U.S. patent application number 11/729542 was filed with the patent office on 2007-10-04 for heat exchanger.
This patent application is currently assigned to DENSO Corporation. Invention is credited to Yukinori Hatano, Shizuo Maruo, Takeshi Okinotani, Hirokazu Takeuchi, Akira Yanagida.
Application Number | 20070227714 11/729542 |
Document ID | / |
Family ID | 38513637 |
Filed Date | 2007-10-04 |
United States Patent
Application |
20070227714 |
Kind Code |
A1 |
Takeuchi; Hirokazu ; et
al. |
October 4, 2007 |
Heat exchanger
Abstract
A heat exchanger has a flat tube and a header in communication
with the flat tube. The flat tube has a flat passage part and a
groove part. The flat passage part defines a fluid passage therein.
The groove part extends along the flat passage part. An end of the
groove part is recessed from an end of the flat passage part in a
longitudinal direction of the flat tube. The header has a tube
insertion hole having a shape corresponding to an outline of the
flat passage part. The end of the flat passage part is received in
and fixed to the tube insertion hole of the header.
Inventors: |
Takeuchi; Hirokazu;
(Chita-gun, JP) ; Okinotani; Takeshi;
(Nagoya-city, JP) ; Yanagida; Akira; (Kariya-city,
JP) ; Hatano; Yukinori; (Okazaki-city, JP) ;
Maruo; Shizuo; (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: |
38513637 |
Appl. No.: |
11/729542 |
Filed: |
March 29, 2007 |
Current U.S.
Class: |
165/151 ;
165/173 |
Current CPC
Class: |
F28F 1/08 20130101; F28D
1/05383 20130101; F28F 1/022 20130101; F28F 9/04 20130101 |
Class at
Publication: |
165/151 ;
165/173 |
International
Class: |
F28D 1/04 20060101
F28D001/04; F28F 9/02 20060101 F28F009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2006 |
JP |
2006-098467 |
Claims
1. A heat exchanger comprising: a flat tube; and a header in
communication with the flat tube, wherein the flat tube has a flat
passage part that defines a fluid passage therein through which a
fluid flows and a groove part, the groove part has a plate shape
having a thickness smaller than a thickness of the flat passage
part, the groove part extends along the flat passage part and an
end of the groove part is recessed from an end of the flat passage
part by a predetermined distance in a longitudinal direction of the
flat tube, the header has a tube insertion hole having a shape
corresponding to an outline of the flat passage part, and the end
of the flat passage part is received in the tube insertion
hole.
2. The heat exchanger according to claim 1, wherein the flat tube
has a plurality of flat passage parts including the flat passage
part, the plurality of flat passage parts is aligned in a direction
in which a width of the flat passage part is measured, and the
groove part is disposed between the adjacent flat passage parts and
connects the adjacent flat passage parts.
3. The heat exchanger according to claim 2, wherein the groove part
has a flat plate shape.
4. The heat exchanger according to claim 2, wherein the groove part
is provided by a plate including a bend.
5. The heat exchanger according to claim 4, wherein the plate
includes a first plate portion and a second plate portion connected
through the bend, the first plate portion and the second plate
portion are staggered in a direction in which the thickness of the
flat passage part is measured.
6. The heat exchanger according to claim 1, wherein the groove part
is a first groove part, and the flat tube further has a second
groove part, wherein the first groove part and the second groove
part project from opposite sides of the flat passage part in a
direction in which a width of the flat passage part is
measured.
7. The heat exchanger according to claim 6, wherein the flat tube
is one of a plurality of flat tubes, the plurality of flat tubes
are aligned in the direction in which the width of the flat passage
part is measured, the header has a plurality of tube insertion
holes including the tube insertion hole, and each of the plurality
of tube insertion holes has a shape corresponding to the outline of
the flat passage part of each of the plurality of tubes.
8. The heat exchanger according to claim 1, wherein the end of the
flat passage part is brazed with a perimeter of the tube insertion
hole.
9. The heat exchanger according to claim 1, wherein the end of the
flat passage part is located within the header and is spaced from
an inner surface of the header by a predetermined distance, the
inner surface opposed to the tube insertion hole in the
longitudinal direction of the flat tube.
10. The heat exchanger according to claim 1, wherein the end of the
groove part is in contact with an outer surface of the header.
11. The heat exchanger according to claim 1, wherein the header
includes a header plate and a header tank, the header plate and the
header tank are joined to each other and define a tank space
therebetween, and the header plate has the tube insertion hole.
12. The heat exchanger according to claim 1, wherein the flat tube
is one of a plurality of flat tubes, the plurality of flat tubes is
arranged in line in a direction in which the thickness of the flat
passage part is measured, the heat exchanger further comprising: a
plurality of fins disposed between the plurality of flat tubes.
13. The heat exchanger according to claim 12, wherein the plurality
of fins is one of a plurality of corrugated fins and a plurality of
plate fins.
14. The heat exchanger according to claim 12, wherein the plurality
of fins are joined to outer surfaces of the flat passage parts of
the plurality of flat tubes, and clearances are maintained between
the groove part and the adjacent fins for providing draining
grooves.
15. The heat exchanger according to claim 1, wherein the flat tube
is coupled to the header such that the longitudinal direction of
the flat tube is perpendicular to a longitudinal direction of the
header, and a direction in which the thickness of the flat passage
part is measured is parallel to the longitudinal direction of the
header.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on Japanese Patent Application No.
2006-98467 filed on Mar. 31, 2006, the disclosure of which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a heat exchanger having
flat tubes.
BACKGROUND OF THE INVENTION
[0003] In a heat exchanger, e.g., an evaporator, it is known to
form draining grooves on flat tubes for smoothly draining
condensation adhered to fins away from the heat exchanger. A heat
exchanger having flat tubes with such draining grooves is for
example disclosed in Japanese Unexamined Patent Publications No.
7-190661 and No. 10-197173.
[0004] In manufacturing such flat tubes with the draining grooves,
it is generally required to reduce a materials cost. To meet this
demand, the flat tubes are formed by extrusion as thin as possible
such that the thickness at a position corresponding to the draining
groove is close to the limit of the extrusion (e.g., 0.3 mm).
[0005] In a header of the heat exchanger, tube insertion holes for
receiving ends of the flat tubes are formed such as by stamping in
the shape corresponding to the outline of the flat tubes including
the draining grooves. With the above decrease of the thickness of
the tubes, it is necessary to reduce a dimension of the tube
insertion holes. However, it is difficult to form the tube
insertion holes to correspond to the reduced thickness of the flat
tubes, particularly, at portions corresponding to the draining
grooves, which are very thin as the limit of the extrusion.
Otherwise, the thickness of the flat tubes may be increased to
increase the thickness at the positions corresponding to the
draining grooves so as to ease the forming of the tube insertion
holes. However, this may result in an increase of the materials
cost.
SUMMARY OF THE INVENTION
[0006] The present invention is made in view of the foregoing
matter, and it is an object of the present invention to provide a
heat exchanger in which a tube insertion hole is easily formed on a
header.
[0007] According to an aspect of the present invention, a heat
exchanger has a flat tube and a header in communication with the
tube. The flat tube has a flat passage part defining a fluid
passage therein through which a fluid flows and a groove part. The
groove part has a plate shape having a thickness smaller than a
thickness of the flat passage part. The groove part extends along
the flat passage part and an end of the groove part is recessed
from an end of the flat passage part by a predetermined distance in
a longitudinal direction of the flat tube. The header has a tube
insertion hole having a shape corresponding to an outline of the
flat passage part, and the end of the flat passage part is received
in the tube insertion hole.
[0008] The end of the groove part is recessed from the end of the
flat passage part and is not received in the header. Therefore, it
is not necessary to form the tube insertion hole in a shape
corresponding to a whole outline of the flat tube. That is, the
tube insertion hole has the shape corresponding to the outline of
the flat passage part. Accordingly, it is easy to form the tube
insertion hole on the header.
[0009] For example, the tube has a plurality of flat passage parts.
The flat passage parts are aligned in a direction in which a width
of the flat passage part is measured. The groove part is disposed
between and connect the adjacent flat passage parts. Also in this
case, the end of the groove part is recessed from the end of the
adjacent flat passage parts in the longitudinal direction of the
flat tube. Thus, only the ends of the flat passage parts are
received in the tube insertion holes of the header. The tube
insertion holes merely have the shape corresponding to the outline
of the flat passage part. Therefore, the tube insertion holes are
easily formed.
[0010] Alternatively, the tube has two groove parts on opposite
sides of the flat passage part. The groove parts have plate shape
projecting from the sides of the flat passage part in the direction
in which the width of the flat passage part is measured. Also in
this case, the ends of the groove parts are recessed from the end
of the flat passage part so that only end of the flat passage part
is received in the tube insertion hole. Therefore, the tube
insertion hole merely has the shape corresponding to the outline of
the flat passage part. Thus, the tube insertion hole is easily
formed. For example, the tubes may be arranged in the direction in
which the width of the flat passage part is measured such that the
groove parts of adjacent tubes do not overlap with each other.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Other objects, features and advantages of the present
invention will become more apparent from the following detailed
description made with reference to the accompanying drawings, in
which like parts are designated by like reference numbers and in
which:
[0012] FIG. 1A is a schematic perspective view of a heat exchanger
according to a first embodiment of the present invention;
[0013] FIG. 1B is an enlarged view of a part of the heat exchanger
denoted by a bashed line 1B in FIG. 1A;
[0014] FIG. 2A is a plan view of an end of a flat tube of the heat
exchanger when viewed along an arrow A1 in FIG. 1B;
[0015] FIG. 2B is a schematic cross-sectional view of the flat tube
taken along a line IIB-IIB in FIG. 2A;
[0016] FIG. 2C is a partial plan view of a header plate of a header
of the heat exchanger according to the first embodiment;
[0017] FIG. 2D is a cross-sectional view of the header according to
the first embodiment;
[0018] FIG. 3 is an explanatory view for showing insertion of the
flat tube into the header according to the first embodiment;
[0019] FIG. 4 is a cross-sectional view of the header in which the
end of the flat tube is coupled according to the first
embodiment;
[0020] FIG. 5A is a plan view of an end of a flat tube of a heat
exchanger according to a second embodiment of the present
invention;
[0021] FIG. 5B is a schematic cross-sectional view of the flat tube
taken along a line VB-VB in FIG. 5A;
[0022] FIG. 5C is a partial plan view of a header plate of a header
of the heat exchanger according to the second embodiment;
[0023] FIG. 5D is a cross-sectional view of the header according to
the second embodiment;
[0024] FIG. 6A is a plan view of an end of a flat tube of a heat
exchanger according to a third embodiment of the present
invention;
[0025] FIG. 6B is a schematic cross-sectional view of the flat tube
taken along a line VIB-VIB in FIG. 6A;
[0026] FIG. 6C is a partial plan view of a header plate of a header
of the heat exchanger according to the third embodiment; and
[0027] FIG. 6D is a cross-sectional view of the header according to
the third embodiment.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS
First Embodiment
[0028] A first embodiment of the present invention will now be
described with reference to FIGS. 1A through 4. A heat exchanger 1
shown in FIG. 1 is for example an evaporator of a refrigerating
cycle and is generally located outside of a compartment/room. The
heat exchanger 1 has flat tubes 2, corrugated fins 3 and headers 4.
In FIG. 1, the flat tubes 2 and the corrugated fins 3 are simply
illustrated for convenience of illustration.
[0029] In the figures, an arrow D1 denotes a longitudinal direction
of the flat tubes 2, an arrow D2 denotes a direction perpendicular
to the longitudinal direction D1 and in which a width of the flat
tube 2 (flat passage part) is measured. Also, an arrow D3 denotes a
direction in which a thickness of the flat tube 2 (flat passage
part) is measured. In this embodiment, the direction D3 also
corresponds to a longitudinal direction of the header 4 of the heat
exchanger 1. The direction D3 is perpendicular to the directions
D1, D2. Hereafter, the direction D1 is referred to as a tube
longitudinal direction, the direction D2 is referred to as a tube
transverse direction, and the direction D3 is referred to as a
header longitudinal direction.
[0030] The tubes 2 are arranged parallel to each other such that
flat surfaces of the adjacent tubes 2 are opposed to each other in
the header longitudinal direction D3. The corrugated fins 3 are
arranged between the tubes 2 and thermally connected to the flat
surfaces of the tubes 2.
[0031] The headers 4 are disposed at longitudinal ends of the stack
of tubes 2 and corrugated fins 3. Longitudinal ends of the tubes 2
are coupled to the headers 4. The headers 4 are provided with a
refrigerant inlet port and a refrigerant outlet port, respectively.
The heat exchanger 1 further has end plates 5 at ends of the stack
of tubes 2 and corrugated fins 3 for protecting the corrugated fins
3 arranged on outermost layers of the stack of tubes 2 and
corrugated fins 3.
[0032] As shown in FIGS. 1B, 2A, 2B, each of flat tubes 2 has flat
passage parts 6a, 6b, 6c aligned in the tube transverse direction
D2. In the illustrated example, the tube 2 has three flat passage
parts. Each of the flat passage parts 6a, 6b, 6c generally has a
flat shape. As shown in FIG. 2B, in a cross-section of each flat
passage part 6a, 6b, 6c defined in a direction perpendicular to the
tube longitudinal direction D1, a dimension (thickness) in the
header longitudinal direction D3 is smaller than a dimension
(width) in the tube transverse direction D2 (left and right
direction in FIG. 2B).
[0033] Further, each of the flat passage parts 6a, 6b, 6c has a
plurality of refrigerant passages 7 therein. The refrigerant
passages 7 are aligned in the tube transverse direction D2. The
refrigerant passages 7 extend in the tube longitudinal direction D1
from an end to the other end and allows communication between the
upper and lower headers 4.
[0034] Also, each tube 2 has a first groove plate 8a and a second
groove plate 8b as groove parts. The first flat passage part 6a and
the second flat passage part 6b are connected through the first
groove plate 8a. Likewise, the second flat passage part 6b and the
third flat passage part 6c are connected through the second groove
plate 8b.
[0035] The first and second groove plates 8a, 8b have a thin plate
shape. Thus, a thickness of the first and second groove plates 8a,
8b is smaller than the dimension (thickness) of the first to third
flat passage parts 6a, 6b, 6c in the header longitudinal direction
D3. In the stack of tubes 2 and corrugated fins 3, outer surfaces
of the flat passage parts 6a, 6b, 6c are joined to the corrugated
fins 3, and clearances are maintained between the corrugated fins 3
and the first and second groove plates 8a, 8b.
[0036] The first and second groove plates 8a, 8b extend in the tube
longitudinal direction D1. Thus, the clearances provided between
the first and second groove plates 8a, 8b and the corrugated fins 3
serve as draining groves for draining condensation in the tube
longitudinal direction D1.
[0037] As shown in FIG. 2A, ends 11 of the first and second groove
plates 8a, 8b are recessed from ends 10 of the first to third flat
passage parts 6a, 6b, 6c in the tube longitudinal direction D1 such
that notches 9 are formed at the longitudinal end of the tube 2.
For example, in FIG. 2A, a length of the first and second groove
plates 8a, 8b from a line IIB-IIB (reference position) to the ends
11 thereof is smaller than a length of the flat passage parts 6a,
6b, 6c from the line IIB-IIB to the ends 10 thereof.
[0038] Each of the headers 4 is constructed of a header plate 12
and a header tank 13. The header plate 12 and the header tank 13
have length in the header longitudinal direction D3. The headers 4
are arranged such that the header plate 12 of one header 4 is
opposed to the header plate 12 of the other header 4 relative to
the tube longitudinal direction D1.
[0039] As shown in FIG. 2C, each header plate 12 is formed with a
plurality of first to third tube insertion holes 16a, 16b, 16c on
its wall 15. Each of the first to third tube insertion holes 16a,
16b, 16c has a shape corresponding to the outline of the
cross-sectional shape of each of the flat passages parts 6a, 6b,
6c. The first to third tube insertion holes 16a, 16b, 16c are
aligned in the tube transverse direction D2. Each tube 2 is coupled
to the header 4 such that the ends 10 of the flat passage parts 6a,
6b, 6c are received in the tube insertion holes 16a, 16b, 16c.
[0040] In the illustrated example, each of the flat passage parts
6a, 6b, 6c has a hexagonal outline in the cross-section thereof.
Thus, each of the tube insertion holes 16a, 16b, 16c forms a
hexagonal opening.
[0041] For example, the tube 2 is formed by extrusion as thin as
possible. In this case, the thickness of the flat passage parts 6a,
6b, 6c is about 1 mm in the header longitudinal direction D3, for
example. Also, the thickness of the first and second groove plates
8a, 8b in the header longitudinal direction D3 is approximately 0.3
mm, which is generally a minimum thickness (limit) of the
extrusion.
[0042] In a case that groove plates are ended at the same position
as the ends of flat passage parts i.e., the ends of the groove
plates are aligned with the ends of the passage parts, it is
necessary to form an opening as the tube insertion hole in the
shape corresponding to an entire outline of the cross-section of
the tube including the groove plates. In this case, since the
groove plates are very thin as the limit of extrusion, it is
necessary to form the opening with a very small dimension as a
limit of stamping, particularly, at positions corresponding to the
groove plates.
[0043] In the first embodiment, on the other hand, the ends 11 of
the first and second groove plates 8a, 8b are not inserted to the
tube insertion holes 16a, 16b, 16c of the header plate 12.
Therefore, it is not necessary to form openings with such very
small dimension as the limit of stamping for receiving the ends 11
of the first and second groove plates 8a, 8b. The tube insertion
holes 16a, 16b, 16c only for receiving the ends 10 of the tubes 2,
which have the relatively simple outline, are formed on the wall 15
of the header plate 12. Since the dimension of the tube insertion
holes 16a, 16b, 16c are relatively large, the tube insertion holes
16a, 16b, 16c are easily formed.
[0044] Even if the tube 2 is extruded as thin as possible close to
the limit of extrusion, the tube insertion holes 16a, 16b, 16c are
easily formed by stamping. With this, the amount of material for
the tubes 2 is reduced. As such, a materials costs of the tubes 2
reduces.
[0045] As shown in FIG. 2D, the header plate 12 and the header tank
13 are brazed at longitudinal sides thereof (right and left ends in
FIG. 2D), thereby to provide a tank space 17 between them for
allowing the refrigerant to flow.
[0046] The tube 2 is coupled to the header 4, as shown in FIG. 3.
Specifically, the ends 10 of the flat passage parts 6a, 6b, 6c are
inserted into the tube insertion holes 16a, 16b, 16c in the tube
longitudinal direction D1. FIG. 4 shows a coupled condition of the
tube 2 and the header 4.
[0047] As shown in FIG. 4, when the tube 2 is coupled to the header
4, the ends 11 of the first and second groove plates 8a, 8b are
held on the wall 15 of the header plate 12. Thus, the ends 10 of
the flat passage parts 6a, 6b, 6c are held at a predetermined
position between the header plate 12 and the header tank 13 with
the tank space 17. Namely, the ends 10 of the flat passage parts
6a, 6b, 6c are inserted by the predetermined length (inserting
margin) D within the tank space 17, and a predetermined clearance
19 is maintained between the ends 10 of the flat passage parts 6a,
6b, 6c and an inner surface 18 of the header tank 13.
[0048] In this condition, the outer peripheries of the flat passage
parts 6a, 6b, 6c and the perimeters of the tube insertion holes
16a, 16b, 16c are brazed to have fluid-tightness. Accordingly, the
tubes 2 and the headers 4 are joined.
[0049] Since the clearance 19 is maintained between the ends 10 of
the flat passage parts 6a, 6b, 6c and the inner surface 18 of the
header tank 13, the flow of the refrigerant in the refrigerant
passages 7 and the tank space 17 is facilitated. Here, the
dimension of the notches 9 in the tube longitudinal direction D1
can be determined in accordance with the inserting margin D and the
dimension of the clearance 19, which is required for allowing the
refrigerant to smoothly flow in the tank space 17.
[0050] The ends 11 of the first and second groove plates 8a, 8b are
configured to be held on the wall 15 of the header plate 12.
Therefore, it is not always necessary to make the ends 11 of the
first and second groove plates 8a, 8b fully contact the wall 15 of
the header plate 12. Namely, it is not necessary to process the
notches 9 precisely. The notches 9 are easily formed.
[0051] Also, since the tube insertion holes 16a to 16c have the
relatively simple shape, the quality of brazing between the ends 10
of the flat passage parts 16a to 16c and the header plate 12
improves.
Second Embodiment
[0052] A second embodiment will be described with reference to
FIGS. 5A to 5D. Here, the shape of draining grooves of the flat
tubes 2 is different from that of the flat tube 2 of the first
embodiment. Hereafter, like parts are denoted by like reference
numerals and a description thereof will not be repeated.
[0053] As shown in FIGS. 5A and 5B, the flat tube 2 has first to
third flat passage parts 21a, 21b, 21c aligned in the tube
transverse direction D2. Also, the flat tube 2 has a first groove
part 22 between the first and second flat passage parts 21a, 21b
and a second groove part 23 between the second and third flat
passage parts 21b, 21c. The first groove part 22 and the second
groove part 23 have a plate shape but includes a bend.
[0054] Specifically, the first groove part 22 includes a first
plate portion 22a, a second plate portion 22c and a bend portion
22b between the first and second plate portions 22a, 22c. The bend
portion 22b is located at a substantially middle position of the
first groove part 22 in the tube transverse direction D2. The first
plate portion 22a and the second plate portion 22c are staggered in
the header longitudinal direction D3 by the bend portion 22b.
[0055] For example, the first plate portion 22a connects to a first
surface of the first flat passage part 21a (lower surface in FIG.
2B), and the second plate portion 22c connects to a second surface
of the second flat passage part 21b (upper surface in FIG. 2B). The
bend portion 22b connects the first and second plate portions 22a,
22c.
[0056] Likewise, the second groove part 23 includes a first plate
portion 23a, a second plate portion 23c and a bend portion 23b
between the first and second plate portions 23a, 23c. The bend
portion 23b is located at a substantially middle position of the
second groove part 23 in the tube transverse direction D2. The
first plate portion 23a and the second plate portion 23c are
staggered in the header longitudinal direction D3 by the bend
portion 23b.
[0057] For example, the first plate portion 23a connected to a
first surface of the second flat passage part 21b (lower surface in
FIG. 2B), and the second plate portion 23c connects to a second
surface of the third flat passage part 21c (upper surface in FIG.
2B). The bend portion 23b connects the first and second plate
portions 23a, 23c.
[0058] Although not illustrated in FIGS. 5A to 5B, corrugated fins
are arranged between the adjacent tubes 2 that are stacked in the
header longitudinal direction D3, similar to the first embodiment.
The corrugated fins are thermally connected to the tubes 2. Each of
the first and second groove parts 22, 23 provides two draining
grooves. The dimension (depth) of the draining grooves
substantially corresponds to a distance between the first surface
and the second surface of the flat passage parts 21a, 21b, 21c in
the header longitudinal direction D3. Thus, the depth of the
draining grooves is larger than that of the first embodiment.
Accordingly, the condensation is more efficiently collected in the
draining grooves and more efficiently drained, as compared to the
first embodiment.
[0059] Similar to the first embodiment, ends 11 of the first and
second groove parts 22, 23 are recessed from ends 10 of the flat
passage parts 21a, 21b, 21c in the tube longitudinal direction D1
to have the notches 9 at the longitudinal end of the tube 2. When
the longitudinal end of the tube 2 is inserted to tube insertion
holes 24a, 24b, 24c of the header plate 12, the ends 11 of the
first and second groove parts 22, 23 are held on the wall 15 of the
header plate 12. Therefore, the inserting margin D of the ends 10
of the flat passage parts 21a, 21b, 21c relative to the header 4 is
determined.
[0060] FIG. 2C shows the shape of the tube insertion holes 24a,
24b, 24c. Here, the tube insertion holes 24a, 24b, 24c have the
shape corresponding to the outline of the first to third flat
passage parts 21a, 21b, 21c, respectively. The first and third tube
insertion holes 24a, 24c for receiving the end 10 of the first and
third flat passage parts 21a, 21c have a pentagonal shape and the
second tube insertion hole 24b for receiving the ends 10 of the
second flat passage part 21b has a parallelogram shape.
[0061] Since the ends 11 of the first and second groove parts 22,
23 are recessed from the ends 10 of the first to third flat passage
parts 21a, 21b, 21c in the tube longitudinal direction D1, it is
not necessary to form openings or holes on the header plate 12 for
receiving the ends 11 of the first and second groove parts 22, 23.
Namely, the tube insertion holes 24a, 24b, 24c are formed only for
receiving the ends 10 of the flat passage parts 21a, 21b, 21c,
which have the relatively simple shape. Therefore, the tube
insertion holes 24a, 24b, 24c are easily formed on the header plate
12.
[0062] Similar to the first embodiment, even if the tube 2 is
extruded as thin as possible, the tube insertion holes 24a, 24b,
24c are easily processed such as by stamping. Also, the amount of
material of the tubes 2 reduces. As such, the materials cost of the
tubes 2 reduces.
Third Embodiment
[0063] A third embodiment will be described with reference to FIGS.
6A to 6D. Here, the shape and arrangement of the flat tubes is
different from that of the flat tubes of the first and second
embodiments. Hereafter, like parts are denoted by like reference
numerals and a description thereof will not be repeated.
[0064] As shown in FIGS. 6A and 6B, two flat tubes 20a, 20b are
aligned in the tube transverse direction D2. The first flat tube
20a has a first flat passage part 25a having a hexagonal outline in
a cross-section defined in the tube transverse direction D2. The
first flat passage part 25a defines refrigerant passages 7 therein.
The first flat tube 20a further has projections 26a, 26b as the
groove parts. The projections 26a, 26b project from opposite sides
of the first flat passage part 25a in the tube transverse direction
D2. The projections 26a, 26b are in the form of thin plate.
[0065] Likewise, the second flat tube 20b has a second flat passage
part 25b having a hexagonal outline in a cross-section defined in
the tube transverse direction D2. The second flat passage part 25b
defines refrigerant passages 7 therein. The second flat tube 20b
further has projections 27a, 27b as the groove parts. The
projections 27a, 27b project from opposite sides of the second flat
passage part 25b in the tube transverse direction D2. The
projections 27a, 27b are in the form of thin plate.
[0066] The projection 26b of the first flat tube 20a and the
projection 27a of the second flat tube 20b are adjacent to each
other in the tube transverse direction D2, but are not connected to
each other.
[0067] The first flat tubes 20a are arranged in line in the header
longitudinal direction D3 and the second flat tubes 20b are
arranged in line in the header longitudinal direction D3. Further,
the corrugated fins are arranged between the adjacent first and
second flat tubes 20a, 20b and thermally connected to the first and
second flat tubes 20a, 20b, similar to the first and second
embodiments. Thus, clearances are maintained between the corrugated
fins and the projections 26a, 26b, 27a, 27b. The clearances provide
the draining grooves for draining the condensation.
[0068] Each corrugated fin has a width corresponding to a distance
between an end of the projection 26a and an end of the projection
27b in the tube transverse direction D2. Thus, the sides of the
corrugated fins are protected by the projections 26a, 27b.
[0069] As shown in FIG. 6A, the ends 11 of the projections 26a,
26b, 27a, 27b are recessed from the ends 10 of the flat passage
parts 25a, 25b in the tube longitudinal direction D1. Thus, the
notches 9 are provided at the longitudinal ends of the first and
second flat tubes 20a, 20b.
[0070] As shown in FIGS. 6C and 6D, tube insertion holes 28a, 28b
are formed on the header plate 12 for receiving the ends 10 of the
flat passage parts 25a, 25b. For example, the tube insertion holes
28a, 28b are hexagonal openings to corresponds to the outline of
the flat passage parts 25a, 25b.
[0071] When the longitudinal ends of the first and second flat
tubes 20a, 20b are inserted into the tube insertion holes 28a, 28b
of the header plate 12 in the tube longitudinal direction D1, the
ends 11 of the projections 26a, 26b, 27a, 27b are held on the wall
15 of the header plate 12. As such, the inserting margin D of each
flat passage parts 25a, 25b relative to the header plate 12 is
determined.
[0072] Also in this case, it is not necessary to form openings for
inserting the ends of the projections 26a, 26b, 27a, 27b, which
serve as the draining grooves, on the header plate 12. Because the
shape of the tube insertion holes 28a, 28b for receiving the ends
10 of the flat passage parts 25a, 25b are relatively simple, the
tube insertion holes 28a, 28b are easily processed by such as
stamping.
[0073] Even if the first and second tubes 20a, 20b are extruded as
thin as possible, the tube insertion holes 28a, 28b are easily
formed on the header plate 12 such as by stamping. Since the first
and second tubes 20a, 20b are formed as thin as possible, the
amount of material of the flat tubes 20a, 20b is reduced. As such,
the materials cost of the tubes 20a, 20b reduces.
Other Embodiments
[0074] In the above embodiments, the wall 15 of the header plate 12
on which the tube insertion holes 16a to 16c, 24a to 24c, 28a, 28b
are formed is flat. However, the wall 15 is not limited to the flat
wall, but may have any shapes. For example, the wall 15 may have
curved shape or M-letter shape in a cross-section defined in a
direction perpendicular to the header longitudinal direction D3. In
this case, the shape of the notches 9 may be changed to correspond
to the shape of the wall 15 of the header plate 12, such as a
curved shape or a M-letter shape.
[0075] In the above embodiments, the ends 11 of the groove plates
8a, 8b, 22, 23, 26a, 26b, 27a, 27b are held on the wall 15 of the
header plate 12 so as to position the ends 10 of the flat passage
parts 6a, 6b, 6c, 21a, 21b, 25a, 25b within the tank space 17, when
the ends 10 of the tubes 2, 20a, 20b are inserted into the tube
insertion holes 16a, 16b, 16c, 24a, 24b, 24c, 28a, 28b. However,
the ends 10 of the flat passage parts 6a, 6b, 6c, 21a, 21b, 25a,
25b may be positioned by another way. For example, the flat tubes
2, 20a, 20b are positioned relative to the header 4 by using
different jigs so that the ends 11 are not in contact with the wall
15 of the header plate 12 and clearances are maintained between the
ends 11 and the wall 15 of the header plate 12.
[0076] In the above embodiments, the corrugated fins 3 are provided
as outer fins of the heat exchanger 1. However, the outer fins may
be another fins, such as plate fins.
[0077] Also, the number of flat passage parts 6a, 6b, 6c, 21a, 21
b, 21c of one flat tube 2 is not limited to three. Further, the
outlines of the flat passage parts 6a, 6b, 6c, 21a, 21b, 21c, 25a,
25b in the cross-section are not limited to the illustrated
shape.
[0078] In the third embodiment, it is not always necessary that
each tube 20a, 20b has two projections 26a, 26b, 27a, 27b. Instead,
each tube 20a, 20b may have one projection. For example, the
projections 26a 27b may be eliminated.
[0079] In the above embodiments, use of the heat exchanger is not
limited to the evaporator of the refrigerating cycle. Also, a fluid
flowing in the heat exchanger 1 is not limited to the
refrigerant.
[0080] In the above embodiments, the heat exchanger 1 is
constructed such that the fluid flows through the tubes 2 from one
header 4 to the other header, i.e., in one direction. However, the
structure of the heat exchanger 1 is not limited to the above. That
is, the present invention may be employed to a heat exchanger
having a fluid inlet and a fluid outlet on the same header and in
which the fluid flows in a U-turn manner. Also, the present
invention may be employed to a heat exchanger having a corrugated
flat tube in which the fluid flows in a serpentine manner.
[0081] The example embodiments of the present invention are
described above. However, the present invention is not limited to
the above example embodiment, but may be implemented in other ways
without departing from the spirit of the invention.
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