U.S. patent application number 13/145741 was filed with the patent office on 2011-11-17 for heat exchanger and heat pump type hot water supply apparatus equipped with same.
Invention is credited to Akihiro Fujiwara, Takayuki Hyoudou, Satoshi Inoue, Tomonori Kikuno, Hyunyoung Kim, Yoshikazu Shiraishi, Kaori Yoshida.
Application Number | 20110277494 13/145741 |
Document ID | / |
Family ID | 42355941 |
Filed Date | 2011-11-17 |
United States Patent
Application |
20110277494 |
Kind Code |
A1 |
Kikuno; Tomonori ; et
al. |
November 17, 2011 |
HEAT EXCHANGER AND HEAT PUMP TYPE HOT WATER SUPPLY APPARATUS
EQUIPPED WITH SAME
Abstract
A heat exchanger 21 is provided with a metal tube 47 that has a
support member 55 inhibiting deformation in the thickness direction
in a fluid flow channel 53, and a multiple-hole metal tube 45 that
is stacked on one side of the metal tube 47 in the thickness
direction and has an opposing surface disposed opposite an outer
surface 61 on the one side of the metal tube 47 and joined by at
least part thereof to the outer surface 61 on the one side.
Inventors: |
Kikuno; Tomonori; (Osaka,
JP) ; Inoue; Satoshi; (Osaka, JP) ; Fujiwara;
Akihiro; (Osaka, JP) ; Kim; Hyunyoung; (Osaka,
JP) ; Shiraishi; Yoshikazu; (Osaka, JP) ;
Yoshida; Kaori; (Osaka, JP) ; Hyoudou; Takayuki;
(Osaka, JP) |
Family ID: |
42355941 |
Appl. No.: |
13/145741 |
Filed: |
January 20, 2010 |
PCT Filed: |
January 20, 2010 |
PCT NO: |
PCT/JP2010/050648 |
371 Date: |
July 21, 2011 |
Current U.S.
Class: |
62/324.1 ;
165/177 |
Current CPC
Class: |
F28F 3/02 20130101; F28F
1/022 20130101; F28D 7/04 20130101; F28F 13/12 20130101; F28F
2225/04 20130101; F28F 3/044 20130101; F24D 17/02 20130101; F28D
7/0033 20130101 |
Class at
Publication: |
62/324.1 ;
165/177 |
International
Class: |
F25B 30/00 20060101
F25B030/00; F28F 1/00 20060101 F28F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 22, 2009 |
JP |
2009-011561 |
Mar 25, 2009 |
JP |
2009-074136 |
Claims
1. A heat exchanger comprising: a metal tube that has a flat shape
with a width greater than a thickness, a fluid flow channel formed
inside thereof along a longitudinal direction, respective outer
surfaces formed on one side and the other side in a thickness
direction, and a support portion formed in the fluid flow channel
and inhibiting deformation in the thickness direction; and a
multiple-hole metal tube stacked on one side of the metal tube in
the thickness direction, the multiple-hole metal tube that has a
flat shape with a width greater than a thickness, a plurality of
fluid flow channels formed inside thereof along the longitudinal
direction, and an opposing surface disposed opposite the outer
surface on said one side of the metal tube and joined by at least
part thereof to the outer surface on said one side.
2. The heat exchanger according to claim 1, wherein the support
portion has a plurality of columnar bodies arranged along the
longitudinal direction of the fluid flow channel, one end of each
of the columnar bodies in an axial direction is joined to an inner
surface on either side in the thickness direction of the fluid flow
channel, and the other end of each of the columnar bodies in the
axial direction is disposed on an inner surface side on the other
side in the thickness direction of the fluid flow channel.
3. The heat exchanger according to claim 2, wherein both ends in
the axial direction of at least one of the plurality of columnar
bodies are respectively joined to the inner surface on one side and
the inner surface on the other side of the fluid flow channel.
4. The heat exchanger according to claim 1, wherein the support
portion has a plurality of first columnar bodies arranged along the
longitudinal direction of the fluid flow channel on an inner
surface on one side in the thickness direction of the fluid flow
channel and a plurality of second columnar bodies arranged along
the longitudinal direction of the fluid flow channel on an inner
surface on the other side in the thickness direction of the fluid
flow channel, the first columnar bodies extend from the inner
surface on said one side toward the inner surface on said other
side, and the second columnar bodies extend from the inner surface
on said other side toward the inner surface on said one side, and
distal end portions thereof abut on or are disposed close to
respective distal end portions of the plurality of first columnar
bodies.
5. The heat exchanger according to claim 4, wherein at least one of
the plurality of first columnar bodies and at least one of the
plurality of second columnar bodies are joined together at the
distal end portions thereof
6. The heat exchanger according to claim 1, wherein the support
portion is a corrugated plate-like body disposed along the
longitudinal direction of the fluid flow channel.
7. The heat exchanger according to claim 1, wherein the support
portion has a plurality of protruding portions arranged along the
longitudinal direction of the fluid flow channel, and each of the
protruding portions protrudes from an inner surface on either side
in the thickness direction of the fluid flow channel toward an
inner surface on the other side in the thickness direction.
8. The heat exchanger according to claim 7, wherein a size of each
of the protruding portions in a width direction is less than a size
thereof in said longitudinal direction.
9. The heat exchanger according to claim 7, wherein the protruding
portions are formed by causing the outer surfaces on one side and
other side in the thickness direction to recede toward said other
side or said one side.
10. The heat exchanger according to claim 1, wherein the support
portion has a plurality of first protruding portions arranged along
the longitudinal direction of the fluid flow channel on an inner
surface on one side in the thickness direction of the fluid flow
channel, and a plurality of second protruding portions arranged
along the longitudinal direction of the fluid flow channel on an
inner surface on the other side in the thickness direction of the
fluid flow channel, and the first protruding portions protrude from
the inner surface on said one side toward the inner surface on said
other side, and the second protruding portions protrude from the
inner surface on said other side toward the inner surface on said
one side.
11. The heat exchanger according to claim 10, wherein the first
protruding portions are formed by causing the outer surface on one
side in the thickness direction to recede toward said other side,
and the second protruding portions are formed by causing the outer
surface on said other side in the thickness direction to recede
toward said one side.
12. The heat exchanger according to claim 10, wherein some or all
of the plurality of first protruding portions are provided at
positions opposite the second protruding portions in the thickness
direction.
13. The heat exchanger according to claim 12, wherein the first
protruding portions and the second protruding portions respectively
have elongated shapes in a plan view thereof, and the first
protruding portions and the second protruding portions, which are
facing each other in the thickness direction, are provided so as to
cross each other in a plan view thereof.
14. The heat exchanger according to claim 13, wherein a
longitudinal direction of the first protruding portions is inclined
to one side in a width direction of the metal tube with respect to
the longitudinal direction of the metal tube, a longitudinal
direction of the second protruding portions is inclined to the
other side in the width direction with respect to the longitudinal
direction of the metal tube, and an inclination angle of the first
protruding portions with respect to the longitudinal direction is
equal to an inclination angle of the second protruding portions
with respect to the longitudinal direction.
15. The heat exchanger according to claim 12, wherein the first
protruding portions and the second protruding portions respectively
have elongated shapes in a plan view thereof, and a longitudinal
direction of the first protruding portions and the second
protruding portions, which are facing each other in the thickness
direction, is parallel to the longitudinal direction of the metal
tube.
16. The heat exchanger according to claim 12, wherein the plurality
of first protruding portions are arranged so that three or more
rows thereof extending in the longitudinal direction are formed,
and in a row positioned in a central portion in the width direction
from among these rows, the first protruding portions are provided
at positions opposite the second protruding portions in the
thickness direction.
17. The heat exchanger according to claim 16, wherein in rows
positioned at both sides of the row positioned in the central
portion in the width direction, the first protruding portions are
provided at positions displaced in the longitudinal direction with
respect to the second protruding portions.
18. The heat exchanger according to claim 17, wherein the plurality
of first protruding portions are arranged so that a plurality of
rows thereof extending in a inclination direction inclined with
respect to the longitudinal direction are formed, the plurality of
second protruding portions are arranged so that a plurality of rows
thereof extending in the inclination direction are formed, and the
rows of the first protruding portions in the inclination direction
and the rows of the second protruding portions in the inclination
direction are disposed alternately along the longitudinal
direction.
19. The heat exchanger according to claim 1, wherein the fluid flow
channel includes a first fluid flow channel and a second fluid flow
channel provided parallel to each other in the width direction and
extending in the longitudinal direction, the first fluid flow
channel is formed by folding a metal sheet at a position along the
longitudinal direction and bending the metal sheet into a tubular
shape so that one end side in the width direction of the metal
sheet abuts on a surface on one side of the metal sheet, and said
one end side is joined to said one surface along the longitudinal
direction, the second fluid flow channel is formed by folding the
metal sheet at another position along the longitudinal direction
and bending the metal sheet into a tubular shape so that another
end side in the width direction of the metal sheet abuts on said
one surface at a position adjacent to said one end side, and the
other end side is joined to said one surface along the longitudinal
direction, and the support portion is constituted by parts of the
metal sheet, each part extending from said one end side and said
other end side in the thickness direction or a direction inclined
from the thickness direction.
20. The heat exchanger according to claim 1, wherein the
multiple-hole metal tube is a first multiple-hole metal tube, and
the heat exchanger further comprises a second multiple-hole metal
tube stacked on said other side of the metal tube in the thickness
direction, the second multiple-hole metal tube that has a flat
shape with a width greater than a thickness, a plurality of fluid
flow channels formed inside thereof along the longitudinal
direction, and an opposing surface that is disposed opposite an
outer surface on said other side of the metal tube and joined by at
least part thereof to the outer surface on said other side.
21. The heat exchanger according to claim 1, wherein substantially
the entire opposing surfaces are joined to the outer surfaces.
22. The heat exchanger according to claim 1, which is spirally
wound so that one end in the longitudinal direction is disposed
inside and another end in the longitudinal direction is disposed
outside.
23. A heat pump type hot water supply apparatus comprising: a
coolant circuit having a compressor, the heat exchanger according
to claim 1, a pressure reducing mechanism, an evaporator, and a
pipe for connecting these elements; and a hot water storage circuit
having a tank storing water, a water inlet pipe for introducing
water from the tank into the fluid flow channel of the heat
exchanger, and a hot water outlet pipe for returning water heated
by the heat exchanger into the tank.
Description
TECHNICAL FIELD
[0001] The present invention relates to a heat exchanger and a heat
pump type hot water supply apparatus equipped with same.
BACKGROUND ART
[0002] Seam welding, which is a type of resistance welding, excels
in productivity because the zones that are to be joined can be
joined continuously, and seam welding is used for various
applications.
[0003] For example, as disclosed in Patent Documents 1 and 2, seam
welding is used when rounding a steel sheet to form a metal tube.
More specifically, a steel tube is manufactured by disposing
electrodes in the vicinity of two end surfaces of a steel sheet
that has been rounded in a tubular shape such that the end surfaces
face each other and forming a continuous seam by passing an
electric current to the steel sheet via the electrodes, while
moving the electrodes relative to the end surfaces.
[0004] Further, seam welding is also used in manufacturing fuel
tanks for vehicles. More specifically, flange portions provided on
the circumference of two metal sheets having receding portions are
overlapped and the flange portions are welded together to
manufacture a fuel tank by passing an electric current, while
clamping the flange portions between a pair of roller
electrodes.
[0005] Patent Document 1: Japanese Patent Application Publication
No. S 62-50088.
[0006] Patent Document 2: Japanese Patent Application Publication
No. S 54-112370.
[0007] When a heat exchanger for use in an air conditioner, a heat
pump type hot water supply apparatus, or the like is manufactured,
it is necessary to join together a metal tube having inside thereof
a coolant flow channel where a coolant flows and a metal tube
having inside thereof a fluid flow channel where fluid such as
water or coolant flows. When the aforementioned resistance welding
is used for joining these metal tubes together, the following
problems are encountered.
[0008] Thus, when metal tubes are joined together by resistance
welding, it is necessary to weld a plurality of stacked metal
tubes, while pressurizing the metal tubes in the stacking direction
by a pair of roller electrodes. However, where hollow metal tubes
are resistance welded, while being pressurized with a pair of
roller electrodes, the metal tubes collapse and the hollow portions
are almost entirely eliminated. Therefore, the metal tubes cannot
function sufficiently as flow channels for coolants or fluids and
the desired efficiency of heat exchange cannot be obtained. Where
the pressurization in the stacking direction of the plurality of
metal tubes is insufficient, the metal tubes cannot be sufficiently
joined and the efficiency of heat exchange is therefore
decreased.
[0009] Further, an elongated heat exchanger obtained by joining
metal tubes is sometimes used in a compact form obtained by bending
in order to save space. In such a case, the metal tubes sometimes
collapse in the bending zone and the hollow portions are almost
entirely eliminated. Where the hollow portions of metal tubes are
eliminated, the metal tubes cannot function sufficiently as flow
channels for coolants or fluids and the desired efficiency of heat
exchange cannot be obtained.
SUMMARY OF THE INVENTION
[0010] The present invention has been created with the foregoing in
view and it is an object of the present invention to provide a heat
exchanger with excellent heat exchange efficiency and a heat pump
type hot water supply apparatus equipped with such a heat
exchanger.
[0011] The heat exchanger in accordance with the present invention
includes a metal tube (47) that has a flat shape with a width
greater than a thickness, a fluid flow channel (53) formed inside
thereof along a longitudinal direction, respective outer surfaces
(61, 63) formed on one side and the other side in a thickness
direction, and a support portion (55) formed in the fluid flow
channel (53) and inhibiting deformation in the thickness direction;
and a multiple-hole metal tube (45) stacked on one side of the
metal tube (47) in the thickness direction and having a flat shape
with a width greater than a thickness, a plurality of fluid flow
channels (51) formed inside thereof along the longitudinal
direction, and the multiple-hole metal tube (45) having an opposing
surface (65) disposed opposite the outer surface (61) on the one
side of the metal tube (47) and joined by at least part thereof to
the outer surface (61) on the one side.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a configuration diagram illustrating a heat pump
type hot water supply apparatus according to an embodiment of the
present invention.
[0013] FIG. 2 is a perspective view illustrating a heat exchanger
according to the first embodiment of the present invention.
[0014] FIG. 3 is a cross-sectional view taken along the line in
FIG. 2.
[0015] FIG. 4 is a cross-sectional view taken along the IV-IV line
in FIG. 3.
[0016] FIG. 5 is a front view illustrating a method for
manufacturing a heat exchanger by resistance welding.
[0017] FIG. 6 is a perspective view illustrating a metal tube and a
multiple-hole metal tube that have been resistance welded.
[0018] FIG. 7 is a cross-sectional view illustrating a heat
exchanger according to the second embodiment of the present
invention.
[0019] FIG. 8 is a cross-sectional view illustrating a heat
exchanger according to the third embodiment of the present
invention.
[0020] FIG. 9 is a cross-sectional view illustrating a heat
exchanger according to the fourth embodiment of the present
invention.
[0021] FIG. 10 is a perspective view illustrating a metal tube in
the heat exchanger according to the fourth embodiment.
[0022] FIG. 11 is a plan view illustrating the metal tube in the
heat exchanger according to the fourth embodiment.
[0023] FIG. 12 is a side view illustrating the metal tube in the
heat exchanger according to the fourth embodiment.
[0024] FIG. 13 is a cross-sectional view taken along the XIII-XIII
line in FIG. 11.
[0025] FIG. 14A is a cross-sectional view taken along the XIVa-XIVa
line in FIG. 11. FIG. 14B is a cross-sectional view taken along the
XIVb-XIVb line in FIG. 11. FIG. 14C is a cross-sectional view taken
along the XIVc-XIVc line in FIG. 11.
[0026] FIG. 15 is a cross-sectional view illustrating Variation
Example 1 of the metal tube.
[0027] FIG. 16 is a cross-sectional view illustrating Variation
Example 2 of the metal tube.
[0028] FIG. 17A is a perspective view illustrating a heat exchanger
according to the fifth embodiment of the present invention. FIG.
17B is a plan view illustrating a metal tube of the heat exchanger.
FIG. 17C is a cross-sectional view taken along the XVIIc-XVIIc line
in FIG. 17B. FIG. 17D is a cross-sectional view taken along the
XVIId-XVIId line in FIG. 17B.
[0029] FIG. 18A is a cross-sectional view illustrating bending of
the heat exchanger according to the fifth embodiment. FIG. 18B is a
cross-sectional view illustrating bending of a heat exchanger with
a shape of protruding portions different from that of the
aforementioned heat exchanger.
[0030] FIG. 19 is a plan view illustrating a variation example of
the metal tube in the heat exchanger according to the fifth
embodiment.
[0031] FIG. 20 is a perspective view illustrating a heat exchanger
according to the sixth embodiment of the present invention.
[0032] FIG. 21A is a perspective view illustrating a metal sheet
for forming a metal tube of the heat exchanger according to the
sixth embodiment. FIG. 21B is a perspective view illustrating the
metal tube of the heat exchanger according to the sixth embodiment.
FIG. 21C is a cross-sectional view illustrating the metal tube of
the heat exchanger according to the sixth embodiment.
[0033] FIG. 22A is a plan view illustrating a variation example of
the metal tube in the heat exchanger according to the sixth
embodiment. FIG. 22B is a cross-sectional view thereof.
[0034] FIG. 23A is a perspective view illustrating a heat exchanger
according to the seventh embodiment of the present invention. FIG.
23B is a perspective view illustrating a variation example thereof.
FIG. 23C is a perspective view illustrating another variation
example.
[0035] FIGS. 24A and 24B are cross-sectional views illustrating yet
another variation example of the heat exchanger according to the
seventh embodiment. FIG. 24C is a cross-sectional view illustrating
yet another variation example of the heat exchanger according to
the seventh embodiment.
[0036] FIG. 25 is a cross-sectional view illustrating a heat
exchanger according to the eighth embodiment of the present
invention.
[0037] FIGS. 26A and 26B are plan views illustrating a process for
manufacturing a metal tube for a heat exchanger according to the
ninth embodiment of the present invention. FIG. 26C is a
cross-sectional view taken along the XXVIc-XXVIx line in FIG.
26B.
[0038] FIG. 27A is a plan view illustrating the state in which the
relative positions of the first protruding portion and second
protruding portion of the metal tube in the heat exchanger
according to the ninth embodiment have shifted. FIG. 27B is a
cross-sectional view taken along the XXVIIb-XXVIIb line in FIG.
27A.
DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE INVENTION
[0039] An embodiment of the present invention will be described
below in greater detail with reference to the appended
drawings.
[0040] <Heat Pump Type Hot Water Supply Apparatus>
[0041] FIG. 1 is a configuration diagram illustrating a heat pump
type hot water supply apparatus 11 according to an embodiment of
the present invention. As shown in FIG. 1, the heat pump type hot
water supply apparatus 11 is provided with a coolant circuit 13
where a coolant is circulated and a hot water storage circuit 17
for boiling low-temperature water by heat exchange with the coolant
of the coolant circuit 13 and storing high-temperature water in a
tank 15.
[0042] The coolant circuit 13 has a compressor 19, a heat exchanger
(water heat exchanger) 21, an expansion valve (pressure reducing
mechanism) 23, an evaporator 25, and pipes connecting these
components. For example, carbon dioxide can be used as the coolant
circulating in the coolant circuit 13. When carbon dioxide is used
as the coolant, the coolant is compressed to a pressure equal to or
higher than a critical pressure by the compressor 19.
[0043] The hot water storage circuit 17 has the tank 15 for storing
water, a water inlet pipe 27 for introducing water from the tank 15
into the heat exchanger 21, a hot water outlet pipe 29 for
returning water heated by heat exchange with the heat exchanger 21
into the tank 15, and a pump 31 that causes water to circulate in
the hot water storage circuit 17.
[0044] The hot water supply apparatus 11 is provided with a control
unit 33 that controls the coolant circuit 13 and the hot water
storage circuit 17. By driving the compressor 19 of the coolant
circuit 13 and the pump 31 of the hot water storage circuit 17, the
control unit 33 introduces low-temperature water located in the
tank 15 from a water outlet port provided in the bottom portion of
the tank 15 into the heat exchanger 21 through the water inlet pipe
27. The low-temperature water introduced into the heat exchanger 21
is heated in the heat exchanger 21 and returned into the tank 15
from the water inlet port provided in the upper portion of the tank
15 via the hot water outlet pipe 29. As a result, high-temperature
water is stored in the upper portion inside the tank 15, and the
water temperature decreases toward the lower portion of the
tank.
[0045] The tank 15 is provided with a hot water supply pipe 35 for
taking out the high-temperature water stored in the tank 15 from
the upper portion thereof and supplying the high-temperature water
into a bath or the like and a water supply pipe 37 for supplying
low-temperature water such as tap water to the bottom portion of
the tank 15.
[0046] <Heat Exchanger>
First Embodiment
[0047] FIG. 2 is a perspective view illustrating the heat exchanger
21 according to the first embodiment of the present invention. As
shown in FIG. 2, the heat exchanger 21 has a structure that is
spirally wound so that one end 41 in the longitudinal direction is
disposed on the inner side and the other end 43 in the longitudinal
direction is disposed on the outer side.
[0048] The heat exchanger 21 performs heat exchange between the
coolant circulating in the coolant circuit 13 and water circulating
in the hot water storage circuit 17 in the hot water supply
apparatus 11 shown in FIG. 1. The directions of the coolant and
water flowing in the heat exchanger 21 are mutually opposite
directions as shown in FIG. 1. Therefore, where either of the
coolant and water flows from the one end 41 to the other end 43 of
the heat exchanger 21, the other fluid flows from the other end 43
toward the one end 41. The temperature of water can thus be
regulated by performing heat exchange between the water and coolant
as the coolant and water pass through inside the heat exchanger
21.
[0049] FIG. 3 is a cross-sectional view taken along the line in
FIG. 2. As shown in FIG. 3, the heat exchanger 21 has a structure
in which a first multiple-hole metal tube 45, a metal tube 47, and
a second multiple-hole metal tube 49 are stacked in the thickness
direction in the order of description. These metal tubes 45, 47, 49
are integrated by joining the opposing outer surfaces thereof by
joining by the below-described resistance welding.
[0050] The first multiple-hole metal tube 45 and the second
multiple-hole metal tube 49 have a flat shape with a width greater
than a thickness. A plurality of coolant flow channels 51 extending
in the longitudinal direction are formed inside these multiple-hole
metal tubes 45, 49. The plurality of coolant flow channels 51 are
mutually independent and arranged side by side in a row in the
width direction. The coolant circulating in the coolant circuit 13
flows in the coolant flow channels 51. In the first multiple-hole
metal tube 45 and the second multiple-hole metal tube 49, a drift
current of the coolant flowing in the coolant flow channels 51 can
be inhibited because the tubes have multiple holes.
[0051] The metal tube 47 has a flat shape with a width greater than
a thickness. A fluid flow channel 53 extending in the longitudinal
direction is formed inside the metal tube 47. Water circulating in
the hot water storage circuit 17 flows in the fluid flow channel
53. The metal tube 47 has an outer surface 61 at one side and an
outer surface 63 at the other side in the thickness direction. The
first multiple-hole metal tube 45 has an opposing surface 65, which
is opposite the outer surface 61 on one side of the metal tube 47,
and is stacked on the one side in the thickness direction of the
metal tube 47. The second multiple-hole metal tube 49 has an
opposing surface 67, which is opposite the outer surface 63 on the
other side of the metal tube 47, and is stacked on the other side
in the thickness direction of the metal tube 47.
[0052] At least part of the opposing surface 65 of the first
multiple-hole metal tube 45 is fused to the outer surface 61. At
least part of the opposing surface 67 of the second multiple-hole
metal tube 49 is fused to the outer surface 63. By increasing the
ratio of fusion of the opposing surfaces 65, 67 to the outer
surfaces 61, 63, it is possible to increase the degree of intimate
contact between the opposing surfaces 65, 67 and the outer surfaces
61, 63 and increase the heat exchange efficiency of the heat
exchanger 21. The ratio of fusion of the opposing surfaces 65, 67
to the outer surfaces 61, 63 can be adjusted by changing welding
conditions during resistance welding. More specifically, the ratio
of fusion of the opposing surfaces 65, 67 to the outer surfaces 61,
63 can be increased by setting conditions such as to decrease the
welding rate (feed rate) during resistance welding, increase the
current value during welding, and increase the pressurizing force
in the thickness direction during welding. Therefore, from the
standpoint of heat exchange efficiency of the heat exchanger 21, it
is preferred that substantially the entire opposing surfaces 65, 67
be fused to the outer surfaces 61, 63.
[0053] FIG. 4 is a cross-sectional view taken along the Iv-Iv line
in FIG. 3. As shown in FIG. 3 and FIG. 4, the metal tube 47 has, in
a fluid flow channel 53 thereof, support members (support portions)
55 that inhibit deformation in the thickness direction. The support
members 55 are constituted by a plurality of first columnar bodies
55a arranged side by side in three rows along the longitudinal
direction of the fluid flow channel 53 at an inner surface 57 on
one side in the thickness direction of the fluid flow channel 53
and a plurality of second columnar bodies 55b that are arranged
side by side in three rows along the longitudinal direction of the
fluid flow channel 53 at an inner surface 59 on the other side in
the thickness direction of the fluid flow channel 53.
[0054] The first columnar body 55a is joined by the base end
portion thereof to the inner surface 57 and extends toward the
inner surface 59. The second columnar body 55b is joined by the
base end portion thereof to the inner surface 59 and extends toward
the inner surface 57. The plurality of first columnar bodies 55a
and the plurality of second columnar bodies 55b are arranged in a
spot-like pattern almost equidistantly from the one end 41 to the
other end 43 of the heat exchanger 21 in each of the rows.
[0055] The distal end portion of the first columnar body 55a abuts
on or is disposed close to the distal end portion of the opposite
second columnar body 55b. The first columnar body 55a and the
second columnar body 55b, which are thus disposed opposite each
other, form a pair and restrict deformation of the metal tube 47 in
the thickness direction during resistance welding.
[0056] The first columnar body 55a and the second columnar body 55b
may be also joined by the distal end portions thereof. Whether the
distal end portions are joined to each other can be regulated by
changing welding conditions during resistance welding. More
specifically, the ratio of the distal end portions joined together
can be increased, for example, by decreasing the welding rate (feed
rate) during resistance welding, increasing the current value
during welding, and increasing the pressurizing force in the
thickness direction during welding.
[0057] By increasing the joining ratio of the distal end portions
of the first columnar body 55a and second columnar body 55b, it is
possible to increase the rigidity of the metal tube 47. By
contrast, when the joining ratio of the distal end portions is low,
flexibility of the metal tube 47 can be maintained at a certain
level. Therefore, the expansion-shrinkage of the metal caused by
temperature variations and strains caused by vibrations can be
moderated even when the heat exchanger 21 is used in an environment
in which temperature variations and vibrations can easily
occur.
[0058] Metals having thermal conductivity, corrosion resistance,
rigidity, and machinability can be used as materials of the metal
tube 47, first multiple-hole metal tube 45, and second
multiple-hole metal tube 49. Examples of suitable metals include
aluminum and aluminum alloys. The support members 55 may be from a
material identical to that of the outer peripheral portion of the
metal tube 47.
[0059] As described hereinabove, in the present embodiment, the
support members 55, which inhibit deformation of the metal tube 47
in the thickness direction, are located in the fluid flow channel
53. Therefore, the metal tube 47 and multiple-hole metal tubes 45,
49 that are stacked in the thickness direction can be joined by
resistance welding, while pressurizing the tubes in the thickness
direction by a pair of roller electrodes 71, 73. Since the heat
exchanger can be manufactured by resistance welding that excels in
productivity, the cost can be reduced. Further, in the present
embodiment, the metal tube 47 has support members 55 in the fluid
flow channel 53. Therefore, deformation of the metal tube 47 can be
inhibited even in long-term use of the heat exchanger.
[0060] Further, according to the present embodiment, the plurality
of first columnar bodies 55a and second columnar bodies 55b that
have distal end portions abutted on each other or disposed close to
each other are arranged along the longitudinal direction of the
fluid flow channel 53. Therefore, deformation of the metal tube 47
along the longitudinal direction can be inhibited over a long
period. Moreover, since a configuration is used in which these
columnar bodies 55a, 55b are arranged in a spot-like pattern in the
longitudinal direction, the increase in resistance to flow of fluid
in the fluid flow channel 53 caused by the arrangement of support
members 55 can be inhibited and smooth fluid flow can be
ensured.
[0061] Further, in the present embodiment, when some or all of the
plurality of first columnar bodies 55a and the plurality of second
columnar bodies 55b are joined to each other by the distal end
portions thereof, the rigidity of the metal tube 47 can be
increased. As a result, deformation of the metal tube 47 can be
inhibited over a long period.
[0062] According to the present embodiment, since the multiple-hole
metal tubes 45, 49 are stacked on both sides in the thickness
direction of the metal tube 47, the efficiency of heat exchange
between the coolant and water can be further increased.
[0063] In the present embodiment, when the opposing surfaces of the
multiple-hole metal tubes 45, 49 facing the outer surfaces of the
metal tube 47 are substantially entirely fused, the efficiency of
heat exchange between the coolant and water can be further
increased.
[0064] In the present embodiment, since a spirally wound
configuration is used in which the one end 41 in the longitudinal
direction is disposed on the inner side and the other end 43 in the
longitudinal direction is disposed on the outer side, the dead
space can be reduced and the heat exchanger 21 can be reduced in
size.
[0065] Further, in the present embodiment, since the support
members 55 that inhibit deformation of the metal tube 47 in the
thickness direction are present in the fluid flow channel 53, the
following effect can be obtained in addition to the abovementioned
effect of inhibiting deformation during resistance welding. Thus,
the heat exchanger 21 of the present embodiment is sometimes used
in a bent form for example such as shown in FIG. 2. For example, in
the case of the form illustrated by FIG. 2, some portions of the
entire heat exchanger 21 in the longitudinal direction are curved,
whereas other portions remain straight. In the curved portions, the
support members 55 of the metal tube 47 have a function of
inhibiting deformation of the metal tube 47 in the thickness
direction during bending. Meanwhile, in the straight portions, the
support members 55 of the metal tube 47 function as barriers such
that collide with the fluid flowing inside the metal tube 47 and
cause moderate turbulence. Heat transfer between the fluid and the
metal tube 47 is enhanced by the moderate turbulence of the fluid.
This result is likewise demonstrated in the below-described other
embodiments.
[0066] (Manufacturing Method)
[0067] An example of the method for manufacturing the heat
exchanger 21 will be described below. FIG. 5 is a front view
illustrating the method for manufacturing the heat exchanger 21. As
shown in FIG. 5, for example, a resistance welding apparatus 100
can be used for manufacturing the heat exchanger 21.
[0068] First, the resistance welding apparatus 100 will be
explained. The resistance welding apparatus 100 is provided with a
pair of roller electrodes 71, 73, a pressurizing device 75 that
applies pressure to the roller electrode 71, a power supply device
79 that supplies electric power to the pressurizing device 75 and
the roller electrodes 71, 73, and a control unit (not shown in the
figure) that controls the operation of each unit.
[0069] The roller electrode 71 and the roller electrode 73 have a
substantially round columnar shape and respectively have rotating
shafts 72, 74 in the center thereof. The rotating shaft 72 and the
rotating shaft 74 are disposed substantially parallel to each
other. The width of the roller electrodes 71, 73 in the axial
direction is designed to be greater than the width of the metal
tube 47 and multiple-hole metal tubes 45, 49 that are the welding
objects.
[0070] A motor (not shown in the figure) is connected to the
rotating shaft 72, 74, and the shafts are supported on a support
table (not shown in the figure) in a state in which each shaft can
rotate about the axis thereof. The motor is connected to the power
supply device 79. The roller electrode 71 and the roller electrode
73 rotate in the mutually opposite direction. For example, in the
configuration shown in FIG. 5, the roller electrode 71 rotates
counterclockwise and the roller electrode 73 rotates clockwise.
Further, the roller electrode 71 is supported on the support table
so as to enable the movement thereof in the direction of
approaching the roller electrode 73 and in the opposite direction
(up-down direction in FIG. 5). These roller electrodes 71, 73 are
connected to the power supply device 79, and electric power is
supplied thereto from the power supply device 79 during resistance
welding. It is possible to use a configuration in which only the
roller electrode 71 moves in the up-down direction, as in the
present embodiment, or a configuration in which the two roller
electrodes 71, 73 move in the up-down direction.
[0071] The pressurizing device 75 is provided with a cylindrical
cylinder 78, a piston 77 disposed inside the cylinder 78, and a
pump (not shown in the figure) that generates energy such as air
pressure or oil pressure. Where electric power is supplied from the
power supply device 79 to the pressurizing device 75, the pump is
driven and the piston 77 is slidingly moved in a predetermined
direction inside the cylinder 78. As a result, the roller electrode
71 is pressurized. The pressurized roller electrode 71 moves toward
the roller electrode 73, and the metal tube 47 and the
multiple-hole metal tubes 45, 49 disposed between the roller
electrodes 71, 73 are pressurized in the thickness direction.
[0072] Each manufacturing step will be described below. First, in a
metal tube forming step, the metal tube 47, first multiple-hole
metal tube 45, and second multiple-hole metal tube 49 are
fabricated.
[0073] The metal tube 47 is obtained by bending a long thin metal
sheet (not shown in the figure) so that the end portions thereof in
the width direction face each other and an internal space is formed
along the longitudinal direction and then joining together the
opposing end sides. The internal space extending in the
longitudinal direction serves as the fluid flow channel 53.
[0074] Prior to bending the metal sheet, the base end portions of
the first columnar bodies 55a and the base end portions of the
second columnar bodies 55b are joined by welding or the like at
predetermined positions in the regions that will be the opposing
inner surface 57 and inner surface 59 after the bending is
completed. Then, the metal sheet is bent, while controlling the
bending position so that the first columnar bodies 55a and the
second columnar bodies 55b face each other, and the end portions of
the metal sheet are joined together. As a result, the metal tube 47
is obtained in which the first columnar bodies 55a and the second
columnar bodies 55b are provided in the internal fluid flow channel
53.
[0075] The first multiple-hole metal tube 45 and the second
multiple-hole metal tube 49 are obtained, for example, by extruding
a metal material by using a die provided with an extrusion outlet
port having a cross-sectional shape such as shown in FIG. 3.
[0076] The metal tube 47, first multiple-hole metal tube 45, and
second multiple-hole metal tube 49 obtained in the metal tube
forming step are then stacked. As shown in FIG. 5, the first
multiple-hole metal tube 45, metal tube 47, and second
multiple-hole metal tube 49 are arranged so that longitudinal
directions and thickness directions thereof are oriented in the
same respective directions and the metal tubes are stacked in the
thickness direction in the order of description.
[0077] The first multiple-hole metal tube 45, metal tube 47, and
second multiple-hole metal tube 49 that have thus been stacked in
the stacking step are supplied between the roller electrodes 71,
73, fed along the longitudinal direction, while being pressurized
in the thickness direction by the roller electrodes 71, 73. In this
process, an electric current is supplied through the roller
electrodes 71, 73 and the opposing outer surfaces of the metal
tubes are resistance welded (seam welded) together. As a result,
the linear heat exchanger 21 is obtained in which the metal tubes
are integrated as shown in FIG. 6. In the heat exchanger 21, the
outer surfaces 61, 63 of the metal tube 47 and the opposing
surfaces 65, 67 of the multiple-hole metal tubes 45, 49 are fused
and a nugget 76 is continuously formed along the longitudinal
direction in the side portion.
[0078] The resistance welding conditions include the pressurizing
force created by the roller electrodes 71, 73, conduction time,
standby time, current value during welding, welding rate (feed
rate), electrode shape, and the like. These conditions are set as
appropriate according to the welding object, application, etc. The
abovementioned resistance welding may be intermittent welding in
which conduction periods and standby periods are repeated or
continuous welding in which the conduction is continuous.
[0079] In the present embodiment, since the first columnar bodies
55a and the second columnar bodies 55b are provided in the fluid
flow channel 53 of the metal tube 47, where pressurization is
performed by the roller electrodes 71, 73 in the thickness
direction, the metal tube 47 is slightly deformed in the thickness
direction and the distal end portions of some or all of the
plurality of first columnar bodies 55a and the plurality of second
columnar bodies 55b abut on each other. Where the distal end
portions thus abut on each other, deformation of the metal tube 47
in the thickness direction can be inhibited. Further, since the
electric current flowing through the roller electrodes 71, 73 to
the metal tube 47 flows not only through the outer peripheral
portion of the metal tube 47, but also through the first columnar
bodies 55a and the second columnar bodies 55b that abut on each
other by the distal end portions thereof, the fusion of the
adjacent opposing surfaces 65, 67, which are provided with the
first columnar bodies 55a and the second columnar bodies 55b that
abut on each other by the distal end portions thereof, and the
outer surfaces 61, 63 is enhanced. As a result, the fusion ratio of
the opposing surfaces 65, 67 and the outer surfaces 61, 63 can be
increased.
[0080] Further, when an electric current flows through the roller
electrodes 71, 73, the electric current also flows through the
first columnar bodies 55a and the second columnar bodies 55b.
Therefore, depending on the resistance welding conditions, the
distal end portions are joined together in some or all of the pairs
of the plurality of columnar bodies.
[0081] The heat exchanger 21 can be used as is, that is, in the
linear form such as shown in FIG. 6, or may be used upon bending
spirally as shown in FIG. 2. In the case of the form shown in FIG.
2, the bending is performed so that the thickness direction of the
metal tubes 45, 47, 49 is in the radial direction of the
spiral.
[0082] As described hereinabove, with the manufacturing method
using resistance welding, the metal tube 47 having the support
members 55 in the fluid flow channel 53 and the multiple-hole metal
tubes 45, 49 are stacked and disposed between the roller electrodes
71, 73, and the metal tube 47 and the multiple-hole metal tubes 45,
49 are moved along the longitudinal direction and resistance
welded, while being pressurized in the thickness direction.
Therefore, deformation of the metal tube 47 by pressure during
resistance welding can be inhibited.
[0083] Thus, during such resistance welding, the welding can be
performed in a state in which a sufficient pressure is applied by
the roller electrodes 71, 73 in the thickness direction so that the
outer surfaces 61, 63 of the metal tube 47 and the opposing
surfaces 65, 67 of the multiple-hole metal tubes that are disposed
opposite the outer surfaces are brought into intimate contact with
each other. As a result, the joining surface area of the outer
surfaces 61, 63 and the opposing surfaces 65, 67 can be increased,
deformation of the fluid flow channel 53 is inhibited and a flow
channel necessary for the fluid to flow smoothly is ensured.
Therefore, the efficiency of heat exchange between the coolant and
fluid can be increased. Furthermore, since the metal tubes can be
joined by resistance welding, which is a simple method,
productivity can be increased.
Second Embodiment
[0084] FIG. 7 is a cross-sectional view illustrating the heat
exchanger according to the second embodiment of the present
invention. As shown in FIG. 7, in the heat exchanger 21, the
structure of the support members 55 is different from that of the
first embodiment. Other components are assigned with same reference
numerals as in the first embodiment and the explanation thereof is
herein omitted.
[0085] The support members (support portions) 55 according to the
second embodiment are constituted by a plurality of columnar bodies
arranged along the longitudinal direction of the fluid flow channel
53. One end in an axial direction of each columnar body is joined
to an inner surface (inner surface 57 or inner surface 59) on
either side in the thickness direction of the fluid flow channel
53, and the other end in the axial direction of each columnar body
is disposed on the inner surface side on the other side in the
thickness direction of the fluid flow channel 53. All of the
plurality of columnar bodies may be joined by one end thereof to
the inner surface on the same side, or some of them may be joined
to the inner surface on the other side.
[0086] Both ends in the axial direction of some or all of the
plurality of columnar bodies are respectively joined to the inner
surface 57 on one side and the inner surface 59 on the other side
of the fluid flow channel 53. When both ends of the columnar bodies
are joined, the rigidity of the metal tube 47 can be increased.
Where only one end of the columnar bodies is joined and the other
end is not joined, the flexibility of the metal tube 47 can be
maintained at a certain level.
[0087] The metal tube 47 according to the second embodiment may be
fabricated in the same manner as the metal tube 47 according to the
first embodiment. Thus, the metal tube 47 is obtained by bending a
flat metal sheet (not shown in the figure) so as to form a hollow
portion along the longitudinal direction and joining by welding the
side end portions thereof. The hollow portion along the
longitudinal direction serves as the fluid flow channel 53.
[0088] Prior to bending the metal sheet, one end of each columnar
body is joined by welding or the like in the region that will be
the inner surface 57 or the inner surface 59 after the bending is
completed. Then, the metal sheet is bent and the side end portions
of the metal sheet are joined together. As a result, the metal tube
47 is obtained in which the support members 55 constituted by a
plurality of columnar bodies are provided in the internal fluid
flow channel 53.
[0089] According to the second embodiment, since a plurality of
columnar bodies are arranged along the longitudinal direction of
the fluid flow channel 53, deformation of metal tube 47 in the
longitudinal direction can be inhibited over a long period.
Furthermore, since the columnar bodies are arranged in a spot-like
pattern in the longitudinal direction, the increase in resistance
to the flow of fluid in the fluid flow channel 53 that is caused by
the support members 55 can be inhibited and the fluid can smoothly
flow in the fluid flow channel.
[0090] Further, according to the second embodiment, one end of each
columnar body is joined to the inner surface 57 or the inner
surface 59 in the thickness direction of the fluid flow channel 53.
Therefore, the columnar bodies can be prevented from displacing
when pressurized in the thickness direction by the roller
electrodes 71, 73 during resistance welding. As a result, a
sufficient pressure can be applied in the thickness direction by
the roller electrodes 71, 73 to the metal tube 47 and the
multiple-hole metal tubes 45, 49 during resistance welding.
[0091] Further, in the present embodiment, a plurality of columnar
bodies are provided in the fluid flow channel 53 of the metal tube
47. Therefore, where pressurization is performed in the thickness
direction by the roller electrodes 71, 73, the metal tube 47 is
slightly deformed in the thickness direction and other ends of some
or all of the plurality of columnar bodies abut on the inner
surface 57 or the inner surface 59 of the metal tube 47. Such an
abutment of other ends of the columnar bodies inhibits deformation
of the metal tube 47 in the thickness direction. Further, since the
electric current flowing through the roller electrodes 71, 73 to
the metal tube 47 flows not only through the outer peripheral
portion of the metal tube 47, but also through the columnar bodies
that abut by the other ends thereof on the inner surface, the
fusion of the adjacent opposing surfaces 65, 67, which are provided
with the columnar bodies that abut by the other ends thereof on the
inner surface, and the outer surfaces 61, 63 is enhanced. As a
result, the fusion ratio of the opposing surfaces 65, 67 and the
outer surfaces 61, 63 can be increased.
[0092] Further, since the electric current also flows through the
columnar bodies when flowing through the roller electrodes 71, 73,
the columnar bodies can be joined to the inner surface 57 or the
inner surface 59 under certain conditions of resistance
welding.
Third Embodiment
[0093] FIG. 8 is a cross-sectional view illustrating the heat
exchanger according to the third embodiment of the present
invention. As shown in FIG. 8, the structure of the support member
55 of the heat exchanger 21 is different from that of the first
embodiment. Other components are assigned with same reference
numerals as in the first embodiment and the explanation thereof is
herein omitted.
[0094] The support member (support portion) 55 according to the
third embodiment is a plate-like body that is disposed along the
longitudinal direction of the fluid flow channel 53 and has a
corrugated cross-section perpendicular to the longitudinal
direction. The plate-like body is disposed so that peaks of
depressions and protrusions are continuous along the width
direction of the fluid flow channel 53.
[0095] The metal tube 47 according to the third embodiment may be
fabricated by bending a flat metal sheet (not shown in the figure)
so as to form a hollow portion along the longitudinal direction,
joining the side end portions together by welding or the like, and
then inserting a corrugated plate-like body into the hollow
portion, or by disposing a corrugated plate-like body at a
predetermined position of the metal sheet prior to bending and then
performing bending and welding the side end portions to each
other.
[0096] According to the third embodiment, since the support member
55 is a corrugated plate-like body, deformation of the metal tube
47 in the longitudinal direction can be inhibited over a long
period. Further, since the rigidity of the support member 55 itself
can be increased over that attained when the support member 55 is
in the form of the above-described columnar bodies, such a
configuration is particularly advantageous when a larger
pressurization force is desired to be obtained with the pair of
roller electrodes 71, 73. Furthermore, since the corrugated
plate-like body acts to disperse the fluid flow, it is possible to
regulate the fluid flow and produce a flow with low turbulence.
Fourth Embodiment
[0097] FIG. 9 is a cross-sectional view illustrating the heat
exchanger 21 according to the fourth embodiment of the present
invention. FIGS. 10 to 13 illustrate the metal tube 47 used in the
heat exchanger 21. As shown in FIGS. 9 to 13, the structure of the
support portion of the metal tube 47 of the heat exchanger 21 is
different from that of the first embodiment. Other components are
assigned with same reference numerals as in the first embodiment
and the explanation thereof is herein omitted.
[0098] The metal tube 47 according to the fourth embodiment has a
flat shape with a width greater than a thickness. Side portions at
both sides in the width direction of the metal tube 47 have a
circular-art cross-sectional shape, but such a shape is not
limiting. For example, the side portions of the metal tube 47 may
have a linear cross-sectional shape as shown in FIG. 3 or other
shape. Further, the side portions at both sides in the width
direction of the metal tube 47 protrude outward in the width
direction from the first multiple-hole metal tube 45 and the second
multiple-hole metal tube 49, but such a configuration is not
limiting. For example, the side portions of the metal tube 47 may
have a shape that does not protrude outward in the width direction
as shown in FIG. 3. The fluid flow channel 53 extending in the
longitudinal direction is formed inside the metal tube 47.
[0099] As shown in FIGS. 11 to 13, the metal tube 47 has, in the
fluid flow channel 53 thereof, the support portions 55 that inhibit
deformation in the thickness direction. The support portions 55 are
constituted by a plurality of first protruding portions 55a
arranged along the longitudinal direction of the fluid flow channel
53 at the inner surface 57 on one side in the thickness direction
of the fluid flow channel 53 and a plurality of second protruding
portions 55b arranged along the longitudinal direction of the fluid
flow channel 53 at the inner surface 59 on the other side in the
thickness direction of the fluid flow channel 53. Each first
protruding portion 55a extends from the inner surface 57 on one
side toward the inner surface 59 on the other side, and each second
protruding portion 55b extends from the inner surface 59 on the
other side toward the inner surface 57 on one side.
[0100] These first protruding portions 55a and second protruding
portions 55b are formed by press forming a metal sheet as described
hereinbelow. Therefore, the outer surface 61 on the one side in the
thickness direction recedes on the inner surface 59 side, thereby
causing the first protruding portions 55a to protrude to the inner
surface 59 side in the fluid flow channel 53. The outer surface 63
on the other side in the thickness direction recedes on the inner
surface 57 side, thereby causing the second protruding portions 55b
to protrude to the inner surface 57 side in the fluid flow channel
53. A first receding portion 55c is formed on the rear surface
(outer surface 61) of the first protruding portion 55a, and a
second receding portion 55d is formed on the rear surface (outer
surface 63) of the second protruding portion 55b.
[0101] As shown in FIG. 11, in a plan view of the metal tube 47,
the support portions 55 have the following specific features
because the first protruding portions 55a and second protruding
portions 55b are arranged in a regular manner.
[0102] The support portions 55 are arranged regularly so as to form
five rows (row A1 to row A5), each row extending in the
longitudinal direction. The first protruding portions 55a and
second protruding portions 55b are arranged together in the row A1
to row A5. In the row A3 among these rows, the second protruding
portions 55b are disposed at positions facing the first protruding
portions 55a in the thickness direction. Thus, the second
protruding portions 55b are provided at all of the respective
positions facing the first protruding portions 55a of the row A3
shown in FIG. 11. This row A3, from among the five rows, is
positioned in the central portion in the width direction of the
metal tube 47.
[0103] Further, the support portions 55 are arranged regularly so
as to form a plurality of rows, namely, row B1, row B2, row B3, . .
. extending in the oblique direction at an angle to the
longitudinal direction. The first protruding portions 55a are
disposed by five protruding portions in each of rows B2, B4, B6,
but disposed by one protruding portion in each of rows B1, B3, B5.
This one first protruding portion 55a is disposed in the row A3.
The second protruding portions 55b are disposed by five protruding
portions in each of rows B1, B3, B5, but disposed by one protruding
portion in each of rows B2, B4, B6. This one second protruding
portion 55b is disposed in the row A3. Thus, the rows B2, B4, B6 of
the first protruding portions 55a in the oblique direction and the
rows B1, B3, B5 of the second protruding portions 55b in the
oblique direction are arranged alternately along the longitudinal
direction.
[0104] Therefore, in the fourth embodiment, the first protruding
portions 55a and second protruding portions 55b are disposed
opposite each other only in the row A3 (see FIG. 14C), and in other
rows A1, A2, A4, A5, the first protruding portions 55a and the
second protruding portions 55b are disposed alternately in the
longitudinal direction (see FIGS. 14A and 14B). In other words, in
the rows A1, A2, A4, A5, the first protruding portions 55a are
provided at positions shifted in the longitudinal direction with
respect to the second protruding portions 55b. Thus, only the row
A3 is configured such that the first protruding portions 55a and
the second protruding portions 55b are opposite each other.
[0105] Further, as shown in FIG. 11, an angle .theta.1 between an
oblique direction D2 and the longitudinal direction D1 and an angle
.theta.2 between an oblique direction D3 and the longitudinal
direction D1 are set to mutually different values. The oblique
direction D2 as referred to herein is an arrangement direction of
the aforementioned rows B1, B2, . . . . The oblique direction D3 is
a regular arrangement direction crossing the rows B1, B2, . . . .
In the present embodiment, the angle .theta.1 is set to about 50
degrees and the angle .theta.2 is set to about 40 degrees, and the
oblique direction D2 and the oblique direction D3 cross each other
at about 90 degrees.
[0106] In the configuration according to the fourth embodiment,
since the angle .theta.1 and the angle .theta.2 are set to
different values, as mentioned hereinabove, protruding portions
55a, 55b are not disposed on the same line in the width direction
with a position at which a random first protruding portion 55a (or
second protruding portion 55b) is disposed. The first protruding
portions 55a and second protruding portions 55b can thus be
disposed with a certain degree of randomness in the fluid flow
channel 53 and therefore pulsations can be generated in the flow of
fluid in the fluid flow channel 53. As a result, for example, the
occurrence of drift in the fluid flow channel 53 can be inhibited
and the development of turbulent flow of the fluid in the fluid
flow channel 53 can be enhanced, thereby increasing the efficiency
of heat exchange.
[0107] Further, as shown in FIG. 14C, the distal end of the first
protruding portion 55a is disposed at a predetermined distance t
from the distal end of the second protruding portion 55b opposite
thereto in the thickness direction. Therefore, the gap between the
distal ends of the first protruding portions 55a and the second
protruding portions 55b also serves as a flow channel for coolant.
As a result, the reduction of the fluid flow channel 53 caused by
the provided first protruding portions 55a and second protruding
portions 55b can be inhibited. Further, in the present embodiment,
the distal end portions of the first protruding portions 55a are
disposed at the predetermined distance from the distal end portions
of the second protruding portions 55b opposite thereto in the
thickness direction, but the protruding portions may be also
disposed without the distance t therebetween and the distal end
portions thereof may abut on each other.
[0108] The metal tube 47 can be formed, for example, in the
following manner. First, a plate-like metal sheet is pressed to
form a plurality of protruding portions in predetermined positions,
the protruding portions protruding in the thickness direction of
the metal sheet. Then, the metal sheet is bent at positions
corresponding to circular-arc side portions at both sides in the
width direction of the metal tube 47 and a flat shape is obtained.
The end portions of the obtained metal sheet are joined together by
welding or the like. The plurality of protruding portions formed by
pressing serve as the first protruding portions 55a and second
protruding portions 55b.
[0109] As described hereinabove, in the fourth embodiment, some of
the plurality of first protruding portions 55a are provided at
positions opposite the second protruding portions 55b in the
thickness direction. Therefore, where the first protruding portions
55a and the second protruding portions 55b disposed at positions
opposite thereto abut on each other, subsequent deformation of the
metal tube 47 is inhibited even when a pressure is applied in the
thickness direction to the metal tube 47 during the resistance
welding or bending such as described hereinabove. As a result,
deformation in the thickness direction of the metal tube 47 during
resistance welding or bending can be effectively inhibited.
[0110] Further, in the fourth embodiment, the first protruding
portions 55a and second protruding portions 55b are disposed
opposite each other in the central portion in the width direction.
Therefore, the effect of inhibiting the deformation of the metal
tube 47 can be further increased.
[0111] Further, in the fourth embodiment, the first protruding
portions 55a and second protruding portions 55b are disposed
opposite each other in the central portion in the width direction,
as mentioned hereinabove, but in the rows positioned at both sides,
the first protruding portions 55a are provided at positions
displaced in the longitudinal direction with respect to the second
protruding portions 55b. Therefore, deformation in the thickness
direction of the metal tube 47 in the central portion in the width
direction can be effectively inhibited, and narrowing of the fluid
flow channel can be inhibited and a smooth fluid flow can be
realized at both sides in the width direction. Further, since the
first protruding portions 55a or second protruding portions 55b are
provided on both sides in the width direction, when an unexpectedly
high pressure is applied in the thickness direction, the distal end
portions of the first protruding portions 55a abut on the inner
surface 59 of the metal tube 47 and the distal end portions of the
second protruding portions 55b abut on the inner surface 57 of the
metal tube 47, thereby making it possible to inhibit subsequent
deformation of the metal tube 47.
[0112] Further, in the forth embodiment, as described hereinabove,
the plurality of first protruding portions 55a are arranged so as
to form five rows A1 to A5, each row extending in the longitudinal
direction, and the first protruding portions 55a are also arranged
so as to form a plurality of rows B2, B4, B6 extending in the
oblique direction at an angle to the longitudinal direction. The
second protruding portions 55b are also arranged so as to form a
plurality of rows B1, B3, B5, each row extending in the oblique
direction. The oblique rows of the first protruding portions 55a
and the oblique rows of the second protruding portions 55b are
disposed alternately along the longitudinal direction. When such a
configuration is used, steps (protruding portions) in the thickness
direction can be disposed continuously and at an angle with respect
to the longitudinal direction in the fluid flow channel 53. In
addition, steps (first protruding portions 55a) on one side in the
thickness direction and steps (second protruding portions 55b) on
the other side can be disposed alternately. Therefore, the
occurrence of pulsations in the flow of fluid in the fluid flow
channel 53 can be effectively prevented. As a result, drift in the
fluid flow channel can be inhibited and the development of
turbulent flow of the internal fluid can be enhanced, thereby
making it possible to enhance the heat transfer effect.
[0113] Further, in the fourth embodiment, the metal tube 47 is
shaped by pressing a metal sheet to form a plurality of protruding
portions, which protrude in the thickness direction of the metal
sheet, at predetermined positions, bending the metal sheet to
obtain the aforementioned flat shape, and then joining together the
end portions of the metal sheet. Therefore, it is not necessary to
join by welding, for example, the columnar bodies serving as
support portions to the metal sheet. As a result, the process is
simplified and the production cost can be reduced.
Fifth Embodiment
[0114] FIG. 17A is a perspective view illustrating the heat
exchanger 21 according to the fifth embodiment of the present
invention. The structure of the protruding portion 55 serving as
the support portion of the heat exchanger 21 is different from that
of the first embodiment. Other components are identical to those of
the heat exchanger 21 according to the first embodiment and
therefore assigned with same reference numerals as in the first
embodiment and the explanation thereof is herein omitted.
[0115] FIG. 17B is a plan view illustrating the metal tube 47 of
the heat exchanger 21. This metal tube 47 is provided with a
plurality of first protruding portions 55a and a plurality of
second protruding portions 55b as support portions 55. The
plurality of first protruding portions 55a are arranged along the
longitudinal direction of the fluid flow channel 53 at the inner
surface on one side in the longitudinal direction of the fluid flow
channel 53. The plurality of second protruding portions 55b are
disposed along the longitudinal direction of the fluid flow channel
53 at the inner surface on the other side in the thickness
direction of the fluid flow channel 53. Each first protruding
portion 55a protrude from the inner surface on the one side toward
the inner surface on the other side, and each second protruding
portion 55b protrude from the inner surface on the other side
toward the inner surface on the one side. Each first protruding
portion 55a and each second protruding portion 55b can be formed,
for example, by press forming a metal sheet in the same manner as
in the fourth embodiment.
[0116] As shown in FIG. 17B, the size in the width direction W of
each first protruding portion 55a and second protruding portion 55b
is less than the size thereof in the longitudinal direction L.
Thus, each of the first protruding portions 55a and second
protruding portions 55b has an elongated shape in the plan view
thereof. The longitudinal direction of the first protruding
portions 55a and second protruding portions 55b is substantially
parallel to the longitudinal direction L of the metal tube 47.
[0117] In the fifth embodiment, all of the plurality of first
protruding portions 55a are provided, as shown in FIGS. 17C and
17D, at positions that are opposite the second protruding portions
55b in the thickness direction. It is also possible to provide some
of the plurality of first protruding portions 55a at positions that
are opposite the second protruding portions 55b in the thickness
direction and provide the remaining first protruding portions 55a
at positions that are not opposite the second protruding portions
55b. In such a configuration, the first protruding portions 55a
provided at positions that are not opposite the second protruding
portions 55b function as obstacles that create appropriate
turbulence in the fluid in the fluid flow channel 53. Where the
fluid becomes appropriately turbulent, heat transfer between the
fluid and the metal tube 47 is enhanced. Therefore, heat exchange
efficiency of the heat exchanger can be increased.
[0118] According to the fifth embodiment, the opposing first
protruding portions 55a and second protruding portions 55b are
disposed along the longitudinal direction. Therefore, such a
configuration is particularly advantageous in terms of the effect
of ensuring contact surface area of the first protruding portions
55a and second protruding portions 55b when the heat exchanger 21
is bent, for example, spirally as shown in FIG. 2.
[0119] When the heat exchanger 21 is bent as shown in FIG. 2, the
elongation of material in the portion of the metal tube 47 on the
radially outer side is large and the elongation of material in the
portion on the radially inner side is small, as shown in FIG. 18A.
Therefore, relative positions of the first protruding portions 55a
and second protruding portions 55b can be easily displaced. In the
fifth embodiment, the longitudinal direction of the first
protruding portions 55a and the longitudinal direction of the
second protruding portions 55b are arranged along the longitudinal
direction of the metal tube 47. Therefore, the contact state of the
first protruding portions 55a and second protruding portions 55b
can be maintained even when the relative positions of the first
protruding portions and second protruding portions are somewhat
displaced. As a result, bending with a small curvature radius can
be performed.
[0120] Where the size of the first protruding portions 55a in the
longitudinal direction and the size of the second protruding
portions 55b in the longitudinal direction are decreased, as shown
in FIG. 18B, the allowance range in which the aforementioned
contact state can be maintained against the displacement of the
relative positions is decreased accordingly.
[0121] FIG. 19 is a plan view illustrating a variation example of
the metal tube 47 in the heat exchanger 21 according to the fifth
embodiment. As shown in FIG. 19, in the metal tube 47 according to
this variation example, the first protruding portions 55a and the
second protruding portions 55b have a wedge-like shape. In other
words, the first protruding portions 55a and the second protruding
portions 55b have a substantially triangular shape in a plan view
thereof. In this variation example, the first protruding portions
55a and the second protruding portions 55b are disposed so that the
apexes of the triangles face the flow direction F of the fluid in a
plan view. As a result, the fluid flows smoothly along the side
surfaces of the first protruding portions 55a and second protruding
portions 55b and therefore the occurrence of pressure loss inside
the metal tube 47 can be inhibited.
[0122] Further, in the fifth embodiment illustrated by FIGS. 17 to
19, the size of the protruding portions 55 in the width direction,
that is, the size in the direction perpendicular to the flow
direction F of the fluid, is less than the size of the protruding
portions 55 in the longitudinal direction. As a result, the
increase in resistance encountered by the fluid flowing in the
metal tube 47 can be inhibited.
Sixth Embodiment
[0123] FIG. 20 is a perspective view illustrating the heat
exchanger 21 according to the sixth embodiment of the present
invention. The structure of the metal tube 47 of the heat exchanger
21 according to the sixth embodiment is different from that of the
first embodiment. Other components are identical to those of the
heat exchanger 21 according to the first embodiment and therefore
assigned with same reference numerals as in the first embodiment
and the explanation thereof is herein omitted.
[0124] The metal tube 47 in this heat exchanger 21 is provided with
the fluid flow channel 53 and the support portion 55. The fluid
flow channel 53 has a first fluid flow channel 53a and a second
fluid flow channel 53b extending in the longitudinal direction L
and arranged parallel to each other in the width direction W. The
support portion 55 is provided in the fluid flow channel 53
constituted by the first fluid flow channel 53a and the second
fluid flow channel 53b arranged parallel to each other in the width
direction W. The metal tube 47 is obtained by bending a flat metal
sheet M and joining the predetermined portions as shown in FIG.
21A.
[0125] The first fluid flow channel 53a is formed in the following
manner. First, the metal sheet M is bent at a bending position B1
extending along the longitudinal direction L and the metal sheet M
is bent into a tube so that the end side El on one side in the
width direction of the metal sheet M comes into contact with a
surface S on one side of the metal sheet M. Then, the end side E1
is joined for example by welding to the surface S along the
longitudinal direction L, thereby forming the first fluid flow
channel 53a.
[0126] Likewise, the second fluid flow channel 53b is formed in the
following manner. First, the metal sheet M is bent at a bending
position B2 extending along the longitudinal direction L and the
metal sheet M is bent into a tube so that the end side E2 on one
side in the width direction of the metal sheet M comes into contact
with the surface S on one side of the metal sheet M. Then, the end
side E2 is joined for example by welding to the surface S along the
longitudinal direction L, thereby forming the second fluid flow
channel 53b.
[0127] As shown in FIG. 21C, the support portion 55 is constituted
by portions of the metal sheet M, that is, by portions extending
upward in the height direction (thickness direction of the metal
tube 47) from the end side E1 and end side E2. In the support
portion 55, zones in the vicinity of the end side E1 and end side
E2 abut on each other. Further, the support portion 55 branches to
both sides in the width direction W from the vicinity of the
central portion in the height direction. The branched portions of
the support portion 55 extend obliquely from the height direction
to the left and to the right.
[0128] Since the metal tube 47 according to the sixth embodiment is
formed in the above-described mariner by using the metal sheet M,
the metal tube has a substantially B-like cross-sectional shape.
The support portion 55 thus extending along the longitudinal
direction L can be formed by a simple manufacturing method.
Further, since the support portion 55 of the metal tube 47 extends
continuously along the longitudinal direction L, the configuration
demonstrates excellent effect of inhibiting deformation in the
thickness direction.
[0129] FIG. 22A is a plan view illustrating a variation example of
the metal tube 47 according to the sixth embodiment. FIG. 22B is a
cross-sectional view of the metal tube. As shown in FIGS. 22A and
22B, the metal tube 47 has a plurality of protruding portions 55c
and a plurality of protruding portions 55d in the first fluid flow
channel 53a and in the second fluid flow channel 53b,
respectively.
[0130] The plurality of protruding portions 55c are arranged in a
row along the longitudinal direction L at the inner surface 57 on
one side in the thickness direction of the fluid flow channels 53a,
53b. The plurality of protruding portions 55d are arranged in a row
along the longitudinal direction L at the inner surface 59 on the
other side in the thickness direction of the fluid flow channels
53a, 53b. The protruding portions 55c extend from the inner surface
57 on one side toward the inner surface 59 on the other side, and
the protruding portions 55d extend from the inner surface 59 on the
other side toward the inner surface 57 on one side.
[0131] The protruding portions 55c and protruding portions 55d may
be disposed opposite each other in the thickness direction or at
positions that are not opposite each other. When the protruding
portions are disposed at the opposing positions, the protruding
portions 55c and the protruding portions 55d, together with the
support portion 55, function as support portions inhibiting
deformation of the metal tube 47 in the thickness direction. When
the protruding portions are disposed at positions that are not
opposite each other, the protruding portions 55c and the protruding
portions 55d function as obstacles that create appropriate
turbulence in the fluid in the fluid flow channel 53. Where the
fluid becomes appropriately turbulent, heat transfer between the
fluid and the metal tube 47 is enhanced.
[0132] In the metal tube 47 according to the sixth embodiment, the
support portion 55 can be formed in the fluid flow channel 53 by
using the above-described manufacturing method. Therefore, the
protruding portions for increasing the heat transfer performance
can be provided in the fluid flow channels 53a, 53b by a free
design (design focused on the increase in heat transfer
performance), as in the variation example illustrated by FIGS. 22A
and 22B.
Seventh Embodiment
[0133] FIG. 23A is a perspective view illustrating the heat
exchanger 21 according to the seventh embodiment of the present
invention. The structure of the metal tube 47 of the heat exchanger
21 according to the seventh embodiment is different from that of
the first embodiment. Other components are identical to those of
the heat exchanger 21 according to the first embodiment and
therefore assigned with same reference numerals as in the first
embodiment and the explanation thereof is herein omitted.
[0134] The metal tube 47 in the heat exchanger 21 according to the
seventh embodiment is constituted by a first metal tube 47a and a
second metal tube 47b arranged parallel to each other in the width
direction W. The first metal tube 47a and the second metal tube 47b
are cylindrical flat pipes formed separately from each other by an
appropriate method, for example, extrusion forming. Therefore, the
fluid flow channel 53 of the metal tube 47 is constituted by the
first fluid flow channel 53a inside the first metal tube 47a and
the second fluid flow channel 53b inside the second metal tube 47b.
These first fluid flow channel 53a and second fluid flow channel
53b are partitioned by the support portion 55. In other words, the
support portion 55 is provided in the fluid flow channel 53
constituted by the first fluid flow channel 53a and the second
fluid flow channel 53b arranged parallel to each other in the width
direction W.
[0135] The support portion 55 is constituted by a side wall 55a of
the first metal tube 47a and a side wall 55b of the second metal
tube 47b. The side wall 55a and the side wall 55b are in surface
contact with each other. Protruding portions 55c and protruding
portions 55d such as shown in FIGS. 22A and 22B may be provided in
the fluid flow channels 53a, 53b.
[0136] In the seventh embodiment, the cylindrical flat pipes can be
formed in a simple manner by an appropriate method, for example,
extrusion forming. Therefore, the production cost can be
reduced.
[0137] The number of flat tubes arranged parallel to each other in
the width direction W is not limited to 2 and may be 3, as shown in
FIG. 23B, or 4 or more.
[0138] As shown in FIG. 23C, an integrated flat tube in which the
first fluid flow channel 53a and second fluid flow channel 53b are
partitioned by the support portion 55 by using a method such as
extrusion forming can be also used as the metal tube 47. The
support portion 55 of the metal tube 47 is formed continuously in
the longitudinal direction L and partitions the first fluid flow
channel 53a and second fluid flow channel 53b.
[0139] The metal tube 47 such as shown in FIG. 24B may be also
used. This metal tube 47 is obtained by combining two tubular
members 47a, 47b with a substantially P-like cross-sectional shape,
as shown in FIG. 24A. The tubular members 47a, 47b are formed by
bending a metal sheet. Thus, the tubular member 47a is formed by
folding the metal sheet at a bending position extending along the
longitudinal direction and bending the metal sheet to a
substantially P-like shape such that the end side on one side in
the width direction of the metal sheet is brought into contact with
the surface on one side of the metal sheet. The tubular member 47b
is formed in a similar manner.
[0140] The tubular member 47a has the first fluid flow channel 53a,
and the tubular member 47b has the second fluid flow channel 53b.
The tubular member 47a and the tubular member 47b have flat
portions 48a, 48b extending in the width direction W from
cylindrical portions constituting the fluid flow channels 53a, 53b.
The first fluid flow channel 53a and the second fluid flow channel
53b are arranged parallel to each other in the width direction W.
The flat portion 48a is disposed below the tubular member 47b, and
the flat portion 48b is disposed below the tubular member 47a. The
side wall of the tubular member 47a functions as the support
portion 55a, and the side wall of the tubular member 47b functions
as the support portion 55b. The support portion 55a and the support
portion 55b are in surface contact with each other.
[0141] With the metal tube 47 in which the tubular members 47a, 47b
are thus combined, the entire upper surface and the entire lower
surface in the thickness direction are flat. Therefore, the surface
area of contact with the multiple-hole metal tubes 45, 47 can be
increased. As a result, heat exchange efficiency of the heat
exchanger 21 can be increased.
[0142] Further, in the metal tube 47 shown in FIG. 24C, the fluid
flow channels 53a, 53b of the tubular member 47a and tubular member
47b are less than those shown in FIG. 24B, and the support member
55a and the support member 55b are separated so as to avoid surface
contact thereof. As a result, a third fluid flow channel 53c is
additionally formed between the first fluid flow channel 53a and
the second fluid flow channel 53b.
Eighth Embodiment
[0143] FIG. 25 is a cross-sectional view illustrating the heat
exchanger 21 according to the eighth embodiment of the present
invention. The structure of the metal tube 47 of the heat exchanger
21 according to the eighth embodiment is different from that of the
first embodiment. Other components are identical to those of the
heat exchanger 21 according to the first embodiment and therefore
assigned with same reference numerals as in the first embodiment
and the explanation thereof is herein omitted.
[0144] The metal tube 47 of this heat exchanger 21 is formed by
spirally bending a metal sheet. The metal tube 47 has the support
portion 55 and the fluid flow channel 53. The fluid flow channel 53
is constituted by the first fluid flow channel 53a and the second
fluid flow channel 53b partitioned in the width direction W by the
support portion 55. In other words, the support portion 55 is
provided in the fluid flow channel 53 constituted by the first
fluid flow channel 53a and the second fluid flow channel 53b
arranged parallel to each other in the width direction W.
[0145] The support portion 55 corresponds to a portion obtained by
bending the end portion on one side of the metal sheet in the width
direction W in a L-like shape with a width substantially of the
same order as the thickness of the first fluid flow channel 53a.
The metal sheet is bent spirally so that the support portion 55 is
positioned close to the center of the metal tube 47 in the width
direction W. Because of such spiral bending, a joining surface 50a
and a joining surface 50b are in surface contact with each other.
The joining surface 50a and the joining surface 50b can be joined
by an appropriate method such as the above-described resistance
welding, brazing, and soldering.
[0146] When joining by brazing, for example, the following joining
can be performed. First, a braze layer is formed in advance over
the entire both surfaces of the metal sheet. Then, the sheet is
spirally bent in the above-described manner and processed into the
shape of the metal tube 47. In this case, since the braze layer has
been formed on the joining surface 50a and the joining surface 50b,
the joining surfaces 50a, 50b can be joined together by heating the
metal tube 47 in a heating furnace (not shown in the figure) or the
like. Further, as shown in FIG. 25, a pre-assembled body obtained
by pre-assembling the metal tube 47 in a state prior to joining the
joining surfaces 50a, 50b and the multiple-hole metal tubes 45, 49
may be heated in a heating furnace or the like. Since the braze
layer has been formed on both surfaces (upper and lower surfaces)
in the thickness direction of the metal tube 47, not only the
joining surfaces 50a, 50b, but also the metal tube 47 and the
multiple-hole metal tubes 45, 49 can be joined together at the same
time by heating the pre-assembled body in the heating furnace.
[0147] In the eighth embodiment, the entire upper surface and the
entire lower surface in the thickness direction of the metal tube
47 can be flat. Therefore, the contact surface area with the
multiple-hole metal tubes 45, 47 can be increased. As a result,
heat exchange efficiency of the heat exchanger 21 can be
improved.
[0148] Further, the metal tube 47 has a plurality of protruding
portions 55c and a plurality of protruding portions 55d in the
first fluid flow channel 53a and the second fluid flow channel 53b,
respectively. As described above, in the metal tube 47 according to
the eighth embodiment, the support portion 55 can be formed, by
forming the tube by the above-described manufacturing method.
Therefore, the protruding portions for increasing the heat transfer
performance can be provided in the fluid flow channels 53a, 53b by
a free design (design focused on the increase in heat transfer
performance).
Ninth Embodiment
[0149] FIGS. 26A and 26B are plan views illustrating the process
for manufacturing the metal tube 47 for the heat exchanger 21
according to the ninth embodiment of the present invention. FIG.
26C is a cross-sectional view taken along the XXVIc-XXVIc line in
FIG. 26B. The structure of the protruding portion 55 serving as the
support portion of the heat exchanger 21 is different from that of
the first embodiment. Other components are identical to those of
the heat exchanger 21 according to the first embodiment and
therefore assigned with same reference numerals as in the first
embodiment and the explanation thereof is herein omitted.
[0150] The metal tube 47 is provided with a plurality of first
protruding portions 55a and a plurality of second protruding
portions 55b serving as support portions 55. The plurality of first
protruding portions 55a are arranged along the longitudinal
direction of the fluid flow channel 53 at the inner surface on one
side in the thickness direction of the fluid flow channel 53. The
plurality of second protruding portions 55b are provided along the
longitudinal direction of the fluid flow channel 53 at the inner
surface on the other side in the thickness direction of the fluid
flow channel 53. Each first protruding portion 55a protrudes from
the inner surface on the one side toward the inner surface on the
other side, and each second protruding portion 55b protrudes from
the inner surface on the other side toward the inner surface on the
one side. The first protruding portions 55a and the second
protruding portions 55b are formed by press forming a metal sheet
in the same manner as in the fourth embodiment.
[0151] As shown in FIG. 26B, the first protruding portions 55a and
the second protruding portions 55b have an elongated shape in a
plan view therefor. The first protruding portion 55a and the second
protruding portion 55b opposing each other in the thickness
direction are provided so as to cross each other in a plan view
thereof. The longitudinal direction of the first protruding
portions 55a is inclined to one side in the width direction W of
the metal tube 47 with respect to the longitudinal direction L of
the metal tube 47. The longitudinal direction of the second
protruding portions 55b is inclined toward the other side in the
width direction W with respect to the longitudinal direction L of
the metal tube 47. The inclination angle of the first protruding
portions 55a with respect to the longitudinal direction is equal to
the inclination angle of the second protruding portions 55b with
respect to the longitudinal direction.
[0152] As shown in FIGS. 26B and 26C, the end surfaces of the first
protruding portion 55a and second protruding portion 55b abut on
each other in a contact region T.
[0153] The metal tube 47 according to the ninth embodiment is
formed in the following manner. First, as shown in FIG. 26A, the
plurality of protruding portions 55 are formed with a predetermined
spacing on almost the entire surface of the metal sheet M. These
protruding portions 55 include a plurality of first protruding
portions 55a formed in a region on one side (upper side in FIG.
26A) on a central line B3 positioned as a boundary close to the
center of the metal tube M in the width direction W and a plurality
of second protruding portions 55b formed in a region on the other
side (lower side in FIG. 26A). In the metal sheet M, the first
protruding portions 55a and second protruding portions 55b are
formed in the same direction at the same inclination angle.
[0154] Where the metal sheet M is folded along the central line B3,
the first protruding portions 55a and the second protruding
portions 55b are disposed in a mutual arrangement such as to cross
each other, as shown in FIG. 26B, and the end side El on one side
and the end side E2 on the other side in the width direction W of
the metal sheet M come close to each other. The metal tube 47 is
obtained by joining the end sides E1, E2 together by an appropriate
method, for example, welding.
[0155] When the abovementioned metal sheet M is folded, the
opposing positions of the corresponding first protruding portions
55a and second protruding portions 55b are somewhat displaced as
shown in FIGS. 27A and 27B. Even in such cases, since the first
protruding portions 55a and second protruding portions 55b are
disposed to cross each other, the contact surface area of the
mutual contact region T assumes an almost same value, provided that
the displacements in various directions take place within a range
in which the crossed state of the first protruding portions 55a and
second protruding portions 55b is maintained. As a result, even
where a certain displacement occurs when the metal tube 47 is
formed, the effect of inhibiting the deformation in the thickness
direction of the metal tube 47 can be prevented from reducing.
[0156] Further, when the heat exchanger 21 is fabricated by
stacking the metal tube 47 and the multiple-hole metal tubes 45, 49
and then the heat exchanger 21 is spirally bent, for example as
shown in FIG. 2, even if the relative positions of the opposing
first protruding portions 55a and second protruding portions 55b
are somewhat displaced, the mutual contact surface area can be
prevented from decreasing. Thus, even if a certain displacement
occurs, the contact surface area of the contact region T assumes an
almost same value. Therefore, the variation in of the effect of
inhibiting the deformation in the thickness direction can be
inhibited over the entire metal tube 47. As a result, such
inconveniences as the occurrence of an extremely large deformation
in part of the metal tube 47 can be inhibited. Therefore, the
variation in the degree of pressure loss among the zones of the
metal tube 47 can be inhibited.
[0157] Thus, as mentioned hereinabove, portions where the elongated
first protruding portions 55a and second protruding portions 55b
are in contact with each other function to inhibit deformation in
the thickness direction. Meanwhile, portions where the elongated
first protruding portions 55a and second protruding portions 55b
are not in contact with each other function as obstacles that
create appropriate turbulence in the fluid in the fluid flow
channel 53. Where the fluid becomes appropriately turbulent, heat
transfer between the fluid and the metal tube 47 is enhanced.
Therefore, heat exchange efficiency of the heat exchanger 21 can be
increased.
[0158] Further, in the ninth embodiment, the first protruding
portions 55a and second protruding portions 55b provided in the
metal sheet M may be formed at the same inclination angle with
respect to the same direction. Therefore, the design is simple.
Moreover, in the ninth embodiment, the size of the first protruding
portions 55a or second protruding portions 55b in the width
direction W can be reduced by comparison with the case in which
either the first protruding portions 55a or the second protruding
portions 55b are disposed parallel to the width direction W of the
metal tube 47. As a result, the increase in resistance encountered
by the fluid flowing inside the metal tube 47 can be inhibited.
[0159] (Other Manufacturing Methods)
[0160] In the heat exchanger 21 according to the above-described
first to ninth embodiments, the metal tube 47 and the multiple-hole
metal tubes 45, 49 can be joined by using not only the
above-described method based on resistance welding, but also other
methods such as brazing and soldering. Brazing as referred to
herein is a joining method performed using a braze having a melting
point equal to or higher than 450.degree. C. and soldering is a
joining method performed using a solder having a melting point of
less than 450.degree. C.
[0161] With the joining method using brazing, a braze is disposed,
for example, between the metal tube 47 and the multiple-hole metal
tube 45 and between the metal tube 47 and the multiple-hole metal
tube 49, and the components are heated in this state in a heating
furnace or the like. As a result, the braze is melted and the metal
tube 47 and the multiple-hole metal tubes 45, 49 are joined to each
other.
[0162] For example, ultrasonic soldering can be used as a joining
method based on soldering. With this method, a solder is disposed
between the metal tube 47 and the multiple-hole metal tube 45 and
between the metal tube 47 and the multiple-hole metal tube 49, an
ultrasonic soldering probe is brought into contact with at least
one component from among the metal tube 47, multiple-hole metal
tube 45, and multiple-hole metal tube 49, and ultrasonic vibrations
are applied thereto under heating. As a result, the solder is
melted and the metal tube 47 and the multiple-hole metal tubes 45,
49 are joined to each other.
Summary of Embodiments
[0163] The embodiments are summarized below.
[0164] (1) The heat exchanger includes a metal tube that has a flat
shape with a width greater than a thickness, a fluid flow channel
formed inside thereof along a longitudinal direction, respective
outer surfaces formed on one side and the other side in a thickness
direction, and a support portion formed in the fluid flow channel
and inhibiting deformation in the thickness direction; and a
multiple-hole metal tube stacked on one side of the metal tube in
the thickness direction, the multiple-hole metal tube that has a
flat shape with a width greater than a thickness, a plurality of
fluid flow channels formed inside thereof along the longitudinal
direction, and an opposing surface disposed opposite the outer
surface on the one side of the metal tube and joined by at least
part thereof to the outer surface on the one side.
[0165] In such a configuration, a support portion that inhibits
deformation in the thickness direction is provided in the fluid
flow channel of the metal tube. Therefore, the heat exchanger can
be manufactured by using resistance welding by which the flat metal
tube and flat multiple-hole metal tube stacked in the thickness
direction are welded, while being pressurized in the thickness
direction by a pair of roller electrodes. Since the heat exchanger
can thus be manufactured by resistance welding that excels in
productivity, the cost can be reduced.
[0166] Further, since the support portion is provided in the fluid
flow channel, the metal tube and multiple-hole metal tubes can be
sufficiently pressurized in the thickness direction by the pair of
roller electrodes during resistance welding. As a result, the
joining surface area of the outer surfaces of the metal tube and
the opposing surfaces of the multiple-hole metal tubes opposite
thereto can be increased and therefore a heat exchanger with
excellent heat exchange efficiency can be obtained.
[0167] Further, with such a configuration, since the metal tube has
a support portion in the fluid flow channel, deformation of the
metal tube can be inhibited even in a long-term use of the heat
exchanger.
[0168] Moreover, with such a configuration, since the metal tube
has a support portion in the fluid flow channel, for example, even
when the heat exchanger is bent as shown in the below-described
FIG. 2, the excess deformation of the metal tube can be inhibited.
As a result, the fluid flow channel can be prevented from being
excessively narrowed or closed.
[0169] (2) The support portion may have a plurality of columnar
bodies arranged along the longitudinal direction of the fluid flow
channel, one end of each of the columnar bodies in an axial
direction may be joined to an inner surface on either side in the
thickness direction of the fluid flow channel, and the other end of
each of the columnar bodies in the axial direction may be disposed
on an inner surface side on the other side in the thickness
direction of the fluid flow channel.
[0170] In such a configuration, since a plurality of columnar
bodies are arranged along the longitudinal direction of the fluid
flow channel, deformation of the metal tube in the longitudinal
direction can be inhibited over a long period. Furthermore, since
the columnar bodies are arranged in a spot-like pattern in the
longitudinal direction, the increase in resistance to the flow of
fluid in the fluid flow channel that is caused by the support
portion can be inhibited and the fluid can smoothly flow in the
fluid flow channel. In addition, in this configuration, one end of
each columnar body is joined to the inner surface of the fluid flow
channel. Therefore, the columnar bodies can be prevented from
tilting or tumbling even when pressurized in the thickness
direction by roller electrodes during resistance welding. As a
result, deformation of the fluid flow channel is inhibited and the
desired flow channel can be ensured.
[0171] (3) Both ends in the axial direction of at least one of the
plurality of columnar bodies may be respectively joined to the
inner surface on one side and the inner surface on the other side
of the fluid flow channel.
[0172] In such a configuration, since columnar bodies are provided
that are joined to the inner surface on one side and the inner
surface on the other side of the fluid flow channel, the rigidity
of the metal tube can be further increased. As a result,
deformation of the metal tube can be inhibited over a longer
period.
[0173] (4) In another possible configuration, the support portion
has a plurality of first columnar bodies arranged along the
longitudinal direction of the fluid flow channel on an inner
surface on one side in the thickness direction of the fluid flow
channel and a plurality of second columnar bodies arranged along
the longitudinal direction of the fluid flow channel on an inner
surface on the other side in the thickness direction of the fluid
flow channel; the first columnar bodies extend from the inner
surface on the one side toward the inner surface on the other side;
and the second columnar bodies extend from the inner surface on the
other side toward the inner surface on the one side, and distal end
portions thereof abut on or are disposed close to respective distal
end portions of the plurality of first columnar bodies.
[0174] In such a configuration, when a pressure is applied in the
thickness direction to the metal tube and multiple-hole metal tubes
by a pair of roller electrodes during resistance welding, the first
columnar bodies and second columnar bodies that have been abutted
on each other by the distal end portions are in the abutted state
and the columnar bodies that have distal end portions disposed
close to each other abut on each other by the distal end portions,
thereby making it possible to receive and stop the pressure in the
thickness direction. As a result, deformation of the metal tubes in
the thickness direction during resistance welding can be
effectively inhibited. In the present configuration, a plurality of
first columnar bodies and a plurality of second columnar bodies
that have distal portions abutted on each other or disposed close
to each other are arranged in the longitudinal direction of the
fluid flow channel. Therefore, deformation of the metal tubes in
the longitudinal direction can be inhibited over a long period.
Furthermore, since the columnar bodies are arranged in a spot-like
pattern in the longitudinal direction, the increase in resistance
to the flow of fluid in the fluid flow channel that is caused by
the support portion can be inhibited and the fluid can smoothly
flow in the fluid flow channel.
[0175] (5) At least one of the plurality of first columnar bodies
and at least one of the plurality of second columnar bodies may be
joined together at the distal end portions thereof.
[0176] In such a configuration, since the first columnar bodies and
second columnar bodies are provided that are joined together at the
distal end portions thereof, the rigidity of the metal tubes can be
further increased. As a result, deformation of the metal tubes can
be inhibited over a longer period.
[0177] (6) The support portion may be a corrugated plate-like body
disposed along the longitudinal direction of the fluid flow
channel.
[0178] In such a configuration, since the corrugated plate-like
body is disposed along the longitudinal direction, deformation of
the metal tubes in the longitudinal direction can be inhibited over
a long period. Further, the corrugated plate-like body acts to
disperse the fluid flow. Therefore, it is possible to regulate the
fluid flow and produce a flow with low turbulence. Since the
rigidity of the support body itself can be increased over that in
the case of the above-described columnar bodies, such a
configuration is particularly advantageous when a larger
pressurization force is desired to be obtained with the pair of
roller electrodes.
[0179] (7) The support portion may have a plurality of protruding
portions arranged along the longitudinal direction of the fluid
flow channel, and each of the protruding portions may protrude from
an inner surface on either side in the thickness direction of the
fluid flow channel toward an inner surface on the other side in the
thickness direction.
[0180] In such a configuration, since a plurality of protruding
portions are arranged along the longitudinal direction of the fluid
flow channel, deformation of the metal tubes can be inhibited over
a long period.
[0181] (8) A size of each of the protruding portions in a width
direction may be set less than the size thereof in the longitudinal
direction.
[0182] In such a configuration, by reducing the size of each
protrusion in the width direction, that is, the size in the
direction perpendicular to the fluid flow direction, below the size
in the longitudinal direction, it is possible to inhibit an excess
increase in the resistance encountered by the fluid flowing in the
metal tube. Further, the size of each protruding portion in the
longitudinal direction may be designed as appropriate to a value
required to inhibit deformation of the metal tubes in the thickness
direction. As a result, the resistance encountered by the fluid can
be reduced and the effect of inhibiting the deformation of the
metal tube in the thickness direction can be maintained.
[0183] (9) The protruding portions are not limited to the
abovementioned columnar bodies and can be formed, for example, by
causing the outer surface on one side in the thickness direction to
recede toward the other side or the outer surface on the other side
in the thickness direction to recede toward the one side.
[0184] In such a case, the protruding portions can be formed, for
example, by pressing a metal sheet. Therefore, the production is
simple and cost can be reduced.
[0185] (10) The support portion may have a plurality of first
protruding portions arranged along the longitudinal direction of
the fluid flow channel on an inner surface on one side in the
thickness direction of the fluid flow channel, and a plurality of
second protruding portions arranged along the longitudinal
direction of the fluid flow channel on an inner surface on the
other side in the thickness direction of the fluid flow channel,
the first protruding portions may protrude from the inner surface
on the one side toward the inner surface on the other side, and the
second protruding portions may protrude from the inner surface on
the other side toward the inner surface on the one side.
[0186] With such a configuration, the plurality of the first
protruding portions and the plurality of the second protruding
portions are arranged along the longitudinal direction of the fluid
flow channel Therefore, deformation of the metal tube in the
longitudinal direction can be inhibited over a long period.
[0187] (11) Such first protruding portions and second protruding
portions are not limited to the abovementioned first columnar
bodies and second columnar bodies and can be formed, for example,
by causing the outer surface on one side and the outer surface on
the other side in the thickness direction to recede.
[0188] In the case of such a configuration, the protruding portions
can be formed, for example, by pressing a metal sheet. Therefore,
the production is simple and cost can be reduced.
[0189] (12) Some or all of the plurality of first protruding
portions are preferably provided at positions opposite the second
protruding portions in the thickness direction.
[0190] With such a configuration, where the first protruding
portions and the second protruding portions disposed at positions
opposite thereto abut on each other, subsequent deformation of the
metal tube 47 is inhibited even when a pressure is applied in the
thickness direction to the metal tube 47 during the resistance
welding or bending such as described hereinabove. As a result,
deformation in the thickness direction of the metal tube during
resistance welding or bending can be effectively inhibited.
[0191] (13) The first protruding portions and the second protruding
portions may respectively have elongated shapes in a plan view
thereof, and the first protruding portions and the second
protruding portions, which are facing each other in the thickness
direction, may be provided so as to cross each other in a plan view
thereof.
[0192] With such a configuration, even when the relative positions
of the opposing first protruding portions and second protruding
portions are somewhat displaced in various directions when forming
the metal tube 47, bending of the heat exchanger, and the like,
changes in the mutual contact surface area thereof can be
inhibited. Thus, where displacements in various directions take
place within a range in which the crossed state of the first
protruding portions and second protruding portions is maintained,
the mutual contact surface area assumes an almost same value.
Therefore, even when a certain displacement occurs, the first
protruding portions and second protruding portions come into
contact with each other over a contact surface area of an almost
same value. Therefore, the variation in the effect of inhibiting
the deformation in the thickness direction decreases over the
entire metal tube. As a result, when the heat exchanger is bent, a
stable deformation inhibition effect can be obtained over the
entire metal tube. Therefore, the variation in the degree of
pressure loss among the zones of the metal tube can be
inhibited.
[0193] In this configuration, elongated first protruding portions
and second protruding portions are disposed to cross each other,
and there are portions in which the first protruding portions and
second protruding portions are in contact with each other and
portions adjacent thereto in which the first protruding portions
and second protruding portions are not in contact with each other.
These contact-free portions function as obstacles that create
appropriate turbulence in the fluid in the fluid flow channel Where
the fluid becomes appropriately turbulent, heat transfer between
the fluid and the metal tube is enhanced. Therefore, heat exchange
efficiency of the heat exchanger can be increased.
[0194] Further, this configuration is effective when the metal tube
is formed by bending a metal sheet (flat sheet) and joining
together the end sides of the metal sheet. In this case, the first
protruding portions and second protruding portions are formed at
the metal sheet in advance, before the metal sheet is bent. Even
when the opposing positions of the opposing first protruding
portions and second protruding portions somewhat shift during
bending, where the displacement in various directions takes place
within the range in which the crossing state of the first
protruding portions and second protruding portions is maintained,
the mutual contact surface area assumes an almost same value. As a
result, decrease in the deformation inhibition effect in the
thickness direction of the metal tube can be suppressed even if the
displacement occurs when the metal tube is formed.
[0195] (14) It is preferred that a longitudinal direction of the
first protruding portions be inclined to one side in a width
direction of the metal tube with respect to the longitudinal
direction of the metal tube; a longitudinal direction of the second
protruding portions be inclined to the other side in the width
direction with respect to the longitudinal direction of the metal
tube; and an inclination angle of the first protruding portions
with respect to the longitudinal direction be equal to an
inclination angle of the second protruding portions with respect to
the longitudinal direction.
[0196] In this configuration, the first protruding portions and the
second protruding portions provided at the metal tube may be formed
in the same direction and at the same inclination angle. Therefore,
the design and processing are simple. Furthermore, in this
configuration, the size component of the first protruding portions
55a or the second protruding portions 55b in the width direction of
the metal tube can be reduced by comparison with that in the case
in which either of the first protruding portions and second
protruding portions are disposed parallel to the width direction of
the metal tube. As a result, an excess increase in the resistance
encountered by the fluid flowing in the metal tube can be
inhibited.
[0197] (15) The first protruding portions and the second protruding
portions may respectively have elongated shapes in a plan view
thereof, and a longitudinal direction of the first protruding
portions and the second protruding portions, which are facing each
other in the thickness direction, may be parallel to the
longitudinal direction of the metal tube.
[0198] In such a configuration, the effect of ensuring the contact
surface area of the opposing first protruding portions and second
protruding portions is especially advantageous when the heat
exchanger is bent spirally or in a zigzag shape. Thus, when the
heat exchanger is bent as mentioned above, in the curved portion of
the metal tube, the elongation of material on the radially outer
side is less than the elongation of material on the radially inner
side. Therefore, relative positions of the first protruding
portions and second protruding portions are easily displaced.
Accordingly, in this configuration, the longitudinal direction of
the first protruding portions and the second protruding portions is
along the longitudinal direction of the metal tube and therefore
excellent effect of maintaining the mutual contact state is
demonstrated even when the relative positions are displaced in the
longitudinal direction by the abovementioned bending. As a result,
bending with a small curvature radius is possible.
[0199] (16) It is preferred that the plurality of first protruding
portions be arranged so that three or more rows thereof extending
in the longitudinal direction are formed, and in a row positioned
in a central portion in the width direction from among these rows,
the first protruding portions be provided at positions opposite the
second protruding portions in the thickness direction.
[0200] With such a configuration, since the first protruding
portions and the second protruding portions are opposite each other
in the central portion in the width direction, deformation of the
metal tube can be inhibited with good balance in the central
portion in the width direction. Further, "the row positioned in the
central portion in the width direction" as referred to herein means
the row closest to the center of the metal tube in the width
direction. Therefore, when the number of the plurality of rows (the
aforementioned three or more rows) extending in the longitudinal
direction is an even number, "the row positioned in the central
portion in the width direction" can mean two rows.
[0201] (17) It is preferred that in rows positioned at both sides
of the row positioned in the central portion in the width
direction, the first protruding portions be provided at positions
displaced in the longitudinal direction with respect to the second
protruding portions.
[0202] With such a configuration, as mentioned hereinabove, in the
central portion in the width direction, the first protruding
portions and the second protruding portions are disposed opposite
each other, whereas in the rows positioned at both sides, the first
protruding portions are provided at positions displaced in the
longitudinal direction with respect to the second protruding
portions. Therefore, deformation of the metal tube in the thickness
direction in the central portion in the width direction can be
inhibited with good balance, narrowing of the fluid flow channel at
both sides in the width direction is inhibited, and a smooth flow
of the fluid can be realized. Further, since the first protruding
portions and the second first protruding portions are provided at
both sides in the width direction, when an unexpectedly high
pressure is applied in the thickness direction, the distal end
portions of the first protruding portions or the distal end
portions of the second protruding portions abut on an inner surface
or an inner surface of the metal tube, thereby making it possible
to inhibit subsequent deformation of the metal tube.
[0203] (18) It is preferred that the plurality of first protruding
portions be arranged, as described hereinabove, so that three or
more rows thereof extending in the longitudinal direction are
formed, and also that the first protruding portions be arranged so
that a plurality of rows thereof extending in a inclination
direction inclined with respect to the longitudinal direction are
formed; the second protruding portions be also arranged so that a
plurality of rows thereof extending in the inclination direction
are formed; and the rows of the first protruding portions in the
inclination direction and the rows of the second protruding
portions in the inclination direction be disposed alternately along
the longitudinal direction.
[0204] Where such a configuration is used, steps (protruding
portions) in the thickness direction can be disposed continuously
with an inclination against the longitudinal direction and the
steps (first protruding portions) on one side and the steps (second
protruding portions) on the other side in the thickness direction
can be disposed alternately. Therefore pulsations can be
effectively generated in the flow of fluid in the fluid flow
channel As a result, the drift in the fluid flow channel can be
inhibited and the development of turbulent flow of the fluid in the
fluid flow channel can be enhanced, thereby increasing the
efficiency of heat exchange.
[0205] (19) The configuration is preferred in which the fluid flow
channel includes a first fluid flow channel and a second fluid flow
channel provided parallel to each other in the width direction and
extending in the longitudinal direction; the first fluid flow
channel is formed by folding a metal sheet at a position along the
longitudinal direction and bending the metal sheet into a tubular
shape so that one end side in the width direction of the metal
sheet abuts on a surface on one side of the metal sheet, and the
one end side is joined to the one surface along the longitudinal
direction; the second fluid flow channel is formed by folding the
metal sheet at another position along the longitudinal direction
and bending the metal sheet into a tubular shape so that another
end side in the width direction of the metal sheet abuts on the one
surface at a position adjacent to the one end side, and the other
end side is joined to the one surface along the longitudinal
direction; and the support portion is constituted by parts of the
metal sheet, each part extending from the one end side and the
other end side in the thickness direction or a direction inclined
from the thickness direction.
[0206] With such a configuration, a metal with a substantially
B-like cross section can be obtained by forming a metal sheet in
the above-described manner. In such a metal tube, the support
portion extending along the longitudinal direction can be formed
and a pair of fluid flow channel can be formed by forming the metal
sheet in the above-described manner. Therefore, the metal tube is
manufactured in a simple manner. Further, since the support portion
of the metal tube extends continuously along the longitudinal
direction, an excellent effect of inhibiting deformation in the
thickness direction is demonstrated.
[0207] (20) In the heat exchanger, the multiple-hole metal tube may
be a first multiple-hole metal tube and the heat exchanger may
further include a second multiple-hole metal tube stacked on the
other side of the metal tube in the thickness direction, the second
multiple-hole metal tube that has a flat shape with a width greater
than a thickness, a plurality of fluid flow channels formed inside
thereof along the longitudinal direction, and an opposing surface
that is disposed opposite an outer surface on the other side of the
metal tube and joined by at least part thereof to the outer surface
on the other side.
[0208] In such a configuration, multiple-hole metal tubes are
stacked on both sides in the thickness direction of the metal tube.
Therefore, the heat exchange surface area can be increased and the
efficiency of heat exchange between the coolant and the fluid can
be further increased.
[0209] (21) It is preferred that substantially the entire opposing
surfaces be joined to the outer surfaces.
[0210] In such a configuration, substantially entire opposing
regions of the metal tube and multiple-hole metal tubes are joined
to each other. Therefore, the efficiency of heat exchange between
the coolant and the fluid can be further increased.
[0211] (22) For example, the heat exchanger may be configured by
spirally winding so that one end in the longitudinal direction is
disposed inside and another end in the longitudinal direction is
disposed outside.
[0212] With such a configuration, because the heat exchanger is
spirally wound, dead space can be reduced and the heat exchanged
can be reduced in size. Further, since the support portion is
provided in the fluid flow channel of the metal tube, the fluid
flow channel can be prevented from decreasing is size or closing
due to deformation of the metal tube occurring during bending from
a linear shape to the spiral shape and the decrease in heat
exchange efficiency can be inhibited.
Other Embodiments
[0213] The present invention is not limited to the abovementioned
embodiments and can be variously changed or modified without
departing from the essence thereof. For example, in the fourth
embodiment, an exemplary configuration is explained in which the
first protruding portions 55a protrude from one inner surface 57,
the second protruding portions 55b protrude from the other inner
surface 59, and some of the first protruding portions 55a and some
of the second protruding portions 55b are disposed at mutually
opposing positions, but such a configuration is not limiting.
[0214] For example, in Variation Example 1 shown in FIG. 15, the
first protruding portions 55a protrude from one inner surface 57,
the second protruding portions protrude from the other inner
surface 59, and these first protruding portions 55a and second
protruding portions 55b are disposed alternately in the
longitudinal direction and thickness direction, instead of being
disposed at the mutually opposing positions. With such a
configuration, the distal end portions of the first protruding
portions 55a extend close to the other inner surface 59, and the
distal end portions of the second protruding portions 55b extend
close to the one inner surface 57. As a result, when a pressure is
applied to the metal tube 47 in the thickness direction, the first
protruding portions 55a abut on the other surface 59, and the
second protruding portions 55b abut on the one inner surface 57 and
therefore subsequent deformation of the metal tube 47 is inhibited.
In the Variation Example 1, the first protruding portions 55a and
the second protruding portions 55b are formed by pressing.
[0215] Further, for example, in Variation Example 2 shown in FIG.
16, the protruding portions 55 may protrude only from one inner
surface 57. In such a configuration, the distal end portions of the
protruding portions 55 extend to the vicinity of the other inner
surface 59. As a result, the protruding portions 55 abut on the
other inner surface 59 and subsequent deformation of the metal tube
47 is inhibited even when a pressure is applied to the metal tube
47 in the thickness direction. In this Variation Example 2 the
protruding portions 55 are formed by pressing.
[0216] Further, in the abovementioned embodiments, a heat exchanger
that is spirally bent is explained by way of example, but the heat
exchanger in accordance with the present invention is not limited
to the spiral configuration and can be used in a linear
configuration or can be processed into a variety of other shapes. A
plurality of spiral heat exchangers such as shown in FIG. 1 may be
stacked.
[0217] Further, in the abovementioned embodiments, the case of heat
exchange between water and a coolant is explained by way of
example, but the heat exchanger in accordance with the present
invention may be used for heat exchange between coolants or for
heat exchange between the coolant and another fluid.
[0218] Further, in the abovementioned embodiments, the case in
which the support member is a columnar body or a corrugated
plate-like body is explained by way of example, but a variety of
other configurations such as a configuration in which a plurality
of plate-like bodies are arranged in a spot-like pattern in the
fluid flow channel of the metal tube substantially parallel to the
thickness direction thereof and a configuration in which a
plurality of spherical bodies are disposed in the fluid flow
channel can be also used. Further, in addition to the case in which
the support member is a corrugated plate-like body in the form of
an S-like curve, as in the abovementioned embodiments, the support
member can be in the form of a corrugated plate-like body composed
by angular protrusions and depressions.
[0219] Further, in the abovementioned first embodiment and second
embodiment, the configuration in which the columnar bodies are
arranged in three rows is explained by way of example, but the
columnar bodies in accordance with the present invention may be
disposed in one row, in two rows, or in a plurality of rows (four
or more rows).
[0220] Further, in the abovementioned embodiments, the case is
explained in which the first embodiment, second embodiment, and
third embodiment are implemented individually, but two or more
implementation modes thereof may be combined.
[0221] Further, in the abovementioned embodiments, a three-layer
configuration is explained that is obtained by stacking the first
multiple-hole metal tube, metal tube, and second multiple-hole
metal tube in the order of description, but a two-layer
configuration including only one multiple-hole metal tube and the
metal tube or a configuration including four or more layers may be
also used.
[0222] Further, in the abovementioned embodiments, the case in
which each metal tube has a flat shape having a substantially
quadrangular cross section is explained by way of example, but
another flat shape, for example, such that has a cross section with
a curved side portion in the width direction, may be also used.
[0223] Further, in the abovementioned embodiments, the case is
explained in which the metal tube and the multiple-hole metal tube
are joined by a melt joining method by which the outer surface of
the metal tube and the opposing surface of the multiple-hole metal
tube are locally fused together in the vicinity of the boundary
thereof, but in accordance with the present invention, the joining
may be also performed by resistance welding in a state in which a
fusion metal with a melting point lower than those of the metal
tube and the multiple-hole metal tube is disposed between the outer
surface of the metal tube and the opposing surface of the
multiple-hole metal tube.
[0224] Further, in the abovementioned embodiments, the case in
which the roller electrode is fixed and welding is performed by
moving the metal tube which is the object of welding is explained
by way of example, but the resistance welding may be also performed
by fixing the metal tube and moving the roller electrode.
[0225] Further, in the abovementioned embodiments, the case in
which the heat exchanger is used in a heat pump type hot water
supply apparatus is explained by way of example, but the heat
exchanger in accordance with the present invention can be also used
for other applications such as air conditioners.
[0226] Further, in the abovementioned fourth embodiment, the case
in which the metal sheet is pressed to form the protruding portions
is explained by way of example, but the protruding portions may be
also formed by joining another member to the metal sheet, for
example, by welding.
[0227] Further, in the abovementioned fourth embodiment, the
configuration in which the plurality of protruding portions are
arranged in a spot-like pattern is explained by way of example, but
the protruding portions may also have a continuous ridge-like shape
along the longitudinal direction.
[0228] Further, in the abovementioned fourth embodiment, the case
is explained in which some of the plurality of first protruding
portions are provided at positions opposite the second protruding
portions in the thickness direction, but all of the plurality of
first protruding portions may be provided at positions opposite the
second protruding portions in the thickness direction.
[0229] Further, in the abovementioned fourth embodiment, the
configuration is explained in which the first protruding portions
and second protruding portions are arranged in five rows extending
in the longitudinal direction, but the first protruding portions
and second protruding portions may be disposed in different
rows.
[0230] Further, in the abovementioned embodiments, the case is
explained in which the protruding portions with the size in the
width direction such as shown, for example, in FIG. 17B and FIG.
19, less than the size in the longitudinal direction are provided
on one inner surface and other inner surface in the thickness
direction of the metal tube 47, but such protruding portions may be
provided only on either inner surface in the thickness direction of
the metal tube 47.
[0231] Further, in the abovementioned ninth embodiment, the case is
explained in which the inclination angle of the first protruding
portions 55a with respect to the longitudinal direction L is equal
to that of the second protruding portions 55b, but such
configuration is not limiting and the inclination angle of the
first protruding portions 55a may be different from the inclination
angle of the second protruding portions 55b. Further, a
configuration may be used in which the first protruding portions
55a are disposed along the longitudinal direction L and the second
protruding portions 55b are disposed along the width direction.
EXPLANATION OF REFERENCE NUMERALS
[0232] 11 hot water supply apparatus
[0233] 13 coolant circuit
[0234] 15 tank
[0235] 17 hot water storage circuit
[0236] 19 compressor
[0237] 21 heat exchanger
[0238] 23 expansion valve
[0239] 25 evaporator
[0240] 45 first multiple-hole metal tube
[0241] 47 metal tube
[0242] 49 second multiple-hole metal tube
[0243] 51 coolant flow channel
[0244] 53 fluid flow channel
[0245] 55 support member (support portion)
[0246] 55a first columnar body
[0247] 55b second columnar body
[0248] F flow direction of fluid
* * * * *