Information
-
Patent Grant
-
6340055
-
Patent Number
6,340,055
-
Date Filed
Thursday, May 25, 200024 years ago
-
Date Issued
Tuesday, January 22, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Bennett; Henry
- McKinnon; Terrell
Agents
- Harness, Dickey & Pierce, PLC
-
CPC
-
US Classifications
Field of Search
US
- 165 153
- 165 173
- 165 175
- 165 178
- 165 177
- 165 174
- 029 890045
- 029 890053
-
International Classifications
-
Abstract
A tube for a heat exchanger has notch portions at a longitudinal direction end portion to be inserted into a header tank. Further, several passage holes are provided in the tube to extend in a longitudinal direction of the tube in which refrigerant flows. The notch portions are formed by cutting parts of the tube to be defined by cut surfaces. The passage holes are not provided at portions corresponding to the cut surfaces. Therefore, the passage holes are securely prevented from being crushed and cut when the notch portions are formed by cutting. As a result, joining failure between the tube and the header tank can be prevented.
Description
CROSS REFERENCE TO RELATED APPLICATION
This application is based upon and claims the benefit of Japanese Patent Applications No. 11-145323 filed on May 25, 1999, the contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to heat exchangers suitable for a radiator, an evaporator, or the like in a refrigerating cycle.
2. Description of the Related Art
JP-A-1-351783 proposes a heat exchanger in which, as shown in
FIG. 15A
, notch portions
211
a
indicated with slant lines are provided at both long-side end portions of a tube
211
to reduce a size of the heat exchanger in a direction parallel to an air flow direction.
On the other hand, as shown in
FIG. 15B
, a tube
211
, which is generally used at a high internal pressure state for a heat exchanger such as a condensers a radiator, or a heat exchanger of a super critical refrigerating cycle, adopts a multi-hole structure having several passage holes
211
b
arranged in the cross-sectional long-side direction thereof, thereby improving a withstand pressure of the tube
211
. The super critical refrigerating cycle uses refrigerant such as carbon dioxide, ethylene, ethane, or nitrogen oxide, a pressure of which exceeds a super critical pressure.
SUMMARY OF THE INVENTION
However, it has been revealed by the inventors that the following problems were liable to occur when the structure proposed in JP-A-11-351783 was applied to the tube
211
having the multi-hole structure. Specifically, the passage holes
211
b
are formed at the same time when the tube
211
is formed by extrusion molding or the like. If the notch portions
211
a
are formed on the tube
211
by cutting after the passage holes
211
b
are formed, as shown in
FIG. 16A
, the cut surface is liable to be crushed at a vicinal region of the passage holes
211
b
. When the cut surface is crushed to form a crushed portion
160
and the tube
211
is inserted into a header tank with the crushed portion
160
, the crushed portion
160
forms a space between the tube
211
and the header tank, and the space induces joining failure (welding failure) therebetween readily. Further, if the tube
211
has manufacture variations when it is formed and it is cut, as shown in
FIG. 16B
, one of the passage holes
211
b
may be cut. The cut hole
211
b
forms a space (gap), which can induce the joining failure between the tube
211
and the header tank readily.
The present invention has been made in view of the above problems. An object of the present invention is to prevent joining failure between a multi-hole structured tube and a header tank in a heat exchanger.
According to the present invention, a tube for a heat exchanger has an end portion in a longitudinal direction thereof. The end portion is formed by a cut surface, which extends in the longitudinal direction of the tube and defines an end portion width, which is smaller than a tube width at a portion of the tube other than the end portion. The end portion width and the tube width are perpendicular to the longitudinal direction and parallel to a cross-sectional long side direction of the tube. The tube has a plurality of passage holes arranged in the cross-sectional long side direction within the end portion width, and a hole of the passage holes disposed most adjacently to the cut surface defines a specific distance δ
0
from the cut surface.
Accordingly, the hole and the cut surface can be prevented from being crushed when the cut surface is formed. When the end portion of the tube is inserted into a header tank, no gap is produced between the tube and the header tank, thereby preventing joining failure between the tube and the header tank.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and features of the present invention will become more readily apparent from a better understanding of the preferred embodiments described below with reference to the following drawings, in which;
FIG. 1
is a perspective view showing a heat exchanger in a first preferred embodiment of the present invention;
FIG. 2
is a cross-sectional view showing a joining portion between a header and a tube in the first embodiment;
FIG. 3
is an exploded perspective view showing the header and the tube;
FIG. 4
is a front view showing a separator;
FIG. 5
is a front view showing a cap;
FIG. 6A
is a front view showing a longitudinal direction end portion of the tube in the first embodiment;
FIG. 6B
is a plan view showing the longitudinal direction end portion of the tube in a direction indicated by arrow VIB in
FIG. 6A
;
FIG. 7
is a cross-sectional view showing a core portion of the heat exchanger in the first embodiment;
FIG. 8
is a cross-sectional view showing a core portion of a heat exchanger as a comparative example;
FIG. 9A
is a front view showing a longitudinal direction end portion of a tube in a second preferred embodiment;
FIG. 9B
is a plan view showing the longitudinal direction end portion of the tube, in a direction indicated by arrow IXB in
FIG. 9A
;
FIG. 10A
is a front view showing a longitudinal direction end portion of a modified tube in the second embodiment;
FIG. 10B
is a plan view showing the longitudinal direction end portion of the tube in a direction indicated by arrow XB in
FIG. 10A
;
FIG. 11A
is a front view showing a longitudinal direction end portion of a tube in a third preferred embodiment;
FIG. 11B
is a plan view showing the longitudinal direction end portion of the tube in a direction indicated by arrow XIB in
FIG. 11A
;
FIG. 12A
is a front view showing a longitudinal direction end portion of a tube in a modified embodiment of the present invention;
FIG. 12B
is a plan view showing the longitudinal direction end portion of the tube in a direction indicated by arrow XIIB in
FIG. 12A
;
FIG. 13
is a cross-sectional view showing a core portion of a heat exchanger in another modified embodiment of the present invention;
FIG. 14A
is a front view showing a longitudinal direction end portion of a tube in another modified embodiment of the present invention;
FIG. 14B
is a plan view showing the longitudinal direction end portion of the tube in a direction indicated by arrow XIVB in
FIG. 14A
;
FIG. 15A
is a front view showing a longitudinal direction end portion of a tube according to a prior art;
FIG. 15B
is a plan view showing the longitudinal direction end portion of the tube in a direction indicated by arrow XVB in
FIG. 15A
; and
FIGS. 16A and 16B
are enlarged cross-sectional views partially showing a tube for explaining conventional problems.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
(First Embodiment)
In a first preferred embodiment of the present invention, a heat exchanger according to the present invention is adopted to an evaporator
100
of a super critical refrigerating cycle using carbon dioxide as refrigerant.
Referring to
FIG. 1
, the evaporator
100
has several flat tubes
111
extending in a vertical direction in which refrigerant (fluid) flows. The tubes
111
are formed from aluminum members by extrusion molding. Aluminum corrugated fins
112
are respectively disposed between and joined to adjacent two of the tubes
111
, thereby increasing a radiation area for facilitating heat exchange between refrigerant and air. Both front and back surfaces of each of the corrugated fins
112
are clad with brazing filler metal. The fins
112
and the tubers
111
are integrated with one another by brazing, thereby forming a core portion
110
of the evaporator
100
.
Side plates
113
for reinforcement are brazed to the fins
112
by the brazing filler metal coated on the fins
112
at both ends of the core portion
110
in a lamination direction of the tubes
111
. Header tanks (herebelow, referred to as header)
120
are joined to the tubes
111
at upper and lower ends in the longitudinal direction of the tubes
111
. The headers
120
extend in a direction perpendicular to the longitudinal direction of the tube
111
and communicate with the respective tubes
111
. In
FIG. 1
, the lower side header
120
is to distribute refrigerant into the respective tubes
111
, and the upper side header
120
is to collect refrigerant discharged from the tubes
111
. The evaporator
100
has two joint blocks
131
,
132
. The joint block
131
is connected to a pressure reducing valve side (not shown), and the joint block
132
is connected to a compressor side (not shown) in the super critical refrigerating cycle.
As shown in
FIGS. 2 and 3
, each of the headers
120
is composed of a first plate
121
having first insertion holes
121
a
into which the flat tubes
111
are respectively inserted, and a second plate
122
joined to the first plate
121
to form a passage in which refrigerant flows. The second plate
122
integrally has an inner pillar member
123
, which extends in the longitudinal direction of the header
120
and protrudes toward the side of the first plate
121
. A front end portion of the inner pillar member
123
is joined to the inner wall of the first plate
121
, so that the inner walls of the plates
121
and
122
are connected to each other via the inner pillar member
123
. The inner pillar member
123
divides the inner space of the tube
120
into first and second spaces
120
a
and
120
b
, respectively extending in the longitudinal direction of the header
120
.
In the present embodiment, the front end portion of the inner pillar member
123
at a side of the first plate
1221
is partially cut by milling, thereby forming communication passages
123
a
. The communication passages
123
a
are, as shown in
FIG. 2
, provided correspondingly to the first insertion holes
121
a
. The inner pillar member
123
has across-section, a width W of which increases as it approaches either one of the inner walls of the plates
121
and
122
. The cross-section of the inner pillar member
123
is arched so that each of the spaces
120
a
and
120
b
has a generally circular cross-section. The width W of the inner pillar member
123
is a dimension in a direction parallel to a longer radial direction of the flat (elliptic) header
120
.
The first plate
121
is formed from an aluminum member (A3003 system) by pressing, and the second plate
122
is formed from an aluminum member (A3003 system) by extrusion. Front and back surfaces of each of the plates
121
,
122
are clad with brazing filler metal, and the plates
121
,
122
having the inner pillar member
123
, the tubes
111
, and the side plates
113
are integrally brazed to one another by the brazing filler metal.
Referring back to
FIG. 1
, a separator
130
is disposed within the header
120
to divide the first and second spaces
120
a
,
120
b
into several spaces in the longitudinal direction of the header
120
. Refrigerant flows in the core portion
110
with an S-like shape due to the separator
130
. As shown in
FIG. 4
, the separator
130
is composed of first and second disk portions
131
,
132
, a connecting portion
133
connecting the disk portions
131
,
132
therebetween, and a protruding portion
134
protruding from the connecting portion
133
toward the side of the first plate
121
. The portions
131
-
134
are integrally formed from an A3003 system aluminum plate member by pressing.
On the other hand, as shown in
FIG. 3
, the first plate
121
has a second insertion hole
121
b
for receiving the protruding portion
134
therein. The separator
130
is brazed to the inner walls of the plates
121
,
122
and the inner pillar member
123
in the sate where the protruding portion
134
is inserted into the second insertion hole
121
b.
Referring back again to
FIG. 1
, aluminum header caps
140
are brazed to the header
120
to close respective ends of the first and second spaces
120
a
,
120
b
in the longitudinal direction of the header
120
. As shown in
FIG. 5
, each of the caps
140
has columnar protruding portions
141
for being inserted into the first and second spaces
120
a
,
120
b
, and each protruding portion
141
has a generally spherical surface portion
142
at a front end thereof. The caps
140
are also brazed to the header
120
(both the plates
121
,
122
) by brazing filler metal sprayed on the caps
140
.
Next, the structure of the tube
111
will be explained below.
As shown in
FIG. 2
, the tubes
111
has a maximum cross-sectional long side dimension (tube width T
W0
), which is larger than inner wall width T
W1
and is equal to or smaller than outer wall width T
W2
of the header
120
. As shown in
FIG. 6A
, the tube
111
has a longitudinal end portion, both cross-sectional long side ends of which are cut to form notch portions
111
a
as indicated by slant lines in the figure, and the longitudinal end portion is inserted into the header
120
.
Incidentally, the inner wall width T
W1
of the header
120
is a maximum dimension defined by the inner wall of the header
120
in a direction parallel to the cross-sectional long side of the tube
111
, i.e., parallel to an air flow direction. The outer wall width T
W2
of the header
120
is a maximum dimension defined by the outer wall of the header in the direction parallel to the cross-sectional long side of the tube
111
, i.e., parallel to the air flow direction.
On the other hand, as shown in
FIG. 6B
, several passage holes
111
b
each having a circular shape in cross-section are provided in the tube
111
to extend in the longitudinal direction of the tube
111
. The passage holes
111
b
are arranged in the cross-sectional long side direction of the tube
111
within a dimension (end portion width) L, which is smaller than the inner wall width T
W1
of the header
120
. The dimension L is a dimension of a portion of the tube
111
, which is to be inserted into the first insertion hole
121
a
. Therefore, the dimension L is determined in consideration of manufacture tolerances (variations) of the tube
111
, the first plate
121
, the first insertion hole
121
a
, and the notch portions
111
a.
A distance δ
0
between one of the passage holes
111
b
disposed at the end in the long side direction of the tube
11
and the cut surfaces S of one of the notch portions
111
a
is the sum of dimensions δ
1
, δ
2
, and δ
3
. The dimension δ
1
is a dimension required for preventing the passage holes
111
b
from being crushed when the notch portions
111
a
are formed, i.e., when the both ends of the tubes
111
are removed by cutting to form the notch portions
111
a
. The dimension δ
2
is a dimensional tolerance between two passage holes
111
b
, i.e., a positional tolerance of a pillar portion having a length
111
c
and provided between the two passage holes
111
b
. The dimension δ
3
is a positional cut tolerance (positional variation amount) of the cut surfaces S. Incidentally, the length
111
c
is a pitch of the passage holes
111
b
, and the distance δ
0
is larger than the pitch
111
c.
As shown in
FIG. 7
, one of the cross-sectional long side ends of the tube
111
, which is disposed at the air flow downstream side, is tapered as a tapered portion
151
, a thickness of which is decreased as it approaches the front end (air flow downstream side) thereof. Accordingly, the tapered portion
151
of the tube
111
forms gaps
150
at both sides thereof with the fins
112
not to contact the fins
112
.
Because of this, the cross-sectional long side end of the tube
111
at the air flow downstream side has a curve Rr, which is smaller than a curve Rf at the air flow upstream side. Each of the gaps
150
has a dimension L
2
parallel to the cross-sectional long side direction of the tube
111
, and the dimension L
2
is larger than a half (=Rf) of the thickness h of the tube
111
. The thickness h of the tube
111
is a length of the tube in a cross-sectional short side direction of the tube
111
, and is approximately twice of the curve Rf at the air flow upstream side in the present embodiment. Incidentally, in
FIG. 7
, reference numerals
112
a
denotes louvers, which hare formed by partially cutting and bending the fin
112
to prevent a temperature boundary layer from being produced between the fin
112
and air.
Next, features of the present invention will be explained below.
The passage holes
111
b
are arranged in the cross-sectional long-side direction within the dimension L, which is smaller than the inner wall width T
W1
of the header
120
. Therefore, the tube
111
of the present embodiment has portions corresponding to the notch portions
111
a
where no passage holes
111
b
are formed at the cross-sectional long side end portions. The passage holes
111
b
are prevented from being provided in the vicinity of the cut surfaces S.
Therefore, when the cross-sectional long side end portions of the tube
111
are removed by cutting to form the notch portions
111
a
, the cut surfaces S are prevented form being crushed or sagged. In addition, the passage holes
111
b
are securely prevented from being cut when the notch portions
111
a
are formed. As a result, when the tube
111
is inserted into the first insertion hole
121
a
, no gap is produced between the tube
111
and the first plate
121
. Therefore, joining failure (welding failure) does not occur between the tube
111
and the header
120
.
Thus, according to the present embodiment, the joining failure (welding failure) is prevented from occurring between the tube
111
and the header
120
while preventing an increase in manufacture cost of the tube
111
(evaporator
100
). In addition, the tube
111
has the notch portions
111
a
. Therefore, the effects described above can be achieved while maintaining a sufficient heat exchange capacity of the evaporator
100
.
As described above referring to
FIG. 7
, the gaps
150
are formed at the cross-sectional long side and air flow downstream side end of the tube
111
. Condensed water condensed on the surfaces of the fin
112
and the tube
111
gathers in the gaps
150
by a surface tension thereof (capillary phenomenon by the gaps
150
) and flows downwardly along the tube
111
. As a result, the drainage property of condensed water is improved. Further, because the thickness of the tapered portion
151
is decreased as it approaches the front end thereof at the air flow downstream side, each of the gaps
150
has a wedge shape sharpened with an acute angle at the air flow upstream side thereof. This makes it secure to gather and drain condensed water.
When the passage holes
111
b
are formed entirely in the cross-sectional long side direction of the tube
111
as a conventional manner, as shown in
FIG. 8
, some of the passage holes
111
b
provided at the tapered portion
151
are crushed. Because of this, teeth used at the extrusion processing of the tube
111
are thinned to be broken readily. As opposed to this, according to the present embodiment, any of the passage holes
111
b
are not formed at the tapered portion
151
. Therefore, the teeth used at the extrusion processing need not be thinned, thereby preventing the damage to the teeth.
(Second Embodiment)
In the first embodiment, the tube
111
has no hole extending in the longitudinal direction of the tube
111
, at the cross-sectional long side ends with respect to the cut surfaces S. In a second preferred embodiment, as shown in
FIG. 9A
, holes
111
b
arranged in the cross-sectional long side direction of the tube
111
include holes provided at the cross-sectional long side ends with respect to the cut surfaces S. In this case, as shown in
FIG. 9B
, a pitch
111
c
of the passage holes
111
b
is increased to a pitch P at portions corresponding to the cut surfaces S as compared to the other portions. More specifically, a half of the pitch P is larger than the pitch
111
c
, so that the distance of one of the passage holes
111
b
, which is provided most adjacently to one of the cut surfaces S from the one of the cut surfaces S is set to be larger than the pitch
111
c
. In this embodiment, only the holes
111
b
provided between the cut surfaces S function as passage holes in which refrigerant flows.
In the tube
111
according to the present embodiment, any of the holes
111
b
are not provided in the vicinity of the cut surfaces S. Therefore,the cut surfaces S are prevented from being sagged or deformed when the cross-sectional long side end portions of the tube
111
are removed by cutting. Incidentally, as shown in
FIGS. 10A and 10B
, each shape of the holes
111
b
provided at the cross-sectional long side ends with respect to the cut surfaces S is not limited to a circular shape, but may be other shapes.
(Third Embodiment)
In the first embodiment, the cut surface S is provided between the passage holes
111
b
and the tapered portion
151
. However, as shown in
FIGS. 11A and 11B
, the cut surface S may be provide by cutting a part of the tapered portion
151
in a thickness direction of the tube
111
. Accordingly, a cut length of the cut surface S can be decreased, resulting in decrease in man-hour of the step for forming the notch portions
111
a
. This further results in decreased manufacture cost of the tube
111
. Here the cut length of the cut surface S is a dimension of the cut surface S in the thickness direction of the tube
111
.
In the embodiments described above, the present invention is applied to the evaporator, but is not limited to that. The present invention can be applied to other heat exchangers such as a radiator for a super critical refrigerating cycle and a condenser for a refrigerating cycle. The tubes
111
may be disposed to extend in a horizontal direction. Also, in the embodiments described above, although the tube width T
W0
is set to be less than the outer wall width T
W2
of the header
120
, the tube width T
W0
may be set to be larger than the outer wall width T
W2
of the header
120
.
In the third embodiment, although the tapered portions
151
are formed at the both ends in the cross-sectional long side direction of the tube
111
, the tapered portions
151
may be formed at only one of the ends of the tube
111
. In the embodiments described above, the notch portions
111
a
are provided at the both ends in the cross-sectional long side direction of the tube
111
. However, as shown in
FIGS. 12A and 12B
, the notch portion
111
a
may be provided at only one of the ends of the tube
111
. The shape of each passage hole
111
b
is not limited to a circle in cross section, but may be other shapes such as a rectangle shown in
FIG. 13
, a polygon, or an elliptic shape.
In the first and second embodiments, the tapered portion(s)
151
is formed at the cross-sectional long side end(s) of the tube
111
. However, as shown in
FIGS. 14A and 14B
, the tube
111
can dispense with the tapered portion
151
. Further, as shown in
FIG. 7
, the tapered surface of the tapered portion
151
is flat and extends linearly in cross section in the first and third embodiments. However, the tapered surface may be curved in cross section. It is apparent that one of the embodiments described above can be combined with another one of the embodiments appropriately.
While the present invention has been shown and described with reference to the foregoing preferred embodiments, it will be apparent to those skilled in the art that changes in form and detail may be made therein without departing from the scope of the invention as defined in the appended claims.
Claims
- 1. A heat exchanger comprising:a flat tube having an end portion in a longitudinal direction thereof, the end portion having an end portion width smaller than a tube width which is a width of the tube at a portion other than the end portion, the end portion width and the tube width being perpendicular to the longitudinal direction and parallel to a cross-sectional long side direction of the tube, the tube defining therein a plurality of passage holes in which a first fluid flows, the plurality of passage holes being arranged in the cross-sectional long side direction within the end portion width to open at the end portion; a fin joined to the tube to facilitate heat exchange between the first fluid flowing inside the tube and a second fluid flowing outside the tube; and a tank connected to the end portion of the tube to communicate with the plurality of passage holes, wherein: the end portion is formed by a cut surface which extends in the longitudinal direction and determines the end portion width; the plurality of passage holes include a hole disposed most adjacently to the cut surface and defining a specific distance δ0 from the cut surface to be prevented from being crushed when the cut surface is formed.
- 2. The heat exchanger of claim 1, wherein the specific distance δ0 is represented by a formula of:δ0=δ1+δ2+δ3, in which δ1 is a dimension required for preventing the hole from being crushed when the cut surface is formed; δ2 is a dimensional tolerance between the plurality of passage holes; and δ3 is a positional cut tolerance of the cut surface.
- 3. The heat exchanger of claim 1, wherein:the tank has an inner wall width and an outer wall width respectively defined by an inner wall and an outer wall of the tank and parallel to the cross-sectional long side direction of the tube; and the inner wall width is larger than the end portion width and is smaller than the tube width.
- 4. The heat exchanger of claim 1, wherein:the plurality of passage holes are arranged in the cross-sectional long side direction of the tube with a pitch; and the specific distance between the hole and the cut surface is larger than the pitch.
- 5. The heat exchanger of claim 1, wherein:the tube has an upstream side end portion and a downstream side end portion in the cross-sectional long side direction in which the second fluid flows from the upstream side end to the downstream side end; and the downstream side end portion defines a gap with the fin, the gap having a length parallel to the cross-sectional long side direction and larger than a half of a thickness in a cross-sectional short side direction of the tube.
- 6. The heat exchanger of claim 1, wherein:the tube has an upstream side end portion and a downstream side end portion in the cross-sectional long side direction in which the second fluid flows from the upstream side end to the downstream side end; and the downstream side end portion is tapered so that a thickness of the downstream side end portion in a cross-sectional short side direction of the tube is decreased toward a front tip thereof.
- 7. The heat exchanger of claim 6, wherein the cut surface is formed by cutting a part of the tapered downstream side end portion.
- 8. The heat exchanger of claim 1, wherein:the tank has an insertion hole; and the end portion of the tube is inserted into the insertion hole.
- 9. The heat exchanger of claim 1, wherein the cut surface includes first and second cut surfaces respectively provided at both ends of the end portion in the cross-sectional long side direction to define the end portion width therebetween.
- 10. A heat exchanger comprising:a flat tube having an end portion in a longitudinal direction thereof, the end portion having an end portion width smaller than a tube width, which is a width of the tube at a portion other than the end portion, the end portion width and the tube width being perpendicular to the longitudinal direction and parallel to a cross-sectional long side direction of the tube, the tube having therein a plurality of passage holes in which a first fluid flows, the plurality of passage holes being arranged in the cross-sectional long side direction to respectively extend in the longitudinal direction of the tube; a fin joined to the tube to facilitate heat exchange between the first fluid flowing inside the tube and a second fluid flowing outside the tube; and a tank connected to the end portion of the tube to communicate with the plurality of passage holes, wherein: the end portion is formed by a cut surface which extends approximately in the longitudinal direction between first and second passage holes of the plurality of passage holes and determines the end portion width; and a pitch of the first and second passage holes is larger than a pitch of the plurality of passage holes other than the first and second passage holes.
- 11. The heat exchanger of claim 10, wherein:the tank has an inner wall width and an outer wall width respectively defined by an inner wall and an outer wall of the tank and parallel to the cross-sectional long side direction of the tube; and the inner wall width is larger than the end portion width and is smaller than the tube width.
- 12. The heat exchanger of claim 10, wherein:the tube has an upstream side end portion and a downstream side end portion in the cross-sectional long side direction in which the second fluid flows from the upstream side end to the downstream side end; and the downstream side end portion defines a gap with the fin, the gap having a length parallel to the cross-sectional long side direction and larger than a half of a thickness in a cross-sectional short side direction of the tube.
- 13. The heat exchanger of claim 10, wherein:the tube has an upstream side end portion and a downstream side end portion in the cross-sectional long side direction in which the second fluid flows from the upstream side end to the downstream side end; and the downstream side end portion is tapered so that a thickness of the downstream side end portion in a cross-sectional short side direction of the tube is decreased toward a front tip thereof.
- 14. The heat exchanger of claim 13, wherein the cut surface is formed by cutting a part of the tapered downstream side end portion.
- 15. The heat exchanger of claim 10, wherein:the tank has a insertion hole; and the end portion of the tube is inserted into the insertion hole.
- 16. The heat exchanger of claim 10, wherein the cut surface includes first and second cut surfaces respectively provided at both ends of the end portion in the cross-sectional long side direction to define the end portion width therebetween.
- 17. A heat exchanger comprising:a flat tube having a longitudinal side end portion in a longitudinal direction thereof, the longitudinal side end portion having an end portion width smaller than a tube width at a portion of the tube other than the end portion, the end portion width and the tube width being perpendicular to the longitudinal direction and parallel to a cross-sectional long side direction of the tube, the tube defining therein a plurality of passage holes in which a first fluid flows, the plurality of passage holes being arranged in the cross-sectional long side direction; a fin joined to the tube to facilitate heat exchange between the first fluid flowing inside the tube and a second fluid flowing outside the tube; and a tank connected to the longitudinal side end portion of the tube to communicate with the plurality of passage holes, wherein: the tube has an upstream side end portion and a downstream side end portion in the cross-sectional long side direction in which the second fluid flows from the upstream side end to the downstream side end, the downstream side end portion being tapered so that a thickness of the downstream side end portion in a cross-sectional short side direction of the tube is decreased toward a front tip thereof; and the longitudinal side end portion of the tube is formed by a cut surface which is formed by cutting a part of the tapered downstream side end portion to extend in the longitudinal direction.
- 18. The heat exchanger of claim 7, wherein the plurality of passage holes are arranged within the end portion width to always extend in and open at the longitudinal end portion.
- 19. A heat exchanger comprising:a tube having a notch portion at an end in a longitudinal direction of the tube to have an longitudinal end portion, the longitudinal end portion being defined by a cut surface of the notch portion to have an end portion width perpendicular to the longitudinal direction, the end portion width being smaller than a tube width of a portion other than the end portion in the tube; a fin joined to the tube to facilitate heat exchange between a first fluid flowing inside the tube and a second fluid flowing outside the tube; and a tank connected to the longitudinal end portion of the tube, wherein: the tube has a plurality of passage holes arranged in a direction parallel to the end portion width with a pitch, each of the plurality of passage holes communicating with the tank and extending in the tube in the longitudinal direction; and the plurality of passage holes includes a hole which is disposed most adjacently to the cut surface with a specific distance from the cut surface, the specific distance being larger than the pitch.
- 20. The heat exchanger of claim 19, wherein all of the plurality of passage holes extend in and open at the longitudinal
Priority Claims (1)
Number |
Date |
Country |
Kind |
11-145323 |
May 1999 |
JP |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
A-11-351783 |
Dec 1999 |
JP |