U.S. patent application number 11/699975 was filed with the patent office on 2007-08-02 for method of manufacturing heat exchanger and heat exchanger.
This patent application is currently assigned to DENSO Corporation. Invention is credited to Masaki Harada, Sumio Susa, Haruhiko Watanabe.
Application Number | 20070175620 11/699975 |
Document ID | / |
Family ID | 38320882 |
Filed Date | 2007-08-02 |
United States Patent
Application |
20070175620 |
Kind Code |
A1 |
Watanabe; Haruhiko ; et
al. |
August 2, 2007 |
Method of manufacturing heat exchanger and heat exchanger
Abstract
A heat exchanger has a core including tubes and a core plate
coupled to the core. The core plate has a coupling wall on which
tube insertion holes are formed for receiving ends of the tubes.
The coupling wall has an end portion and a clearance portion both
coupled to the tubes. The clearance portion is integrally connected
to the end portion and spaced from an imaginary plane, on which the
end portion is located. A paste brazing material is applied to a
joining portion between the core plate and each tube by a brazing
material applying device through a space provided between the
clearance portion and the imaginary plane.
Inventors: |
Watanabe; Haruhiko;
(Obu-city, JP) ; Susa; Sumio; (Anjo-city, JP)
; Harada; Masaki; (Kariya-city, JP) |
Correspondence
Address: |
HARNESS, DICKEY & PIERCE, P.L.C.
P.O. BOX 828
BLOOMFIELD HILLS
MI
48303
US
|
Assignee: |
DENSO Corporation
Kariya-city
JP
|
Family ID: |
38320882 |
Appl. No.: |
11/699975 |
Filed: |
January 30, 2007 |
Current U.S.
Class: |
165/173 ;
228/183 |
Current CPC
Class: |
F28D 2021/0082 20130101;
B23P 15/26 20130101; F28F 9/0224 20130101; F28F 9/18 20130101; F28D
1/05366 20130101; B23K 2101/14 20180801; B23K 1/0012 20130101 |
Class at
Publication: |
165/173 ;
228/183 |
International
Class: |
F28F 9/02 20060101
F28F009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 31, 2006 |
JP |
2006-021666 |
Claims
1. A method of manufacturing a heat exchanger, comprising: forming
a core plate having a coupling wall for coupling to tubes, wherein
the coupling wall includes an end portion and a clearance portion,
the clearance portion is spaced from an imaginary plane on which
the end portion is located, and tube insertion holes are formed
across the end portion and the clearance portion; preliminarily
fixing the core plate and the tubes by inserting ends of the tubes
into the tube insertion holes of the core plate; applying a paste
brazing material to joining portions between the core plate and the
tubes by a brazing material applying device; and heating the
preliminarily fixed core plate and tubes for brazing the joining
portions.
2. The method according to claim 1, wherein the forming includes
forming an inclined surface on a perimeter of each tube insertion
hole, the inclined surface inclined relative to a direction
perpendicular to the imaginary plane, and in the applying, the
paste brazing material is applied between the inclined surface and
an outer wall of the tube.
3. The method according to claim 1, wherein the tubes have a
substantially flat tubular shape.
4. The method according to claim 1, wherein each of the core plate
and the tubes has an outer surface made of one of copper, copper
alloy, and nickel.
5. The method according to claim 1, wherein the paste brazing
material has a melting point between 550 and 700.degree. C.
6. The method according to claim 1, wherein in the applying, the
paste brazing material is applied to a part of each joining
portion, and in the heating, the core plate is arranged such that
the part to which the paste brazing material is applied is located
higher than a remaining part of the respective joining portion.
7. The method according to claim 1, wherein the core plate has a
coefficient of linear expansion smaller than that of the tubes.
8. The method according to claim 1, wherein in the applying, the
paste brazing material is applied to a part of the joining portion
by entering an end of the brazing material applying device in a
space defined between the clearance portion and the imaginary
plane.
9. The method according to claim 1, wherein in the applying, the
paste brazing material is applied to a part of the joining portion,
the part being formed on the clearance portion, and in the heating,
the core plate is arranged such that the clearance portion is
located higher than the end portion.
10. The method according to claim 1, wherein the brazing material
applying device has a straight end portion.
11. The method according to claim 1, wherein the preliminarily
fixing includes arranging fins between the tubes.
12. A heat exchanger comprising: a core having tubes and fins; and
a header tank having a core plate, the core plate having a coupling
wall formed with tube insertion holes, wherein ends of the tubes
are received in and brazed with the tube insertion holes, wherein
the coupling wall includes an end portion and a clearance portion,
the end portion is located on an imaginary plane, and the clearance
portion is spaced from the imaginary plane.
13. The heat exchanger according to claim 12, wherein the tube
insertion holes extend across the clearance portion and the end
portion, and the clearance portion is at least partly located
within the core.
14. The heat exchanger according to claim 12, wherein the imaginary
plane is perpendicular to a longitudinal direction of the tubes,
and the clearance portion is inclined relative to the imaginary
plane.
15. The heat exchanger according to claim 12, wherein the clearance
portion has a curved wall.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on Japanese Patent Application No.
2006-21666, filed on Jan. 31, 2006, the disclosure of which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a method of manufacturing a
heat exchanger and a heat exchanger manufactured by the method.
BACKGROUND OF THE INVENTION
[0003] In general, a heat exchanger has a core constructed of a
stack of tubes and fins and a pair of header tanks at ends of the
core. For example, in Japanese Unexamined Patent Publication No.
2005-118826 (US 2005/0082350), a header tank is constructed of a
tank main body and a core plate. The core plate has a substantially
box shape with a closed end on one side and an open end on the
other side. The core plate is joined to the tank main body such
that the open end engages with the tank main body. The core plate
is formed with tube insertion holes on a plate portion of the
closed end. Ends of the tubes are inserted in and brazed to the
tube insertion holes.
[0004] In such a heat exchanger, a core plate and ends of tubes are
for example brazed in the following manner. First, a paste brazing
material is applied adjacent to the tube insertion holes of the
core plate. Next, the tubes and the core plate are preliminarily
fixed by inserting the ends of the tubes into the tube insertion
holes of the core plate. Thereafter, the preliminarily fixed tubes
and core plate is heated. Thus, the brazing material melts and
flows into joining portions between the tubes and the core plate.
Accordingly, the core plate and the tubes are brazed.
[0005] In the above brazing method, since the paste brazing
material is applied beforehand, it will be displaced or drop when
inserting the ends the tubes to the tubes insertion holes. Further,
since the paste brazing material is applied adjacent to the tube
insertion holes, it is concerned that the paste brazing material
will not be distributed sufficiently and entirely in the joining
portions during the heating. These issues result in decrease of
brazability.
[0006] To solve the above issues, the paste brazing material may be
directly applied to the joining portions after the core plate and
the tubes are preliminarily fixed. In this case, however, it has
been found difficult to apply the paste brazing material to the
joining portions by using a brazing material applying device having
a straight end, such as a general dispenser.
[0007] FIG. 11 shows an example when a paste brazing material is
applied by a dispenser 200 having a straight end. In general, ends
of fins 921 disposed between tubes 922 are located adjacent to a
core plate 911 to provide sufficient heat exchanging performance.
Therefore, the straight end of the dispenser 200 interferes with
the ends of the fins 921, as shown by double dashed line in FIG.
11. It is difficult to enter the end of the dispenser 200 to a
predetermined portion between the tubes 922. In a case that the end
of the fin 921 is not formed at a position close to the core plate
911, it is easy to apply the brazing material. However, this causes
a decrease of heat exchanging performance.
SUMMARY OF THE INVENTION
[0008] The present invention is made in view of the foregoing
matter, and it is an object of the present invention to provide a
method of manufacturing a heat exchanger with an enhanced
brazability between a core plate and tubes, which does not cause a
decrease in a heat exchanging capacity, and a heat exchanger
manufactured by the method.
[0009] According to an aspect of the present invention, a heat
exchanger has a core plate and tubes. The core plate has a coupling
wall formed with tube insertion holes. The coupling wall includes
an end portion and a clearance portion. The clearance portion is
spaced from an imaginary plane on which the end portion is located.
The tube insertion holes are formed across the clearance portion
and the end portion. The core plate is preliminarily fixed to the
tubes by inserting ends of the tubes into the tube insertion holes
of the core plate. Then, a paste brazing material is applied to
joining portions between the core plate and the tubes by a brazing
material applying device. Thereafter, the preliminarily fixed core
plate and tubes are heated, thereby brazing the joining
portions.
[0010] In the core plate, since the clearance portion is spaced
from an imaginary plane on which the end portion is located, a
space is provided between the clearance portion and the imaginary
plane. Therefore, the paste brazing material is applied to the
joining portion by entering an end of the brazing material applying
device in the space provided by the clearance portion. Thus,
interference of the brazing material applying device with fins
between the tubes reduces. Accordingly, brazability improves
without reducing a heat exchanging capacity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Other objects, features and advantages of the present
invention will become more apparent from the following detailed
description made with reference to the accompanying drawings, in
which like parts are designated by like reference numbers and in
which:
[0012] FIG. 1 is a schematic front view of an intercooler as a heat
exchanger according to an embodiment of the present invention;
[0013] FIG. 2 is a cross-sectional view of a part of the
intercooler taken along a line II-II in FIG. 1;
[0014] FIG. 3 is a schematic cross-sectional view of a joining
portion between a core plate and a tube of the intercooler when
viewed along a longitudinal direction of the tube in FIG. 2;
[0015] FIGS. 4A to 4C are explanatory cross-sectional views for
showing manufacturing steps of the intercooler according to the
embodiment;
[0016] FIGS. 5A to 5C are explanatory cross-sectional views for
showing manufacturing steps of the intercooler when taken along a
line V-V in FIG. 3;
[0017] FIG. 6 is a schematic cross-sectional view for showing a
portion to which a paste brazing material is applied according to
the embodiment;
[0018] FIG. 7 is a schematic cross-sectional view of a part of an
intercooler according to another embodiment of the present
invention;
[0019] FIG. 8 is a schematic cross-sectional view of a part of an
intercooler according to further another embodiment of the present
invention;
[0020] FIG. 9 is a schematic cross-sectional view of a part of an
intercooler according to still another embodiment of the present
invention;
[0021] FIG. 10 is a schematic cross-sectional view of a part of an
intercooler according to yet another embodiment of the present
invention; and
[0022] FIG. 11 is a schematic cross-sectional view for showing an
example of a paste brazing material applying step in a
manufacturing process of a heat exchanger as a related art.
DETAILED DESCRIPTION OF EMBODIMENT
[0023] An embodiment of the present invention will now be described
with reference to FIGS. 1 to 6. FIG. 1 shows an intercooler 100
that cools air having been pressurized in a supercharger before the
air sucked into an engine, as a heat exchanger.
[0024] The intercooler 100 has a core 120 and a pair of header
tanks 110. The core 120 has tubes 122, outer fins 121 for radiating
heat and side plates 124 as core reinforcement members. The tubes
122 and the outer fins 121 are alternately stacked, and the side
plates 124 are joined to outer fins 121 that are located at ends
(upper and lower ends in FIG. 1). The tubes 122, the outer fins 121
and the side plates 124 are integrally brazed.
[0025] The header tanks 110 are arranged at ends 122a of the tubes
122 (left and right ends in FIG. 1). Each of the header tanks 110
extends in a direction perpendicular to a longitudinal direction of
the tubes 122 and in communication with passages defined in the
tubes 122. As shown in FIG. 2, the tube ends 122a are inserted in
and brazed to tube insertion holes 111a formed on the header tanks
110 with a brazing material 220.
[0026] Each tube 122 has a substantially flat tubular shape, and an
inner fin (not shown) is brazed inside of the tube 122. Also, the
outer fins 121 are brazed to an outside of the tube 122. The inner
fins and the outer fins 121 are for example made of copper in view
of thermal conductivity and the like. The tubes 122 and the side
plates 124 are for example made of copper alloy in view of
strength, thermal conductivity and the like.
[0027] As shown in FIG. 2, each header tank 110 has a tank main
body 112, a core plate 111 and a bottom wall member (not shown)
that provides the bottom of the header tank 110. The tube insertion
holes 111a are formed on the core plate 111. The respective
components of the header tank 110 are for example formed of copper
alloy plates. The core plate 111 and the tank main body 112 are
joined to each other such as by brazing or welding to form a tank
inside space 110a.
[0028] At least the surfaces of the respective components of the
header tank 110 are made of copper, a copper alloy material, or a
nickel material. For example, the core plate 111 can be formed of a
stainless plate member having a copper coating on its surface, so
as to have sufficient strength.
[0029] One of the header tanks 110 (e.g., a right header tank in
FIG. 1) is provided with an inlet joint 113. The other header tank
110 (e.g., a left header tank in FIG. 1) is provided with an outlet
joint 114. The inlet joint 113 is coupled to a discharge side of
the supercharger (not shown), and the outlet joint 114 is coupled
to a suction side of the engine (not shown).
[0030] The inlet joint 113 provides an inlet port for introducing
air into the right header tank 110. The outlet joint 114 provides
an outlet port for discharging air from the left header tank
110.
[0031] Each of the header tanks 110 narrows with a distance from
the inlet or outlet joint 113, 114. Namely, a sectional area (tank
inner space 110a) of each header tank 110 gradually reduces with
the distance from the inlet or outlet joint 113, 114 so that the
air is substantially uniformly introduced in the tubes 122.
Further, stays 130 for fixing the intercooler 100 to a vehicle
body, frame member or the like are joined to the outer surfaces of
the header tanks 110.
[0032] To manufacture the intercooler 100, the respective
components of the core 120 are preliminarily fixed with the core
plate 111 such as by engaging or using jigs, and then integrally
brazed. Then, the tank main bodies 112 and other necessary
components are welded to the core plates 111. Here, the tank main
bodies 112 and other components may be integrally brazed, instead
of welding.
[0033] Hereafter, a joining structure and a joining method of the
core plate 111 and the tubes 122 will be described in detail with
reference to FIGS. 2 to 6. FIG. 3 shows a schematic cross-sectional
view of a joining portion between the core plate 111 and the tube
112 when viewed from the right side in FIG. 2.
[0034] As shown in FIG. 2, the core plate 111 has a main wall
(coupling wall) 110b coupled to the core 120 and a pair of side
walls 110c on ends of the main wall 110b. The side walls 110c are
joined to ends of the tank main body 112. The ends 111b of the main
wall 110b are inclined relative to a direction perpendicular to the
longitudinal direction of the tube 122 (up and down direction in
FIG. 2). Thus, the ends 111b of the main wall 110b extend in
directions separating from a center of the core 120.
[0035] Namely, the main wall 110b includes an end portion 111c and
clearance portions (ends of the main wall 110b) 111b. The end
portion 111c is located on an imaginary plane P1 and coupled to the
core 120. The clearance portions 111b are inclined relative to the
imaginary plane P1, i.e., spaced from the imaginary plane P1 for
providing spaces P2 between the clearance portions 111b and the
imaginary plane P1.
[0036] As shown in FIG. 3, each tube insertion hole 111a extends
from one of the clearance portion 111b to the other clearance
portion 111b through the end portion 111c. When the core plate 111
is coupled to the core 120, the boundary between the end portion
111c and the clearance portion 111b is located within the core 120.
In other words, the space P2 is also provided within the core
120.
[0037] Next, a method of brazing of the core plates 111 and the
tubes 122 will be described. First, the core plates 111 having the
above described shape and the core 120 are coupled. Specifically,
as shown in FIG. 4A, the tube ends 122a are inserted in the tube
insertion holes 111a, thereby to preliminarily fix the core 120 and
the core plates 111. As shown in FIG. 5A, a burring portion 111e
having an inclined surface 111d is formed around each tube
insertion hole 111a. The inclined surface 111d is inclined or
curved along a tube insertion direction shown by an arrow in FIG.
5A.
[0038] Therefore, the tube end 122a is guided along the inclined
surface 111d when being inserted into the tube insertion hole 111a.
As such, the tube ends 122a are easily inserted in the tube
insertion holes 111a. The step shown in FIGS. 4A and 5A corresponds
to a preliminarily fixing step.
[0039] Next, as shown in FIGS. 4B and 5B, a paste brazing material
210 is applied to the joining portion 122b between the core plate
111 and the tube 122 by using a dispenser 200 as a brazing material
applying device. In the example shown in FIG. 4B, the dispenser 200
is a generally used dispenser having a straight end (straight pipe
shape).
[0040] Since the core plate 111 has the clearance portions 111b,
the spaces P2 are provided, as shown in FIG. 2. Therefore, the
straight end of the dispenser 200 can enter the spaces defined
between the outer fins 121 and the core plate 111 and reach an
inner position shown by a double dashed line in FIG. 4B.
[0041] In the example shown in FIG. 4B, the end of the dispenser
200 can reach at least the boundary between the clearance portions
111b and the end portion 111c. Thus, as shown by a dashed line in
FIG. 6, the paste brazing material 210 can be applied along a part
of the joining portion 122b, the part included in the clearance
portion 111c.
[0042] Accordingly, the paste brazing material 210 can be applied
over a relatively wide area of the joining portion 122b. The step
shown in FIGS. 4B and 5B correspond to a brazing material applying
step (hereafter, applying step).
[0043] In the applying step, as shown in FIG. 5B, the paste brazing
material 210 is applied between the inclined surface 111d of the
burring portion 111c and an outer surface of the tube 122. The
brazing material 210 is formed of mixture of alloy powder and high
polymeric organic substance binder. For example, the alloy powder
contains 75 wt % copper (Cu), 15 wt % tin (Sn), 5 wt % nickel (Ni)
and 5 wt % phosphorous (P). The brazing material 210 has a melting
point of approximately 600.degree. C.
[0044] After the applying step, a preliminarily fixed assembly of
the core 120 and the core plates 111 is placed in a reducing
atmosphere furnace (not shown) to perform a joining step. FIGS. 4C
and 5C shows this joining step.
[0045] Specifically, the preliminarily fixed assembly is placed
such that a core plane surface is substantially parallel to a
horizontal direction. In other words, the preliminarily fixed
assembly is placed such that the longitudinal directions of the
core plate 111 and the tubes 122 are substantially parallel to the
horizontal direction. Also in this case, the preliminarily fixed
assembly is placed such that the part of the joining portion 122b
to which the brazing material 210 is applied is higher than a
middle portion of the joining portion 122b. That is, the
preliminarily fixed assembly is placed such that each joining
portion 122b is situated in the direction denoted by an up and down
arrow in FIG. 6.
[0046] Further, reducing gas, e.g., hydrogen (H.sub.2), is
introduced into the furnace. The preliminarily fixed assembly is
heated in a temperature condition between 600.degree. C. and
800.degree. C.
[0047] Thus, oxide films on the respective components of the
preliminarily fixed assembly, such as the core plate 111 and the
tubes 122, are removed by the phosphorous contained in the brazing
material 210 and the reducing gas. Further, as the paste brazing
material 210, which has been only applied to the upper portion of
the joining portion 122b, melts, the melted brazing material flows
into a lower portion of the joining portion 122b to which the paste
brazing material 210 has not been applied. Namely, the brazing
material can be filled into the brazing material non-applied
portion in the joining portion 122b with capillarity.
[0048] In the applying step, the paste brazing material 210 is
applied between the inclined surface 111d and the outer surface of
the tube 122, as shown in FIG. 5B. Therefore, the joining portion
122b between the core plate 111 and the tube 120 is effectively
filled with the brazing material 210 in the joining step.
[0049] In the embodiment, the core pate 111 has a coefficient of
liner expansion smaller than that of the tubes 122. Therefore, the
tube 122 relatively moves toward the core plate 111 due to the
difference of liner expansion when heated in the joining step, so a
clearance of the joining portion 122b reduces. Accordingly,
brazability improves.
[0050] Further, since the core plate 111 has the clearance portions
111b, it is less likely that the dispenser 200 having the straight
end will interfere with the outer fins 121 between the tubes 122.
In a case shown in FIG. 11, it is difficult to apply the brazing
material to a relatively wide area of the joining portion, because
the dispenser 200 will interfere with the outer fin 921. Otherwise,
it is necessary to reduce arrangement area of the outer fin 921 at
a position adjacent to the core plate 911. However, this may result
in a decrease of a heat radiation area.
[0051] In the embodiment, the paste brazing material 210 is applied
to a relatively wide area in the joining portion 122b by using the
space P2 defined by the clearance portions 111b of the core plate
111. It is not necessary to reduce the arrangement area of the
outer fin 121. Also, the paste brazing material 210 is applied
after the preliminarily fixing step. Therefore, it is not necessary
to concern about dropping of the paste brazing material 210 in the
preliminarily fixing step. Accordingly, brazability improves
without reducing a heat exchanging capacity.
[0052] In the embodiment, since the intercooler 100 needs the
thermal strength, compressive strength and the like, the components
to be brazed have copper or copper alloy at least on those surfaces
to improve brazability. Also, the surfaces of the core plate 111
and the tubes 122 can be made of nickel, instead of copper and
copper alloy.
[0053] In general, members made of copper or copper alloy reduce
strength with heat in the joining step. In the embodiment,
therefore, the paste brazing material 210 having a relatively low
melting point is used so as to set the temperature relatively lower
in the joining step.
[0054] It is preferable to use a brazing material having the
melting point between 550.degree. C. to 700 C. as the paste brazing
material 210. When a brazing material having the melting point
lower than 550.degree. C. is used, it is difficult to sufficiently
maintain the brazing strength. On the other hand, when a brazing
material having the melting point higher than 700.degree. C. is
used, it is necessary to increase the temperature in the joining
step, resulting in the decrease of strength of the components to be
brazed.
[0055] Further, a copper brazing material having the melting point
between 550.degree. C. to 700.degree. C. is delicate and it is
difficult to clad on the surface of the components to be brazed.
Therefore, it is preferable to use the paste brazing material
having the melting point between 550.degree. C. to 700.degree.
C.
[0056] In the applying step, the paste brazing material 210 is only
applied to the part of the joining portion 122b. In the joining
step, the preliminarily fixed assembly is placed such that the part
to which the paste brazing material 210 is applied is situated
higher than the remaining part to which the brazing material 210 is
not applied. Thus, the paste brazing material 210 flows downward as
melted and the clearance of the joining portion 122b is entirely
filled with the brazing material 220. Accordingly, even if the
paste brazing material 210 is partly applied, brazability can be
maintained.
[0057] In the example of FIG. 6, the paste brazing material 210 is
applied to the joining portion defined between one clearance
portion 111b and the tube 122, and the core plate 111 and the tubes
122 are placed such that the clearance portion 111b to which the
brazing material 210 is applied is higher than the end portion
Further, since the paste brazing material 210 is not applied to the
lower portion of the joining potion 122b, it is less likely that
the paste brazing material will overflow from the lower end of the
joining portion 122b. Thus, the quality of brazing of the joining
portion 122b improves and the amount of brazing material reduces.
Also, as compared with a case that the paste brazing material 210
is entirely applied to the joining portion 122b, work-hour in the
applying step reduces.
Other embodiments
[0058] In the above embodiments, the paste brazing material 210 is
only applied to the upper portion of the joining portion 122b.
However, the brazing material 210 can be also applied to the lower
portion of the joining portion 122b.
[0059] The shape of the core plate 111 is not limited to the
example shown in FIG. 2 as long as the main wall 110b separates
from the center of the core 120 toward its end. In other words, the
shape of the core plate 111 is not limited as long as a space for
permitting the end of the dispenser 200 is provided. FIGS. 7 and 8
show examples of the shape of the core plate.
[0060] In FIG. 7, a core plate 311 has a main wall 310b coupled to
the core 120. The main wall 310b is substantially curved or have a
substantially arc-shaped cross-section. The main wall 310b has an
end portion 311c on the imaginary plane P1 and clearance portions
311b spaced from the imaginary plane P1. The clearance portions
311b have the curved shape. In FIG. 8, a core plate 411 has a main
wall 410b coupled to the core 120. The main wall 410b have a
substantially V-shaped cross-section. For example, the main wall
410b have an end portion 410c on the imaginary plane P1 and
inclined surfaces 411b converging at the end portion 410c. Also in
these examples, spaces for entering the dispenser 200 are
provided.
[0061] Further, in a case that the paste brazing material 210 is
applied only to the upper portion of the joining portion 122b, the
core plate may have only one clearance portion on the side that is
arranged upper side in the joining step. For example, as shown in
FIG. 9, a core plate 511 has an end portion 510c on the imaginary
plane P1 and a clearance portion 511b inclined relative to the
imaginary line P1 to provide a space.
[0062] Also, it is not always necessary that two clearance portions
have the same inclination angle relative to the imaginary plane P1
as shown in FIG. 2. For example, as shown in FIG. 10, a core plate
611 have an end portion 610c on the imaginary plane P1 and two
clearance portions 611b, 611c that are inclined relative to the
imaginary plane P1 at different inclination angles. In the joining
step, the core plate 611 is placed such that the clearance portion
611b that has a larger inclination angle is located higher than the
clearance portion 611c. Further, the core plate may have any other
shape.
[0063] In the above embodiment, the inclined surface 111d is formed
around the perimeter of the tube insertion hole 111a by burring, as
shown in FIG. 5B. However, the method of forming the inclined
surface 111d is not limited to the burring. For example, the
inclined surface 111d may be formed by chamfering.
[0064] In the above embodiment, the tubes 122 are flat tubes, and
the joining portion 122b have a longitudinal axis in a direction
perpendicular to the longitudinal direction of the core plate 111.
This structure is effective in view of strength and the like.
However, the shape of the tubes 122 is not limited to the flat
shape. For example, the tubes 122 may have a substantially circular
cross-sectional shape.
[0065] Further, it is not always necessary that the tubes 122 and
the outer fins 121 are alternately stacked. The core 120 may have
another structure. For example, the core 120 may be configured such
that tubes intersect plate fins.
[0066] In the above embodiment, it is exemplary discussed about the
intercooler 100. However, the present invention can be employed to
other heat exchangers such as an oil cooler.
[0067] In the above embodiment, at least the surfaces of the core
plate 111 and the tubes 122 are made of copper, copper alloy or
nickel. However, the present invention can be applied to a heat
exchanger in which components to be brazed such as core plates and
tubes are made of materials other than copper or nickel.
[0068] The exemplary embodiments of the present invention are
described above. However, the present invention is not limited to
the above embodiments, but may be implemented in other ways without
departing from the spirit of the invention.
* * * * *