JPH0741331B2 - Welding tube for heat exchanger and manufacturing method thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a welded tube used for an aluminum heat exchanger such as an automobile radiator and a condenser, and a manufacturing method thereof.

[Conventional technology]

Conventionally, as this type of welded tube, for example, JP-A-55
The one disclosed in Japanese Patent Publication No. 126365 is known.

This will be described with reference to FIG. In the figure, reference numeral 1 is an aluminum heat exchanger welding tube having a substantially θ-shaped cross section.

The aluminum heat exchanger welded tube 1 is manufactured, for example, as follows. First, as shown in, for example, FIGS. 6 (a) and 6 (b), an aluminum plate 2 having a brazing material clad on its surface is divided into two stages by roll homing so that both side portions 3 and 3 thereof are in the same direction. Approximately 90
Bend every time. Next, this aluminum plate body 2 is bent into a flat tube shape by using a bending machine (not shown), and the both side parts 3, 3 are brought into contact with each other and protruded inward. Fix in this state with a jig. Alternatively, the fins and the tubes are alternately assembled and fitted to the seat plate and fixed to the jig as the heat exchanger core. Then, bring it into the heating furnace,
The parts to be joined are brazed by heating in a heating furnace according to a conventional method.

The brazing method is preferably a method using a non-corrosive flux, but may be a normal vacuum brazing method.

In this way, the manufactured aluminum heat exchanger welded tube 1 has a shape in which the welded part 5 has both side parts 3, 3 of the aluminum plate body 2 protruding inward as shown in FIG. The core of the aluminum heat exchanger can be formed by combining with the fin material.

[Problems to be Solved by the Invention] However, as shown in FIG. 7, the aluminum heat exchanger welded tube 1 manufactured by this conventional method has R portions 4 and 4 of both side portions 3 and 3, Since the plate thickness is the same as the plate thickness of the aluminum plate body 2, a concave groove 6 having a substantially triangular cross section is formed outside the welded portion 5.

Therefore, this aluminum heat exchanger welding tube 1
When the heat exchanger core is formed by using, the gap is formed between the seat plate 7 and the fitting hole 8 due to the presence of the concave groove 6, and a brazing pool is formed at the time of brazing with the seat plate 7. However, there is a risk of liquid leakage due to defective brazing. Therefore, the 8th
As shown in the drawing, when the projection 9 is provided on the seat plate 7 so as to close the concave groove 6 and the fitting hole 8 ′ is formed along the shape of the aluminum heat exchanger welding tube 1, the projection 9 is deformed and the aluminum There is a possibility that the welded tube 1 for the heat exchanger may not fit. Therefore, it is troublesome to manage the seat plate 7 in order to prevent the protrusion 9 from being deformed.

In addition, the conventional welding tube 1 for aluminum heat exchangers
Since the tips of the both side portions 3, 3 are separated from the facing wall surface 9, the wall surface 10 is recessed toward the tip of the both side portions 3, 3 as shown in FIG. Due to this recess, brazing failure with the fitting hole 8 of the seat plate 7 is induced, and liquid leakage at the seat plate portion easily occurs.

[Object of the Invention]

The present invention has been made in order to solve such a conventional problem, and an object thereof is to form an R-shape in a welded portion substantially at a right angle so that an outer concave groove is made as small as possible to easily form a brazing reservoir. Another object of the present invention is to provide a welded tube for a heat exchanger made of aluminum and a method of manufacturing the welded tube, which can prevent depression of the wall surface facing each other by bringing the welded portion into contact with the wall surface facing each other.

[Means for solving problems]

The heat exchanger welded tube according to the present invention is an aluminum plate material having a brazing material clad on the surface thereof, is bent in the same direction on both sides by roll homing, and is then made to project inward with both sides abutting. Then, in a welded tube for heat exchangers whose cross-sectional shape is approximately θ formed by brazing the relevant contact part, both sides of the aluminum plate material with the brazing material clad on the surface are bent at approximately right angles. At the same time, the tip end portion is brought into contact with the facing wall surface and integrally brazed.

In addition, the method for manufacturing a welded tube for a heat exchanger according to the present invention, an aluminum plate material having a brazing material clad on its surface is bent in the same direction on both sides by roll homing, and then both sides are in contact with each other. In the method for producing a welded tube for a heat exchanger whose cross-sectional shape is approximately θ, by brazing the corresponding contact portion after projecting inward with
Aluminum plate material with brazing material clad on the surface,
When both side portions are bent in the same direction at substantially right angles by roll homing, roll homing is performed in at least three stages.

[Operation of the invention]

In the present invention, since both side portions of an aluminum plate material having a brazing material clad on its surface are bent at substantially right angles, the concave groove formed outside the welded portion becomes extremely small, and the seat plate The gap formed when it is inserted into the fitting hole of is small, and the brazing material clad with the seat plate and the aluminum plate body easily accumulates in this part when the seat plate and the aluminum heat exchanger welded tube are brazed . Therefore, there is no risk of causing brazing failure. Further, since the tips of both sides of the aluminum plate body forming the welded portion are in contact with the opposing wall surfaces, they are not recessed by external force after being inserted into the fitting holes of the seat plate. The accuracy of brazing with the fitting hole is improved.

Further, according to the present invention, since the roll homing is performed in at least three stages, the R portions formed on both sides of the aluminum plate body are approximately 90 degrees, and when the both sides are joined, they can be formed on the outside. Almost no gaps in the vertical part.

Example of Invention

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a welded tube 20 for an aluminum heat exchanger according to this embodiment. This aluminum heat exchanger welded tube 20 has a cross-sectional shape of approximately θ, and a welded portion 21 is formed inside the substantially central portions of both wall surfaces 22 and 23. This welded portion 21 is made of an aluminum plate body 30 that constitutes one wall surface 22.
Bend in approximately 90 degrees in the same direction, and
Are joined to each other, and the tip end portion 32 thereof is brought into contact with the facing wall surface 23. still. Welded part 21
Is brazed integrally with its tip 32.

When the aluminum heat exchanger welded tube 20 thus constructed is inserted into the fitting hole 26 of the seat plate 25 as shown in FIG. 2, for example, the seam portion 27 outside the welded portion 21 is formed. Since it is almost flush with the brazing filler metal, the brazing filler metal does not spread sufficiently during brazing to prevent brazing defects. Further, since the welded portion 21 is in contact with the opposing wall surface 23, the wall surface 23 is prevented from being recessed inward. Therefore, the fitting hole 26 of the seat plate 25
It is possible to prevent the wall surface 23 from being dented inward by an external force when it is inserted into.

Next, a method of manufacturing the aluminum heat exchanger welded tube 20 shown in FIG. 1 will be described.

First, a long aluminum plate body 30 having a surface clad with a brazing material is prepared.

Next, as shown in FIG. 3 (a), the aluminum plate body 30 is subjected to primary bending processing on both side portions 31, 31 thereof using roll homing rolls 40, 40 having a bending angle of 45 degrees. . Next, as shown in FIG. 3B, both side portions 31 and 31 of the roll homing rolls 41 and 41 having a bending angle of 70 degrees are secondarily bent. Further, as shown in FIG. 3 (c), the roll homing rolls 42, 42 having a bending angle of 90 degrees are used, and both side portions 31, 31 are substantially omitted.
Bend to 90 degrees.

By processing up to these three steps, as shown in FIG. 4, both side parts 31, 31 of the aluminum plate body 30 are rounded at their bent portions.
Is less than the plate thickness, and the bent part is almost 90 degrees.

Then, the plate made of aluminum bent in this way
In the case of 30, the both side portions 31, 31 are bent in the same direction according to a conventional method, and the both side portions 31, 31 are joined so that the cross-sectional shape is substantially θ.

Then, the side portions 31, 31 are joined together, and the tip end portion 32,
It is fixed by a jig in a state where 32 is in contact with the facing wall surface 23, or is fixed to the jig while being assembled into a core and fitted in a fitting hole of a seat plate.

Then, according to a conventional method, it is carried into a heating furnace and heated at a desired temperature to braze each joint part.

Thus, the aluminum heat exchanger welded tube 20 shown in FIG. 1 can be obtained.

As described above, according to the present embodiment, since the outer joint portion 27 of the welded portion 21 can be made small, the fitting hole 26 of the seat plate 25 can be formed.
When inserted in, there is no risk of forming a gap, and no brazing failure occurs. Further, since the welded portion 21 is in contact with the facing wall surface 23, there is no problem that the facing wall surface 23 is recessed.

Although the brazing method is not particularly limited in the above embodiment, the brazing method using a non-corrosive flux is preferable because it is simple. When a non-corrosive flux is used, the aluminum plate body, the brazing material, etc. may be appropriately selected.

[Advantages of the Invention] As described above, according to the present invention, since the seam on the outer side of the welded portion can be made small, the fitting hole of the seat plate can be the fitting hole of the ordinary flat tube and the ordinary seat. By managing the plate, the fitting property of the seat plate into the fitting hole is improved, and the airtightness of the seat plate with the fitting hole is improved.

[Brief description of drawings]

FIG. 1 is an end view showing an embodiment in which the heat exchanger welded tube according to the present invention is applied to an aluminum heat exchanger welded tube, and FIG. 2 shows an aluminum heat exchanger welded tube according to the embodiment. FIG. 3 (a) to FIG. 3 (c) are enlarged views showing a state of being inserted into the fitting hole of the plate, FIGS. 3 (a) to 3 (c) are explanatory views showing a manufacturing process of the heat exchanger welded tube according to the present invention, and FIG. Fig. 5 is an enlarged view of the bent portion manufactured in c), Fig. 5 is an end view of a conventional welding tube for an aluminum heat exchanger, and Figs. 6 (a) and 6 (b) are for the same aluminum heat exchanger. Explanatory drawing which shows the manufacturing process of a welding tube, 7th
The figure is an enlarged view showing a state in which the same welding tube for aluminum heat exchanger is inserted into the fitting hole of the seat plate, and FIG. 8 is a seat plate corresponding to the concave groove of the conventional welding tube for aluminum heat exchanger. FIG. 9 is an enlarged view showing a modified example of the fitting hole of FIG. 9, and FIG. 9 is an enlarged view showing a recess in a conventional aluminum weld tube for a heat exchanger. 20 …… Welded tube for aluminum heat exchanger, 21 ……
Welded part, 22, 23 ... Wall surface, 25 ... Seat plate, 26 ... Fitting hole, 2
7 …… Seam part, 30 …… Aluminum plate, 31 …… Side part, 32 …… Tip part, 40,41,42 …… Rollers for roll home.

Claims (3)

[Claims] 1. An aluminum plate material having a brazing material clad on its surface is bent in the same direction by roll homing, and is then inwardly projected in a state where both side parts are in contact with each other. In a welded tube for heat exchangers, which has a cross-section of approximately θ, is brazed with aluminum, and both ends of an aluminum plate with a brazing material clad on its surface are bent at substantially right angles, A heat exchanger welded tube, characterized in that the two are abutted against the opposite wall surface and brazed integrally. 2. An aluminum plate material having a brazing material clad on its surface is bent by roll homing in the same direction on both sides, and is then inwardly projected with both side parts abutting, and then the corresponding contact part. In a method of manufacturing a welded tube for a heat exchanger having a substantially θ-shaped cross section by brazing, a plate made of aluminum with a brazing material clad on the surface is roll-homed on both sides in the same direction. A method for manufacturing a welded tube for a heat exchanger, which comprises performing roll-homing in at least three stages when bending at a substantially right angle. 3. A process of bending an aluminum plate material by roll homing at its right and left sides in the same direction at a substantially right angle, including a step of bending at about 45 degrees, a step of bending at about 70 degrees, and a step of bending at about 90 degrees. The method for manufacturing a welded tube for a heat exchanger according to claim 2, characterized in that the welded tube is molded separately.