JPH0149587B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of brazing a pipe and a pipe fitting, for example in an automobile radiator.
It is effective when used for brazing the water inlet provided in the tank and the overflow pipe.

Conventionally, when brazing the pipe and the mounting body, as shown in Fig. 1, the overflow pipe 9a is connected to the mounting hole 9o.
The brazing material A was placed around the mounting hole 9o while being inserted into the mounting hole 9o, and the brazing material A was melted in this state. However, in this method, the pipe 9
If a is inclined, the problem arises that the molten brazing filler metal A flows out along the outer periphery of the pipe 9a, making it impossible to obtain sufficient brazing strength.

On the other hand, it has also been known to previously clad a pipe fitting 9 with a brazing filler metal A, as shown in FIGS. 2 and 3, and to braze the pipe 9a with the brazing filler metal A. However, in this case, it has been difficult to use it to connect a water inlet and an overflow pipe in, for example, an automobile radiator for the following reasons.

That is, if the filler metal is clad in the filler metal that is the pipe fitting, the molten filler metal will locally accumulate at the open end of the filler hole, making it difficult to attach and remove the cap. Furthermore, since the surface of the water inlet becomes rough due to local aggregation of brazing metal, the opening pressure of the cap becomes inconsistent, and as a result, the cap does not function properly. Conversely, even if the overflow pipe is clad with a brazing material, the molten brazing material accumulates locally, making it impossible to reliably seal the joint between the overflow pipe and the rubber pipe.

Therefore, in conventional radiators, after the tank core plate, inlet pipe, outlet pipe, etc. are vacuum brazed separately, the overflow pipe is individually welded to the water inlet.

The present invention has been devised in view of the above points, and an object of the present invention is to enable brazing of a pipe and a pipe attachment body while maintaining sufficient attachment strength.

Therefore, in the present invention, an annular brazing material is used instead of a cladding material, and an annular holding portion is formed in the pipe to prevent the brazing material from flowing out.

Next, the structure of an aluminum radiator for automobiles manufactured by the manufacturing method of the present invention will be explained. In FIG. 4, an inlet pipe 2 through which engine cooling water flows into the tank 1 is brazed to the upper tank 1. 3 is a lower tank, to which an outlet pipe 4 for returning engine cooling water to the engine (not shown) is brazed. Both ends of a large number of tubes 5 through which engine cooling water passes are brazed to core plates 6 and 7. Fins 8 bent in a meandering manner are interposed between each of the tubes 5 and are brazed to each other. At both ends of the core portion consisting of the tubes 5, core plates 6, 7, and fins 8, The tanks 1 and 3 are attached by brazing them to the core plates 6 and 7. A water inlet 9 equipped with an overflow pipe 9a is brazed to the upper tank 1. The open end of the water inlet 9 is closed by a cap 12, and a rubber pipe (not shown) is connected to the overflow pipe 9a, thereby connecting the tank 1 and a reserve tank (not shown). On the other hand, a seat tank 10 equipped with a pipe 10a is brazed to the lower tank 3. Note that the water inlet 9 and the overflow pipe 9a are brazed together, and the pipe 10a
and Sheet Kotoku 10 are brazed together. The water inlet 9 is provided with a mounting hole 90 into which an overflow pipe 9a is fitted, and a holding portion 9b is protruded in a circular shape from the end of the overflow pipe 9a over its outer periphery. (5th,
6) and this overflow pipe 9
The rising portion of the holding portion 9b of a is located a predetermined distance l from the inner peripheral edge corner portion 90a of the mounting hole 90 of the water inlet 9. Further, the seat pot 10 is provided with a mounting hole into which the pipe 10a is fitted, and a holding portion 10 is formed in an annular shape protruding from the end side of the pipe 10a over its outer periphery. Then, the inner peripheral end corner of the mounting hole of the seat pot 10 and the pipe 10a
There is also a predetermined distance between the holding portion and the rising portion of the holding portion.

Next, an embodiment of the manufacturing method of the present invention will be described with reference to FIGS. 4 to 6. For example, tanks 1 and 3, core plates 6 and 7, made of a metal material in which the surface of a core material made of an aluminum alloy of A3003 is coated with a brazing material A made of an aluminum alloy such as X4104;
and tube 5 are prepared. In addition, an inlet pipe 2, an outlet pipe 4, a fin 8, a water inlet 9, an overflow pipe 9a, a seat pot 10, and a pipe 10a are made of the same material as the core material of the tanks 1 and 3.
Prepare. and fins 8 between each of the tubes 5.
interposed between the ends of the tube 5 and the core plates 6 and 7.
to fit into. After assembling the core part 11 in this way, the tanks 1 and 3 are attached to the inner peripheral walls of the core plates 6 and 7.
core plate 6, so that the outer peripheral walls of the core plate 6,
Attach tanks 1 and 3 to 7 so that they do not come off. The inlet pipe 2 is fitted into the burring hole of the tank 1 by driving. Further, the outlet pipe 4 is also fitted into the burring hole of the tank 3 by driving.

On the other hand, the overflow pipe 9a has a holding part 9b formed in a protruding annular shape at the end thereof, and the annular brazing material A is inserted into the outer periphery of the overflow pipe 9a from the tip 9c on the side where the holding part 9b is formed. The brazing material A is a 4004 series aluminum alloy containing about 12% silicon, and the wire diameter is 0.8.
~2.0mm.

Next, the overflow pipe 9a in this state
into the mounting hole 90 of the water inlet 9 from the tip 9c side until the brazing filler metal A contacts the peripheral wall 90b of the water inlet 9. Therefore, in the state after fitting, a gap l of about 1 to 2 mm, which corresponds to the wire diameter of the brazing material A, is created between the inner circumferential end corner 90a of the mounting hole 90 and the rising portion of the holding portion 9b. Further, in this state, the tip 9c of the overflow pipe 9a protrudes from the inner wall 90c of the water inlet 9 by a minute amount of 0.5 mm or less.

Thereafter, the tip of the overflow pipe 9a is expanded using a tube expansion tool (not shown), and the overflow pipe 9a is caulked to the mounting hole 90.

After the overflow pipe 9a is caulked and fixed to the inlet 9 through the above steps, the inlet 9 is fitted into the upper tank 1.

Similarly, the pipe 10 is also attached to the seat kettle 10 in advance.
A is inserted into the seat pot 10 mounting hole, and in this state, the seat pot 10 is fitted into the lower tank 3.

The radiator is assembled in this manner and placed in a vacuum brazing furnace maintained in a high temperature atmosphere. In this vacuum brazing furnace, the brazing material A clad in the tanks 1 and 3, the core plates 6 and 7, and the fins 8, and the annular brazing material A inserted into the outer periphery of the overflow pipe 9a and the pipe 10a. Each component is brazed with the melted brazing material A.

That is, the upper tank 1 and the inlet pipe 2, the water inlet 9, and the core plate 6 are brazed with the brazing material A that was clad in the upper tank 1, and the lower tank and the outlet pipe 4, the seat plate 10, and the core plate 7 are brazed. The space between them is brazed with the brazing material A that was clad in the lower tank, and the space between the tube 5 and the fin 8 is brazed with the brazing material A that was clad in the tube 5.

Then, the overflow pipe 9a and the water inlet 9
As shown in FIG. 6, a ring-shaped brazing material A is used to braze the space between the two and the two. In particular, this brazing filler metal A is
Since it is held between 0b and the holding part 9b,
Even if the radiator is subjected to vibrations when being transported into the furnace, the annular brazing filler metal A will not shift. Further, even if the brazing filler metal A melts in the furnace, the holding portion 9b prevents the melted brazing filler metal from flowing out, so that the brazing filler metal A is reliably held around the attachment hole 90.

Moreover, the brazing filler metal A does not adhere to the overflow pipe 9a and the water inlet 9 except around the attachment hole 90. Therefore, the engagement between the water inlet 9 and the cap 12 is not inhibited by the brazing material. Further, the overflow pipe 9a and the rubber hose can be brought into complete contact with the outer periphery of the pipe 9a, resulting in good watertightness.

In addition, in the above-mentioned example, the brazing according to the method of the present invention was used for brazing between the inlet 9 and the overflow pipe 9a and between the seat pot 10 and the pipe 10a. If it is not desirable to cover the brazing filler metal, use the tanks 1 and 3, inlet pipe 2, and outlet pipe 4.
An annular brazing material may also be used for brazing between.

Furthermore, it goes without saying that the brazing method according to the present invention can be widely used in fields other than radiators.

As explained above, in the present invention, the annular brazing material is heated and melted with the annular brazing material sandwiched between the pipe holding part and the peripheral wall of the pipe attachment body, so that the annular brazing material can be held reliably. In addition, even if the brazing material melts, it can be prevented from flowing out, and therefore sufficient brazing strength can be obtained. Furthermore, the pipe is inserted into the mounting hole so that its tip protrudes a predetermined amount from the inner periphery of the pipe fitting, and the pipe is expanded at its tip and caulked to the pipe fitting to perform brazing. Therefore, the pipe does not shift or come off when it is transported into the furnace or when it is brazed in the furnace. Therefore, it has the excellent effect of being able to reliably braze the pipe and the pipe fitting.

Additionally, if a gap is formed between the outer circumference of the pipe and the pipe mounting hole, molten brazing filler metal will enter the gap due to capillary action, but the tip of the pipe will be expanded and caulked to the pipe mounting body. Since they are bonded, it is possible to reliably prevent the brazing filler metal from entering the pipe attachment body. Therefore, it has the excellent effect of reliably preventing various adverse effects caused by the penetration of the brazing filler metal into the pipe attachment body. Furthermore, if the brazing filler metal enters the gap, the tip of the pipe is expanded and caulked, so the filler metal stays in the gap. Therefore, it has the excellent effect of being able to reliably braze the pipe and the pipe fitting.

[Brief explanation of drawings]

Figures 1 to 3 are cross-sectional views illustrating conventional brazing methods, Figure 4 is a front view of a radiator showing an example of brazing by the method of the present invention, and Figures 5 and 6 are the method of the present invention. It is a sectional view explaining an example. 9... Water inlet (pipe mounting body), 9a... Overflow pipe, A... Brazing metal.

Claims (1)

[Claims] 1. An annular holding part is formed protruding from the outer periphery near the end of the pipe, and a mounting hole is formed in the pipe attachment body, the inner diameter of which is greater than the outer diameter of the pipe and less than the outer diameter of the annular holding part, Next, an annular brazing material is arranged to be interposed between the end of the pipe and the annular holding part, and the pipe is mounted so that the end protrudes from the inner periphery of the pipe fitting by a predetermined amount. A method for brazing a pipe and a pipe fitting by inserting the pipe into a hole, expanding the end of the pipe, fitting the pipe into the pipe fitting, and heating the pipe in that state to melt the brazing material.