JP2504832Y2 - Brazing structure of heat exchanger tank - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a brazing structure at a joint between a tank body and a tube plate of an aluminum heat exchanger.

[Prior art]

BACKGROUND ART Conventionally, a brass tank has been widely used as a heat exchanger tank, and the tank is composed of an elongated tank body having one end opened and a tube plate having a relatively deep groove portion having a U-shaped cross section at its peripheral edge. Then, the opening of the tank body is fitted into the groove of the U-shaped cross section of the tube plate. As an example, as in the welding structure of the heat exchanger of No. Sho 61-63589, by placing a rod-shaped soft brazing material (solder) on the fitting portion between the tank body and the tube plate and melting it with a burner, Both fitting parts were liquid-tightly joined.

Such a soft brazing filler metal has a strength that is only about 1/10 of the strength of the base metal of the tank body and tube plate. Therefore, it is necessary to make the joint area between the soft brazing material and the base material as wide as possible.

Next, the tank structure of the aluminum heat exchanger comprises an elongated box-shaped tank body having one end opened, and a tube plate having a groove portion on the peripheral edge thereof, and the opening edge of the tank body fitted in the groove portion.

Both sides of the tank body and the tube plate are clad with brazing material. This brazing material is made of an aluminum alloy, is melted in a high temperature furnace and is held at the joint between the tank body and the tube plate, and both are integrally brazed and fixed. Further, end portions of a large number of flat tubes penetrate the tube plate, and the penetration portions are integrally brazed and fixed in the furnace simultaneously with the brazing of the tank.

The brazing structure of the tank of such a conventional heat exchanger made of aluminum is formed as shown in FIG. That is, the opening of the tank main body 2 is formed by expanding in an inclined stepped manner, and the skirt 1 is formed therein. Then, the groove portion 3 is formed on the peripheral edge of the tube plate 4. When the hem 1 of the tank body 2 is fitted into the groove 3, the V-shaped depth v formed between the outer surface of the hem 1 and the groove 3 is 4 mm.
The height h between the end of the hem 1 and the step is about 2 mm. That is, the depth of the groove was larger than the stepped height of the hem.

The conventional structure of the aluminum heat exchanger is the same as the concept of brazing (soldering) of brass brazing material.

The tank thus assembled and the tube plate are inserted into a vacuum furnace, and the brazing material made of an aluminum alloy coated on the surface of the tank body 2 is melted in the furnace.

Then, as shown in FIG. 3, the brazing material melted from the inner and outer surfaces of the tank main body 2 and the inner and outer surfaces of the tube plate 4 is held at the joint between the skirt 1 and the groove 3, and thus brazing is performed.

[Problems to be solved]

However, in such a brazing structure, the brazing material flowing down from the outer surface of the tank body 2 into the groove 3 may be unevenly retained in the gap between the groove 3 and the skirt 1. This is because the outer circumference of the tank cannot be heated uniformly in the vacuum furnace. The brazing filler metal tends to collect in the better heating condition. That is, if the heating conditions are uniform, the third
As shown in the figure, the brazing material 6 is held up to the height h of the hem 1,
If the heating conditions are non-uniform, the brazing filler metal is attracted to the part with good conditions, and there is a part that is held up to the depth v of the groove 3. However, the total brazing material is in constant quantity.
For example, a 1 mm aluminum body is covered with a brazing material of 0.1 mm aluminum alloy on its outer surface. Moreover, not all of the brazing material contributes to brazing, and some of it remains on the outer circumference of the tank body. Therefore, when a part of the groove 3 is filled with the brazing filler metal to a depth v as shown in FIG. 3, a larger amount of the brazing filler metal moves to that part, and the brazing filler metal 1 moves to the other part and the brazing filler metal 1 There will be a shortage of brazing material at the joint. Then, so-called waxing may occur in the insufficient portion, and leakage may occur in a part of the tank.

The brazing material of the aluminum alloy contains magnesium, which jumps out of the surface of the aluminum in a vacuum furnace to break the film on the surface and enable brazing. On the outer surface of the tank, the magnesium particles smoothly scatter into the vacuum furnace and destroy the skin.However, inside the tank, the magnesium particles that have jumped out of the brazing filler metal on the inner surface are hard to be discharged to the outside, and once they have jumped out of the inner surface. However, it often adheres to the inner surface again, and it has been confirmed by experiments that the brazing material on the inner surface of the tank has little effect on the brazing between the tank body and the tube plate.

Therefore, as a result of various experiments and researches, the present invention has focused on the fact that the brazing sealing property is more important than the brazing area in the aluminum tank in which the surface of the base material is covered with the aluminum alloy. That is, since the hard brazing material made of aluminum alloy has the same strength as the base metal when it is melted and solidified, it is not necessary to take a brazing structure like the conventional soft brazing material. In consideration of the fact that the amount of brazing filler metal that can be used is extremely small, a condition under which the brazing filler metal is uniformly held at the joint between the skirt portion 1 and the groove portion 3 was found, and the present invention was devised based on the condition.
The structure is as follows.

[Means for solving the problem]

That is, the surface is coated with a brazing material made of an aluminum alloy, and each of them is made of a molded product of aluminum or its alloy plate and has one end opened and the opening is expanded and formed in an inclined stepped shape. A tank body 2 having a skirt 1 and a tube plate 4 fitted into an annular groove 3 formed at the periphery of the skirt 1, and the brazing filler metal in the furnace in the fitted state. In the case where both are melted and integrally brazed and fixed, the cross section including the outer wall 9 of the groove portion 3 is formed in a square shape, and the outer wall 9 of the groove portion 3 is formed.
The skirt portion 1 is formed so that a brazing space 7 having a V-shaped cross-section that expands outward is formed between the inner surface and the outer surface of the skirt portion 1.
Is fitted into the groove portion, and a substantial inner surface height v of the outer wall 9 of the groove portion 3 in the brazing space 7 having a V-shaped cross section is set to be the first stepped edge from the opening edge of the skirt portion 1. 8
Is substantially equal to or smaller than the height h up to, and the height v is formed to be 1 mm to 3 mm.

[Action]

Therefore, in the brazing structure of the present invention, the height v of the substantially inner surface of the groove portion 3 of the brazing space 7 having a V-shaped cross section is 1 mm to 3 mm, and the height v is the first step from the opening edge of the skirt 1. Since the height h to the attached edge 8 is set to be substantially the same as or smaller than the height h, the molten brazing material is not higher than the edge of the low groove portion 3 and is concentrated in one place as in the conventional FIG. It can be evenly dispersed and held without any trouble, and a reliable sealing property can be secured over the entire circumference of the tank.

It should be noted that the meaning that the height v and the height h are almost the same here means that there is a difference in manufacturing error and assembling error in the press-formed product of the tank body and the tube plate of this kind, which is regarded as the same. Is the meaning.

〔Example〕

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a cross section of a tank having the brazing structure of the present invention, and FIG. 2 is an enlarged view of a main part thereof.

This heat exchanger is a heat exchanger for automobiles made of aluminum, and has a pair of tanks vertically spaced apart from each other (a lower tank is omitted), and a flat tube 5 and a fin (not shown) are provided between them. Is formed. And both ends of the flat tube 5 of the core are respectively tube plates 4
Through the tube insertion hole. An annular groove portion 3 having a V-shaped cross section is formed on the peripheral edge of the tube plate 4.

Next, the hem portion 1 of the tank body 2 is formed in an inclined stepped shape. And from this opening of the hem 1 to the stepped edge 8
The height h up to (Fig. 2) is 1 mm to 4 mm. Further, when the skirt 1 is fitted in the groove 3, a brazing space 7 having a V-shaped cross section that expands is formed between the groove and the outer surface of the skirt 1, and the outer wall of the groove 3 in the space 7 is formed. 9
Is formed to have a height v of 1 mm to 3 mm. At the same time, there is a relationship of v ≦ h with respect to v.

In order to assemble the present heat exchanger with such components, a large number of flat tubes 5 are arranged in parallel, corrugated fins (not shown) are interposed between the flat tubes 5, and both ends of the flat tubes 5 are respectively attached to a tube plate. 4 through the tube insertion hole. A corrugated fin (not shown) having a brazing material clad in advance is used. Further, the skirt 1 of the tank body 2 is fitted into the groove 3 of the tube plate 4. Then, while holding the whole with an appropriate jig, the flat tubes 5 are inserted in a high temperature vacuum furnace such that the flat tubes 5 are parallel to the direction of gravity. Then, the brazing material clad on the surface of each component is melted and held between the groove 3 and the skirt 1.

It should be noted that the brazing material is such that the brazing material other than the place is also adsorbed in the gap between the two parts due to the capillary phenomenon.

In addition, the brazing material is held at the insertion portion between the tube plate 4 and the flat tube 5 and also at the contact portion between the flat tube 5 and the corrugated fin (not shown). Then, the brazing material is solidified and the joints thereof are fixed by brazing.

[Experimental example]

Next, in the brazing structure of the tank of the aluminum heat exchanger, the hem 1 is formed in the groove 3 of the tube plate 4 thereof.
And a brazing space 7 having a V-shaped cross section between them.
When the groove is formed, the substantial inner surface height v of the outer wall 9 of the groove 3 is formed.
The effect of the relationship between the length h of the hem portion 1 of the tank body 2 on the quality of brazing was confirmed by experiments. The results are shown in the table below. In this experiment, the tank body 2
The tube plate 4 has a thickness of 1 mm and 1.2.
The same result was obtained for both cases. A brazing material was previously clad on the surfaces of the tank body 2 and the tube plate 4, and the thickness of the brazing material was 0.1 mm on the outer surface side and 0.1 mm on the inner surface side, which was about 0.2 mm in total. Then, the two were fitted into each other and combined together, and then inserted into a vacuum furnace, and the joints thereof were integrally brazed, and a leak test was conducted. In this leak test, the tank of the heat exchanger is submerged in water, and when air is supplied from the inlet pipe of the tank and the tank inner thickness is 1.2 kg / cm ² , leakage from the root of the tank body and tube plate I inspected whether it would happen.

In the above table, ○ indicates that one of 100 samples did not leak, and Δ indicates 1 out of 100 samples.
~ 2 leaks are shown, x indicates sample 100
It shows that there were three or more leaks for each heat exchanger tank.

 From the above table, the following facts have become clear.

When the substantial inner surface height v of the outer wall 9 of the groove portion 3 of the tube plate 4 is 1 mm to 3 mm and the height v is substantially equal to or less than the height h of the hem portion 1 of the tank body 2. , It became clear that no leakage occurred.

Therefore, according to the present invention, the present invention sets the substantial inner surface height v of the outer wall 9 in the groove portion 3 of the tube plate 4 in the aluminum heat exchanger to 1 mm to 3 mm, and
The height v is substantially equal to or less than the height h of the hem portion 1 of the tank body 2.

[Effect of device]

The brazing structure of the present invention is configured as described above,
It has the following effects.

In this structure, the height v of the inner wall of the outer wall 9 of the groove 3 of the tube plate 4 is substantially equal to or less than the height h of the hem 1 of the tank body 2, and the height v is 1 mm to 3 mm. Therefore, the brazing material melted from the surface of the tank body 2 and the tube plate 4 in the furnace can be surely held uniformly in the entire groove portion 3, and the reliability of the brazing portion can be improved.

This is to ensure that the brazing filler metal collected from the surfaces of the tank main body 2 and the tube plate 4 into the groove portion 3 and the skirt portion 1 will not be distributed to unnecessary portions, and that the brazing filler metal will be evenly distributed over the entire circumference of the joining portion. This is because it can be distributed and held.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a main part of a heat exchanger of the present invention, FIG. 2 is an enlarged view of the main part, and FIG. 3 is an enlarged explanatory view of a brazing structure of a conventional heat exchanger. 1 ... hem, 2 ... tank body, 3 ... groove, 4 ... tube plate, 5 ... flat tube, 6 ... brazing material,
7 ... Brazing space, 8 ... Stepped edge, 9 ... Outside wall

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoichiro Yoshida 31-2 Sakuraoka-cho, Shibuya-ku, Tokyo Toyo Radiator Co., Ltd. (72) Yu Nonaka 31-2 Sakuraoka-cho, Shibuya-ku, Tokyo Toyo Radiator (72) Inventor Motoyoshi Masuda No. 31-2 Sakuraokacho, Shibuya-ku, Tokyo Toyo Radiator Co., Ltd. (72) Inventor Hideki Nagai No. 31-2 Sakuraoka-cho, Shibuya-ku, Tokyo Toyo Radiator Co., Ltd. (56) References Actual Open Sho 61-63589 (JP, U) Actual Open Sho 61-63590 (JP, U) Actual Kosho 62-47034 (JP, Y1)

Claims (1)

(57) [Scope of utility model registration request] 1. A brazing material made of an aluminum alloy is coated on the surface of the aluminum alloy and a molded product of aluminum or its alloy plate is formed. A tank body 2 having an open skirt 1 and a tube plate 4 fitted into an annular groove 3 formed at the rim of the skirt 1 are provided, and in the furnace in the fitted state, In the case where the brazing material is melted and integrally brazed and fixed, the cross section including the outer wall 9 of the groove portion 3 is formed in a square shape, and the inner surface of the outer wall 9 of the groove portion 3 and the skirt portion 1 are formed. The skirt 1 is fitted into the groove so that a brazing space 7 having a V-shaped cross section that expands outward is formed between the groove portion and the brazing space 7 having the V-shaped cross section. 3, the substantial inner surface height v of the outer wall 9 is For a heat exchanger, characterized in that the height h from the opening edge of the portion 1 to the first stepped edge 8 is substantially equal to or smaller than the height h, and the height v is formed to 1 mm to 3 mm. Brazing structure of the tank.