JPH06304745A - Tube for heat exchanger - Google Patents

Abstract

PURPOSE:To obtain a tube for heat exchanger capable of suppressing diffusion of a brazing filler metal without causing brazing defect. CONSTITUTION:The tube constituting cooling medium path is produced with using a clad material 8 cladding a brazing filler metal 7 on one side of a base material 6. The base material 6 uses an aluminum sheet formed to a rectangular shape having a certain width D1. The brazing filler metal 7 with using an aluminum brazing filler metal containing Si is arranged with width D2 shorter than D1 width of the base material 6 so that both ends of the width direction are inside both ends of the base material 6. Accordingly, when a tubular body is formed face to face with both ends of the clad material 8 in the width direction, the prescribed intervals d1, d2 are formed between both ends of the brazing filler metal 7 with peripherally abutting both ends of the base material 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tube forming a fluid passage of a heat exchanger such as a radiator or a refrigerant condenser.

[0002]

2. Description of the Related Art Generally, a tube used for a heat exchanger has a base material (for example, Al--Mn system) 1 as shown in FIG.
A brazing material (for example, an aluminum brazing material containing Si) 120 having the same width as that of the base material 110 on one surface (or both surfaces) of 10
Clad material 100 clad with is used, and the clad material 100 is formed into a tubular shape, both end surfaces facing each other in the circumferential direction are joined by welding (see FIG. 7), and then formed into a predetermined tube shape. (See FIG. 8). However, in the tube 130 manufactured by the above method,
When the both end surfaces of the clad material 100 are welded, due to the influence of heat during welding, etc., a thicker portion of the brazing material 120 near the welded portion (the portion indicated by A in FIGS. 8 and 9) than other portions ( 9B). Note that FIG. 9 corresponds to FIG.
FIG. 4 is an enlarged view of the vicinity of the welded portion of FIG.

When this tube (see FIG. 10 (a)) is brazed, Si contained in the brazing material 120 diffuses into the base material 110 at the time of temperature rise during brazing to form a Si diffusion layer (FIG. 10). (See (b)). After that, the brazing filler metal 120 melts as the temperature rises, and the Si diffusion layer further melts (see FIG. 10C), but since the amount of Si is naturally large in the thick portion of the brazing filler metal 120, other A larger amount of Si diffuses into the base material 110 than in the portion. Therefore, the base metal 110 in the thick portion of the brazing filler metal 120 near the welded portion is selectively melted, which may eventually lead to the penetration of the base metal 110 (FIG. 10 (d). )reference). Note that FIG. 10 schematically shows a process in which Si diffuses into the base material 110 at the time of raising the temperature of brazing. Therefore, conventionally, in order to prevent the penetration of the base material 110 due to the diffusion of Si, the brazing temperature is lowered, the brazing time is shortened, the cladding rate is lowered (the brazing material 120 is thinned), and the like. Measures were taken.

[0004]

However, taking measures for lowering the brazing temperature, shortening the brazing time, lowering the cladding rate, etc., will provide the optimum brazing temperature, brazing time, and cladding rate. Can't do it. Therefore, the above-mentioned measures have a problem that a brazing defect is likely to occur. The present invention has been made based on the above circumstances, and an object thereof is to provide a tube for a heat exchanger capable of preventing penetration of a base material due to diffusion of a brazing filler metal without causing defective brazing. It is in.

[0005]

In order to achieve the above object, the present invention provides a clad material in which a brazing material is clad on one or both sides of a base material such that both end surfaces in the width direction face each other in the circumferential direction. In a tube for heat exchanger, which is formed into a tubular shape and is joined to the both end surfaces by welding, and then formed into a predetermined tube shape, the clad material is at both ends in the width direction of the brazing material. The technical means is to make the width of the brazing material shorter than the width of the base material by a predetermined length so that the end surface is located inside the end surface of the base material in the width direction.

[0006]

In the heat exchanger tube of the present invention having the above-described structure, the width of the brazing material is shortened by a predetermined length with respect to the width of the base material to form the clad material into a tubular shape. When the both end surfaces of the material are brought into contact with each other in the circumferential direction, a space corresponding to a predetermined length is formed between the both end surfaces of the brazing material. Therefore, when both end surfaces of the base material are joined by welding, by setting a predetermined length so that the effect of heat applied to the brazing material is small, it is possible to prevent the thick part of the brazing material from occurring near the welded part. can do.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the heat exchanger tube of the present invention used in a refrigerant condenser will be described with reference to FIGS. FIG. 1 is a sectional view of the clad material. Refrigerant condenser 1
As shown in FIG. 5 (a front view of the refrigerant condenser 1), a large number of tubes 2 and fins 3 are alternately stacked, and side plates 4 are arranged on both outer sides in the stacking direction. The headers 5 are connected to both ends of each of them and are manufactured by integral brazing.

The tube 2 forms a refrigerant passage and is manufactured by using a clad material 8 in which a brazing material 7 is clad on one surface of a base material 6. The base material 6 uses a JIS standard A3003 grade aluminum plate (containing about 1.2% Mn, melting point: 643 to 654 ° C.) and is formed into a rectangular shape having a constant width D1. The brazing material 7 is JIS standard A
4045 grade aluminum braze (about 10% Si
(Melting point: 577 to 590 ° C.) is used, and the width D2 is set to be shorter than the width D1 of the base material 6 so that both end surfaces in the width direction are located inside the both end surfaces of the base material 6. (See Figure 1). That is, at both ends of the clad material 8, the unclad portion of the brazing material 7 (the portion where the base metal 6 is exposed)
Are provided with substantially the same lengths d1 and d2.

The fin 3 is a roller molded product obtained by processing a thin aluminum plate into a wavy shape, and has a louver (not shown) formed on its surface for increasing heat exchange efficiency. Header 5
Is a split type, and includes a plate header 5a into which the end of each tube 2 is inserted, a tank header 5b that is combined with the plate header 5a to form a cylinder, and a cylinder including the plate header 5a and the tank header 5b. It is composed of a cap 5c that closes the openings at both ends. The plate header 5a, the tank header 5b, and the cap 5c
Is an aluminum press-molded product having a brazing material 7 clad on its surface.

Next, the manufacturing process of the tube 2 will be described. First, the cylindrical body 8a is formed by facing both widthwise end faces of the clad material 8 in the circumferential direction. Then, both end surfaces of the base material 6 facing each other in the circumferential direction of the tubular body 8a are joined by welding (see FIG. 2). After that, by deforming the joined cylindrical body 8a into a predetermined tube shape, the desired tube 2
(See FIG. 3) is manufactured. In this manufacturing process, the lengths d1 and
Since the brazing filler metal 7 is not clad over d2, when the tubular body 8a is formed, a predetermined distance is provided between both end faces of the brazing filler metal 7 with both end faces of the base metal 6 abutting in the circumferential direction. Interval (D
1-D2) will be formed (see FIG. 2). Therefore, when the joining surface of the base material 6 is joined by welding, the influence of heat on the brazing material 7 is reduced as compared with the conventional clad material 8 in which the brazing material 7 is clad to the end surface of the base material 6. You can Therefore, as shown in FIG. 4 (enlarged view of the vicinity of the welded portion in FIG. 3), a thick portion of the brazing filler metal 7 does not occur near the welded portion, and as a result, the brazing filler metal 7 to the base metal 6 is formed.
It is possible to prevent the base material 6 from penetrating by the brazing material 7 by suppressing the diffusion of the. Further, in this embodiment, the amount of the brazing material 7 used is smaller than that of the conventional clad material 8, so that the brazing material cost can be reduced.

In this embodiment, the clad material 8 in which the brazing material 7 is not clad at both ends of the base material 6 is used, but the conventional clad in which the brazing material 7 is clad to the end surface of the base material 6 is used. Alternatively, the brazing material 7 at both ends of the clad material may be removed by a cutter or the like before use. Further, in the present embodiment, the clad material 8 in which the brazing material 7 is clad is used only on one side of the base material 6, but the clad material 8 in which the brazing material 7 is clad on both sides of the base material 6 is also used. Well, in that case, the brazing material 7 located inside the tubular body 8a also
Similar to the brazing filler metal 7 located outside the tubular body 8a, the width D of the brazing filler metal 7 is set so that the base metal 6 is exposed at both ends of the clad material 8.
2 is set shorter than the width D1 of the base material 6.

[0012]

EFFECTS OF THE INVENTION The heat exchanger tube of the present invention has a brazing filler metal at the time of welding because a predetermined gap is formed between both end faces of the brazing filler metal facing in the circumferential direction when the cladding material is formed into a tubular shape. The effect of heat received by is reduced. For this reason,
It is possible to prevent the brazing filler metal from diffusing into the base metal without forming a thick portion of the brazing filler metal in the vicinity of the welded portion. Therefore,
It is not necessary to take measures such as lowering the brazing temperature, shortening the brazing time, and lowering the cladding rate as in the conventional case, and it is possible to eliminate defective brazing.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a clad material according to this example.

FIG. 2 is a cross-sectional view of a cylindrical body obtained by molding a clad material.

FIG. 3 is a cross-sectional view of a tube obtained by molding a tubular body.

FIG. 4 is an enlarged view of the vicinity of a welded portion of the tube shown in FIG.

FIG. 5 is a front view of the refrigerant condenser according to the present embodiment.

FIG. 6 is a cross-sectional view of a conventional clad material.

FIG. 7 is a cross-sectional view of a tubular body obtained by molding a conventional clad material.

8 is a cross-sectional view of a tube obtained by molding the cylindrical body shown in FIG.

9 is an enlarged view of the vicinity of a welded portion of the tube shown in FIG.

FIG. 10 is a schematic diagram illustrating a process of diffusing a brazing material (prior art).

[Explanation of symbols]

 2 tubes (tubes for heat exchangers) 6 base material 7 brazing material 8 clad material

Claims (1)

[Claims] 1. A clad material in which a brazing material is clad on one surface or both surfaces of a base material is formed into a tubular shape so that both widthwise end surfaces face each other in the circumferential direction, and the both end surfaces are joined by welding. After that, in the heat exchanger tube formed into a predetermined tube shape, the clad material is located at both ends in the width direction, and the end surface of the brazing material is located inside the end surface of the base material in the width direction. Thus, the tube for a heat exchanger, wherein the width of the brazing material is shorter than the width of the base material by a predetermined length.