U.S. patent application number 13/003831 was filed with the patent office on 2011-06-09 for heat exchanger and method of manufacturing same.
This patent application is currently assigned to TOYOTA JIDOSHA KABUSHIKI KAISHA. Invention is credited to Hirofumi Inoshita, Hirohito Matsui, Masahiro Morino, Yasuji Taketsuna.
Application Number | 20110132591 13/003831 |
Document ID | / |
Family ID | 41570290 |
Filed Date | 2011-06-09 |
United States Patent
Application |
20110132591 |
Kind Code |
A1 |
Morino; Masahiro ; et
al. |
June 9, 2011 |
HEAT EXCHANGER AND METHOD OF MANUFACTURING SAME
Abstract
Provided are a heat exchanger having a novel structure and
efficiently cooling a heat generating body, and a method of
manufacturing the heat exchanger. A heat exchanger has flow paths
formed by being closed by an upper plate and a lower plate which
have rectilinearly formed upstanding fins parallelly arranged at
specific intervals, and gaps extend between adjacent fins in the
top-bottom direction along the direction in which the fins extend.
Either of or both the upper plate and the lower plate are provided
with projections arranged in the longitudinal direction of the flow
path and projecting inward of the flow path.
Inventors: |
Morino; Masahiro;
(Okazaki-shi, JP) ; Taketsuna; Yasuji;
(Okazaki-shi, JP) ; Inoshita; Hirofumi;
(Nagoya-shi, JP) ; Matsui; Hirohito; (Okazaki-shi,
JP) |
Assignee: |
TOYOTA JIDOSHA KABUSHIKI
KAISHA
Toyota-shi
JP
NIPPON SOKEN, INC.
Nishio-shi
JP
|
Family ID: |
41570290 |
Appl. No.: |
13/003831 |
Filed: |
July 14, 2009 |
PCT Filed: |
July 14, 2009 |
PCT NO: |
PCT/JP2009/062701 |
371 Date: |
January 12, 2011 |
Current U.S.
Class: |
165/185 |
Current CPC
Class: |
F28F 3/12 20130101; F28F
13/06 20130101; H01L 2924/0002 20130101; B21D 53/04 20130101; F28F
3/02 20130101; H01L 2924/0002 20130101; H01L 2924/00 20130101; H01L
23/473 20130101 |
Class at
Publication: |
165/185 |
International
Class: |
F28F 3/00 20060101
F28F003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 24, 2008 |
JP |
2008-190946 |
Claims
1. A heat exchanger having a plurality of upstanding fins formed
linearly and arranged in parallel with each other at predetermined
intervals, and an upper plate and a lower plate placed top and
bottom in an upstanding direction of the fins to enclose spaces
between the adjacent fins to provide a plurality of passages
defined by the enclosed spaces, wherein at least one of the upper
and lower plates includes a plurality of protrusions arranged in a
longitudinal direction of each passage to protrude therein, and the
protrusions formed in the adjacent passages are arranged in a
staggered pattern in a direction perpendicular to a flat surface of
the passages.
2. The heat exchanger according to claim 1 having: a fin member
including the fins integrally formed on a base constituting either
one of the upper and lower plates; and a cover plate constituting
the other one of the upper and lower plates which is connected to
the fins in an opposite side from the base, wherein the protrusions
are formed on either the base or the cover plate.
3. The heat exchanger according to claim 2, wherein the fin member
is formed by extrusion-molding.
4. The heat exchanger according to claim 3, wherein the protrusions
are formed by press working.
5. The heat exchanger according to claim 1, wherein ones of the
protrusions adjacently arranged in a longitudinal direction of each
passage are placed at such intervals as to prevent cooling
performance to be generated between the protrusions from falling
below a predetermined reference value.
6. A heat exchanger including a plurality of upstanding fins formed
linearly and arranged in parallel with each other at predetermined
intervals and an upper plate and a lower plate placed top and
bottom in an upstanding direction of the fins to enclose spaces
between the adjacent finds to provide a plurality of passages
defined by the enclosed spaces, wherein one of the upper and lower
plates includes a plurality of protrusions protruding into the
passages in a longitudinal direction thereof; the heat exchanger
includes: a fin member including the fins integrally formed on a
base constituting either one of the upper and lower plates; and a
cover plate constituting the other one of the upper and lower
plates which is connected to the fins in an opposite side from the
base, the protrusions being formed on either the base or the cover
plate; the fin member is formed by extrusion-molding; the
protrusions are formed by press-fitting a punch in the base or the
cover plate on an opposite side from a passage surface to extrude a
material toward the passage surface side; and when the protrusions
are to be formed, a plate-shaped holding member is inserted in the
spaces between the adjacent fins to hold the fins.
7. A heat exchanger including a plurality of passages defined by a
plurality of upstanding fins formed linearly in parallel having
predetermined spaces and an upper plate and a lower plate placed
top and bottom in an upstanding direction of the fins to enclose
the spaces between the adjacent fins, wherein one of the upper and
lower plates includes a plurality of protrusions protruding into
the passages in a longitudinal direction thereof; the heat
exchanger includes: a fin member including the fins integrally
formed on a base constituting either one of the upper and lower
plates; and a cover plate constituting the other one of the upper
and lower plates which is connected to the fins in an opposite side
from the base, the protrusions being formed on either the base or
the cover plate; the fin member is formed by extrusion-molding, the
fin member is formed as an intermediate fin member having raised
portions each continuous in the extruding direction in each space
between the adjacent finds; and the protrusion are formed by
inserting pressing plates separately formed in the extruding
direction into the spaces to squash the raised portions except
separating portions to form the protrusions.
8-10. (canceled)
Description
[0001] This is a national phase application filed under 35 U.S.C.
371 of PCT/JP2009/062701 filed on Jul. 14, 2009, which claims the
benefit of priority from the prior Japanese Patent Application No.
2008-190946 filed on Jul. 24, 2008, the entire contents of all of
which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a heat exchanger provided
with passages defined by a plurality of straight fins arranged in
parallel, the heat exchanger being configured to allow a
refrigerant or cooling medium to pass through the passages to
thereby dissipate heat from a heating element. Particularly, the
invention relates to a heat exchanger in which passages for
allowing a refrigerant to pass are formed to enhance heat
dissipation effect and a method of manufacturing the heat
exchanger.
BACKGROUND OF THE INVENTION
[0003] Hybrid electric vehicles or the like incorporate a
semiconductor device in an inverter to drive a motor, and a
water-cooling heat exchanger is adopted for cooling the
semiconductor device. With respect to the inverter mounting the
semiconductor device, higher output power has been desired while a
reduction in size and weight also has been demanded increasingly.
Accordingly, a demand for a heat exchanger excellent in a heat
dissipation effect has been increased. Patent Literature I
described below discloses a conventional heat exchanger having
improved cooling performance. FIG. 16 is a sectional view of a heat
exchanger of Patent Literature 1 in a plan view.
[0004] A heat exchanger 100 includes a case 101 provided with a
supply port 102 and a discharge port 103. In the case 101, passages
(flow paths) are formed to allow a refrigerant to pass from the
supply port 102 to the discharge port 103. In this heat exchanger
100, the passages are defined by a plurality of fins 111 and the
passages are divided into three in the linear direction; first,
second, and third fin groups 201, 202, and 203. Each of the fin
groups 201 to 203 includes a plurality of the fins 111 arranged in
parallel with the lateral direction. The fins 111 of each fin group
201 to 203 are arranged in alignment with those of the adjacent fin
groups to form a plurality of straight passages. The straight flow
passages are however interrupted in between the fin groups 201,
202, and 203 and merging sections 105 and 106 are formed there.
[0005] Further, the heat exchanger 100 is provided with separating
fins 112 placed between the laterally extending fins 111 to form a
wide passage 107 wider than the passages defined between the fins
111. In the third fin group 203, two adjacent separating fins 112
are connected to close one end of the passage 107. Then, in this
heat exchanger 100, semiconductor devices serving as heating
elements are placed respectively in nine sections partitioned by
the merging sections 105 and 106 and the separated passage 107
defined by the separating fins 112. To be specific, in the heat
exchanger 100, the refrigerant taken into the exchanger 100 from
the supply port 102 passes through the linear passages formed
between the fins 111. Multiple refrigerant flows join together at
the merging sections 105 and 106 to equalize flow distribution and
then diverge into downstream passages.
Patent Literature
[0006] Patent Literature 1: JP2007-335588A
SUMMARY OF INVENTION
Technical Problem
[0007] When the passages defined by the fins are straight as in the
heat exchanger 100, the refrigerant is apt to flow in laminar flow.
Therefore, while the refrigerant flows fast in the central portion
of each passage, the flow is slow in boundary layers or areas where
the refrigerant contacts with the fins 111. As a result, the heat
of each heating element transferred to the fins is hard to be
dissipated, interfering enhancement of the cooling performance.
With regard to this point, an effective way to efficiently
dissipate the heat from the fins by the refrigerant is to break the
boundary layers by disturbing the flow of the refrigerant. However,
traversing passages like the merging sections 105 and 106 in the
heat exchanger 100 are not enough to achieve the above effect.
[0008] In recent years, a semiconductor device tends to have larger
heat generating density because of its reduced size. This leads to
a demand for improvement of the cooling performance of the heat
exchanger to be used in an inverter or the like. In response to
that, the heat exchanger in which the fins are arranged in an
offset pattern has been proposed. However, the heat exchanger
having such offset fin arrangement requires complicated working,
leading to an increase in manufacturing cost. Especially, when the
conventional fin member is formed by casting or other methods, a
high processing cost is needed, which results in a high cost of the
heat exchanger itself. Further, such fin member is hard to finely
machine and thus the improvement of cooling performance could not
be achieved.
[0009] The present invention has been made to solve the above
problems and has a purpose to provide a heat exchanger having a
novel structure capable of efficiently cooling a heating element
and a manufacturing method of the heat exchanger.
Solution to Problem
[0010] According to one aspect of the present invention, there is
provided a heat exchanger having a plurality of upstanding fins
formed linearly and arranged in parallel with each other at
predetermined intervals, and an upper plate and a lower plate
placed top and bottom in an upstanding direction of the fins to
enclose spaces between the adjacent fins to provide a plurality of
passages defined by the enclosed spaces, wherein at least one of
the upper and lower plates includes a plurality of protrusions
arranged in a longitudinal direction of each passage to protrude
therein, and the protrusions formed in the adjacent passages are
arranged in a staggered pattern in a direction perpendicular to a
flat surface of the passages.
[0011] Further, in the above heat exchanger, it is preferable that
the heat exchanger has: a fin member including the fins integrally
formed on a base constituting either one of the upper and lower
plates; and a cover plate constituting the other one of the upper
and lower plates which is connected to the fins in an opposite side
from the base, wherein the protrusions are formed on either the
base or the cover plate.
[0012] In the above heat exchanger, preferably, the fin member is
formed by extrusion-molding.
[0013] In the above heat exchanger, preferably, the protrusions are
formed by press working.
[0014] In the above heat exchanger, preferably, ones of the
protrusions adjacently arranged in a longitudinal direction of each
passage are placed at such intervals as to prevent cooling
performance to be generated between the protrusions from falling
below a predetermined reference value.
[0015] According to another aspect of the invention, there is
provided a heat exchanger including a plurality of upstanding fins
formed linearly and arranged in parallel with each other at
predetermined intervals and an upper plate and a lower plate placed
top and bottom in an upstanding direction of the fins to enclose
spaces between the adjacent fins to provide a plurality of passages
defined by the enclosed spaces, wherein one of the upper and lower
plates includes a plurality of protrusions protruding into the
passages in a longitudinal direction thereof; the heat exchanger
includes: a fin member including the fins integrally formed on a
base constituting either one of the upper and lower plates; and a
cover plate constituting the other one of the upper and lower
plates which is connected to the fins in an opposite side from the
base, the protrusions being formed on either the base or the cover
plate; the fin member is formed by extrusion-molding; the
protrusions are formed by press-fitting a punch in the base or the
cover plate on an opposite side from a passage surface to extrude a
material toward the passage surface side; and when the protrusions
are to be formed, a plate-shaped holding member is inserted in the
spaces between the adjacent fins to hold the fins.
[0016] According to another aspect of the invention, there is
provided a method for manufacturing a heat exchanger including a
plurality of upstanding fins formed linearly in parallel with
having predetermined spaces and an upper plate and a lower plate
placed top and bottom in an upstanding direction of the fins to
enclose spaces between the adjacent fins, wherein one of the upper
and lower plates includes a plurality of protrusions protruding
into the passages in a longitudinal direction thereof; the heat
exchanger includes: a fin member including the fins integrally
formed on a base constituting either one of the upper and lower
plates; and a cover plate constituting the other one of the upper
and lower plates which is connected to the fins in an opposite side
from the base, the protrusions being formed on either the base or
the cover plate; the fin member is formed by extrusion-molding; the
fin member is formed as an intermediate fin member having raised
portions each continuous in the extruding direction in each space
between the adjacent fins; and the protrusions are formed by
inserting pressing plates separately formed in the extruding
direction into the spaces to squash the raised portions except
separating portions to form the protrusions.
Advantageous Effects of Invention
[0017] According to a heat exchanger of the invention, a
refrigerant flowing through passages is disturbed its flow by
protrusions so that boundary layers contacting with fins are
broken, and thereby the refrigerant deriving heat from the fins
smoothly flows downstream without causing stagnation. Accordingly,
the cooling performance is enhanced. Therefore, even when the heat
generating density has been increased due to a small-sized heating
element, the heating element can be cooled compared to the
conventional one because the cooling performance has been improved.
Further, the heat exchanger of the invention is simply configured
in a manner that passages defined by straight fins are provided
with protrusions, simplifying its structure and working and leading
to cost reduction in manufacturing operation. In particular, the
heat exchanger in the invention is manufactured by applying a fin
member formed by extrusion-molding and a base and a cover plate
formed with protrusions by pressing, so that mass production of the
heat exchanger is achieved, capable of supplying the heat exchanger
at low cost.
BRIEF DESCRIPTION OF DRAWINGS
[0018] FIG. 1 is a perspective view of a heat exchanger according
to an embodiment;
[0019] FIG. 2 is a perspective view of the heat exchanger from
which a holding frame is removed;
[0020] FIG. 3 is a perspective view of a fin member of the heat
exchanger;
[0021] FIG. 4 is a diagram showing a flow of a refrigerant flowing
inside a passage of the heat exchanger;
[0022] FIG. 5 is a graph showing a result of a cooling performance
test conducted by flowing the refrigerant inside the passage of the
heat exchanger;
[0023] FIG. 6. is a perspective view of the heat exchanger in use
state;
[0024] FIG. 7 is a conceptual view showing one step of a working
process to form the fin member for the heat exchanger;
[0025] FIG. 8 is a sectional view of a press device for forming
protrusions;
[0026] FIG. 9 is a perspective view of a heat exchanger from which
a holding frame is removed in another embodiment;
[0027] FIG. 10 is a simplified diagram showing a working process of
forming protrusions in the fin member shown in FIG. 9;
[0028] FIG. 11 is a plan view showing one example of arrangement of
the protrusions in the passages;
[0029] FIG. 12 is a sectional view of a press device for forming
protrusions;
[0030] FIG. 13 is a perspective view showing a method of forming
the protrusions by pressing;
[0031] FIG. 14 is a sectional view of the fin member immediately
after the extrusion-molding before the protrusions are to be formed
as shown in FIG. 13;
[0032] FIG. 15 is a perspective view of the fin member formed with
the protrusions formed by the method shown in FIG. 13; and
[0033] FIG. 16 is a planar sectional view of a conventional heat
exchanger.
DETAILED DESCRIPTION OF EMBODIMENTS
[0034] A detailed description of a preferred embodiment of a heat
exchanger and a method of manufacturing the same embodying the
present invention will now be given referring to the accompanying
drawings. FIG. 1 is a perspective view showing a heat exchanger of
the present embodiment.
[0035] A heat exchanger 1 includes a plurality of fins 11 arranged
in a main body 2 formed in a rectangular tubular shape. The main
body 2 has an inlet-side opening 21 and an outlet-side opening
which open at both ends to form a plurality of passages 3. In the
main body 2 of the heat exchanger 1, a refrigerant is allowed to
flow in a direction indicated by an arrow Q in the figure, thus the
passages 3 extend through from the inlet-side opening 21 to the
outlet-side opening.
[0036] In the heat exchanger 1 shown in FIG. 1, the inlet-side
opening 21 and the outlet-side opening largely open on either side
of the main body 2. During use, on the other hand, the inlet-side
opening 21 and the outlet-side opening are closed and connected
respectively to a refrigerant supply pipe or a refrigerant
discharge pipe, both of which are not shown. The refrigerant supply
pipe is connected to a supply pump for pumping a refrigerant at a
constant pressure to the heat exchanger 1 and the refrigerant
discharge pipe is connected to a tank for collecting the
refrigerant discharged from the heat exchanger 1.
[0037] The heat exchanger 1 includes a holding frame 13 having a
U-shaped cross section and an upper opening and a cover plate 14
fitted on that opening, forming the tubular-shaped main body 2. A
fin member 10 is incorporated in the main body 2 to form the
plurality of passages 3. Herein, FIG. 2 is a perspective view of
the heat exchanger 1 of FIG. 1 from which the holding frame 13 is
removed and FIG. 3 is a perspective view of the fin member 10 from
which the cover plate 14 is removed.
[0038] The fin member 10 is integrally formed with the plurality of
fins 11 protruding from a base 12. The base 12 is a rectangular
flat plate and formed with the fins 11 upstanding therefrom in a
perpendicular direction to the base 12. The fins 11 have the same
height with each other and the same length with the base 12 in a
longitudinal direction. The adjacent fins 11 are arranged in
parallel with one another. The thus configured fin member 10 is
inserted in the holding frame 13 without backlash and the cover
plate 14 is placed on the holding frame 13 so that the plate 14
abuts on tips of the fins 11. The heat exchanger 1 is integrally
configured by welding the fin member 10 mounted in the holding
frame 13, the holding frame 13, and the cover plate 14.
[0039] In the heat exchanger 1, spaces between the adjacent fins 11
are enclosed by the base 12 as a lower plate and the cover plate 14
as an upper plate to define the passages 3 arranged in parallel.
The fins 11 at both end sides of the fin member 10 form spaces from
the upstanding wall plates of the flame 13, the spaces being
enclosed by the base 12 and the cover plate 14 to form the passages
3.
[0040] When the refrigerant flows through the inlet-side opening 21
to the main body 2 in the direction Q in FIG. 1, the refrigerant
branches off to the passages 3 partitioned by the fins 11. In the
heat exchanger 1 of the present embodiment, the passages 3 defined
by the fins 11 are straight paths and therefore the refrigerant
tends to flow in laminar flow as same as the conventional
technique, resulting in poor cooling performance. Accordingly, the
heat exchanger 1 of the embodiment is provided with a configuration
to disturb the refrigerant flow. Specifically, the cover plate 14
defining the passages 3 is formed with protrusions 23 serving as
obstacles to the refrigerant flowing through the passages 3.
[0041] The protrusions 23 are provided on an opposite side of
recesses 25 formed on one side of the cover plate 14 in the
thickness direction as shown in FIG. 2, each protrusion 23 being
spaced at a predetermined interval from each other in the vertical
and lateral directions. To be more concrete, the protrusions 23 are
provided to be insertable in the spaces between the adjacent fins
11 so that the protrusions are present at fixed intervals in each
passage 3 when the cover plate 14 is set to assemble the heat
exchanger 1 as shown in FIG. 1.
[0042] FIG. 4 is a diagram showing the flow of the refrigerant
inside the passage 3. Since the passage 3 defined by the fins 11 is
linearly formed, the flow of the refrigerant could be a laminar
flow, leading to the same problem with the conventional technique
if the passage 3 is left as it is. In the present embodiment,
therefore, the flow of the refrigerant is disturbed by the
existence of the protrusions 23 to break a boundary layer
contacting with the fins 11 generated in the laminar flow, thereby
efficiently dissipating heat of the fins 11.
[0043] Further, especially in the heat exchanger 1 of the present
embodiment, the protrusions 23 are placed at the specific intervals
inside each passage 3 to maintain the cooling performance. FIG. 5
is a graph showing a result of a cooling performance test conducted
by flowing the refrigerant in the passage 3. The horizontal axis of
the graph indicates specific positions taken out from an arbitrary
part of the passage 3 and the vertical axis indicates the cooling
performance (heat transfer coefficient). Passage points p1, p2, and
p3 in the horizontal axis represent the positions in which the
protrusions 23 are formed, and the refrigerant flows in the
direction from the point p1 to the point p3.
[0044] The graph of FIG. 5 shows that the cooling performance of
the refrigerant flowing through the passage 3 is not constant but
changes like a waveform. In other words, the heat transfer
coefficient differs from position to position in the passage.
Especially, in the graph k, the cooling performance goes up toward
each of the points p1, p2, and p3 representing the existence of the
protrusions 23 and reaches at peak immediately after each of the
points p1, p2, and p3 and then the graph gradually goes down. This
is because the flow of the refrigerant is disturbed by the
protrusions 23 and the refrigerant flows to efficiently remove the
heat from the fins 11. On the other hand, the graph goes down
thereafter. This is conceivably because the flow of the refrigerant
returns to the laminar flow as it comes away from the protrusions
23, so that the flow of the boundary layer contacting with the fins
11 tends to be stagnant.
[0045] In response to this, in the present embodiment, the cooling
performance required to dissipate heat of the heating element is
set to be a reference value "s" and the position of each protrusion
23 is determined in a manner that the heat transfer coefficient
would not fall below the reference value "s". Specifically, the
distance between the protrusions 23 arranged in the longitudinal
direction of the passage 3 is determined so that the heat transfer
coefficient indicated with the graph k goes up just before the
graph falls below the reference value "s". The distance between the
protrusions 23 differs depending on a size of the passage 3, a flow
rate of the refrigerant to be supplied, the height of the
protrusions 23, a heat generating amount of the heating elements,
and others. Further, since the protrusions 23 also serve to
interfere with the flow of the refrigerant to cause pressure
increase, the height of each protrusion 23 in the present
embodiment is determined to be one third of the passage 3, taking
into account of the capability of the supply pump and others.
[0046] In the heat exchanger 1 in use, as shown in FIG. 6 for
example, a heat spreader 6 for thermal diffusion is placed on the
cover plate 14 and semiconductor devices 7 serving as heating
elements are orderly arranged on the heat spreader 6. When the
semiconductor devices 7 used for an inverter or the like generate
heat, the heat is transferred to the heat spreader 6 and diffused
to be further transferred through the main body 2 to the fins 11.
In the main body 2, the refrigerant is supplied from the inlet-side
opening 21 and flows toward the outlet-side opening in the opposite
side of the main body 2. As a result, the heat transferred to the
fins 11 is taken away by the refrigerant flowing in contact with
the fins 11, so that heat dissipation is carried out.
[0047] The refrigerant flowing in each passage 3 is disturbed in
flow by the protrusions 23 to break the boundary layers contacting
with the fins 11. Since the protrusions 23 are arranged with
predetermined intervals, the refrigerant is caused to flow in each
passage 3 while being constantly agitated. Thus, the refrigerant
having removed the heat efficiently flows downstream. Especially,
the cooling performance is maintained equal to or higher than the
reference value "s" in FIG. 5.
[0048] Even when the semiconductor devices are downsized, having a
larger heat generating density, the heat exchanger 1 with extremely
enhanced cooling performance compared to the conventional ones can
cool such semiconductor devices. Further, the heat exchanger 1 has
such a simple configuration of only providing the protrusions 23 in
each passage 3 defined by the fins 11 that less number of
components are required, thereby enabling cost reduction.
[0049] The present embodiment realizes reducing the working cost
for manufacturing the heat exchanger 1 having the excellent cooling
performance, and thereby providing the heat exchanger 1 at low
cost. The manufacturing method of such heat exchanger 1 is now
explained.
[0050] First, the fin member 10 for the heat exchanger 1 is formed
by extrusion-molding. A material used herein for the fin member 10
is aluminum having a good heat transfer coefficient. The molten
material is extruded from a molding die for integrally forming the
plurality of fins 11 and the base 12, and a long-fin member having
a several meters length is formed, for example. FIG. 7 is a
conceptual view of a part of a working process to form the fin
member 10.
[0051] An extruded long-fin member 10L is directly transferred to
and cut by a press device shown in the figure after the
extrusion-molding. The long-fin member 10L is integrally formed
with a long base 12L and long fins 11L vertically upstanding from
the long base 12L. Thereafter, the long-fin member 10L is
transferred in the extruding direction F as shown in the figure.
The long-fin member 10L just extruded remains soft because a
material forming the long-fin member 10L is heated to some extent.
Such long-fin member 10L is further forwarded to and cut by a press
device 50 for cutting.
[0052] The cutting press device 50 includes a not-shown lower die
for supporting a bottom part of the long base 12L and a
plate-shaped upper die 51 placed perpendicularly to the extrusion
direction F to be movable vertically downward with respect to the
lower die. The upper die 51 is a flat plate having a uniform
thickness and a flat bottom end surface. Further, a pair of fin
holding jigs 53 is provided on both sides of the upper die 51 to
prevent the fins 11 from buckling and falling down due to the
pressing force of the upper die 51. Each of the fin holding jigs 53
is formed with a plurality of flat plate-shaped supporting teeth 55
to be inserted individually in the spaces between the adjacent fins
11.
[0053] The conveyance of the extruded long-fin member 10L is once.
Then, the supporting teeth 55 of the fin holding jigs 53 are
individually inserted in the spaces between the adjacent long fins
11L of the long-fin member 10L to support every single long fin 11L
from both sides. Subsequently, the upper die 51 comes down to a
space between the pair of fin holding jigs 53 to cut off the long
fins 11L at one time. At the same time, the long base 12L is also
cut off on the same cutting line with the long fins 11. In this
cutting process, the long fin member 10L of long length is cut off
at predetermined pitches, so that the plurality of fin members 10
is successively produced. In addition, the holding frame 13 is also
formed by extrusion-molding and cutting as similar to the above
method.
[0054] A working or machining method for forming the cover plate 14
is now explained. The cover plate 14 is produced in such a way that
a flat plate of a predetermined size is cut off from an aluminum
plate having a uniform thickness and formed with the protrusions 23
in predetermined positions. The protrusions 23 are formed in the
flat plate by press working. FIG. 8 is a sectional view of a press
device for forming protrusions.
[0055] Each protrusion 23 of the heat exchanger 1 is of a
triangular shape, but the shape of the protrusion is not limited
thereto as long as the protrusion can perform the same function as
the protrusion 23. Though FIG. 8 shows a press device for forming
protrusions of cylindrical shape, the explanation of the pressing
method is given regarding the protrusions as same as the
protrusions 23 in FIG. 2.
[0056] In a press device 60 for forming protrusions, a lower
receiving base for holding a flat plate 14X is formed with a die
62. This die 62 is formed with a die hole 61 of circular shape in
cross section. On the other side, an upper pressing base is
provided with a stopper 63 for holding down the flat plate 14X by
use of a not-shown spring and the stopper 63 is formed with a
guiding through hole 64 in which a tubular-shaped punch 65 is
inserted. A diameter of the punch 65 is designed to be wider than
that of the die hole 61. FIG. 8 shows a partial configuration for
forming one protrusion 23, but the press device 60 as a whole
includes a plurality of identical configurations to that shown in
FIG. 8 to form a predetermined number of protrusions 23 in the flat
plate 14X at one time.
[0057] In a protrusion forming process, the flat plate 14X is held
in place between the die 62 and the stopper 63 and thereafter the
punch 65 in the guiding through hole 64 is press-fitted in the flat
plate 14X. At that time, the punch 65 is press-fitted to the
halfway of the flat plate 14X without penetrating through the flat
plate 14X. In the vicinity of the press-fitted region of the flat
plate 14X, a material of the surface of the flat plate 14X is drawn
by the punch 65, but displacement of the flat plate 14X can be
prevented by the stopper 63 to maintain the planar surface to some
extent. In the opposite side of the flat plate 14X from the punch
65, on the other hand, the material of the flat plate 14X is
extruded into the die hole 61 to form a columnar shaped protrusion
23. With respect to the flat plate 14X, a predetermined number of
the protrusions 23 are formed by pressing. Thus the cover plate 14
is formed in one working operation.
[0058] According to the manufacturing method of the heat exchanger
in the present embodiment, the fin member 10 is formed by cutting
the long-fin member 10L by use of the press device 50 immediately
after the long-fin member 10L is extrusion-molded. Therefore, a
large number of the fin members 10 can be produced in a short time
compared to other methods such as casting. In particular, the
material is cut immediately after the extrusion-molding while the
material is still soft, so that the re-heating process can be
omitted, thus shortening the working time. Further, as for the
cover plate 14, the protrusions 23 are formed by press working of
the flat plate 14X by use of the press device 60, so that the
working operation is simplified and working time is shortened,
enabling mass production of the cover plate 14. This can reduce
costs for components of the heat exchanger 1 and hence provide the
heat exchanger 1 itself at low cost.
[0059] An explanation is given for modifications of the above
embodiment of the heat exchanger and the manufacturing method
thereof.
[0060] In the heat exchanger 1 of the above embodiment, the
protrusions 23 are formed in the cover plate 14. Alternately,
protrusions 33 may be formed in a fin member 30 as shown in FIG. 9.
FIG. 9 is a perspective view of a heat exchanger having the same
configuration with the heat exchanger in FIG. 1 from which the
holding frame 13 is removed. In this modification, a heat exchanger
is configured such that the fin member 30 and a cover plate 34 are
attached to the holding frame 13 shown in FIG. 1.
[0061] The fin member 30 is integrally formed with a plurality of
fins 31 perpendicularly formed on a base 32. The protrusions 33 are
arranged in spaces between fins 31 arranged in parallel with each
other at predetermined intervals. The protrusions 33 shown in the
figure are placed in a passage formed in the space between one fin
31 and the holding frame 13. A plurality of the protrusions 33 are
formed in each passage 3 in the longitudinal direction thereof at
predetermined intervals to maintain the cooling performance at the
reference value "s" as shown in FIG. 5. On the other hand, the
cover plate 34 in this modification is a flat plate. However, the
cover plate 34 may also be formed with protrusions to provide a
heat exchanger having protrusions on both upper and lower sides of
each passage 3. Further excellent cooling performance can be
expected if the protrusions in each passage 3 are displaced
alternately, or staggered, between an upper side and a lower
side.
[0062] A method of manufacturing a heat exchanger, especially a
step of working or machining the fin member 30 having the
protrusions 33 is now explained. FIG. 10 is a diagram showing a
working step of forming the protrusions 33 of the fin member 30
shown in a simplified manner. The fin member 30 is formed as with
the fin member 10 which is cut out from the long-fin member 10L as
shown in FIG. 7. Thereafter, the fin member 30 is further subjected
to a pressing step for forming protrusions, in which the
protrusions 33 are formed in the base 32.
[0063] A press device for forming a protrusion includes a pressing
die 72 and a receiving die 74. The pressing die 72 includes a
plurality of punches 71 to be placed under the base 32 and the
receiving die 74 is to receive pressing load. The receiving die 74
is formed with a plurality of supporting projections 73 arranged
corresponding to the spaces between the fins 31 so as to prevent
the fins 31 from buckling and falling down due to the load applied
by the pressing die 72. Each fin 31 of the fin member 30 is
inserted in each space between the supporting projections 73 so
that a tip of the fin 31 abuts on the receiving die 74 and is
thereby supported. With respect to the supported fin member 30, the
punches 71 of the pressing die 72 are held against the base 32 and
the material deformed by press-fitting of the punches 71 is
extruded into the spaces between the fins 31 to form the
protrusions 33 in the base 32.
[0064] In the heat exchanger 1 in FIG. 1, the protrusions 23 are
arranged along each of the passages 3 (see FIG. 2) and further the
protrusions 23 are arranged in rows in the direction perpendicular
to the passages 3. In this case, if a distance between the adjacent
fins 11 is set shorter in order to enhance the cooling performance,
a distance between the adjacent protrusions 23 could also be
shorter. As a result, the adjacent punches could interfere with
each other because the punches for forming the protrusions 23 are
larger than the protrusions 23 in size. Further, the shorter
distance between the adjacent protrusions 23 causes deterioration
of flatness of the cover plate 14. For instance, when the
protrusions 23 are to be formed in the cover plate 14 as shown in
FIG. 2, the material around each recess 25 is drawn by
press-fitting of the punches, generating some dents. Consequently,
the dents around the recess 25 could be overlapped to enlarge
deformation of the material if the distance between the adjacent
recesses 25 is short.
[0065] In the case where the distance between the fins 11 is made
shorter, the protrusions 23 are arranged in a staggered pattern in
the direction perpendicular to the fins 11, as shown in FIG. 11.
Thereby, the distance between the adjacent protrusions 23 is
increased and the interference of the punches can be avoided. It is
thus possible to provide a heat exchanger with the fins 11 arranged
at narrow distances from each other to enhance the cooling
performance. Furthermore, as well as the protrusions 23, the
distance between the adjacent recesses 25 is wider, so that
deterioration of the flatness can be prevented. Incidentally, an
insulating sheet is bonded to a surface on which the recesses 25
are to be formed, and the flatness therefor is assured.
[0066] Working for forming the protrusions provided in each passage
is now explained. The press device for protrusions is disclosed in
FIG. 8 for processing the protrusions, but alternately, an
extrusion-molding type of a press device shown in FIG. 12 may be
adopted. A press device 80 for forming a protrusion includes a die
82 in a receiving base to be placed under the flat plate 14X and
the die 82 is formed with a recess 81 conforming to the shape of
the protrusion to be formed. In a pressing base on the upper side,
a stopper 83 for holding down the flat plate 14X by use of a
not-shown spring is provided. The stopper 83 is formed with a
guiding through hole 84 penetrating through the stopper 83, and a
columnar-shaped punch 85 having an acute-angled tip is inserted in
the hole 84.
[0067] The device of the present embodiment including the punch 85
smaller in diameter than the recess 81 is used to form the
relatively large protrusions 23. On the contrary, the press device
60 in FIG. 8 is suitable for forming relatively small-sized
protrusions. FIG. 12 shows only a partial configuration of the
press device 80 to from one protrusion 23, but the press device 80
is provided with a plurality of identical configurations to that
shown in FIG. 12 to form a predetermined number of the protrusions
23 in the flat plate 14X at one time. Even though the protrusion
formed by the press device 80 in FIG. 12 is of trapezoidal shape,
which is different from the shape of the protrusion in FIG. 2, it
is also herein referred to as a protrusion 23.
[0068] In the press device 80, the flat plate 14X is held between
and positioned by the die 82 and the stopper 83. Thereafter, the
punch 85 in the guiding through hole 84 is press-fitted in the flat
plate 14X. The punch 85 is pressed into the flat plate 14X until
the tip of the punch 85 reaches the recess 81. At this time, in the
vicinity of the pressing region, the surface material of the flat
plate 14X is drawn by the punch 85, but the stopper 83 restricts
displacement of the plate and the flatness is maintained to some
extent. On the opposite side of the flat plate 14X, the material is
extruded into the recess 81, thereby forming the trapezoidal-shaped
protrusion 23. With respect to the flat plate 14X, a predetermined
number of the protrusions 23 are formed by the press working, so
that manufacturing of the cover plate 14 is completed in a single
working.
[0069] The explanation is now given for a working method of forming
extrusions by pressing referring to FIG. 13. In the present
modification, a long-fin member is formed by extrusion-molding and
then a fin member of a predetermined length is cut off from the
long-fin member. Further, the protrusions are formed in the fin
member by pressing as shown in FIG. 13. A fin member 40
extrusion-molded in the present modification has a sectional shape
in the longitudinal direction as shown in FIG. 14. Specifically,
fin members 41 are arranged perpendicularly protruding from a base
42 at predetermined pitches and raised portion43 of trapezoidal
shape in section are formed between the fins 41 which define
passages. Each raised portion 43 is formed in continuous shape in
the longitudinal direction as same as the fins 41.
[0070] A press device 90 for forming protrusions includes a lower
die 91 for supporting the fin member 40 from the bottom side and an
upper die 92 for shaping protrusions. The upper die 92 includes
pressing plates 95, 96, and 97 each inserted in a clearance 45
between the fins 41. One set of the pressing plates 95, 96, and 97
are placed linearly along the clearance 45 and formed with
separating portions 98 in between the plates. A plurality of sets
of the pressing plates 95, 96, and 97 are placed to hold each fin
41 from both sides, the sets of plates being arranged in parallel
to one another as shown in the figure. In the figure, each pressing
plate 95, 96, and 97 is shown in an independent (separated) state,
but the plates are configured to integrally transmit a pressing
load applied by a single pressurizing device.
[0071] The press device 90 is configured to move the upper die 92
downward to the fin member 40 having the sectional view in FIG. 14
so that the pressing plates 95, 69, and 97 are inserted in the
clearances 45 to hold the fins 41. The upper die 92 continues to
move down to squeeze or squash the raised portion 43 pressurized by
the plates 95, 96, and 97. At this time, the portions of the fins
41 located in the separating portions 98 between the plates 95, 96,
and 97 are not squashed, so that protrusions 46 are formed as shown
in FIG. 15.
[0072] Therefore, according to the manufacturing method of the
present embodiment, the protrusions 46 can be formed by use of a
simple die without requiring a processing device having a
complicated die for forming protrusions. Accordingly, a cost for a
processing device can be reduced, leading to cost reduction in
processing a heat exchanger.
[0073] While the presently preferred embodiment of the heat
exchanger and the manufacturing method thereof according to the
present invention has been shown and described, the invention is
not limited to the above embodiments and may be embodied in other
specific forms without departing from the essential characteristics
thereof.
REFERENCE SIGNS LIST
[0074] 1 Heat exchanger
[0075] 2 Main body
[0076] 3 Passage
[0077] 6 Heat spreader
[0078] 7 Semiconductor device
[0079] 10 Fin member
[0080] 11 Fin
[0081] 12 Base
[0082] 13 Holding frame
[0083] 14 Cover plate
[0084] 23 Protrusion
[0085] 50 Press device for cutting
[0086] 60 Press device for forming protrusions
[0087] 62 Die
[0088] 63 Stopper
[0089] 65 Punch
* * * * *