the fins need to be fitted
one by one onto the heat transfer tube while each of the fins is
moved toward the distal side of the tube by a long stroke
corresponding to the length of the heat transfer tube, leading to
significantly troublesome work. This shows that changing the pitch
of the fins is impractically difficult.
[0021] The present invention is to solve the above problems and to
provide an air-conditioning apparatus in which the stacking pitch
of fins is readily changeable.
Solution to Problem
[0022] An outdoor unit according to the present invention includes
a housing, at least two plate fin-tube heat exchanger assemblies
arranged side by side in the housing and each being bent in an
inward direction of the housing such that the heat exchanger
assembly has a facing surface that faces a surface of another heat
exchanger assembly in the housing, and a fan provided above the
housing and causes air taken in from surfaces of the housing to be
exhausted from an upper portion of the housing. Each of the heat
exchanger assemblies includes fins each having notches provided
without fin collars or notches provided with fin collars that are
shorter than stacking intervals between the fins. At least some of
the stacking intervals between the fins in a portion forming the
facing surface are larger than the stacking intervals between the
fins in portions forming surfaces excluding the facing surface.
[0023] An air-conditioning apparatus according to the present
invention includes the above outdoor unit and an indoor unit
connected to the outdoor unit.
Advantageous Effects of Invention
[0024] In the outdoor unit according to the present invention,
since the fins can be distributed more effectively than in the
known art, the heat exchanging efficiency is improved from the
viewpoint of cost performance. Thus, energy saving and cost
reduction are realized.
[0025] In the air-conditioning apparatus according to the present
invention, since the above outdoor unit is employed, the heat
exchanging efficiency is improved from the viewpoint of cost
performance. Thus, energy saving and cost reduction are
realized.
BRIEF DESCRIPTION OF DRAWINGS
[0026] FIG. 1 is a schematic external view illustrating an
exemplary external configuration of an outdoor unit according to
Embodiment 1 of the present invention.
[0027] FIG. 2 is a schematic perspective view illustrating an
internal configuration of the outdoor unit according to Embodiment
1 of the present invention.
[0028] FIG. 3 is a schematic perspective view illustrating a
configuration of heat exchanger assemblies included in the outdoor
unit according to Embodiment 1 of the present invention.
[0029] FIG. 4 is a schematic perspective view illustrating a
configuration of known heat exchanger assemblies.
[0030] FIG. 5 includes schematic perspective views each
illustrating a part of one of heat exchangers included in each of
the heat exchanger assemblies included in the outdoor unit
according to Embodiment 1 of the present invention.
[0031] FIG. 6 is a schematic perspective view illustrating a
configuration of heat exchanger assemblies included in an outdoor
unit according to Embodiment 2 of the present invention.
[0032] FIG. 7 is a circuit diagram schematically illustrating a
basic configuration of an air-conditioning apparatus according to
Embodiment 3 of the present invention.
[0033] FIG. 8 is a schematic diagram illustrating some steps
included in a method of manufacturing a heat exchanger assembly
according to Embodiment 4 of the present invention.
[0034] FIG. 9 is a schematic diagram illustrating some other steps
included in the method of manufacturing a heat exchanger assembly
according to Embodiment 4 of the present invention.
DESCRIPTION OF EMBODIMENTS
[0035] Embodiments of the present invention will now be described
with reference to the drawings.
Embodiment 1
[0036] FIG. 1 is a schematic external view illustrating an
exemplary external configuration of an outdoor unit 101 according
to Embodiment 1 of the present invention. Referring to FIG. 1, an
outline of the external configuration of the outdoor unit 101
according to Embodiment 1 of the present invention will be
described. In the drawings including FIG. 1 to be referred to
below, individual elements are not necessarily scaled in accordance
with their actual sizes.
[0037] The outdoor unit 101 according to Embodiment 1 forms a part
of an industrial-use air-conditioning apparatus used in, for
example, an office building or a factory. The outdoor unit 101 has
an appearance as illustrated in FIG. 1 and is configured to exhaust
air from two positions in an upper portion thereof. The outdoor
unit 101 is connected to a non-illustrated indoor unit, whereby an
air-conditioning apparatus is provided. Devices (a compressor, a
heat-source-side heat exchanger, an expansion device, and a
use-side heat exchanger) included in the outdoor unit 101 and the
indoor unit are connected to one another by pipes, whereby a
refrigeration cycle is formed, and air conditioning of an
air-conditioned space (for example, a room space or the like where
the indoor unit is installed) is performed. The air-conditioning
apparatus will be described in Embodiment 3.
[0038] The outdoor unit 101 includes at least a housing 102, heat
exchanger assemblies 103, bell mouths 104, a cover 105, a
non-illustrated compressor, and non-illustrated pipe components.
The outdoor unit 101 has two fans (for example, propeller fans or
the like corresponding to a fan 55 to be mentioned in Embodiment 3)
provided in the upper portion of the housing 102. The outdoor unit
101 takes in air from surfaces of the housing 102 by an effect
produced by the fans, allows the air to flow through the heat
exchanger assemblies 103, and exhausts the air from the upper
portion of the housing 102. In FIG. 1, the bell mouths 104 are
simplified as cylindrical members.
[0039] The housing 102 has a substantially rectangular
parallelpiped shape and forms an outer shell of the outdoor unit
101. Some of the devices forming the refrigeration cycle are housed
by the housing 102. The heat exchanger assemblies 103 allow the air
taken in by the fans and a refrigerant to exchange heat
therebetween. The number of heat exchanger assemblies 103 is two in
correspondence with the number of fans. The bell mouths 104 guide
the air that is made to flow by the fans provided in the upper
portion of the housing 102. Two bell mouths 104 are provided in
correspondence with the number of fans.
[0040] The cover 105 is provided on one of the four surfaces of the
housing 102 (for example, a surface on which a control board is
provided and maintenance work and other kinds of work are performed
by a worker, that is, a surface illustrated on the near surface)
and covers that surface of the housing 102. The other three
surfaces of the housing 102 that are not covered with the cover 105
allow the heat exchanger assemblies 103 to be exposed to the
peripheral environment in most part of the three surfaces excluding
portions provided with thin columnar or grating members so that
outside air can be taken into the heat exchanger assemblies 103.
Although FIG. 1 illustrates an exemplary case where one surface of
the housing 102 is covered with one cover 105, the number of covers
105 is not specifically limited. One surface of the housing 102 may
alternatively be covered with a plurality of covers 105.
[0041] FIG. 2 is a schematic perspective view illustrating an
internal configuration of the outdoor unit 101. Referring to FIG.
2, an outline of the internal configuration of the outdoor unit 101
will be described. FIG. 2 schematically illustrates the internal
configuration of the outdoor unit 101 with members of the housing
102 excluding a bottom plate 119, and the devices provided in the
housing 102 being removed so as to illustrate flows of the air
produced in the outdoor unit 101. Hence, in FIG. 2, the bell mouths
104 appear to be spaced apart from the housing 102. In addition,
white arrows illustrated in FIG. 2 represent the flow of air
produced by the effect of the fans, and the size of the white
arrows corresponds to the wind speed.
[0042] The heat exchanger assemblies 103 each bent in a
substantially U shape in a top view of the outdoor unit 101 are
provided below the two bell mouths 104 in such a manner as to
surround the two bell mouths 104, respectively. The heat exchanger
assemblies 103 each include two layers. The two heat exchanger
assemblies 103 are arranged symmetrically with respect to a line
connecting the longitudinal centers of the housing 102.
Hereinafter, one of the two heat exchangers that is on the outer
surface in the outdoor unit 101 is referred to as outer heat
exchanger 106, and the other heat exchanger that is on the inner
surface in the outdoor unit 101 is referred to as inner heat
exchanger 107. Sides of the two respective outer heat exchangers
106 that are adjacent to each other are referred to as outer
adjacent surfaces 108. Sides of the two respective inner heat
exchangers 107 that are adjacent to each other are referred to as
inner adjacent surfaces 109.
[0043] The outer heat exchangers 106 and the inner heat exchangers
107 each include, for example, heat transfer tubes each having a
flat cross-sectional shape (hereinafter referred to as flat tubes).
The flat tubes are fitted in plate-like fins that are arranged at
predetermined intervals. The plate-like fins each have fitting
holes provided in the form of notches and in the same number and at
the same intervals as the flat tubes in a plate-long-axis
direction. Alternatively, the outer heat exchangers 106 and the
inner heat exchangers 107 each include, for example, heat transfer
tubes each having a circular cross-sectional shape (hereinafter
referred to as circular tubes). The circular tubes are fitted in
plate-like fins that are arranged at predetermined intervals. The
plate-like fins each have circular fitting holes provided in the
same number and at the same intervals as the circular tubes in the
plate-long-axis direction. The configurations of the outer heat
exchanger 106 and the inner heat exchanger 107 will be described in
detail separately below, referring to FIG. 5.
[0044] The devices such as the compressor provided in the housing
102 are disposed on the bottom plate 119 of the housing 102 in such
a manner as to be surrounded from three surfaces by the heat
exchanger assemblies 103. The two heat exchanger assemblies 103 are
arranged side by side and symmetrically with respect to a gap 110
of a predetermined space and such that excessive spaces are not
provided in the housing 102, with consideration for the ease of
assembling of the pipes projecting from end surfaces 125 of the
heat exchanger assemblies 103 (surfaces of the outer adjacent
surfaces 108 and the inner adjacent surfaces 109 that face the
cover 105) and the space occupied (the space in the housing 102
occupied by the heat exchanger assemblies 103).
[0045] That is, when the housing 102 is seen as a whole as
illustrated in FIG. 1, the two heat exchanger assemblies 103 are
arranged such that two of the three surfaces of each heat exchanger
assembly 103 excluding the adjacent surface (including the outer
adjacent surfaces 108 and the inner adjacent surfaces 109) are
positioned on corresponding ones of the three surfaces of the
housing 102 on which the heat exchanger assemblies 103 are exposed.
One of the two surfaces, excluding the adjacent surface, of the
heat exchanger assembly 103 on the left side in FIG. 2 that is
opposite the adjacent surface is denoted as surface 111, and the
other that is opposite the cover 105 is denoted as surface 112.
Likewise, one of the two surfaces, excluding the adjacent surface,
of the heat exchanger assembly 103 on the right side in FIG. 2 that
is opposite the adjacent surface is denoted as surface 114, and the
other that is opposite the cover 105 is denoted as surface 113.
[0046] Note that a surface of the housing 102 that is opposite the
cover 105 allows the heat exchanger assemblies 103 to be exposed to
the peripheral environment so that outside air can be taken into
the heat exchanger assemblies 103. Therefore, air is also taken in
from the outer adjacent surfaces 108 and the inner adjacent
surfaces 109.
[0047] The flow of air produced in the outdoor unit 101 configured
as above is roughly illustrated in FIG. 2. Specifically, air having
flowed into the housing 102 from three surfaces of the housing 102
by the effect of the fans flows through the heat exchanger
assemblies 103 and the bell mouths 104 and is exhausted from the
upper portion of the housing 102. In this process, since the
surfaces 111 to 114 of the heat exchanger assemblies 103 each have
a larger cross-sectional area of openings that face toward the
outside of the housing 102 than the adjacent surfaces of the heat
exchanger assemblies 103, the draft resistance is smaller on the
surfaces 111 to 114, allowing the air to flow therethrough at a
higher speed. On the other hand, air is also taken in from the
outer adjacent surfaces 108 and the inner adjacent surfaces 109.
However, since the cross-sectional area of openings in each of the
outer adjacent surfaces 108 and the inner adjacent surfaces 109
that face toward the outside of the housing 102 is small, the draft
resistance is large on the outer adjacent surfaces 108 and the
inner adjacent surfaces 109, limiting the air to flow therethrough
at a lower speed.
[0048] FIG. 3 is a schematic perspective view illustrating the
configuration of the heat exchanger assemblies 103. FIG. 4 is a
schematic perspective view illustrating a configuration of a known
heat exchanger assemblies (hereinafter denoted as heat exchanger
assemblies 103'). Referring to FIGS. 3 and 4, the configuration of
the heat exchanger assemblies 103 will be described in comparison
with the configuration of the heat exchanger assemblies 103'.
Members included in the heat exchanger assemblies 103' are denoted
by corresponding reference numerals each suffixed with a prime (')
as a matter of convenience for ease of comparison with the
corresponding members of the heat exchanger assemblies 103 included
in the outdoor unit 101 according to Embodiment 1.
[0049] The heat exchanger assemblies 103 are each ultimately bent
in a substantially U shape, as described above, in which the fins
are stacked and the heat transfer tubes extending therethrough
extend in a direction of a contour line 117. The heat exchanger
assemblies 103 each include two layers: the outer heat exchanger
106 and the inner heat exchanger 107. In the two heat exchanger
assemblies 103, the outer adjacent surfaces 108 of the two
respective outer heat exchangers 106 and the inner adjacent
surfaces 109 of the two respective inner heat exchangers 107 face
each other.
[0050] The outer heat exchangers 106 and the inner heat exchangers
107 included in the heat exchanger assemblies 103 each include heat
transfer tubes (flat tubes or circular tubes). The heat transfer
tubes are fitted in plate-like fins that are arranged at
predetermined intervals. The plate-like fins each have fitting
holes (encompassing notches) provided in the same number and at the
same intervals as the heat transfer tubes in the plate-long-axis
direction. The fins are formed as follows. After pressing is
performed, a desired number of fins obtained by cutting and each
having a desired strip length are sequentially stacked in a collar
section. Subsequently, a plurality of long heat transfer tubes
called hair pins and each including a U-shaped portion 115 are
inserted into the fins.
[0051] The fins included in each of the outer heat exchanger 106
and the inner heat exchanger 107 are stacked at predetermined
intervals and are fixed. That is, as illustrated in FIG. 3, the
intervals between the fins included in each of the outer heat
exchanger 106 and the inner heat exchanger 107 are changed in some
portions. Subsequently, the plurality of heat transfer tubes (flat
tubes or circular tubes) are brazed to U-bends 116 for pipe
connection each being bent in a U shape at an end of a
corresponding one of the heat exchangers, and to other components
such as a distributor, whereby a continuous refrigerant passage
that is folded many times while passing through the fins is
provided. Subsequently, the stack of fins in which the heat
transfer tubes are fitted is bent into an L shape a plurality of
times (twice, for example), whereby the outer heat exchanger 106
and the inner heat exchanger 107 each ultimately have a
substantially U shape in which the fins are stacked and the heat
transfer tubes extending therethrough extend in the direction of
the contour line 117.
[0052] Likewise, the heat exchanger assemblies 103' are each bent
in a substantially U shape. Furthermore, the heat exchanger
assemblies 103' each include two layers: an outer heat exchanger
106' and an inner heat exchanger 107'. In the two heat exchanger
assemblies 103', outer adjacent surfaces 108' of the two respective
outer heat exchangers 106' and inner adjacent surfaces 109' of the
two respective inner heat exchangers 107' face each other. As can
be seen from the above, the heat exchanger assemblies 103 and the
heat exchanger assemblies 103' have similar appearances.
[0053] In general, the outer heat exchangers 106' and the inner
heat exchangers 107' included in the heat exchanger assemblies 103'
each include circular tubes. The circular tubes are fitted in
plate-like fins that are arranged at predetermined intervals. The
plate-like fins each have circular fitting holes provided in the
same number and at the same intervals as the circular tubes in the
plate-long-axis direction. As described in Background Art, the
edges of the circular holes provided in each of the fins are burred
and thus form cylindrical collars so that the area of the fin that
is in close contact with each of the heat transfer tubes is
increased. Furthermore, flat portions of the fins between the
circular holes have slits that improve the heat exchangeability
with draft air. The fins are formed as follows. After pressing is
performed, a desired number of fins obtained by cutting and each
having a desired strip length are sequentially stacked in a collar
section. Subsequently, a plurality of long circular tubes called
hair pins and each including a U-shaped portion 115' are inserted
into the fins.
[0054] As described above, in forming the outer heat exchanger 106'
and the inner heat exchanger 107', the stacking of the fins and the
fitting of the circular tubes are performed with reference to the
collars. Consequently, the fins included in the outer heat
exchanger 106' and the inner heat exchanger 107' are stacked and
fixed at regular intervals corresponding to the height of the
collars. That is, as illustrated in FIG. 4, the intervals between
the fins included in each of the outer heat exchanger 106' and the
inner heat exchanger 107' are constant. Subsequently, the plurality
of circular tubes are brazed to U-bends 116' for pipe connection
each being bent in a U shape at an end of a corresponding one of
the heat exchangers, and to other components such as a distributor,
whereby a continuous refrigerant passage that is folded many times
while passing through the fins is provided. Subsequently, the stack
of fins in which the circular tubes are fitted is bent into an L
shape a plurality of times (twice, for example), whereby the outer
heat exchanger 106' and the inner heat exchanger 107' each
ultimately have a substantially U shape in which the fins are
stacked and the heat transfer tubes extending therethrough extend
in the direction of the contour line 117'.
[0055] The pitch of the fins included in the outer heat exchanger
106' and the inner heat exchanger 107' configured as above is
determined to be constant by the height of the collars formed by
burring. Therefore, as described in Background Art, it is difficult
to change the fin pitch in accordance with the internal
configuration of the outdoor unit.
[0056] In contrast, unlike the known art, the fin pitch of the
outer heat exchanger 106 and the inner heat exchanger 107 included
in each of the heat exchanger assemblies 103 is readily changeable.
That is, unlike the known art, the outer heat exchanger 106 and the
inner heat exchanger 107 included in each of the heat exchanger
assemblies 103 do not include fin collars, and the pitch of the
fins is therefore not determined to be constant by the height of
the collars formed by burring. In another case, since fin collars
that are shorter than the stacking intervals between the fins are
provided, the fin pitch is readily changeable. In the outdoor unit
101 according to Embodiment 1, since the fin pitch is readily
changeable, the fins can be arranged with consideration for the
internal configuration and the cost performance of the outdoor unit
101. Thus, the outdoor unit 101 according to Embodiment 1 can
provide improved heat exchanging efficiency and can save
energy.
[0057] As illustrated in FIG. 2, since the surfaces 111 to 114 of
the heat exchanger assemblies 103 each have a larger
cross-sectional area of openings that face toward the outside of
the housing 102 than the adjacent surfaces (the outer adjacent
surfaces 108 and the inner adjacent surfaces 109) of the heat
exchanger assemblies 103, the draft resistance is smaller on the
surfaces 111 to 114, allowing the air to flow therethrough at a
higher speed. That is, since the adjacent surfaces of the heat
exchanger assemblies 103 each have a small cross-sectional area of
openings that face toward the outside of the housing 102, the draft
resistance is large on the adjacent surfaces, limiting the air to
flow therethrough at a low speed. Hence, in the heat exchanger
assemblies 103, as illustrated in FIG. 3, the intervals between the
fins included in the outer adjacent surfaces 108 and the inner
adjacent surfaces 109 are larger than the intervals between the
fins included in the surfaces 111 to 114.
[0058] FIG. 5 includes schematic perspective views each
illustrating a part of one of the heat exchangers (the outer heat
exchanger 106 and the inner heat exchanger 107) included in each of
the heat exchanger assemblies 103. Referring to FIG. 5, the
configuration of the outer heat exchanger 106 and the inner heat
exchanger 107 will be described in detail. FIG. 5(a) illustrates
either of the outer heat exchanger 106 and the inner heat exchanger
107 that include flat tubes 1. FIG. 5(b) illustrates either of the
outer heat exchanger 106 and the inner heat exchanger 107 that
include circular tubes 1A. The outer heat exchanger 106 and the
inner heat exchanger 107 that include the flat tubes 1 are
generally referred to as flat-tube heat exchanger 120. The outer
heat exchanger 106 and the inner heat exchanger 107 that include
the circular tubes 1A are generally referred to as circular-tube
heat exchanger 120A.
[0059] The outer heat exchanger 106 or the inner heat exchanger 107
illustrated in FIG. 5(a) includes flat heat transfer tubes each
having a cross-sectional shape defined by a partially curved line.
That is, the flat-tube heat exchanger 120 includes a plurality of
flat tubes 1 each having a flat cross section whose long sides are
defined by straight lines and whose short sides are defined by
curved lines each forming, for example, a semicircle or the like.
The plurality of flat tubes 1 are arranged parallel to one another
at predetermined intervals (regular intervals, for example) in a
direction orthogonal to the direction of the passage of the
refrigerant that is made to flow therethrough.
[0060] The flat-tube heat exchanger 120 further includes a
plurality of flat-plate-like (rectangular) fins 2. The fins 2 are
arranged parallel to one another at predetermined intervals in the
direction of the refrigerant passage (a direction orthogonal to the
direction in which the flat tubes 1 are arranged side by side). The
fins 2 each have a rectangular shape with a length in the long-axis
direction of the flat tubes 1 being larger than a length in the
width direction of the flat tubes 1 (the vertical direction in the
drawing). Therefore, the width direction of the flat tubes 1 is
defined as short-side direction, and the long-axis direction of the
flat tubes 1 is denoted as long-side direction.
[0061] The flat tubes 1 each have thereinside a plurality of holes
3 extending side by side in the width direction. A refrigerant is
made to flow in the holes 3. The refrigerant exchanges heat with,
for example, air flowing through the flat-tube heat exchanger 120.
The fins 2 each have a plurality of notches 4 arranged in the
long-side direction. The notches 4 are provided in correspondence
with the flat tubes 1. That is, for example, the notches 4 are
provided in the same number and at the same intervals (excluding
the ones at both ends) as the flat tubes 1. Furthermore, the
notches 4 each have substantially the same width as the flat tubes
1. The notches 4 are provided such that one end of the fin 2 is
open. That is, the notches 4 are provided side by side in a
comb-like pattern in the long-side direction of the fin 2.
[0062] The fin 2 further has gate-type (bridge-type) cut-raised
portions 5 provided by cutting and raising respective portions of
the fin 2 between the notches 4. The cut-raised portions 5 promote
the heat exchange between air and the refrigerant. Furthermore, the
fin 2 has fin collars 6 provided by raising the edges of the
notches 4 perpendicularly with respect to the fin 2. The fin
collars 6 provided by cutting and raising the fin 2 each have a
shorter length than the stacking intervals between the fins 2.
[0063] The plurality of flat tubes 1 are arranged side by side, and
the notches 4 of the fins 2 are fitted onto the thus arranged flat
tubes 1. Subsequently, the flat tubes 1 and the fin collars 6 are
joined to each other with a brazing material or the like, whereby
the flat tubes 1 and the fins 2 are fixed to each other. Regarding
the flat-tube heat exchanger 120 having such a configuration, many
pieces of literature show that capacity performance that is higher
than or equal to that of a known heat exchanger including circular
tubes and fins is provided because of several points such as an
increase in the area of contact surface between the refrigerant and
each of the tubes having a reduced thickness. Furthermore, the size
of the flat-tube heat exchanger 120 is selected in accordance with
the performance required in the outdoor unit 101, and such a
flat-tube heat exchanger 120 is to be included in the outdoor unit
101.
[0064] The outer heat exchanger 106 or the inner heat exchanger 107
illustrated in FIG. 5(b) includes the circular tubes 1A each having
a partially circular cross-sectional shape. The plurality of
circular tubes 1A are arranged in a checkered pattern at
predetermined intervals (regular intervals, for example) in a
direction orthogonal to the direction of the passage of the
refrigerant that is made to flow therethrough. The circular-tube
heat exchanger 120A further includes flat-plate-like fins 2A that
are similar to the fins 2 of the flat-tube heat exchanger 120. The
fins 2A are arranged parallel to one another at predetermined
intervals in the direction of refrigerant passage (a direction
orthogonal to the direction in which the circular tubes 1A are
arranged side by side).
[0065] A refrigerant is made to flow in the circular tubes 1A. The
refrigerant exchanges heat with, for example, air flowing through
the circular-tube heat exchanger 120A. The fins 2A each have a
plurality of notches 4A. The notches 4A are provided in
correspondence with the circular tubes 1A. That is, for example,
the notches 4A are provided in the same number and at the same
intervals (excluding the ones at both ends) as the circular tubes
1A.
[0066] Furthermore, the fins 2A each have gate-type (bridge-type)
cut-raised portions 5A provided by cutting and raising portions of
the fin 2A between the notches 4A. The cut-raised portions 5A
promote the heat exchange between air and the refrigerant.
Furthermore, the fin 2A has fin collars 6A provided by raising the
edges of the notches 4A perpendicularly with respect to the fin 2A.
As with the fin collars 6, the fin collars 6A provided by cutting
and raising the fin 2A each have a shorter length than the stacking
intervals between the fins 2A.
[0067] The plurality of circular tubes 1A are arranged at
predetermined intervals, and the notches 4A of the fins 2A are
fitted onto the thus arranged circular tubes 1A. Subsequently, the
circular tubes 1A and the fin collars 6A are joined to each other
with a brazing material or the like, whereby the circular tubes 1A
and the fins 2A are fixed to each other. The size of the
circular-tube heat exchanger 120A is selected in accordance with
the performance required in the outdoor unit 101, and such a
circular-tube heat exchanger 120A is to be included in the outdoor
unit 101.
[0068] As described above, the outdoor unit 101 includes the heat
exchanger assemblies 103 each including the flat-tube heat
exchangers 120 or the circular-tube heat exchangers 120A, and the
fins in the outer adjacent surfaces 108 and the inner adjacent
surfaces 109 are stacked at a larger fin pitch than in the other
surfaces 111 to 114, whereby the fins can be distributed more
effectively than in the known art. In the outdoor unit 101, since
the fins can be arranged at a density that is suitable for
performance improvement, the heat exchanging efficiency is improved
from the viewpoint of cost performance. Thus, energy saving and
cost reduction are realized. Furthermore, if there is no problem
with performance specifications of the outdoor unit that are the
same as those in the known art, the performance improvement
described above may be translated into a reduction in the total
number of fins, whereby the size and the costs of the outdoor unit
101 can be reduced while substantially the same level of
performance is provided.
[0069] While the above description concerns an exemplary case where
a plurality of cut-raised portions 5 are provided between the
notches 4 of each of the fins 2 so as to produce a more energy
saving effect, the cut-raised portions 5 are not necessarily
provided. Likewise, while the above description concerns another
exemplary case where a plurality of cut-raised portions 5A are
provided between the notches 4A of each of the fins 2A so as to
produce a more energy saving effect, the cut-raised portions 5A are
not necessarily provided.
Embodiment 2
[0070] FIG. 6 is a schematic perspective view illustrating a
configuration of heat exchanger assemblies 103A included in an
outdoor unit according to Embodiment 2 of the present invention.
Referring to FIG. 6, the configuration of the heat exchanger
assemblies 103A will now be described. The configuration of the
outdoor unit according to Embodiment 2 is basically the same as
that of the outdoor unit 101 described in Embodiment 1. The
description of Embodiment 2 focuses on differences from Embodiment
1. Elements that are the same as those of Embodiment 1 are denoted
by corresponding reference numerals, and description thereof is
omitted.
[0071] As with the heat exchanger assemblies 103 described in
Embodiment 1, the heat exchanger assemblies 103A are each bent in a
substantially U shape such that, ultimately, the fins are stacked
and the heat transfer tubes extending therethrough extend in the
direction of the contour line 117. The heat exchanger assemblies
103A each include two layers: an outer heat exchanger 106A and an
inner heat exchanger 107A. In the two heat exchanger assemblies
103A, outer adjacent surfaces 108A of the two respective outer heat
exchangers 106A and inner adjacent surfaces 109A of the two
respective inner heat exchangers 107A face each other.
[0072] The outer heat exchangers 106A and the inner heat exchangers
107A included in the heat exchanger assemblies 103A each include
heat transfer tubes (flat tubes or circular tubes). The heat
transfer tubes are fitted into plate-like fins that are arranged at
predetermined intervals. The plate-like fins each have fitting
holes (encompassing notches) provided in the same number and at the
same intervals as the heat transfer tubes in the plate-long-axis
direction. The fins are formed as follows. After pressing is
performed, a desired number of fins obtained by cutting and each
having a desired strip length are sequentially stacked in a collar
section. Subsequently, a plurality of long heat transfer tubes
called hair pins and each including a U-shaped portion 115 are
inserted into the fins.
[0073] The fins included in each of the outer heat exchanger 106A
and the inner heat exchanger 107A are stacked at predetermined
intervals and are fixed. Subsequently, the plurality of heat
transfer tubes (flat tubes or circular tubes) are brazed to U-bends
116 for pipe connection each being bent in a U shape at an end of a
corresponding one of the heat exchangers, and to other components
such as a distributor, whereby a continuous refrigerant passage
that is folded many times while passing through the fins is
provided. Subsequently, the stack of fins in which the heat
transfer tubes are fitted is bent into an L shape a plurality of
times (twice, for example), whereby the outer heat exchanger 106A
and the inner heat exchanger 107A each ultimately have a
substantially U shape in which the fins are stacked and the heat
transfer tubes extending therethrough extend in the direction of
the contour line 117.
[0074] Unlike the known art, the fin pitch of the outer heat
exchanger 106A and the inner heat exchanger 107A included in each
of the heat exchanger assemblies 103A is readily changeable. That
is, unlike the known art, the pitch of the fins of the outer heat
exchanger 106A and the inner heat exchanger 107A included in each
of the heat exchanger assemblies 103A is not determined to be
constant by the height of collars formed by burring. In another
case, fin collars that are shorter than the stacking intervals
between the fins are provided. Therefore, the fin pitch is readily
changeable. Thus, the outer heat exchanger 106A and the inner heat
exchanger 107A are configured with much consideration for the
thickness of the fins and the stacking intervals between the
fins.
[0075] As described in Embodiment 1, since the surfaces 111 to 114
of the heat exchanger assemblies 103A each have a larger
cross-sectional area of openings that face toward the outside of
the housing than the adjacent surfaces (the outer adjacent surfaces
108A and the inner adjacent surfaces 109A) of the heat exchanger
assemblies 103A, the draft resistance is smaller on the surfaces
111 to 114, allowing the air to flow therethrough at a higher
speed. That is, in the heat exchanger assemblies 103A, since the
cross-sectional area of openings of the adjacent surfaces that face
toward the outside of the housing is small, the draft resistance is
large on the adjacent surfaces, limiting the air to flow
therethrough at a low speed.
[0076] Hence, in the heat exchanger assemblies 103A, as illustrated
in FIG. 6, the intervals between the fins included in the outer
adjacent surfaces 108A and the inner adjacent surfaces 109A are
larger in some portions than the intervals between the fins
included in the surfaces 111 to 114. That is, the stacking
intervals between the fins in a surface 36 of each outer adjacent
surfaces 108A that is nearer to the end is larger than the stacking
intervals between the fins in a surface 38 of the outer adjacent
surfaces 108A that is nearer to the curved portion (bent portion).
Thus, the heat exchanging efficiency can be improved in those
portions nearer to the end portions of the outer adjacent surfaces
108A and the inner adjacent surfaces 109A in each of which the
cross-sectional area of openings that face toward the outside of
the housing is small.
[0077] The outdoor unit according to Embodiment 2 includes the heat
exchanger assemblies 103A in which the fin pitch is readily
changeable as in the heat exchanger assemblies 103 described in
Embodiment 1. Hence, the fins can be arranged at a density that is
suitable for performance improvement with further consideration for
the internal configuration of the outdoor unit, and the fins can be
arranged from the viewpoint of cost performance. Thus, in the
outdoor unit according to Embodiment 2, the heat exchanging
efficiency is further improved, and further energy saving is
realized. Moreover, if there is no problem with performance
specifications of the outdoor unit that are the same as those in
the known art, the performance improvement described above may be
translated into a reduction in the total number of fins 2, whereby
the size and the costs of the outdoor unit 101 can be reduced while
substantially the same level of performance is provided.
Embodiment 3
[0078] FIG. 7 is a circuit diagram schematically illustrating a
basic configuration of an air-conditioning apparatus 50 according
to Embodiment 3 of the present invention. Referring to FIG. 7, the
configuration and operations of the air-conditioning apparatus 50
will now be described. The air-conditioning apparatus 50 includes
an outdoor unit and an indoor unit. A refrigerant is made to
circulate through devices provided in the outdoor unit and the
indoor unit, whereby a cooling operation or a heating operation is
realized. While Embodiment 3 concerns a case where the
air-conditioning apparatus 50 includes the outdoor unit 101
according to Embodiment 1, the air-conditioning apparatus 50 may
alternatively include the outdoor unit according to Embodiment
2.
[0079] The air-conditioning apparatus 50 includes devices such as a
compressor 51, a heat-source-side heat exchanger 52, an expansion
device 53, and a use-side heat exchanger 54 that are connected to
one another by pipes. Among these devices, the compressor 51 and
the heat-source-side heat exchanger 52 are included in the outdoor
unit 101, and the expansion device 53 and the use-side heat
exchanger 54 are included in an indoor unit 60. The expansion
device 53 may be included in the outdoor unit 101, not in the
indoor unit 60. In addition, a non-illustrated flow switching
device such as a four-way valve configured to switch the flow of
the refrigerant may be provided on a discharge side of the
compressor 51.
[0080] The compressor 51 sucks the refrigerant and compresses the
refrigerant, whereby the refrigerant becomes a high-temperature and
high-pressure state. The compressor 51 is, for example, an inverter
compressor or the like whose capacity is controllable. The
heat-source-side heat exchanger 52 allows the refrigerant and air
that is forcibly supplied thereto from a fan 55 to exchange heat
therebetween. The heat exchanger assemblies described in Embodiment
1 or Embodiment 2 are employed as the heat-source-side heat
exchanger 52. The expansion device 53 expands the refrigerant by
reducing the pressure of the refrigerant and includes, for example,
an electronic expansion valve or the like whose opening degree is
variably controllable. The use-side heat exchanger 54 allows the
refrigerant and air that is forcibly supplied thereto from a
non-illustrated air-sending device such as a fan to exchange heat
therebetween. The fan 55 includes fans provided in the same number
as the heat exchanger assemblies included in the heat-source-side
heat exchanger 52. The fan 55 supplies air to the heat-source-side
heat exchanger 52.
[0081] The heating operation and the cooling operation performed by
the air-conditioning apparatus 50 will now be described
briefly.
[Heating Operation]
[0082] When the compressor 51 is driven, the compressor 51 raises
the pressure of the refrigerant, whereby the refrigerant becomes a
high-temperature and high-pressure state and is discharged. The
refrigerant discharged from the compressor 51 is supplied to the
use-side heat exchanger 54 and is cooled while exchanging heat with
air, whereby the refrigerant becomes a low-temperature and
high-pressure state. In this step, heating air is supplied from the
indoor unit 60, whereby an air-conditioned space is heated. The
refrigerant is then discharged from the use-side heat exchanger 54,
undergoes pressure reduction by being expanded by the expansion
device 53, and becomes a low-temperature and low-pressure state.
The refrigerant is then heated in the heat-source-side heat
exchanger 52 and flows into the compressor 51 again.
[Cooling Operation]
[0083] When the compressor 51 is driven, the compressor 51 raises
the pressure of the refrigerant, whereby the refrigerant becomes a
high-temperature and high-pressure state and is discharged. The
refrigerant discharged from the compressor 51 is supplied to the
heat-source-side heat exchanger 52 and is cooled while exchanging
heat with air, whereby the refrigerant becomes a low-temperature
and high-pressure state. The refrigerant is then discharged from
the heat-source-side heat exchanger 52, undergoes pressure
reduction by being expanded by the expansion device 53, and becomes
a low-temperature and low-pressure state. The refrigerant is then
heated in the use-side heat exchanger 54. In this step, cooling air
is supplied from the indoor unit 60, whereby the air-conditioned
space is cooled. The refrigerant discharged from the use-side heat
exchanger 54 flows into the compressor 51 again.
[0084] As described above, the air-conditioning apparatus 50
includes the outdoor unit 101 including the heat exchanger
assemblies 103 each including the flat-tube heat exchangers 120 or
the circular-tube heat exchangers 120A. Accordingly, while the
total number of fins 2 is not changed, the fins 2 are stacked at a
larger fin pitch in each of the outer adjacent surfaces 108 and the
inner adjacent surfaces 109 than in each of the other surfaces 111
to 114. Therefore, the fins 2 can be distributed more effectively
than in the known art. In the air-conditioning apparatus 50, since
the fins can be arranged at a density that is suitable for
performance improvement, the heat exchanging efficiency is improved
from the viewpoint of cost performance. Thus, energy saving and
cost reduction are realized.
Embodiment 4
[0085] FIG. 8 is a schematic diagram illustrating some steps
included in a method of manufacturing a heat exchanger assembly
according to Embodiment 4 of the present invention. Referring to
FIG. 8, a method of manufacturing a flat-tube heat exchanger
included in the heat exchanger assembly 103 will now be described.
Herein, a case where the flat-tube heat exchanger 120 described in
Embodiment 1 is manufactured will be described. In Embodiment 4,
elements that are the same as those of any of Embodiments 1 to 3
are denoted by corresponding reference numerals, and description
thereof is omitted.
[0086] First, a coil of, for example, aluminum thin plate that is
to become fins 2 is prepared. Subsequently, the aluminum thin plate
that is fed from the coil is pressed by using a non-illustrated
progressive die placed on a high-speed pressing machine. Then,
notches 4 are consecutively press-formed in the aluminum thin plate
together with circular pilot holes 16 that are formed at both
outer-side ends of the aluminum thin plate. In this step, an
intermittent hoop feeding operation (arrow 17) is performed by
utilizing positioning pins that are fitted into the pilot holes 16.
In this manner, the aluminum thin plate is fed as a series of fins
18 in a hoop state as illustrated in FIG. 8.
[0087] The series of fins 18 is cut into individual fins 2 by a
cutting operation (arrow 19) performed by a cutter above a
plurality of flat tubes 1 that are arranged side by side.
Subsequently, each of the fins 2 is held by a non-illustrated
transfer mechanism including, for example, a cam and a servo, and
is lowered in a moving and rotating operation (arrow 20). In this
manner, the fins 2 are fitted onto the flat tubes 1 from an open
side of the notches 4. Lastly, the fins 2 are pressed down onto the
flat tubes 1 such that each of the fins 2 is at a predetermined
interval from the last one in a group of fins 21 that have already
been fitted onto the flat tubes 1 and until the rear edges of the
notches 4 come into contact with the tops of the flat tubes 1.
Thus, fitting and positioning of the fins 2 performed on the flat
tubes 1 are complete.
[0088] On the other hand, the flat tubes 1 are placed on a
non-illustrated transporting mechanism (a hoop feeding mechanism,
for example) including, for example, a servo, a ball screw, a
linear guide, and so forth so that the plurality of flat tubes 1
arranged side by side can be moved and positioned altogether in the
long-axis direction. Then, the flat tubes 1 are positioned in the
long-axis direction of the flat tubes 1 in a pitch feeding
operation (arrow 22) performed by the transporting mechanism. The
pitch feeding operation is performed such that a predetermined
interval from the last fin in the group of fins 21 that have
already been fitted onto the flat tubes 1 is provided.
[0089] The cutting operation (arrow 19) and the moving and rotating
operation (arrow 20) performed on the fins 2 and the pitch feeding
operation (arrow 22) performed on the flat tubes 1 are executed in
that order following the hoop feeding operation (arrow 17)
performed by the high-speed press and in synchronization with the
operations performed by the transfer mechanism and the servo
mechanism. Consequently, the fins 2 are stacked at predetermined
intervals. Any lags in the synchronization between the high-speed
press and the transfer mechanism may be absorbed by, for example,
giving some slack in the hoop around transport rollers in such a
manner as to provide a buffer for the hoop, and by increasing or
decreasing the pressing stroke while detecting the amount of
slack.
[0090] Furthermore, the fin pitch is adjustable to a desired value
by changing the length of pitch feeding in the pitch feeding
operation (arrow 22). The length of pitch feeding is adjusted in
accordance with a setting on a controller that controls the
transporting mechanism. A large length of pitch feeding is set for
a group of fins (a group of fins 23 illustrated in FIG. 8) that is
to form the outer adjacent surfaces 108 or the inner adjacent
surfaces 109 in which the wind speed is low. A small length of
pitch feeding is set for a group of fins (a group of fins 24
illustrated in FIG. 8) that is to form any of the surfaces 111 to
114. In this manner, a required number of fins 2 are stacked. Thus,
a fin group assembly 25 including the group of fins 23 that are
stacked at large intervals and the fins 24 that are stacked at
small intervals is obtained. Note that FIG. 8 illustrates a state
where the fin group assembly 25 has been assembled halfway.
[0091] The fin group assembly 25 obtained by completing the
stacking of the fins 2 is fixed to the flat tubes 1 by brazing in a
furnace with a brazing material that has coated over the flat tubes
1 in advance or by bonding with a bonding agent applied in the
gaps. Subsequently, two fin group assemblies 25 are stacked, and
the stack of the two fin group assembly 25 is connected to pipe
components and is folded into an L shape twice, whereby assembling
of the flat-tube heat exchanger 120 having a substantially U shape
is complete (see FIG. 9).
[0092] The flat-tube heat exchanger 120 is manufactured by the
above manufacturing method. Therefore, unlike the known method in
which circular tubes are inserted into a group of fins that have
been stacked in advance, the stacking intervals are quickly
changeable to any of different fin pitches (stacking intervals
between the fins) simply by changing a command value of the
controller regarding the length of pitch feeding that is set for
the transporting mechanism, without using any complicated dies for
changing the height of collars and any large pressing machines.
That is, the manufacturing method according to Embodiment 4
facilitates the change of the stacking pitch of the fins 2 without
increasing the cost of the die for the fins 2, the cost of the
pressing machine, and troublesome assembling work.
[0093] Furthermore, unlike the known art in which the collars are
short and the fins are not stacked with reference to the collars,
the flat-tube heat exchanger 120 is configured such that a desired
number of fins 2 can be fitted onto the flat tubes 1 without moving
the fins over the entire length of the heat transfer tubes and
regardless of the length of the flat tubes 1. Therefore, the
flat-tube heat exchanger 120 is hardly affected by the shapes of
workpieces. Hence, an operation that is quick enough to follow the
speed, at several hundred SPM (strokes per minute), of punching
performed by the high-speed pressing machine is realized readily.
Furthermore, different fin pitches are realized.
[0094] FIG. 9 is a schematic diagram illustrating some other steps
included in the method of manufacturing a heat exchanger assembly
according to Embodiment 4 of the present invention. Referring to
FIG. 9, a method of manufacturing the heat exchanger assembly 103A
described in Embodiment 2 will now be described. Note that FIG. 9
illustrates bending steps that are subsequent to the steps of
manufacturing the flat-tube heat exchanger 120 illustrated in FIG.
8.
[0095] A heat exchanger bending device 150 illustrated in FIG. 9 is
for bending a set of fin group assemblies 25 and includes at least
an L-bending jig 40 and a table 41. The L-bending jig 40 bends the
flat tubes 1 included in the set of fin group assemblies 25
substantially perpendicularly (into a substantially L shape).
Specifically, the L-bending jig 40 includes a holding portion 40a
that holds the set of fin group assemblies 25 and a moving portion
40b that rotates the holding portion 40a substantially
perpendicularly. The holding portion 40a that is holding a
predetermined position of the set of fin group assemblies 25 is
rotated by the moving portion 40b, whereby the flat tubes 1 are
bent. In this step, the flat tubes 1 are bent substantially
perpendicularly in the width direction.
[0096] The set of fin group assemblies 25 is placed on the table 41
and is slid in a predetermined direction (toward right in FIG. 9)
by a non-illustrated driving unit such as rollers. The table 41
includes, for example, a non-illustrated guide rail. When the guide
rail is driven by the driving unit, the set of fin group assemblies
25 placed on the table 41 is slid.
[0097] As illustrated in FIG. 8, each fin group assembly 25
obtained by completing the stacking of the fins 2 is fixed to the
flat tubes 1. Two fin group assemblies 25 are stacked and are
connected to pipe components (for example, the U-shaped portions
115, the U-bends 116, and so forth). In this state, the set of fin
group assemblies 25 is placed on the table 41 of the heat exchanger
bending device 150. The set of fin group assemblies 25 placed on
the table 41 is slid by the table 41. When the set of fin group
assemblies 25 is slid to a predetermined position (the position
having the groups of fins 24 that are to form the outer adjacent
surfaces 108 and the inner adjacent surfaces 109), the set of fin
group assemblies 25 is held by the holding portion 40a of the
L-bending jig 40. In this step, the holding portion 40a holds the
groups of fins 24 in which the stacking intervals are small.
[0098] The set of fin group assemblies 25 held by the holding
portion 40a is bent, while being slid, substantially
perpendicularly by the holding portion 40a that is rotated by the
moving portion 40b (first L-bending). Thus, the set of fin group
assemblies 25 has a first curved portion 44. After the first curved
portion 44 is formed, the holding portion 40a releases the set of
fin group assemblies 25. The set of fin group assemblies 25 is
further slid in the forward direction by the table 41. When the set
of fin group assemblies 25 is slid to a predetermined position (the
position having the groups of fins 24 that are to form the surface
112 or the surface 113), the set of fin group assemblies 25 is held
by the holding portion 40a of the L-bending jig 40 again. In this
step also, the holding portion 40a holds the groups of fins 24 in
which the stacking intervals are small.
[0099] The set of fin group assemblies 25 held by the holding
portion 40a is bent, while being slid, substantially
perpendicularly by the holding portion 40a that is rotated by the
moving portion 40b (second L-bending). Thus, the set of fin group
assemblies 25 has a second curved portion 45. After the second
curved portion 45 is formed, the holding portion 40a releases the
set of fin group assemblies 25. In this manner, the heat exchanger
assembly 103A having a substantially U shape is obtained.
[0100] As described above, since the heat exchanger bending device
150 holds the groups of fins 24 in which the stacking intervals are
small by using the holding portion 40a, the stress applied to the
end surfaces of the fins 2 when the flat tubes 1 are bent is
reduced. Therefore, in the heat exchanger bending device 150, the
occurrence of tilting or buckling of the fins 2 in the bending step
is suppressed efficiently. Hence, even if the fins 2 are relatively
thin or the stacking intervals between the fins 2 are relatively
large, the fins 2 can be arranged at large stacking intervals while
a certain level of manufacturing quality is maintained.
Accordingly, in the method of manufacturing a heat exchanger
assembly according to Embodiment 4, the heat exchanging efficiency
is improved from the viewpoint of cost performance, and a heat
exchanger assembly in which energy saving, cost reduction, and size
reduction are realized is provided.
[0101] While Embodiment 4 concerns an exemplary method of
manufacturing the heat exchanger assembly 103A described in
Embodiment 2, Embodiment 4 may be applied to a method of
manufacturing the heat exchanger assembly 103 described in
Embodiment 1, needless to mention. In that case, however, the
position to be held by the holding portion 40a needs to be
determined carefully.
[0102] While each of Embodiments concerns an exemplary case where
portions of the flat tubes 1 extending in the adjacent surfaces
(the outer adjacent surfaces 108 and the inner adjacent surfaces
109) are shorter than the other portions of the flat tubes 1
extending in the surfaces excluding the adjacent surfaces, the
present invention is not limited thereto. Needless to mention,
similar effects are expected to be produced even if the former
portions of the flat tubes 1 have the same length as or are longer
than the portions of the flat tubes 1 extending in the surfaces
excluding the adjacent surfaces.
[0103] While each of Embodiments concerns an exemplary case where
the outdoor unit includes two substantially U-shaped heat
exchangers that are arranged side by side, similar effects are
expected to be produced even if the outdoor unit includes three or
more heat exchangers, needless to mention, as long as the heat
exchangers each have a surface that is adjacent to a surface of
another heat exchanger. Furthermore, while no special description
is given regarding the number of rows of heat exchangers that are
stacked vertically in each of Embodiments, the heat exchanger may
include one row as described in each of Embodiments, or the heat
exchanger may include two or more rows. Furthermore, while each of
Embodiments concerns an exemplary case where the heat exchanger
includes two layers, the present invention is not limited thereto.
Similar effects are expected to be produced even with a heat
exchanger including one layer or with a heat exchanger including
three or more layers.
REFERENCE SIGNS LIST
[0104] flat tube 1A circular tube 2 fin 2A fin 3 hole 4 notch 4A
notch 5 cut-raised portion 5A cut-raised portion 6 fin collar 6A
fin collar 16 pilot hole 17 arrow 18 series of fins 19 arrow 20
arrow 21 group of fins 22 arrow 23 group of fins 24 group of fins
25 fin group assembly 36 surface nearer to end 38 surface nearer to
curved portion 40 L-bending jig 40a holding portion 40b moving
portion 41 table 44 first curved portion 45 second curved portion
50 air-conditioning apparatus 51 compressor 52 heat-source-side
heat exchanger 53 expansion device 54 use-side heat exchanger 55
fan 60 indoor unit 101 outdoor unit 102 housing 103 heat exchanger
assembly 103A heat exchanger assembly 104 bell mouth 105 cover 106
outer heat exchanger 106A outer heat exchanger 107 inner heat
exchanger 107A inner heat exchanger 108 outer adjacent surface 108A
outer adjacent surface 109 inner adjacent surface 109A inner
adjacent surface 110 gap 111 surface 112 surface 113 surface 114
surface 115 U-shaped portion 116 U-bend 117 contour line 119 bottom
plate 120 flat-tube heat exchanger 120A circular-tube heat
exchanger 125 end surface 150 heat exchanger bending device
* * * * *