JP4216643B2 - Manufacturing method of flat tube for heat exchanger - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a flat tube used in a heat exchanger such as a condenser or an evaporator of an air conditioner.
[0002]
[Prior art]
As a conventional method for producing a flat tube for heat exchange, a plurality of protrusions and grooves are alternately formed symmetrically on the inner surface side of a plate material with a bent portion provided at the center in the width direction as a boundary, and the bent portion There is known a method in which a plate material is folded in half, and the opposite protrusions are brought into close contact with each other and brazed (see Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-182928 (page 8, FIG. 18)
[0004]
[Problems to be solved by the invention]
The plate material is folded into a V shape by roll forming, and the opposing projections are brought into close contact with each other by being folded in a wrist-like process, but in order to bend the bent portion into a U shape in the roll forming process, Not only does the bending point shape of one roll become complicated and disadvantageous in terms of cost, but the thickness of the bending point portion decreases as the bending angle of the plate material decreases, and the tool life is shortened.
[0005]
In addition, the projections and grooves of the plate material are formed by rolls, presses, etc., but the plate material tends to be hardened and hardened at the time of forming the projections and grooves, while the bent portion is flat. In addition, due to this work hardening, the bent portion is deformed when the wrist-like is reshaped, so that the opposing projections are displaced from each other and it is difficult to obtain accuracy.
[0006]
As described above, when the protrusions facing each other shift, the shape formed between the grooves facing each other is shifted and the inner shape becomes unstable, resulting in reduced pressure strength and heat dissipation performance, Further, when the bent portion is deformed and the outer shape becomes unstable, the flat tube may be poorly inserted into the header tank or brazed.
[0007]
Therefore, the present invention provides a method for producing a flat tube for a heat exchanger that can appropriately bend a plate material into two to increase the forming accuracy.
[0008]
[Means for Solving the Problems]
In the present invention, the inner surface side of the bent portion provided in the width direction of the plate material is a convex portion having the same height as the protrusion provided on the inner surface side of the plate material, and the outer surface side of the bent portion is A concave portion is formed in the central portion, the plate material is folded in half from the center of the bent portion, and the opposing protrusions are brought into close contact with each other and brazed.
[0009]
【The invention's effect】
According to the present invention, when the plate material is bent into a V-shape by roll forming in the process of folding the plate material in two and overlapping, the inner surface side of the bent portion of the plate material has the same height as the protrusion. Since it is a convex portion, one roll cross-sectional shape for processing the inner surface side of the plate material can be a simple V-shape, while a concave portion is formed in the center portion on the outer surface side of the bent portion of the plate material, Since the plate thickness at the center of the bent portion is reduced, the V-shaped bending of the plate material can be performed with high precision without complicating the roll shape.
[0010]
And, when the plate material is overlapped and formed into two folds in the wrist-like process after the V-shaped bending process, the convex part of the bent part is overlapped in two from the center to become a solid state, The bending point is not deformed and shifted, and the protrusions can be formed in close contact with each other accurately, and both the inner shape and the outer shape of the flat tube can be accurately formed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0012]
1 to 7 show a first embodiment of the present invention. FIG. 1 is a cross-sectional view of a flat tube obtained by the method of the present invention, and FIG. 2 is a cross-section of a plate material in which protrusions and grooves are processed on the inner surface side. 3 is an enlarged view of the A range portion of FIG. 2, FIG. 4 is a sectional view showing a V-shaped bending state of the plate material, FIG. 5 is an enlarged view of the B range portion of FIG. 4, and FIG. FIG. 7 is an enlarged view of a C range portion of FIG. 6.
[0013]
The heat exchanger to which the flat tube of this embodiment is applied is configured to circulate a heat exchange medium by connecting a plurality of parallel arranged flat tubes between a pair of opposed headers as is generally known. The heat exchange medium introduced into one header is fed to the other header via the flat tube, and the flat tube is circulated. Heat exchange is performed between the heat exchange medium and the air flowing between the flat tubes.
[0014]
In this embodiment, when the heat exchanger is used in a refrigeration cycle or a heat pump cycle in which carbon dioxide is used as a refrigerant as a heat exchange medium, the internal pressure of the heat exchanger is significantly increased. As described above, the flat tube 1 has a structure in which a plurality of passages 3 partitioned by the partition walls 2 are arranged in parallel in order to ensure pressure resistance.
[0015]
As shown in FIGS. 2 and 3, this flat tube 1 is provided with a bent portion 5 at the center in the width direction of a plate material 4 made of an aluminum material. A plurality of protrusions 6 and grooves 7 are alternately formed symmetrically with respect to the bent portion 5 as a boundary, the plate member 4 is folded in two at the bent portion 5, and the opposing protrusions 6 and 6 are brought into close contact with each other. Obtained by brazing.
[0016]
That is, the partition 2 is constituted by the opposed protrusions 6 and 6, and the passage 3 is constituted by the opposed grooves 7 and 7.
[0017]
As described above, a clad material having an aluminum material as a base material and a brazing material layer provided on the inner and outer surfaces is used as the plate material 4 as described above. 7 and.
[0018]
Here, the bent portion 5 is formed with a convex portion 5 a having the same height as the projection 6 on the inner surface side, and a concave portion 5 b provided at the center portion on the outer surface side of the bent portion 5. The thickness t1 of the center of the plate 4 is smaller than the thickness t2 of the portion of the plate 4 where the groove 7 is formed (t1 <t2).
[0019]
The plate 4 obtained in this way is folded in half as follows.
[0020]
FIGS. 4 and 5 show a roll forming step before the plate material 4 is folded in two. In this roll forming step, the lower roll 10 and the upper roll 11 are used to place the plate material 4 on the basis of the center of the bent portion 5. It is designed to be bent into a letter shape.
[0021]
In this roll forming process, the plate 4 is passed through a plurality of pairs of upper and lower pairs of rolls 10 and 11, and the V-shaped bending angle is gradually narrowed. The V groove of the lower roll 11 used in this roll forming process The top portion 11a is formed flat, while the V-projection top portion 10a of the upper roll 10 has a simple V shape.
[0022]
The upper and lower rolls 10 and 11 are used to bend the plate material 4 into a V shape with the center of the bent portion 5 as a base point. In order to perform the V shape bending of the plate material 4 with higher accuracy, for example, as shown in FIG. Thus, it is preferable to provide the notch 8 in the center of the concave portion 5b which is the outer surface side of the bent portion 5.
[0023]
And after bending the board | plate material 4 to the V shape of a required clamping angle by the said roll forming process, as shown in FIG.6, 7, the board | plate material 4 is completely folded in half by the left-right rolls 12 and 13 at a wrist-like process. The flattened tube 1 shown in FIG. 1 is configured by bringing the protrusions 6 and 6 and the convex portions 5a and 5a facing each other into close contact with each other.
[0024]
The flat tube 1 is finally heated in a heating furnace (not shown) in a heating process to braze the opposing protrusions 6 and 6 and the protrusions 5a and 5a together. In this heating process, the flat tube 1 is flattened. A plurality of tubes 1 are connected in communication with a pair of headers (not shown), and a heat exchanger is formed by interposing a radiating fin between each flat tube 1, 1. The tube 1 and the radiating fin are brazed and joined at once, and the above-described projections 6 and 6 and the projections 5a and 5a are brazed and joined simultaneously in the heating step.
[0025]
As described above, according to the present embodiment, when the plate material 4 is bent into a V shape by roll forming in the process of folding the plate material 4 in two and overlapping, the bending portion 5 of the plate material 4 Since the convex portion 5 a having the same height as the protrusion 6 is provided on the inner surface side, the cross-sectional shape of one roll 10 that processes the inner surface side of the plate material 4 can be a simple V-shape. Since the concave portion 5b is formed in the central portion of the outer surface 5 and the thickness of the central portion of the bent portion 5 is thinned, the V-shaped bending of the plate material 4 can be accurately performed without complicating the roll shape. Can be done well.
[0026]
Then, when the plate material 4 is folded and folded in a wrist-like process after the V-shaped bending process, the convex portion 5a of the bent portion 5 is folded in two from the center to become a solid state. Therefore, the bending point is not deformed and shifted, and the protrusions 6 and 6 can be formed in close contact with each other accurately, and both the inner shape and the outer shape of the flat tube 1 can be formed with high accuracy. it can.
[0027]
8 to 13 show a second embodiment of the present invention. FIG. 8 is a cross-sectional view of a plate material in which protrusions and grooves are processed on the inner surface side, FIG. 9 is an enlarged view of a D range portion of FIG. Is a cross-sectional view showing a V-shaped bending state of a plate material, FIG. 11 is an enlarged view of an E range portion of FIG. 10, FIG. 12 is a cross-sectional view showing a processing state of overlapping the plate material in two, and FIG. It is an enlarged view of F range part.
[0028]
In the present embodiment, similarly to the first embodiment, a bent portion 5 is provided at the center in the width direction of the plate material 4, and a plurality of protrusions 6 are symmetrically formed on the inner surface side of the plate material 4 with the bent portion 5 as a boundary. The grooves 7 are formed alternately.
[0029]
Here, in the present embodiment, the bending guide protrusion 5c is provided at the center on the inner surface side of the bending portion 5 with a width smaller than the thickness width of the flat tube 1 to be molded, and the bending guide protrusion 5c. A V-shaped cutout groove 5d is formed with each of the both side forming bases as groove tops.
[0030]
The protruding height of the bending guide protrusion 5c is substantially the same as that of the protrusion 6, and both side surfaces thereof are inclined surfaces, and one of the groove side surfaces of the notch groove 5d is constituted by the side surface of the bending guide protrusion 5c. Yes.
[0031]
In this second embodiment, as shown in FIGS. 10 and 11, after the plate material 4 is bent into a V shape with the notch groove 5d of the bent portion 5 as a base point in the roll forming process as shown in FIGS. In the like process, the flat plate 1 is configured by completely overlapping the plate material 4 in two and bringing the protrusions 6 and 6 facing each other into close contact with each other.
[0032]
Also in this embodiment, the flat tube 1 is brazed and joined between the protrusions 6 and 6 in the heating process after the heat exchanger is configured.
[0033]
In the present embodiment, as described above, the plate material 4 is folded in half with the notch grooves 5d on both sides of the bending guide projection 5c as the base point, so that the plate material 4 is accurate without causing any deviation along the side surface of the bending guide projection 5c. Bending can be performed well, and thus the same effect as in the first embodiment can be obtained.
[0034]
In each of the above-described embodiments, one bent portion 5 is provided in the central portion in the width direction of the plate material 4, but in addition to this, two bent portions are provided in the plate material 4 at a required interval, and the plate material is provided by these bent portions. You may make it fold in half.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a flat tube obtained by the method of the present invention.
FIG. 2 is a cross-sectional view of a plate material according to the first embodiment of the present invention.
FIG. 3 is an enlarged view of an area A in FIG. 2;
FIG. 4 is a cross-sectional view showing a V-shaped bending state of a plate material according to the first embodiment of the present invention.
FIG. 5 is an enlarged view of a B range portion in FIG. 4;
FIG. 6 is a cross-sectional view showing a processed state where the plate material is folded in two in the first embodiment of the present invention.
7 is an enlarged view of a C range portion in FIG. 6;
FIG. 8 is a cross-sectional view of a plate material according to a second embodiment of the present invention.
9 is an enlarged view of a D range portion of FIG.
FIG. 10 is a cross-sectional view showing a V-shaped bending state of a plate material according to a second embodiment of the present invention.
11 is an enlarged view of an E range portion of FIG.
FIG. 12 is a cross-sectional view showing a processing state in which a plate material is overlapped in two according to a second embodiment of the present invention.
13 is an enlarged view of the F range portion of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Flat tube 2 Partition 3 Passage 4 Board | plate material 5 Bending part 5a Convex part 5b Concave part 5c Bending guide protrusion 5d Notch groove 6 Protrusion 7 Groove 8 Notch

Claims (1)

A bent portion (5) is provided in the width direction of the plate material (4), and a plurality of protrusions (6) and grooves (7) are alternately arranged in parallel with the bent portion (5) on the inner surface side of the plate material (4). In the method of manufacturing a flat tube for a heat exchanger by forming and folding the plate material (4) into two at the bent portion (5), brazing the opposing protrusions (6), (6) closely together,
The inner surface side of the bent portion (5) of the plate material (4) is formed as a convex portion (5a) having the same height as the projection (6), and a concave portion (in the central portion on the outer surface side of the bent portion (5) ( 5b), and the plate (4) is folded in half from the center of the bent portion (5), a method for producing a flat tube for a heat exchanger.

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