U.S. patent application number 11/095712 was filed with the patent office on 2005-10-20 for heat exchanger capable of preventing heat stress.
This patent application is currently assigned to DENSO Corporation. Invention is credited to Ozaki, Tatsuo.
Application Number | 20050230089 11/095712 |
Document ID | / |
Family ID | 35067451 |
Filed Date | 2005-10-20 |
United States Patent
Application |
20050230089 |
Kind Code |
A1 |
Ozaki, Tatsuo |
October 20, 2005 |
Heat exchanger capable of preventing heat stress
Abstract
The object of the present invention is to provide a heat
exchanger which can prevent the tubes from being damaged by the
heat stress caused by the temperature difference between the
reinforcement members and the tubes of the core portion. A heat
exchanger comprises a core portion having a plurality of tubes 12a
and fins 12b which are arrange so as to be alternately laid in
layers. In the core portion 12, the tubes 12a are arranged at the
outermost ends in the piling direction V of the tubes 12a and the
fins 12b and the inserts (14) which reinforce the core portion 12
are fixed to the tubes (12a) and tanks (11, 13).
Inventors: |
Ozaki, Tatsuo;
(Okazaki-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: |
35067451 |
Appl. No.: |
11/095712 |
Filed: |
March 31, 2005 |
Current U.S.
Class: |
165/149 |
Current CPC
Class: |
F28F 2265/26 20130101;
F28F 9/001 20130101; F28D 2021/0096 20130101 |
Class at
Publication: |
165/149 |
International
Class: |
F28D 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 5, 2004 |
JP |
2004-111060 |
Claims
What is claimed is:
1. A heat exchanger comprising: a core portion having a plurality
of tubes through which a first fluid flows and which are arrange so
as to be laid in layers, and fins arranged between a plurality of
the tubes and for promoting heat exchanging between the first fluid
and a second fluid flowing through a space between the tubes; and
tanks arranged at ends of the tubes and communicating with a
plurality of the tubes; and reinforcement members fixed to the
tanks and for reinforcing peripheries of the core portion as well
as the tanks; wherein the reinforcement members and the tubes of a
plurality of the tubes arranged at the outermost ends in a piling
direction of the tubes are arrange so that the tube and the
reinforcement member come into contact with each other.
2. The heat exchanger as set forth in claim 1, wherein the
reinforcement members are integrally fixed to the tubes of the core
portion.
3. The heat exchanger as set forth in claim 1, wherein the
reinforcement members and the tubes are independently and
respectively fixed to the tanks.
4. The heat exchanger as set forth in claim 1; wherein the
reinforcement members are formed in a recess shape a sectional area
of which in a direction perpendicular to a longitudinal direction
of the reinforcement members has a bottom portion and an opening;
wherein on the bottom portion of the recess shape a protrusion
protruding toward an outside of the reinforcement member is formed;
and wherein the protrusion and the tube are formed so as to come
into contact with each other.
5. The heat exchanger as set forth in claim 1; wherein in a state
in which the reinforcement member and the tube are integrally fixed
to each other, when viewing from a direction in which the second
fluid flows into spaces between the tubes, the reinforcement member
is formed to have fixing portions at which the reinforcement member
is in contact with the tube and separated portions at which the
reinforcement member is separated from the tube.
6. The heat exchanger as set forth in claim 1, wherein at least a
part of the reinforcement member is made of a material larger in an
iodization tendency than that of the tubes.
7. The heat exchanger as set forth in claim 1, wherein the
reinforcement member is attached with a sacrificial member made of
a material larger in an iodization tendency than that of the
tubes.
8. The heat exchanger as set forth in claim 1, wherein the tubes
have a thickness of 0.3 mm or less.
9. The heat exchanger as set forth in claim 1, wherein the tube and
the reinforcement member are in contact with each other in a range
of more than half the length in a flowing direction of the second
fluid in the tube.
10. The heat exchanger as set forth in claim 9, wherein the
reinforcement member is formed so that a section of the
reinforcement member perpendicular to a longitudinal direction of
the reinforcement member becomes a U shape having a bottom portion
and an opening portion and the bottom portion is formed to come
into contact with the tube.
11. The heat exchanger as set forth in claim 10 wherein, on a
bottom portion of the reinforcement member, holes penetrating
through the bottom portion are formed.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a heat exchanger and is
effective when applied to a heat exchanger, such as a radiator, for
cooling engine cooling water.
[0003] 2. Description of the Related Art
[0004] A conventional radiator, as shown in FIG. 13 of the patent
document 1, through which a cooling water flows, comprises: a core
portion 12 comprising a plurality of tubes 12a disposed in layers
in the V direction in FIG. 13, and fins 12b arranged between the
tubes 12a; and tanks 11 connected to the ends of the tubes 12a in a
longitudinal direction L thereof which tanks distribute and collect
the cooling water flowing through the tubes 12a. In this
configuration, the heat of the cooling water, having absorbed heat
from an engine, etc. and flowing through the tubes 12a in a high
temperature state, is transmitted to the fins 12b and air flowing
through the fins 12b absorbs the heat transmitted to the fins 12b.
Due to this, the radiator can cool the cooling water.
[0005] Further, the radiator 50 disclosed in the patent document 1
comprises: tanks 11 at the both ends in the direction perpendicular
to the longitudinal direction L of the tubes 12a, that is, in the
direction V in which the tubes 12a and the fins 12b are alternately
laid in layers; and inserts 14 fixed to the core portion 12 and for
reinforcing the core portion 12.
[0006] As a result, the core portion 12 is not damaged by a
deformation thereof, such as torsion, caused by an external force.
In addition, the radiator can attain its inherent role in which it
cools the cooling water flowing through the tubes 12a.
[0007] [Patent Document 1]
[0008] Japanese Utility Model Publication No. 2-92491
[0009] On the other hand, the heat exchanger of the patent document
1 has a structure in which the inserts 14 are integrally fixed to
the fins 12b of the core portion 12, for reasons of manufacturing,
in which, for example, when the tubes 12a and the fins 12b are
joined by brazing, the tubes 12a and the fins 12b can be easily
pressed by the inserts 14.
[0010] Due to this, there may be produced a temperature difference
between the insert 14 fixed to the fin 12b cooled by a cooling air
flow (wind) and the tube 12a through which a high temperature
cooling water flows. In the worst case, the thermal stress produced
by the temperature difference may destroy the thin tubes 12a having
thicknesses less than that of the insert 14.
[0011] In the radiator, a state in which there is no temperature
difference between the insert 14 and the tubes 12a when the engine
is not in operation and another state in which there is the
temperature difference therebetween are alternately repeated and,
as a result, the tubes 12a may be destroyed by the repeated
stress.
SUMMARY OF THE INVENTION
[0012] The present invention has been developed with the
above-mentioned problems being taken into consideration, and the
object thereof is to provide a heat exchanger having a core
portion, in which the tubes and the fins are alternately laid in
layers, and reinforcement members for reinforcing the core portion,
wherein the tubes are prevented from being damaged due to the heat
stress caused by the temperature difference between the
reinforcement members and the tubes of the core portion.
[0013] In order to realize the above-mentioned object, in a first
aspect of the present invention, there is provided with a heat
exchanger having a core portion in which tubes and fins are
alternately arranged in layers and reinforcement members for
reinforcing the core portion and characterized in that in the core
portion (12), the tubes (12a) disposed in the outermost sides in
the piled direction (V) and the reinforcement members (14) are
arranged so as to come into contact with each other.
[0014] In this configuration, the reinforcement members (14) are
arranged so as to be in contact with the tubes (12a) and, therefore
the heat of the tubes (12a) can be transmitted to the reinforcement
members (14). Due to this, compared to the case of the patent
document 1 shown in FIG. 13, where the reinforcement member (14)
and the fin (12b) are arranged to be in contact with each other,
the temperature difference between the reinforcement members (14)
and the tubes (12a) can be made smaller. Therefore, a heat stress
caused by the temperature difference is unlikely to be produced. As
a result, it is possible to prevent the tubes (12a) from being
damaged due to the heat stress.
[0015] According to a second aspect, in the heat exchanger
disclosed in the first aspect, the reinforcement members (14) may
be integrally fixed to the tubes (12a) of the core portion (12), so
that the heat of the tubes (12a) can be transmitted to the
reinforcement members (14) therefrom without fail and, as a result,
the temperature difference can be made smaller.
[0016] According to a third aspect, in the heat exchanger disclosed
in the first or second aspect, a heat exchanger is characterized in
that the reinforcement members (14) and the tubes (12a) are
independently and respectively fixed to independent tanks (11,
13).
[0017] If the tube (12a) and the reinforcement member (14) are
fixed to the tank (11, 13) in a state they are integrally fixed to
each other, the first fluid inside the tanks (11, 13) may leak out
from the tanks (11, 13) at the contacting surface between the
surface of the reinforcement member (14) and the surface of the
tube (12a), etc. Thus, it is difficult to fix the tubes (12a) and
the reinforcement members (14) to the tank (11, 13).
[0018] In the third aspect, however, as the tubes (12a) and the
reinforcement members (14) are fixed to the tanks (11, 13)
independently and respectively, it is possible to fix particularly
the reinforcement members (14) to the tanks (11, 13) easily.
Further, the contacting portions (surfaces) between the surfaces of
the reinforcement members (14) and the surfaces of the tubes (12a)
can be eliminated in the tanks (11, 13) and, as a result, it is
possible to prevent the first fluid inside the tanks (11, 13) from
leaking out therefrom.
[0019] According to a fourth aspect, in the heat exchanger
disclosed in any one of the first to the third aspects, the heat
exchanger is characterized in that the reinforcement members (14)
are formed in a recess shape the sectional area of which in the
direction perpendicular to the longitudinal direction of the
reinforcement members (14) has a bottom portion (14a) and an
opening. In the heat exchanger, on the bottom portion (14a) of the
recess shape a protrusion (14b) protruding toward an outside of the
reinforcement member (14) are formed, and wherein the protrusion
(14b) and the tube (12a) are formed so as to come into contact with
each other.
[0020] In this configuration, as the reinforcement members (14)
having a sectional shape which is stronger against bending force
and torsional force reinforce the core portion (12) together with
the tanks (11, 13), the reinforcement ability (the strength of the
reinforcement) for the core portion can be improved.
[0021] According to a fifth aspect, in the heat exchanger disclosed
in any one of the first to the fourth aspects, the heat exchanger
is characterized in that in a state in which the protrusion (14b)
and the tube (12a) are integrally fixed to each other, when viewing
from the direction (W) in which the second fluid flows into spaces
between the tubes (12a); and in that the reinforcement member (14)
comprises fixing portions (ON) at which the reinforcement member
(14) is in contact with the tube (12a) and separated portions (OFF)
at which the reinforcement member (14) is separated from the tube
(12a).
[0022] In this configuration, when the reinforcement members (14)
and the tubes (12a) are fixed to each other, for example, by
brazing or the like, the brazing material concentrates on the
fixing portions (ON) at which the reinforcement member (14) and the
tube (12a) are in contact with each other and, therefore, the
reinforcement member (14) and the tube (12a) can be more securely
fixed to each other.
[0023] In addition, as the second fluid can pass through the
separated portions (OFF), the heat radiation from the first fluid
flowing through the tubes (12a) integrally fixed to the
reinforcement members (14) can be enhanced. Therefore, it is
possible to improve the heat exchanging ability of the heat
exchanger.
[0024] According to a sixth aspect, in the heat exchanger disclosed
in any one of the first to the fifth aspects, at least a part of
the reinforcement member (14) may be made of a material larger in
an iodization tendency than that of the tube (12a). Due to this,
portions of the reinforcement members (14) formed with a material
larger in an iodization tendency than that of the tubes (12a) can
be corroded earlier than the tubes (12a). As a result, it is
possible to prevent from forming pitting holes in the tubes (12a)
due to corrosion and to prevent the first fluid flowing through the
tubes (12a) from leaking out from the tubes (12a).
[0025] According to a seventh aspect, in the heat exchanger
disclosed in any one of the first to the sixth aspects, the
reinforcement member (14) may be attached with a sacrifice (more
corrosive) member made of a material larger in an iodization
tendency than that of the tubes (12a). As a result, it is possible
to prevent the tubes (12a) from being corroded due to the same
reason as in the fifth aspect.
[0026] According to an eighth aspect, in the heat exchanger
disclosed in any one of the first to the seventh aspects, the heat
exchanger is characterized in that the tubes (12a) have a thickness
of 0.3 mm or less.
[0027] From reasons such as the weight reduction of the heat
exchanger main body and the improvement of the heat transmitting
coefficient from the tubes (12a) to the fins (12b), the plate
thickness of tubes (12a) is reduced so as to provide a thin plate
not more than 0.3 mm. If the construction of the patent document 1
shown in FIG. 13 is formed by using the tubes (12a) with less
thickness, the tubes (12a) are remarkably likely to be damaged due
to the heat stress caused by the temperature difference between the
reinforcement members (14) and the tubes (12a).
[0028] In the eighth aspect however, due to the effects of the
construction described in the first to the sixth aspects, the
temperature difference between the reinforcement members (14) and
the tubes (12a) can be made smaller and, therefore, it is possible
to prevent the tubes (12a) from being damaged even if the plate
thickness of the tubes (12a) is reduced into a thickness not more
than 0.3 mm.
[0029] In a ninth aspect of the present invention, according to the
heat exchanger in any one of the first to third aspects, the tube
(12a) and the reinforcement member (14) are in contact with each
other in a range of more than a half of the length (Lt) along the
flowing direction of the second fluid in the tube (12a).
[0030] According to this aspect, the contacting area of the
reinforcement member and the tube is increased in comparison with
those of the radiator according to the third or the fourth aspect
and therefore, the heat of the tubes is transmitted to the
reinforcement member without fail and it is possible to surely
reduce the temperature difference between the reinforcement member
and the tube. In addition, it is possible to prevent the tube from
being inflated or deformed due to the internal pressure of the
tube, by the reinforcement member.
[0031] Moreover, in a case of the heat exchanger of the third or
the fourth aspect according to the present invention, the wide area
on the surface of the tube near the reinforcement member is exposed
to the outside.
[0032] On the other hand, in the ninth aspect according to the
present invention the area of the exposed surface of the tube near
the reinforcement member is reduced and therefore, the corrosion
resistance quality of the tube is advantageously improved.
[0033] In a tenth aspect of the present invention, according to the
heat exchanger of the ninth aspect, the reinforcement member (14)
is formed so that a section of the reinforcement member
perpendicular to a longitudinal direction of the reinforcement
member (14) becomes a U shape having a bottom portion (14a) and an
opening portion, and the bottom portion (14a) is formed to come
into contact with the tube (12a).
[0034] Due to this, it is possible to effectively transmit heat of
the tube to the wall portion (14c) of the reinforcement member. In
addition, as the reinforcement member having a sectional shape with
higher strength with respect to the bending force and the torsional
force reinforces the core portion together with the tanks it is
possible to improve the reinforcement ability for the core
portion.
[0035] In an eleventh aspect of the present invention, according to
the heat exchanger of the tenth aspect, on a bottom portion (14a)
of the reinforcement member (14), holes (14c) penetrating through
the bottom portion (14a) are formed.
[0036] In this configuration, when the reinforcement member and the
tube are joined with each other by brazing, for example, as the
holes are provided on the reinforcement member the brazing material
gathers into the portions in which the reinforcement member and the
tube are in contact with each other so that it is possible to fix
the reinforcement member to the tube more securely. In addition, it
is possible to check the brazing condition through the holes.
[0037] The symbols in the parenthesis attached to each means
described above indicate a correspondence with the specific means
in the embodiments to be described later.
[0038] The present invention may be more fully understood from the
description of the preferred embodiments of the invention set forth
below, together with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] In the drawings:
[0040] FIG. 1 is a plan view showing a first embodiment of the
present invention in which the present invention is applied to a
radiator.
[0041] FIG. 2 is a plan view of the radiator according to the first
embodiment of the present invention.
[0042] FIG. 3 is an enlarged partial view of C portion in FIG.
1.
[0043] FIG. 4A is a partial sectional view taken along the line A-A
in FIGS. 1 and 3.
[0044] FIG. 4B is a partial sectional view taken along the line B-B
in FIGS. 1 and 3.
[0045] FIG. 5 is a front view of a portion of a radiator according
to a second embodiment of the present invention which corresponds
to C portion in FIG. 1.
[0046] FIG. 6 is a plan view of the portion shown in FIG. 5.
[0047] FIG. 7 is a partial sectional view taken along the line E-E
in FIG. 5.
[0048] FIG. 8 is a perspective view of a radiator according to a
third embodiment of the present invention.
[0049] FIG. 9 is an enlarged perspective view of the F portion in
FIG. 8.
[0050] FIG. 10 is a drawing when viewed from the G arrow direction
in FIG. 9.
[0051] FIG. 11 is a perspective view of main components of a
radiator according to a fourth embodiment of the present
invention.
[0052] FIG. 12 is a perspective view of main components of a
radiator according to a fifth embodiment of the present
invention.
[0053] FIG. 13 is a perspective view of a radiator according to
patent document 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0054] (First Embodiment)
[0055] FIGS. 1 and 2 show a radiator 10 according to a first
embodiment of the present invention. The radiator 10 which cools a
cooling water absorbing heat from a heat source such as an engine,
as is generally known, is mounted on a vehicle, so that the
radiator is supplied with and is collided by a cooling air flow
blown from a blower (not shown) installed on the upstream side in
the air flow. The arrows of the upward and the downward in the
figure indicate the upward direction and the downward direction in
a state in which it is mounted on the vehicle.
[0056] A substantially rectangular prism shaped flow-in side tank
is denoted by the number 11 in the figure and is arranged so that
the longitudinal direction thereof becomes the vertical direction
in the arrangement. Naturally, the top surface and the bottom
surface of the flow-in side tank 11 are closed. The flow-in side
tank 11 is provided with a cylindrical cooling water inlet port
11a. The cooling water inlet port 11a is connected with a rubber
hose (not shown in the figure) through which cooling water flows
which has absorbed heat from a heat source such as an engine and
has become high in a temperature.
[0057] The flow-in side tank 11 is provided with a plurality of
holes (not shown) the number of which corresponds to that of the
tubes 12a. An end of each tube 12a is inserted into a hole. The
other end of the tube 12a is inserted into a hole provided in a
flow-out side tank 13 as is the flow-in side tank 11. The flow-out
side tank 13 has a substantially rectangular prism shape and is
arranged so that the longitudinal direction thereof becomes the
vertical direction V in the arrangement.
[0058] The tube 12a has a flat shape which is reduced in a vertical
direction thereof and fins 12b which are formed in a corrugated
shape are arranged so as to come into contact with the flat
surfaces of the tube 12a. In this configuration, the tubes 12a and
the fins 12b are in a state of being piled up in layers in a
vertical direction V in the figure. An assembly comprising the
tubes 12a and the fins 12b are referred hereinafter as a core
portion.
[0059] The flow-out side tank 13 is provided with a cylindrical
cooling water outlet port 13a. The cooling water outlet port 13a is
connected with a rubber hose (not shown in the figure) through
which a cooling water cooled as described below re-circulates
toward the heat source (an engine).
[0060] These components, such as the cooling water inlet port 11a,
the tanks 11 and 13, the cooling water outlet port 13a, the tubes
12a and the fins 12b, are made of an aluminum alloy, and are
integrally assembled in a unit by brazing, welding or the like.
[0061] In the present embodiment, the tubes 12a are arranged at the
ends of the core portion 12 in the vertical direction V thereof
and, therefore, the tubes 12a can be fixed on the inserts 14 which
are the reinforcement members of the core portion 12. Insertion
holes (not shown) in which the parts for securing, such as bolts,
are inserted when they are used for attaching the radiator 10 to a
vehicle are formed on the inserts 14. Thus the inserts 14 often act
as members on which some components are installed, in addition to
having roles as reinforcement members.
[0062] At first, the shape of the insert 14 is explained with
reference to FIG. 4A. The insert 14 is formed from a plate of
thickness about 1.5 to 2 mm by a pressing process so that the
sectional area of the insert 14 perpendicular to the longitudinal
direction of the inserts 14 (the same direction as the longitudinal
direction L of the tubes 12a) is made in a recess shape having a
bottom portion 14a and an opening. Further, on the bottom portion
14a of the insert 14, the insert 14 is provided with a protrusion
14b protruding toward the outside direction of the insert 14 (the
downward direction in FIG. 4A). Due to the protrusion 14b, the
sectional area of the insert 14 perpendicular to the longitudinal
direction of the inserts 14 is made in a shape which has steps and
the width is narrowed to form two steps.
[0063] The surface of a plate of the insert 14 which is the side
from which the protrusion 14b protrudes (the surface on the side
contacting the tube 12a) is clad with a material, such as titanium,
copper, or the alloy thereof, that has an ionization tendency
larger than that of an aluminum alloy which makes up the tubes 12a,
etc.
[0064] Next, the fixing structure of the insert 14 and the tube 12a
is explained. The insert 14 and the tube 12a are integrally fixed
by the brazing, welding or the like as described above, at an area
thereof nearer the center of the core portion 12 from voluntary
point D (refer to FIG. 3 and FIG. 4A) in the longitudinal direction
L of the tubes 12a. On the other hand, the insert 14 and the tube
12a are not integrally fixed and are separated with each other at
an area outside of the core portion 12 from the point D (refer to
FIG. 4B) and are fixed to the tank 13 independently with each other
in a separated state.
[0065] FIG. 3 shows a fixing structure in which the insert 14 is
fixed to the flow-out side tank 13 and the tubes 12a are fixed to
the flow-out side tank 13. The fixing structure in which the
inserts 14 are fixed to the flow-in side tank 11 and the tubes 12a
are fixed to the flow-in side tank 11 are the same.
[0066] Next, the operation of the present embodiment in the above
configuration is explained. The cooling water of high temperature
absorbing heat from the heat source such as an engine flows into
the flow-in side tank 11 from the cooling water inlet port 11a. The
cooling water then is divided to flow into a plurality of the tubes
12a from the flow-in side tank 11 and flows toward the flow-out
side tank 13. At this time, the heat of the cooling water flowing
through the tubes 12a is transmitted to the fins 12b and the air
(indicated by the arrow W) flowing through the fins 12b absorbs the
transmitted heat. Thus, the cooling water which is cooled and is
brought into a low temperature state flows into the flow-out side
tank 13.
[0067] The cooling water which flows from the respective tubes 12a
and is gathered into the flow-out side tank 13 returns from the
outlet port 13a to the engine (the heat source).
[0068] The functions and effects of the first embodiment are listed
below.
[0069] (1) As the tubes 12a are arranged on the ends of the core
portion 12 in the vertical direction V thereof and are fixed on the
inserts 14 which are the reinforcement members of the core portion
12, the tubes 12a can be prevented from being damaged by thermal
stress caused by a temperature difference between the tubes 12a and
the inserts 14.
[0070] Due to this construction, compared to the prior art shown in
FIG. 8 and having a construction in which the inserts 14 and fins
12b are fixed to each other, the temperature difference between the
tubes 12a and the inserts 14 can be made smaller. Therefore, heat
stress caused by the temperature difference is unlikely to be
produced so that the tubes 12a are prevented from being damaged by
the heat stress.
[0071] In addition, the heat of the tubes 12a integrally fixed to
the inserts 14 is transmitted to the inserts 14 and therefore, the
heat radiation ability of the tubes 12a can be enhanced.
[0072] Moreover, compared to the prior art, the number of the tubes
12a are increased (to a total two, upper and lower) by fixing the
tubes 12a to the inserts 14 because the tubes 12a occupy only a
small space. Therefore, the passage area (the total sectional area
of the tubes) through which the cooling water flows is increased so
that the flow resistance of the cooling water can be reduced.
[0073] The conventional fins 12b integrally fixed with the
conventional inserts 14, that is, the fins 12b provided on the both
ends (the upper end and the lower end) in the piling direction V,
has a low heat radiation efficiency because only one side of the
fin 12b is in contact with the tube 12a which is the heat source.
On the other hand, in the present embodiment, as the tubes 12a are
provided on the both ends in the piling direction V, the both sides
of all fins 12b are in contact with the tubes 12a which are the
heat source. Therefore, the heat radiation efficiency of the fins
12b on the both ends (an upper end and a lower end) in the piling
direction V can be improved.
[0074] These effects can be realized with substantially no change
of the dimension of the layers of the tubes 12a and fins 12b in the
piling direction V thereof. Exactly speaking, the dimension of the
layers is increased in the piling direction V by the size of two
tubes 12a but the size of the tube 12a in the piling direction V is
around a few millimeters. In addition, these effects are
particularly remarkable in the case where the thickness of the tube
12a is reduced to 0.3 mm or less because of a recent tendency in
which the weight of the main body of a heat exchanger has been
reduced, the heat transmitting coefficient from the tube 12a to the
fin 21b has been improved, and the like.
[0075] (2) As the respective inserts 14 and the respective tubes
12a are independently fixed to the tanks 11 and 13, the inserts 14
and tanks 11, 13, and the tubes 12a and tanks 11, 13 can be fixed
without leakage of the cooling water.
[0076] On the other hand, when the ends of the insert 14 and the
tube 12 integrally connected to each other are inserted into the
holes on the tanks 11 and 13 and the inserted ends are fixed by
brazing, welding or the like, the cooling water in the tanks 11, 13
may leak out therefrom at the contacting surface between the
surface of the insert 14 and the surface of the tube 12a, or the
like.
[0077] To the contrary, in the present embodiment, the insert 14
and the tube 12a are independently and respectively fixed to the
tanks 11 and 13 so that there is no contacting surface between the
surface of the insert 14 and the surface of the tube 12a from which
contacting surface the cooling water may leak out. Therefore, the
inserts 14 can be easily fixed to the tanks 11, 13 without a
leakage of the cooling water.
[0078] (3) The insert 14 is formed in a sectional shape the width
of which is narrowed to form two steps (refer to FIG. 4A), that is
stronger against a bending force and a torsional force, and the
protrusion 14b is fixed to the flat surface of the tube 12a and,
therefore, the reinforcement ability of the core portion 12 can be
further improved. The expression "stronger against a bending force
and a torsional force" has the same meaning as the expression "the
geometric moment of inertia is larger".
[0079] (4) As the protrusion 14b of the insert 14 contacted with
and fixed by the tube 12a is clad with a material larger in an
ionization tendency than that of the material making up the tube
12a, the corrosion resistance of the tube 12a can be improved.
[0080] If the tube 12a is corroded and forms pitting holes, the
cooling water naturally leaks out therefrom. Because of this, in
the present embodiment, the side surfaces of the protrusion 14b of
the insert 14 are clad with a material such as titanium, copper or
alloy thereof larger in an ionization tendency than that of an
aluminum alloy making up the tube 12a, etc. By this configuration,
the clad material larger in an ionization tendency than that of the
tubes 12a is corroded earlier than the tubes 12a and therefore, the
tubes 12a are prevented from being corroded, in other words, the
anti-corrosive ability of the tubes 12a can be improved.
[0081] (Second Embodiment)
[0082] A radiator according to a second embodiment has
substantially the same configuration as that of the first
embodiment but the shape of the inserts 14 is different from that
of the first embodiment. The inserts 14 of the first embodiment
have a constant sectional shape (refer to FIG. 4A) at the positions
nearer to the center side of the core portion than D point in FIG.
3.
[0083] On the other hand, the inserts 14 of the present invention
when viewing them from the direction from which the cooling air
flows into the core portion (that is, the vertical direction on the
paper of FIG. 5), are formed to have fixing portions (corresponding
to ON portions in FIGS. 5 and 6) in which the insert 14 and a tube
12a are in contact with and fixed to each other and separated
portions (corresponding to OFF portion in FIGS. 5 and 6) in which
the insert 14 and the tube 12a are separated from each other.
[0084] At the fixing portions ON, the insert 14 has a sectional
shape the width of which is narrowed to form two steps, as shown in
FIG. 4A and, on the other hand, at the separated portions OFF the
insert 14 has a sectional shape like a recess as shown in FIG. 7.
The fixing portions ON and the separated portions OFF are
alternately provided in the longitudinal direction L of the tubes
12a.
[0085] According to this construction, in a case where the insert
14 and the tube 12a are fixed to each other, for example, by
brazing, as a brazing material is collected in the fixing portions
ON where the insert 14 and the tube 12a are in contact with each
other, the insert 14 and the tube 12a can be more securely fixed to
each other.
[0086] Moreover, as the cooling air can pass through the separated
portions OFF the heat can be promoted to be radiated from the
cooling water flowing through the tube 12a integrally fixed with
the insert 14. Therefore, the radiation ability of the radiator can
be enhanced.
[0087] This embodiment can perform the same functions and effects
(1) to (4) as described in the first embodiment.
[0088] (Third Embodiment)
[0089] A third embodiment of the present invention will be
explained below. FIG. 8 shows a perspective view of a radiator
according to the third embodiment of the present invention, FIG. 9
shows an enlarged perspective view of F portion in FIG. 8, and FIG.
10 shows a drawing when viewed in the G arrow direction in FIG. 9.
In those figures, parts of this embodiment, the same as or
equivalent to those of the first embodiment, are denoted with the
same symbols attached thereto and these parts are not explained
here.
[0090] In each embodiment described above, the cooling water inlet
port 11a, the tanks 11 and 13, the cooling water outlet port 13a,
the tubes 12a and the fins 12b are made of an aluminum alloy,
however in the present embodiment, parts of the tanks 11, 13, the
cooling water inlet port 11a, and the cooling water outlet port 13a
are made of a resin, such as a nylon or the like.
[0091] As shown in FIGS. 8 and 9, a flow-in side tank 11 for
cooling water comprises a tank body 111 having a substantially
rectangular columnar shape with an open portion at one of the faces
thereof, and a plate-shaped core plate 112 closing the open portion
of the tank body 111. The tank body 111 is made of a resin and is
integrally formed with the cooling water inlet port 11a. The core
plate 112 is made of an aluminum alloy.
[0092] The tank body 111 and the core plate 112 are integrated with
each other by calking the outer peripheries of the core plate 112.
An O-ring (not shown in the figures) for sealing is installed
between the tank body 111 and the core plate 112.
[0093] The holes (not shown in the figures) into which the tubes
12a are inserted are formed on the core plate 112 and one end of
the tube 12a is inserted into the hole. A protruding piece 112a
which fixes the insert 14 by calking is formed on the core plate
112.
[0094] The flow-out side tank 13 for cooling water has a similar
configuration as that of the flow-in side tank 11 and comprises a
tank body 131, a core plate 132 and an O-ring (not shown in the
figures), and protruding pieces 132a are formed on the core plate
132.
[0095] The inserts 14 which are made by pressing a plate material
made of an aluminum alloy and a section perpendicular to the
longitudinal direction of the insert 14 (the same direction as the
longitudinal direction L of the tubes 12a) as shown in FIG. 10 is
formed so that it becomes a U shape having a flat bottom portion
14a and an opening portion.
[0096] The length Li of the insert 14 along the air flowing
direction is made substantially equal to the length Lt of the tube
12a along the air flowing direction and thereby, the contacting
area of the insert 14 and the tube 12a is maintained sufficiently
by joining the bottom portion 14a of the insert 14 to the flat
surface of the tube 12a by brazing, welding or the like.
[0097] The bottom portion 14a of the insert 14 and the flat surface
of the tube 12a are in contact with each other in a range more than
a half of the length Lt of the tube 12a, in the air flowing
direction, and desirably in a range more than two third of the
length Lt.
[0098] As shown in FIG. 8 and FIG. 9, on the bottom portion 14a
holes 14c are formed which penetrate through the bottom portion
14a. A number of the holes 14c having an oval shape the long side
of which is parallel to the longitudinal direction of the insert 14
are arranged along the longitudinal direction of the insert 14.
[0099] Installation pieces 14d which extend from the bottom portion
14a and are bent in a L shape are formed on the both ends in the
longitudinal direction of the insert 14. In detail, the
installation piece 14d extend toward the tank 11 or 13 and in a
state parallel to the longitudinal direction L of the tube 12a
after extending toward the opposite side of the tube 12a (the
outside of the lamination direction of the tubes) from the bottom
portion 14a.
[0100] The installation pieces 14d are held in a sandwiched state
between the main body of the core plate 112, 132 and the protruding
piece 112a, 132a by calking the protruding piece 112a, 132a of the
core plate 112, 132.
[0101] According to the present embodiment, the parts of the tanks
11, 13, the cooling water inlet port 11a and the cooling water
outlet port 13a are made of a resin and therefore, the weight of
the radiator can be reduced and the cost thereof can be
reduced.
[0102] As the bottom portion 14a of the insert 14 and the flat
surface of the tube 12a are made to come into contact with each
other in a range of more than a half of the length Lt of the tube
12a along the air flowing direction, the contact area of the insert
14 and the tube 12a in this embodiment is increased in comparison
with those of the radiators according to the first and the second
embodiments and therefore the heat of the tubes 12a is transmitted
to the insert 14 without fail and it is possible to surely reduce
the temperature difference between the insert 14 and the tube
12a.
[0103] In addition, it is possible to prevent the tubes 12a from
being inflated or deformed due to the internal pressure of the
tubes, by using the insert 14.
[0104] The area of the exposed surface of the tube 12a at the
insert 14 side is reduced in comparison with those of the radiators
according to the first and the second embodiments and therefore,
the corrosion resistance of the tubes 12a is advantageously
improved.
[0105] As the insert 14 which has a sectional shape with higher
strength with respect to the bending force and the torsional force
reinforces the core portion 12 together with the tanks 11, 13, it
is possible to improve the reinforcement performance of the core
portion 12.
[0106] When the insert 14 and the tube 12a are joined with each
other by brazing as the holes 14a are provided on the insert 14 the
brazing material gathers into the portions in which the insert 14
and the tube 12a are in contact with each other (in which there is
no hole 14a) it is possible to fix the insert 14 to the tube 12a
more surely. In addition, it is possible to check the brazing
condition through the holes 14c.
[0107] As the insert 14 and the tube 12a are independently fixed to
the tanks 11, 13 respectively, it is possible to join the insert 14
and the tubes 12a with the tanks 11, 13 without leakage of the
cooling water.
[0108] (Fourth Embodiment)
[0109] A fourth embodiment of the present invention will be
explained below. FIG. 11 shows a perspective view of main
components (corresponding to the F portion in FIG. 8) of a radiator
according to the fourth embodiment of the present invention. In the
figures, the parts of the embodiment same as or equivalent to those
of the third embodiment are denoted with the same symbols attached
thereto and these parts are not explained here.
[0110] As shown in FIG. 11, installation pieces 14d extending from
the bottom portion 14a are provided on the both ends in the
longitudinal direction of the insert 14. More specifically, the
installation piece 14d extends in an oblique direction from the
bottom portion 14a toward the tank 11 or 13 and at the opposite
side of the tube 12a (to the outside in the lamination direction V
of the tubes).
[0111] On the core plate 112 holes (not shown in the figure) into
which the installation pieces 14d are inserted are formed and the
ends of the installation pieces 14d are inserted into the
holes.
[0112] The holes into which the installation pieces 14d are
inserted are independently provided and separated from the holes
into which the tubes 12a are inserted. Though not shown in the
figure, the holes (not shown in the figure) into which the
installation pieces 14d are inserted are formed on the core plate
132 of the flow-out side tank 13 and the ends of the installation
pieces 14d are inserted into the holes.
[0113] According to this embodiment, the insert 14 and the tube 12a
are independently fixed to the tanks 11, 13 respectively, so that
it is possible to join the insert 14 and the tube 12a with the
tanks 11, 13 without the leakage of cooling water.
[0114] (Fifth Embodiment)
[0115] A fifth embodiment of the present invention will be
explained below. FIG. 12 shows a perspective view of main
components (portions corresponding to the F portion in FIG. 8) of a
radiator according to the fourth embodiment of the present
invention. In the figures, the parts of the embodiment same as or
equivalent to those of the third and fourth embodiments are denoted
with the same symbols attached thereto and these parts are not
explained here.
[0116] Though in the fourth embodiment, the insert 14 and the tube
12a are independently fixed to the holes formed on the core plate
112, 132 respectively, as shown in FIG. 12, the end of the insert
14 and the end of the tube 12a both may be inserted into one hole
formed on the core plate 112, 132 so as to be fixed to the hole by
brazing, welding or the like.
[0117] (Other Embodiments)
[0118] In the embodiments described above, the radiator 10 in which
the cooling water absorbing heat from a heat source is made to
radiate heat are used as an example of the heat exchanger, but the
heat exchanger may be a condenser in which a gas-phase refrigerant
is condensed into a liquid-phase refrigerant by heat exchanging in
the heat exchanger. Further, the effects of the present invention
can be naturally realized in a heat exchanger in which a
liquid-phase refrigerant is evaporated into a gas-phase refrigerant
by the heat exchanging in the heat exchanger, that is, an
evaporator.
[0119] In the above-mentioned embodiments, the examples in which
the inserts 14 and the tubes 12a are fixed to each other by
brazing, welding, or the like are shown but the effects of the
present invention can be performed even in a case where the inserts
14 and the tubes 12a come into contact with each other.
[0120] In the above-mentioned embodiments, the examples in which
the tanks 11 and 13 are arranged at the both ends of the tubes 12a
are shown but a configuration in which the tubes are formed in a U
shape and the fluid flows out from and into one tank may be
applied. In this case, the inside space of the tank is necessarily
separated into a flow-out space and a flow-in space.
[0121] In the above-mentioned embodiments, an example in which the
fixing surfaces (the protrusions 14b) at which the insert 14 and
the tube 12a are fixed to each other are clad with a material
larger in an ionization tendency than that of the tubes 12a are
shown but on the reverse side of the tube 12a, that is, on the
bottom surface 14a side of the insert 14a material may be clad.
Alternatively, an independent part (for example, a plate material)
which is made of a material larger in an ionization tendency may be
integrally fixed to the insert 14.
[0122] Further alternatively, the insert 14 itself may be made of a
material larger in an ionization tendency. The basic material
making up the insert 14 may be added with a material larger in an
ionization tendency by a specific ratio with respect to the basic
material, thereby making a part including the material having
larger ionization tendency by a higher ratio (more rich) corrode
first.
[0123] Though in the third to the fifth embodiment, the holes 14c
are formed on the bottom portion 14a of the insert 14, the holes
14c may not be formed on the bottom portion 14a of the insert 14.
In this case, the contacting area of the insert 14 and the tube 12a
is further increased.
[0124] While the invention has been described by reference to
specific embodiments chosen for the purposes of illustration, it
should be apparent that numerous modifications could be made
thereto, by those skilled in the art, without departing from the
basic concept and scope of the invention.
* * * * *