JPH10328855A - Manufacture of conductive joined body joined with different kinds of metal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the reduction of conductivity and mechanical strength in the joined part, in the joined body of such conductive different kinds of metal as copper and aluminum used in a transformer terminal or the like. SOLUTION: The joining device 3 provided a large diameter of rotor 30 and the probe 32 projected from one end surface in the axial direction is used, two conductive members 1, 2 consisting of different kinds of metal are mutually arranged in the joining position, the rotating probe 32 is inserted into the joining part or its vicinity, the part coming into contact with the probe 32 is soften with frictional heat and agitated, whereby two conductive members 1, 2 are joined and the conductive joined body is manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive joined body in which dissimilar metals used for transformer terminals of heavy equipment are joined.

[0002]

2. Description of the Related Art In such heavy equipment, for example, it is necessary to connect a copper (including its alloy) winding of a transformer and an aluminum (including its alloy) power line via terminals. May occur.

[0003] When such terminals are formed of aluminum material, the copper winding on the transformer side and the terminals are connected by different kinds of metal. Conversely, when the terminals are formed of copper material, the power line and the terminals are connected. Dissimilar metal connection results, and in any case, the conductivity is reduced at the dissimilar metal connection.

Therefore, conventionally, the terminals are formed of aluminum or copper, and a part of the terminals is plated with copper or aluminum, thereby avoiding the connection of dissimilar metals between the transformer winding and the power line and the terminals. Has been done.

[0005]

However, since the plating film formed on the terminal is thin and has low adhesion,
When subjected to strong rubbing due to attachment / detachment of a power line or the like, the plating film was peeled off and the base was sometimes exposed. In such a state, the transformer winding or the power line and the terminal are connected to each other by different kinds of metals, so that it has been difficult to maintain high conductivity at the connection portion for a long time.

In addition, since the plating step involves a lot of pollutants and is costly, it is desired to avoid it as much as possible.

[0007] In addition, copper and aluminum
By forming the terminal material by joining by fusion welding of G, TIG, etc., the plating film can be made unnecessary, but in this case, an intermetallic compound is generated at the joining portion, so that the joining portion inside the terminal is The conductivity was reduced, and the mechanical strength of the joint was also reduced, so that the terminal was not sufficient.

The present invention has been made in view of the above-mentioned problems, and is directed to a joined body of a conductive dissimilar metal such as copper and aluminum used for a terminal for a transformer or the like. It is another object of the present invention to provide a method of manufacturing a conductive joined body in which different kinds of metals are joined while preventing a decrease in mechanical strength.

[0009]

According to the present invention, there is provided a bonding apparatus having a rotor having a large diameter and a probe protruding from one end surface in an axial direction of the rotor. At the joint position, the rotating probe is inserted at or near the joint portion, and the contact portion with the probe is softened by frictional heat and agitated.
According to the present invention, there is provided a method of manufacturing a conductive joined body in which different kinds of metals are joined, wherein the method comprises joining the conductive members.

If the above-mentioned manufacturing method is adopted, the two conductive members made of dissimilar metals are joined in a solid state without melting, so that an intermetallic compound which adversely affects the conductivity is not generated, Since the temperature at the time of joining is relatively low, the strength of the joined portion does not decrease due to thermal influence. Therefore, the obtained conductive bonded body has high conductivity and high bonding strength. Furthermore, since it does not form a conductive plating film made of a dissimilar metal on the surface of a single conductive member,
One conductive member is not easily worn by strong rubbing or a force applied from the outside, and a plating step is not required.

Further, in the above, if the two conductive members are overlapped and joined so that the insertion direction of the probe and the overlap surface intersect, the overlap surface is securely joined. The joining area can be set to an arbitrary size by adjusting the amount of superposition.

Furthermore, if the probe is inserted from the soft conductive member side of the conductive member, plasticization due to friction with the probe can be easily performed, and the probe can be easily connected to the soft conductive member. Can be inserted. In addition, since the softer-side conductive member is softened and agitated more, the agitation can be performed smoothly, and almost no defects are generated in the joint portion, and the joint strength is further increased.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a method for manufacturing a conductive joined body in which dissimilar metals are joined according to the present invention will be applied to a transformer terminal for connecting a copper winding of a transformer and an aluminum power line. A description will be given based on the above embodiment with reference to the drawings.

In FIG. 1, (A) is a terminal as a joined body, and the terminal (A) is a step having an L-shaped cross section formed at one longitudinal end of a plate-shaped copper terminal (1). Department (10)
And a stepped portion (20) having an inverted L-shaped cross section formed at one end of the plate-shaped aluminum terminal portion (2) in the longitudinal direction and joined by a joining device (3). It was produced.

In addition, screw holes for detachably connecting transformer windings, power lines, and the like are provided at the distal ends (not shown) of both terminal portions (1) and (2).

The joining device (3) includes a small-diameter pin-shaped probe (3) on the end axis of a large-diameter cylindrical rotor (30).
The rotor (30) and the probe (32) are both copper terminals (1).
And a material harder than the aluminum terminal portion (2).

Next, a method of manufacturing the joined body (terminal) according to this embodiment will be described.

The copper terminal portion (1) and the aluminum terminal portion (2) are brought into abutting condition at one end in the longitudinal direction, and the step portions (10) and (20) formed at the ends are engaged with each other. So that the surfaces of the copper terminal portion (1) and the aluminum terminal portion (2) are flush with each other.

Next, the rotor (3) of the joining device (3)
While rotating the probe (0) and the probe (32) together, the probe (32) is inserted from the surface of the aluminum terminal portion (2) made of a soft metal toward the overlapping surface (4). Insertion is performed until the flat surface (31) provided with the probe (32) of the rotor (30) presses the surface of the aluminum terminal portion (2). In this state, the probe (3
2) penetrates the step portion (20) of the aluminum terminal portion (2), reaches the step portion (10) of the copper terminal portion (1), and intersects with the overlapping surface (4). Then, while maintaining this state, the rotor (30) and the probe (32) are slightly inclined backward in the moving direction and in the width direction of the aluminum terminal portion (2) and the copper terminal portion (1). Move relatively.

The frictional heat generated by the rotation of the probe (32) and the rubbing of the aluminum terminal (2) and the copper terminal (1), or furthermore, the end face (31) of the rotor (30) and the luminium Due to the frictional heat generated due to the rubbing with the terminal portion (2), both the step portions (10) (20) of the copper terminal portion (1) and the aluminum terminal portion (2) near the contact portion with the probe (32). ) Is plasticized and softened and agitated by the probe (32), and as the probe (32) moves, the softened and agitated portion becomes the probe (3).
In response to the advancing pressure of (2), the plastic flows in such a manner as to go backward in the traveling direction of the probe (32) so as to fill the passage groove of the probe (32), and then rapidly loses frictional heat and is cooled and solidified. This phenomenon is sequentially repeated as the probe (32) moves, and finally the steps (10) (20) of the copper terminal (1) and the aluminum terminal (2).
Are friction stir welded over the entire length direction on the overlapping surface (4) to obtain a conductive joined body.

The conductive joint obtained by this embodiment has a copper terminal (1) and an aluminum terminal (2).
Are joined by a friction stir welding method, which is a solid-state welding method, and are joined in a state where the probe (32) of the joining device (3) intersects the overlapping surface (4). Since the probe (32) is inserted from the side of the aluminum terminal (2), which is a material relatively softer than the copper terminal (1), the joint is in a molten state as in the case of fusion welding. There is no generation of intermetallic compounds that adversely affect conductivity and no reduction in strength due to thermal effects.
Moreover, the joining operation is easy and reliable, and the overlapping surface (4) can be joined securely, and a large joining area can be obtained without being affected by the thickness of the copper terminal portion (1) or the aluminum terminal portion (2). As a result, good conductivity and high bonding strength can be obtained.

The terminal (A) obtained as described above does not peel off the plating film as in the case of the plated terminal, even if the transformer winding and the power line are repeatedly attached and detached.
Even if an excessive force is applied from the transformer winding or the power line, the copper terminal portion (1) and the aluminum terminal portion (2) are firmly joined, so that the force can be sufficiently resisted.

In the embodiment shown in FIG. 1, the copper terminal portion (1) and the aluminum terminal portion (2) are provided with steps (10) and (20) having an L-shaped cross section or an inverted L-shaped cross section, respectively. FIG. 2 (a) shows a case where the probe (3) is joined in parallel with the abutting surfaces by abutting flat end surfaces as shown in FIG. 2 (a).
2), as shown in FIG. 2 (b), when the end inclined surfaces of the respective terminal portions are overlapped and joined to each other, or as shown in FIG. May be joined so that the insertion direction of the probe (32) and the overlapping surface (4) intersect with each other in a state where the ends are overlapped in a laminated manner. However, preferably, as shown in FIG. 1, steps (10) and (20) having an L-shaped cross section and an inverted L-shape are provided, and the probe (32) is inserted orthogonally to the overlapping surface (4). However, it is preferable from the viewpoint that both terminal portions can be symmetrically stirred on both sides of the joining surface, and a joining defect due to penetration of a void or the like can be minimized.

In the above embodiment, the copper terminal portion (1) and the aluminum terminal portion (2) are joined, but the material of the conductive member to be joined is not limited to this, and any material may be used. Can be selected. Also, the joined body is not limited to the terminal, and may be any as long as it is used as a conductive joined body.

[0025]

Next, an embodiment of the present invention will be described.

The copper and aluminum plates are strip-shaped (thickness 4
Test pieces cut to a predetermined size (mm × width 50 mm × length 200 mm) were prepared. Further, each of the two test pieces made of copper and aluminum was cut out at one end thereof into a rectangular shape over the entire width direction, so that the thickness was 2 mm.
X Steps having a protruding length of 20 mm and an L-shaped cross section and an inverted L-shaped cross section were provided.

Next, the test pieces made of copper and aluminum are butted in the length direction, and the butted portions are joined by a friction stir welding method in the following manner to produce a test specimen to which different metals are joined. did.

Example 1 Butting mode: Butting of flat surfaces shown in FIG. 2 (a) Friction stir welding method: Insert probe parallel to butting surface Friction stir welding conditions Rotation speed: 1500 rpm Probe: outer diameter 2 mm × Length 4mm Rotor: Outer diameter 12mm

Example 2 Butting Mode: Butt Friction Stir Welding Method with L-Shaped and Reverse L-Shaped Steps shown in FIG. 1 Engagement: A probe is inserted perpendicularly from the aluminum side to the overlapping surface.

Friction stir welding conditions: same as in Example 1.

Example 3 Butting Mode: Butt Friction Stir Welding Method with L-Shaped and Inverted L-Shaped Steps shown in FIG. 1 Engaging: A probe is inserted perpendicularly from the copper side to the overlapping surface.

Friction stir welding conditions: same as in Example 1.

Comparative Example 1 The ends of the aluminum test piece and the copper test piece were butted as shown in FIG. 2A to prepare a MIG-welded test piece.

With respect to each of the test pieces manufactured as described above, the breaking strength and the breaking position were examined, and the conductivity was examined. The conductivity was relatively evaluated by setting the conductivity of Comparative Example 1 to 100. Table 1 shows the results.

[0035]

[Table 1]

According to Table 1, according to the present invention, the conductivity,
It was confirmed that a joined body excellent in both strength could be manufactured.

[0037]

According to the present invention, there is provided a method of manufacturing a conductive joined body by joining two conductive members made of dissimilar metals by a friction stir method. Therefore,
Since each conductive member can be joined in a solid state without melting to produce a conductive joined body, almost no intermetallic compound which adversely affects the conductivity is generated at the joined portion, and the joined members are joined. The conductive joined body can maintain high conductivity. In addition, since it does not melt, a conductive joint having excellent strength can be manufactured without deteriorating the strength of the joint due to thermal influence.

If the conductive members are overlapped and joined so that the probe insertion direction intersects with the overlap surface, the overlap surface can be reliably joined and the amount of overlap can be adjusted. Accordingly, the bonding area can be set to an arbitrary size, and the contact strength of the conductive bonded body can be further increased.

Furthermore, if the probe is inserted from the softer conductive member side of the conductive member, joining work such as insertion of the probe becomes easy, and stirring of both conductive members becomes easier. . Therefore, it is possible to easily manufacture a conductive bonded body having very high conductivity and bonding strength with almost no defects in the bonded portion.

Naturally, since a plating film is not formed, there is no decrease in conductivity due to peeling of the plating film over time, and no plating process is required, so that no pollution occurs.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIGS. 2A to 2C are cross-sectional views showing modified examples of the embodiment according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Copper terminal part (conductive member) 2 ... Aluminum terminal part (conductive member) 3 ... Joining apparatus 4 ... Lamination surface 10, 20 ... Step part 30 ... Rotor 32 ... Probe

Claims (3)

[Claims] 1. A joining device (3) including a rotor (30) having a large diameter and a probe (32) protruding from one end surface in an axial direction thereof, and two conductive members (2) made of dissimilar metals are used. 1) (2) By disposing the rotating probe (32) at or near the joint portion while placing the members at the joining position, and softening and stirring the contact portion with the probe (32) by frictional heat. , Two conductive members (1)
(2) A method for producing a conductive joined body in which dissimilar metals are joined, characterized by joining. 2. The two conductive members (1) and (2) such that the insertion direction of the probe (32) intersects with the overlapping surface (4).
2. The method according to claim 1, wherein the parts are overlapped and joined.
A method for producing a conductive joined body in which dissimilar metals are joined. 3. A probe (3) comprising two conductive members (1).
3. The method according to claim 2, wherein the insertion is performed from the soft conductive member (1) side of (2).