JP7704560B2 - Method for brazing a pipe member to a mating member - Google Patents

Description

The present invention relates to a pipe member, such as a metal pipe, generally used as a supply line for automobiles or various machines and devices, and a method for brazing the pipe member to a mating member, and more specifically to a method for inserting a spool-attached pipe end of the pipe member into the mating member and brazing the pipe member to the mating member.

Conventionally, when brazing the end of a tube to a mating member, the tube end of the tube is inserted into a connection hole drilled in the mating member, and the abutting portion between the outer peripheral wall surface of the tube and the inner peripheral wall surface of the mating member is copper brazed. Figures 4 and 5 show an example of this method, in which a spool 11-2 with a diameter larger than the outer diameter of the metal part is formed on the outer periphery of the tube end 11-1 of a cylindrical metal member (tube member) 11, and then, with copper paste brazing material (not shown) placed on the outer periphery of the spool 11-2 of the tube end 11-1 of the cylindrical metal member 11, the tube end 11-1 of the cylindrical metal member 11 is inserted into a connection hole 12-1 drilled in a mating member (separate pipe, etc.) 12, and the positioning (temporary fixing) after the insertion is performed by projection welding, and then the cylindrical metal member 11 and the mating member 12 are brazed by the fillet 13 formed by heating in a continuous atmospheric furnace.

Methods of brazing metal tubes include forming an expanded section at the tip of a cylindrical metal member, forming a flare at the tip of the expanded section, fitting a ring-shaped brazing material onto the other metal tube, inserting the end of the cylindrical metal member into the expanded section, and heating it in a furnace in this state to perform brazing (see Patent Document 1); and a method of brazing the outer peripheral wall surface of the end of a tube member to the inner peripheral wall surface of a mating member, in which a brazing material ring is fitted into an annular engagement portion provided on the outer peripheral surface of the end of the tube member, the end of the tube member with the brazing material ring is inserted into the mating member, and the brazing material ring is heated and melted to braze the end of the tube member to the mating member (see Patent Document 2).

Special Publication No. 7-39032 JP 2007-105774 A

However, the conventional brazing method for tubular members shown in Figures 4 and 5, i.e., a method in which the tube end of a tubular metal member (tubular member) 11 is inserted into a connecting hole 12-1 drilled in a mating member 12 and the abutting portion between the outer peripheral wall surface of the tubular metal member 11 and the inner peripheral wall surface of the mating member 12 is copper brazed, in which copper paste brazing material (not shown) is placed in a spool 11-2 portion formed at the tube end of the tubular metal member 11, the tube end of the tubular metal member 11 is inserted into a connecting hole 12-1 drilled in the mating member 12, and the tubular metal member 11 and the mating member 12 are copper brazed together in this state, has the following problems.
That is, in the conventional brazing method shown in FIG. 5, when the tube end of a tubular metal member 11 with a spool is inserted into a connection hole 12-1 of a mating member 12 and copper brazing is performed, if the copper brazing is performed in a state where there is no gap (almost 0 mm) between the neck part of the spool 11-2 of the tubular metal member 11 and the mating member 12, the molten copper braze does not penetrate (wrap around) to the gap 14 between the outer circumferential surface of the tube end of the tubular metal member 11 and the connection hole 12-1 of the mating member 12, but flows only to the front side of the mating member 12 as shown in FIG. 5, and the brazing is performed only by the fillet 13 formed between the spool 11-2 of the tubular metal member 11 and the mating member 12, resulting in a problem that sufficient brazing joint strength is not obtained and the probability of fluid leakage from the brazed portion increases.

The present invention has been made to solve the problems of the conventional technology described above, and aims to propose a method of brazing a tube member to a mating member in which molten copper brazing filler can penetrate (wrap around) from the neck part of the spool to the gap between the tube end of the tube member and the connecting hole of the mating member, thereby improving the brazing joint strength, preventing fluid leakage from the brazed part, and reducing the welding current value when temporarily fixing by projection welding.

The method of brazing a tubular member to a mating member of the present invention is a method of brazing a tubular metal member to a mating member by inserting the tube end of the tubular metal member into a connecting hole formed in the mating member while a brazing material is placed in a spool portion formed at the tube end of the tubular metal member (tubular member), and brazing the tubular metal member to the mating member, characterized in that molten brazing material is allowed to penetrate into the outer surface of the spool formed at the tube end of the tubular metal member and into the gap between the outer circumferential surface of the tube end of the tubular metal member and the connecting hole of the mating member and into the lower neck part on the tube end side of the spool, and one or more recesses are formed around the circumferential direction of the spool by press working to reduce the welding current value during projection welding to temporarily fix the outer circumferential surface of the tube end of the tubular metal member to the mating member , and temporary fixing is performed by projection welding to the contact surface between the outer surface of the spool portion and the mating member, and then brazing is performed.

In the brazing method, the shape of the recess formed in the neck portion of the spool of the tubular metal member is preferably a rectangle elongated in the circumferential direction (rectangular or a shape approximating a rectangle elongated in the circumferential direction), and the depth of the recess is preferably set according to the size of the spool (diameter, thickness in the longitudinal direction and radial direction of the tubular metal part, etc.).
In addition, when a plurality of rectangular recesses elongated in the circumferential direction are formed in the spool neck portion of the cylindrical metal member, it is preferable that they are formed at desired intervals in the circumferential direction of the spool.
The circumferential length and the number of the recesses are appropriately set depending on the diameter of the cylindrical metal member, the size of the spool, etc. The brazing material is not particularly limited, but a copper paste brazing material can be used.

According to the brazing method of the present invention between a tube member and a mating member, when the tube end of a cylindrical metal member with a spool is inserted into the connection hole of the mating member to perform copper brazing, the recess formed in the neck part of the spool is connected to the gap between the outer circumferential surface of the tube end of the tube member and the inner circumferential surface of the connection hole of the mating member, forming a path for the penetration of the molten brazing material, so that the molten copper brazing material flows in the axial direction of the tube and fills and fixes the gap between the outer circumferential surface of the tube end of the cylindrical metal member and the inner circumferential surface of the connection hole of the mating member. Therefore, sufficient brazing joint strength can be obtained and leakage of fluid from the brazing part can be prevented. Furthermore, according to the present invention, the recess formed in the neck part of the spool of the cylindrical metal member with a spool acts to reduce the current of projection welding to position (temporarily fix) the cylindrical metal member after insertion.

1 is a side view showing a cylindrical metal member (metal tube) with a spool before brazing in one embodiment of the present invention. FIG. FIG. 2 is a front view of the cylindrical metal member with a spool shown in FIG. 1 . 2 is an enlarged longitudinal sectional side view of a main portion showing a state after brazing of the cylindrical metal member with a spool shown in FIG. 1 and a mating member. FIG. FIG. 2 is a view corresponding to FIG. 1 and showing a cylindrical metal member (metal tube) with a spool before brazing in a conventional method. 5 is a view equivalent to FIG. 3 and illustrating a state after brazing of the cylindrical metal member with a spool shown in FIG. 4 and a mating member.

In one embodiment of the present invention, a cylindrical metal member (metal tube) with a spool before brazing is described with reference to Figs. 1 and 2. In this invention, in the neck portion of the annular spool 3 formed on the outer periphery of the tube end 2 of the cylindrical metal member 1, for example, four rectangular recesses 4 having a desired recess depth and a substantially rectangular shape that is long in the circumferential direction of the cylindrical metal member 1 are formed at cross positions in the circumferential direction of the cylindrical metal member 1. The rectangular recesses 4 can be formed, for example, by pressing. The circumferential length, recess depth, number of rectangular recesses 4, etc. are appropriately determined according to the diameter, thickness, etc. of the cylindrical metal member 1. The reason for forming the rectangular recesses 4 in this way in the neck portion of the annular spool 3 is to penetrate the molten brazing filler not only into the neck portion of the spool 3, but also into the gap 6 between the outer circumferential surface of the tube end 2 of the cylindrical metal member 1 and the inner circumferential surface of the connection hole 5-1 of the mating member 5, and fill the gap 6 with the brazing filler.

Next, a method of brazing the cylindrical metal member 1 with the spool 3 having the above-mentioned structure to a mating member will be described with reference to FIG.
1 and 2, when brazing the tubular metal member 1 with the spool 3 to the mating member 5, a copper paste brazing material (not shown) is placed on the outer periphery of the spool 3 of the tube end 2 of the tubular metal member 1 as in the conventional method, and the tube end 2 of the tubular metal member 1 is inserted into a connection hole 5-1 drilled in the mating member 5. At this time, the four rectangular recesses 4 formed in the neck portion of the spool 3 are connected to the gap 6 between the outer periphery of the tube end 2 of the tubular metal member 1 and the inner periphery of the connection hole 5-1 of the mating member 5, forming a path for the molten brazing material to penetrate, so that the molten brazing material passes through the four rectangular recesses 4 formed in the neck portion of the spool 3 and melts and flows into the gap 6 between the outer periphery of the tube end 2 of the tubular metal member 1 and the inner periphery of the connection hole 5-1 of the mating member 5, and the gap is also filled with the brazing material. Therefore, the tube end 2 of the tubular metal member 1 and the mating member 5 are joined by a fillet 8 formed by heating, for example, in a continuous atmospheric furnace, and a molten and solidified brazing portion 9 between the tube end 2 of the tubular metal member 1 and the mating member 5, as shown in Figure 3.

In this way, according to the present invention, by forming a rectangular recess 4 in the neck portion of the spool 3 of the tubular metal member 1 and connecting the gap 6 between the outer peripheral surface of the tube end 2 of the tubular metal member 1 and the inner peripheral surface of the connection hole 5-1 of the mating member 5, the tubular metal member 1 and the mating member 5 are joined by the fillet 8 formed between the spool 3 of the tubular metal member 1 and the mating member 5 and the molten and solidified brazing portion 9 between the tube end 2 and the mating member 5, so that the brazing between the tubular metal member 1 and the mating member 5 can be made more reliable. In addition, the rectangular recess 4 provided in the neck portion of the spool 3 of the tubular metal member 1 changes the current flowing around the entire circumference of the tubular metal member 1 to an intermittent flow, which makes it possible to reduce the welding current value when temporarily fixing by projection welding.

1 Cylindrical metal member 2 Tube end 3 Spool 4 Rectangular recess 5 Counterpart member 5-1 Connection hole 6 Gap 8 Fillet 9 Brazed portion

Claims (3)

In a method for brazing and joining a tubular metal member to a mating member, a brazing material is placed on a spool portion formed on the end of the tubular metal member, and the end of the tubular metal member is inserted into a connection hole formed in a mating member, the method comprising the steps of:
a tubular metal member having a connecting hole and a connecting portion for connecting the tubular metal member to the connecting hole of the connecting portion , the tubular metal member being connected to the connecting portion of the connecting portion and the connecting portion being connected to the connecting portion ... The brazing method for a tubular member and a mating member according to claim 1, characterized in that the recess formed in the spool neck portion of the cylindrical metal member is a rectangular shape that is elongated in the circumferential direction or a shape that is approximately a rectangular shape that is elongated in the circumferential direction. The method for brazing a tubular member and a mating member according to claim 1 or 2, characterized in that a plurality of rectangular recesses elongated in the circumferential direction are formed at desired intervals in the circumferential direction of the spool at the spool neck portion of the cylindrical metal member.

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