JP3537262B2 - Method and apparatus for fixing copper member - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for fixing a copper member to be a joint to an iron member made of an iron material such as a high-pressure tank, and a welding apparatus capable of realizing the method.

[0002]

2. Description of the Related Art Generally, the process of welding metal materials is
When a welding current flows through an object to be welded, heat is generated due to their contact resistance or the like, and the heat melts and solidifies the metal material to perform welding or joining.

However, since welding of dissimilar metals is diffusion welding due to softening of metal materials having different softening temperatures, thermal conductivities, thermal expansion coefficients, etc., generally, a desired welding quality is obtained as compared with welding of similar metals. It is said to be difficult to obtain. In particular, the diffusion welding of a copper member and an iron member having relatively different characteristics is difficult, so that the use thereof is limited.

The iron high-pressure tank 30 currently being used
A method of fixing the copper pipe 31 as a joint in accordance with the hole 30A will be described with reference to FIG. 5. First, an iron welding auxiliary member 32 made of the same metal material as the high-pressure tank 30 is prepared in advance. The iron welding auxiliary member 32 has a through hole 32A for communicating with the hole 30A of the high-pressure tank 30.
The copper pipe 31 is fitted halfway through the through hole 32A. By performing brazing 33 over 360 degrees along a corner formed by the wall surfaces of both the copper pipe 31 and the welding auxiliary member 32 intersecting, the copper pipe 31 and the welding auxiliary piece 32 are brazed to each other. To integrate.

The copper pipe 31 integrated as described above
The welding auxiliary member 32 is welded to the high-pressure tank 30 by ordinary resistance welding as shown in the figure. In this case, since resistance welding is performed between iron materials, welding can be easily performed under normal welding conditions.

[0006]

However, as is apparent from the above description, in the case of the conventional fixing method, the welding auxiliary member 32 made of the same metal material as the high pressure tank 30 which is the larger workpiece is used. Since the intermediate members such as the copper pipe 31 and the welding auxiliary member 32, which are the smaller objects to be welded, are naturally different from each other, it is necessary to prepare these intermediate members. There was a disadvantage that work was required.

An object of the present invention is to solve such a conventional problem and to provide a method and a welding apparatus for fixing a copper member to an iron member only by diffusion welding between dissimilar metals.

[0008]

Means for Solving the Problems In order to solve the above-mentioned problems, in a first invention, in a method of fixing a copper member to an iron member, a welding end of the copper member formed in advance by projection is used. A predetermined pressure is applied between the copper member and the iron member in a state where the copper member and the iron member are aligned with each other, and a time width between the copper member and the iron member to a peak value is approximately 7 milliseconds or less. Passing a pulse current longer than the response time of the pressing force, and maintaining the predetermined pressing force at the joint between the copper member and the iron member until the fixing of the copper pipe to the iron member is completed. And a method for fixing a copper member.

In order to solve the above-mentioned problem, the second
According to the invention, the metal block held by the pressing mechanism so as to be able to advance and retreat, the first support member fixed to the metal block, the plurality of guide members implanted in the metal block, and the guide member A linear driving member that can travel along the other end of the flexible member and is fixed to the other end side of the flexible member; a second supporting member supported by the linear driving member; the first supporting member and the second supporting member; A pressurizing auxiliary member disposed between the upper welding electrode and the lower welding electrode capable of high-speed response. And a welding device for welding the iron member and the copper member by applying a current to the iron member and the copper member.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. First, in FIG. 1, A is an iron member made of an iron material such as a high-pressure tank of a compressor serving as a first workpiece, B is a copper member such as a copper pipe serving as a second workpiece, and C is copper. It is a clamp electrode capable of clamping the member 2 along its length direction. Although a lower electrode is not shown, it is disposed at a position where it is supported from the inner surface of the iron member A as described later. .

As shown in FIG. 2, the copper member B has a projection B 1 on a welded end face to be welded to the iron member A. The projection B1 is formed, for example, at an angle of approximately 45 degrees with respect to the cylindrical outer surface of the pipe-shaped copper member B. At this time, the width of the front end surface B2 is 0.1 to 0.2 mm.
It is about. The shape of the distal end surface B2 is changed according to the shape of the welded portion of the iron member A, and is processed in advance into a shape that comes into contact with the weld surface of the iron member A.

Next, an iron member A and a pipe-shaped copper member B
The method for fixing by welding will be described.

In FIG. 3A, AC power from an AC power supply AC is transformed by a transformer T1, rectified by a rectifier Re, then flows through a semiconductor switch S1 to a capacitor bank Co to charge the capacitor bank Co. When the capacitor bank Co is charged to a predetermined value, the high-speed semiconductor switch S2 including a thyristor or a power MOSFET is turned on, so that the charged charge of the capacitor bank Co is discharged via the welding transformer T2, and the welding electrode is discharged. A welding current i having a current waveform as shown in FIG.

Here, the welding current i is
o, the waveform decreases in accordance with the discharge time constant determined by the impedance of the discharge circuit including the welding transformer T2, the welding electrode WE, and the like. The current in the region reduced above the value is not very useful for diffusion welding. As a result of various experiments, it is preferable that the time width of the welding current i from the rising time to the vicinity of the peak value is approximately 7 milliseconds or less and the response time of the pressing force applied to the workpiece is within the range. I found out.

When the time width from the time when the welding current i substantially rises to the vicinity of the peak value is about 7 milliseconds or more, the heat can be reduced in a short time because the heat conduction of the pipe-shaped copper member B is very good. Therefore, the joint surfaces of the pipe-shaped copper member B and the iron member A are both softened, but the degree of softening may be poor, and a desired welding strength cannot be obtained. If the time width up to the vicinity of the peak value of the welding current i is shorter than the response time of the pressing force applied to the workpiece, both the joining surfaces of the copper member B and the iron member A are softened. When the pressure is applied, the pressing force cannot follow and the pressing force becomes insufficient.
Undesirable phenomena such as dust occur near the weld.

Therefore, the response speed of the pressurizing function can be improved by using a welding apparatus having a structure as shown in FIG. 4, which will be described below, and the pipe-shaped copper member B is preferably diffusion-welded to the iron member A. It becomes possible.

[0017]

An embodiment of this welding apparatus will be described with reference to FIG. 4. Reference numeral 1 denotes a pressing mechanism such as a cylinder apparatus, and 2 denotes a metal block fixed to the bottom of the pressing mechanism 1 and serving as an electrode holder. Reference numerals 3 and 4 denote left-right symmetrical flexible members, one end of which is fixed to the metal block 2. A first support member 5 made of an electrically insulating material and having a U-shaped cross section has a female screw formed at the center of the bottom, and is fixed to the metal block 2 by a male screw 6. Second support member 7 made of a metal material such as brass
Is supported by flexible members 3 and 4,
The first support member 5 has an inner diameter that is slightly larger than the outer diameter of the first support member 5, and a part of the first support member 5 is in a positional relationship extending to the inside.

[0018] Here, 8 follows the vertical small movement of the second support member 7 at a high speed, and regardless of the softening of the metal material at the welding location of the pipe-shaped copper member B and the iron member A, It is a pressure assisting member that always keeps a constant pressing force at the welding location, and generally uses a spring or an electromagnetic pressure device with excellent response speed. The pressure assisting member 8 is the first
Is supported between the supporting member 5 and the second supporting member 7, and the downward pressing force from the pressing mechanism 1 is transmitted to the second supporting member 7 through the pressing auxiliary member 8. You. The clamp electrode 9 serving as an upper welding electrode is fixed to the second support member 7, and is composed of a plurality of divided electrode portions. These electrode parts automatically open and close with respect to the center line Y to clamp or open the pipe-shaped copper member B. Reference numeral 10 denotes a support arm for supporting the lower welding electrode 11, which is a first iron made of a cylindrical tank or the like.
Is configured to be able to advance and retreat with respect to the hollow portion of the workpiece A, and to be able to ascend and descend.

One end of the main surface 2 A of the metal block 2
, And two other parallel cylindrical guide members 12A and 12A, the other ends of which are fixed ends.
12B. The pair of linear driving members 13A and 13B have the same structure, and the linear driving member 13A is
A linear motion bearing portion 13A1 that performs linear motion guided by A, an electrical insulating member 13A2 provided on the outer surface of the outer cylinder thereof, and an electrode support block portion into which the linear motion bearing portion 13A1 and the electrical insulating member 13A2 are fitted. 13A3. This electrical insulation member 13A2 is
Since the current is prevented from flowing through A1 and is prevented from being welded or electrolytically eroded, the linear motion bearing portion 13A1 is always kept so small that the resistance during its movement is sufficiently negligible.

Next, the diffusion welding operation by this apparatus will be described. First, the clamp electrode 9 is closed from the open state to clamp the pipe-shaped copper member B. Pressing mechanism 1
Is operated and moves downward, the entire upper welding electrode head is lowered by a coupling mechanism (not shown). On the other hand, the support arm 10 enters the hollow part of the first iron work A made of iron, such as a cylindrical tank, by a driving device (not shown),
When it reaches a predetermined position, it rises and stops when the lower welding electrode 11 comes into contact with the inner wall surface of the first iron work A made of iron.
The pipe-shaped copper member B clamped by the clamp electrode 9 is supported by the lower welding electrode 11 and the iron member A is supported.
Abut. The clamp electrode 9, the second support member 7, and the linear drive members 13A, 13B stop at that position, but as the pressurizing mechanism 1 further descends, the pressurizing auxiliary member 8 contracts, and at the same time, the flexible member 3 And 4 are bent, and the metal block 2, the first support member 5, and the guide members 12A, 1
2B descends together with the pressure mechanism 1. Therefore, the pressurizing auxiliary member 8 such as a spring is contracted by the distance that the metal block 2 or the like is lowered after the clamp electrode 9 or the like is stopped, and the flexible members 3 and 4 are bent. Pressing mechanism 1
Under pressure, the pressure assisting members 8 store downward mechanical energy, and they act to absorb upward forces above a certain level.

As described above, the pressure assisting member 8 contracts while the pressure mechanism 1 operates and performs the downward movement, and the outer wall of the first support member 5 moves along the inner wall of the second support member 7. And fall with almost no resistance. When the pressure reaches a predetermined level, the welding current supplied from the power supply conductor (not shown) to the metal block 2 passes through the flexible members 3 and 4, the second support member 7, and the clamp electrode 9 to form a pipe. It flows to the shape copper member B and the iron member A, and further flows to the lower welding electrode 11. At this time, the first support member 5 is made of an electrically insulating material, so that no current flows through the auxiliary pressurizing member 8. Therefore, the pressure assisting member 8 is not eroded or welded, and the elastic force of the pressure assisting member 8 does not change due to the temperature rise due to the electric current.

By applying a welding current i having a pulse width of about 7 milliseconds or less in a state where the pipe-shaped copper member B and the first workpiece A are welded in a state of being pressurized with a predetermined pressing force. Copper and iron materials soften. As the welding portion of both dissimilar metal materials starts to soften, for example, when the pressurizing auxiliary member 8 is a spring, the expansion of the welded portion is instantaneously absorbed by the pressurizing auxiliary member 8 and the pressing force acts. In this state, the pressurizing auxiliary member 8 always applies a pressing force to the welded portion, so that it is possible to apply pressurization with an extremely fast response to sinking due to softening of the metal material accompanying the progress of diffusion welding. . This means that not only welding of dissimilar metal materials but also of similar metal materials with very good heat conduction does not generate dust (sputtering) during welding, so welding of small electronic parts etc. Suitable for.

As the response speed of the pressurizing auxiliary member 8 is higher, the welding current i having a shorter pulse width, that is, the current energy is concentrated in a shorter time, so that the pipe-shaped copper member B, which is a dissimilar metal, and the iron 1 can be flowed through the workpiece A, and even a material having extremely good heat conduction, such as a copper material,
Since it can be softened to a preferable state, satisfactory diffusion welding between the pipe-shaped copper member B and the first iron-made workpiece A can be performed. Therefore, the lower limit of the time width W of the welding current i shown in FIG. 3B is preferably longer than the response time of the pressure assisting member 8. When the time width W of the welding current i is less than or equal to the response time of the auxiliary pressurizing member 8, the welding force between the copper member B and the first iron-made workpiece A is increased as the welding proceeds. To come short of
Chile etc. are generated, which is not preferable.

[0024]

As described above, according to the present invention,
A projection is formed in advance on the welded end of the copper member, and the time between the copper member and the iron member until the peak value is reached is approximately 7 milliseconds or less, and a pulsed current that exceeds the response time of the pressing force flows. In addition, since diffusion welding between different metals is performed, it is extremely easy to fix the copper metal material and the iron metal material, which were considered to be extremely difficult to perform, and to perform diffusion welding of excellent quality. Can be. Further, even for the same kind of metal material having very good heat conduction, dust (sputtering) is not generated at the time of welding, so that the present invention is suitable for welding small electronic parts and the like which do not like the generation of dust.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining diffusion welding of the present invention.

FIG. 2 is a view for explaining a welding end face of one of the objects to be welded according to the present invention.

FIG. 3 is a diagram showing a circuit for explaining a diffusion welding method of the present invention and a welding current waveform.

FIG. 4 is a view for explaining one embodiment of the diffusion welding apparatus of the present invention.

FIG. 5 is a view for explaining a conventional method of fixing a pipe-shaped copper member.

[Explanation of symbols]

A: Iron member as first workpiece B: Copper member as second workpiece AC AC power supply T1 Transformer Re rectifier S1 Switch Co: Capacitor bank S2: High-speed semiconductor switch T2: Welding transformer Rv: Pulse width adjusting resistor 1: Pressurizing mechanism 2: Metal block 3, 4, ... · Flexible member 5 ··· First support member 7 ··· Second support member 8 ··· Elastic member 9 ··· Clamp electrode 10 ···
Supporting arm 11 ... Electrode for lower welding 12 ...
Guide member

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI B23K 103: 22 B23K 103: 22 (58) Investigated field (Int.Cl. ⁷ , DB name) B23K 11/14 B23K 11/20 B23K 11/24 B23K 103: 22

Claims (2)

(57) [Claims] 1. A method of fixing a copper member to an iron member, wherein the welding end of the copper member formed in advance with projection is positioned between the copper member and the iron member in a state where the welding end is aligned with the iron member. A predetermined pressure is applied, and a pulse-like current having a time width up to a peak value of substantially 7 milliseconds or less and a response time of the pressure or more is passed between the copper member and the iron member, Fixing the copper member to the joint between the copper member and the iron member until the fixing of the copper pipe to the copper member is completed. 2. A metal block held by a pressing mechanism so as to be able to advance and retreat, a first support member fixed to the metal block, a plurality of guide members implanted in the metal block, and the guide member A linear drive member capable of traveling along the same, a flexible portion having one end connected to the metal block and the other end connected to the linear drive member to electrically connect them, and supported by the linear drive member A second supporting member, a pressurizing auxiliary member disposed between the first supporting member and the second supporting member, and an upper welding electrode attached to the linear driving member. A resistance welding apparatus characterized in that an electric current flows between the upper welding electrode and the lower welding electrode capable of high-speed response to weld the workpieces to each other.