JPH07305994A - Heat exchanger - Google Patents

Abstract

PURPOSE:To form each component with brazing sheets on which brazing materials suitable for components different in heat capacity are coated. CONSTITUTION:An aluminum brazing sheet for forming components having a thick sheet thickness and a relatively large heat capacity improves the flow of a brazing material, which is dissolved at the time of brazing, by making a ratio of Si to be contained in the brazing material higher. An aluminum brazing sheet for forming components having a thin sheet thickness and a relatively small heat capacity increases a liquidus temperature of a brazing material and suppresses the flow of the brazing material by making a ratio of Si to be contained in the brazing material lower.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat exchanger formed by assembling and brazing parts formed by an aluminum brazing sheet coated with a brazing material.

[0002]

2. Description of the Related Art An aluminum brazing sheet is used for molding parts, tank plates, end plates, tubes, fins, etc., which constitute a conventional heat exchanger, on one or both sides of a core material made of an aluminum alloy. Silicon), Mg (magnesium) and, if necessary, Bi (bismuth), with the balance being Al (aluminum), and formed by coating a brazing filler metal, particularly JP-A 5-2
In the aluminum brazing sheet disclosed in Japanese Patent No. 6589, the Si content of the brazing filler metal on one side is higher than the Si content of the other side so that a satisfactory fillet formation can be obtained on both the outer surface side and the inner surface side. That is, more than 0.8% was formed.

[0003]

However, in an aluminum brazing type heat exchanger in which the material is made thinner and the weight is reduced, the parts joints of combinations having greatly different heat capacities, for example, the vicinity of the joint between the tube and the end plate are used. In the case of brazing (brazing), the thermal load of thin-walled parts with a small heat capacity locally increases, and the Si of the brazing material coated on the brazing sheet diffuses into the core material, causing erosion (erosion) and causing holes in the parts materials. It is easy to cause the problem that the space is empty.

Further, in order to prevent the above-mentioned problems, if the brazing temperature (brazing temperature) is set to be low, the brazing material coated on the brazing sheet will be formed at the joint portion of the above-mentioned combination of parts having greatly different heat capacities. It does not dissolve sufficiently, and brazing defects easily occur.

Therefore, the present invention is to provide a heat exchanger in which each part is molded with a brazing sheet coated with a brazing material suitable for parts having different heat capacities.

[0006]

According to the first aspect of the present invention, a brazing process is performed after assembling a plurality of parts formed by an aluminum brazing sheet formed by coating a brazing material on a core material made of an aluminum alloy. In the heat exchanger formed by attaching, the proportion of Si (silicon) contained in the brazing material coated on the aluminum brazing sheet for forming each part is increased for parts having a relatively large heat capacity, The reason is that the parts with relatively small heat capacity were made smaller.

According to a second aspect of the present invention, the heat is formed by assembling a plurality of parts formed by an aluminum brazing sheet formed by coating a brazing material on a core material made of an aluminum alloy and then brazing the parts. In the exchanger, the proportion of Si (silicon) contained in the brazing material coated on the aluminum brazing sheet for forming each part is increased for parts having a relatively thick plate thickness and Thin parts are made smaller.

Further, according to the third aspect of the present invention, at least the components constituting the tank portion and the tube portion are separately molded by the aluminum brazing sheet formed by coating the brazing material on the core material made of an aluminum alloy. In the heat exchanger, the Si (silicon) content contained in the brazing material of the aluminum brazing sheet for forming the tank portion is the Si (silicon) content contained in the brazing material of the aluminum brazing sheet for forming the tube portion. More than that.

[0009]

Therefore, according to the invention described in claim 1, the aluminum brazing sheet for molding a component having a relatively large heat capacity improves the flow of the brazing filler metal by increasing the proportion of Si contained in the brazing filler metal. However, since the aluminum brazing sheet for forming a component having a relatively small heat capacity can increase the liquidus temperature of the brazing material and suppress the flow of the brazing material by reducing the proportion of Si contained in the brazing material. In addition, the above problems can be achieved.

According to the second aspect of the present invention, a thick plate component has a relatively large heat capacity and a thin plate component has a relatively small heat capacity. The aluminum brazing sheet for forming the brazing filler metal improves the flow of the brazing filler metal by increasing the proportion of Si contained in the brazing filler metal, and the aluminum brazing sheet for molding a thin plate component is By reducing the proportion of Si contained, the liquidus temperature of the brazing material can be raised and the flow of the brazing material can be suppressed, so that the above-mentioned problems can be achieved.

Further, according to the third aspect of the invention, the tank portion is formed of a thick aluminum brazing sheet and the tube portion is formed of a thin aluminum brazing sheet. In addition, a fillet with a large heat transfer area is in contact with the tube to promote heat exchange, and this has the effect of promoting heat transfer between the atmosphere of the furnace and the tube during brazing in the furnace. Since the difference in heat load between the tank and the tube becomes even greater, the aluminum brazing sheet that forms the tank part improves the flow of the brazing filler metal by increasing the proportion of Si contained in the brazing filler metal and forms the tube. In the aluminum brazing sheet described above, by reducing the proportion of Si contained in the brazing material, the liquidus temperature of the brazing material can be raised and the flow of the brazing material can be suppressed, so that the above-mentioned problems can be achieved.

[0012]

EXAMPLES Examples of the present invention will be described below.
A so-called aluminum brazing type heat exchanger 1 as shown in FIG. 1 includes a plurality of tubes 2 and the tubes 2.
And an end plate 3 to which is fixed, and a tank plate 4 that is fixed to the end plate 3 and defines a tank 6.
And the fins 5 arranged between the tubes 2. Although the end plate 3 and the tank plate 4 are separately provided in this embodiment,
The end plate 3 and the tank plate 4 may be integrally formed into a tank portion.

In this heat exchanger 1, the tube 2 is made of a thin aluminum brazing sheet (for example, a plate thickness of 0.3 to 0.5 mm), and the end plate 3 of the tube 2 is smaller than that of the tube 2. Since it has a structure for supporting the tubes 2 and the fins 5, it is formed to be thicker than the tubes 2 in terms of strength, for example, a plate thickness of 0.8 to 1.2 mm. The aluminum brazing sheet has a core material made of an aluminum alloy and at least Si (silicon) or Mg on one or both sides of the core material.
And a clad layer formed by coating a brazing material formed by mixing (magnesium) or the like with aluminum at a predetermined ratio.

In this heat exchanger 1, the tank plate 4, the end plate 3, the tubes 2 and the fins 5 are temporarily assembled, the temperature is raised to a predetermined temperature in a furnace, and the surface of the core material of the aluminum brazing sheet is coated. It is formed by melting the brazing material (cladding layer) thus prepared and fixing the joint portions of the respective parts.

At this time, the end plate 3 and the tube 2
At the joint portion with, the thickness of the end plate 3 (0.8 to 1.2 mm) and the thickness of the tube (0.3 to
0.5 mm), different heat capacities are different (thin plate parts have smaller heat capacities than thick plate parts). The temperature tends to be higher than 3. For this reason, if the temperature is set in accordance with the tube side, the temperature rise of the end plate is suppressed, so that the brazing filler metal is less likely to melt on the end plate, resulting in a problem of adhesion failure. Also, if the temperature is set according to the end plate side, the temperature of the tube will rise significantly, the tube itself will melt, or Si of the brazing material will diffuse into the core material and cause erosion, etc. Problems such as vacancy occur.

Therefore, in the present invention, in the tube 2 having a small plate thickness and a small heat capacity and the tank plate 4 and the end plate 3 having a large plate thickness and a large heat capacity, the clad ratio and the Si content are set as shown in the following table. The end plate thickness is 0.8 to 1.2 m, for example.
m, the tube plate thickness is 0.3 to 0.5 mm, the end plate is BA
Equivalent to 4047 (Si amount: 11.0 to 13.0 wt%) or BA4045 (Si amount: 9.0 to 11.0 wt%), the tube is BA4343 (Si amount: 6.8 to 8.2).
(wt%) equivalent, it is desirable to set the difference in Siwt% of the brazing filler metal of the end plate and the tube to about 2% or more (experimental). The clad rate is
It shows the ratio of the thickness of the entire aluminum brazing sheet to the thickness of the brazing material (clad layer) coated on the aluminum brazing sheet.

[0017]

[Table 1]

As described above, a component having a small heat capacity, such as the tube 2, is formed by the aluminum brazing sheet coated with a brazing material having a relatively low clad ratio and a small amount of Si, so that it will melt. Since the amount of the material is small and the amount of Si is small, the brazing material becomes difficult to flow, so that the diffusion of Si can be prevented and the liquidus temperature (melting point) can be increased.

Further, since parts having a large heat capacity, such as the end plate 3 and the tank plate 4, are formed of an aluminum brazing sheet coated with a brazing material having a relatively large clad ratio and a large amount of Si, they are melted. Since the amount of brazing filler metal to be applied is large and the amount of Si is large, the brazing filler metal easily flows, so that the amount of brazing filler metal on the bonding surface can be secured.

As a result, at the same furnace temperature (brazing temperature), a component having a small heat capacity such as the tube 2, that is, a component having a thin plate thickness can suppress the flow of the brazing material and increase the melting point. Therefore, it is possible to prevent Si from diffusing into the core material, and a component having a large heat capacity, such as the end plate 3 and the tank plate 4, in other words, a component having a large plate thickness, causes the flow of the brazing material. In order to improve the heat resistance and to secure the flow amount of the brazing filler metal, it is possible to efficiently bond the above-mentioned component having a small heat capacity and the component having a large heat capacity.

[0021]

As described above, according to the present invention, the proportion of Si contained in the brazing material coated on the aluminum brazing sheet for forming a component (tube) having a small heat capacity, that is, a so-called thin plate. Smaller,
In addition, by increasing the proportion of Si contained in the brazing material coated on the aluminum brazing sheet for forming parts with large heat capacity, so-called thick plates (end plate and tank plate), the melting point of parts with low heat capacity is increased. It is possible to increase the temperature of the brazing filler metal, suppress the flow of the brazing filler metal, and facilitate the flow of the brazing filler metal of the component having a large heat capacity.

As a result, it is possible to prevent erosion of a component having a small heat capacity, that is, a thin plate, and a brazing defect due to a brazing flow. It is possible to simultaneously braze materials having different heat capacities and to control the temperature of brazing. It is possible to obtain effects such as ease of use, speeding up of brazing, and the like, and it is also possible to achieve effects such as reducing the thickness of parts and improving the degree of freedom in design.

[Brief description of drawings]

FIG. 1 is a partially enlarged perspective view showing an example of a heat exchanger.

[Explanation of symbols]

 1 heat exchanger 2 tube 3 end plate 4 tank plate 5 fins 6 tank

Claims (3)

[Claims] 1. A heat exchanger formed by assembling a plurality of parts formed by an aluminum brazing sheet formed by coating a core material made of an aluminum alloy with a brazing material, and then brazing the parts to form each part. The ratio of Si (silicon) contained in the brazing material coated on the aluminum brazing sheet is set to be large for parts having a relatively large heat capacity and small for parts having a relatively small heat capacity. Heat exchanger. 2. A heat exchanger formed by assembling a plurality of parts formed by an aluminum brazing sheet formed by coating a brazing material on a core material made of an aluminum alloy, and then brazing the parts to form each part. The ratio of Si (silicon) contained in the brazing material coated on the aluminum brazing sheet is increased for parts with a relatively thick plate thickness and decreased for parts with a relatively thin plate thickness. And a heat exchanger. 3. A heat exchanger in which parts constituting at least a tank portion and a tube portion are separately molded by an aluminum brazing sheet formed by coating a brazing material on a core material made of an aluminum alloy, wherein the tank The content of Si (silicon) contained in the brazing material of the aluminum brazing sheet forming the tube portion is higher than the content of Si (silicon) contained in the brazing material of the aluminum brazing sheet forming the tube portion. Exchanger.