JPH0323615A - How to join capacitor lead wires - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Industrial Field of Application The present invention relates to a device for joining an aluminum wire and a copper-undercoated tin wire (hereinafter referred to as Cp wire), and particularly to a method for joining lead wires for electrolytic capacitors. O. PRIOR TECHNOLOGY As a conventional method for joining lead wires for capacitors of this type, an arc welding method having a structure as shown in FIG. 7 has been proposed.

The aluminum wire 1 is held by the e-pole welding electrodes 21L and 2b, the Cp wire 3 is held by the ■-pole conductor chuck 4, and the conductor chuck 4 is driven in an arc shape in the direction of the gold arrow. After bringing the aluminum wire 1 and the Cp wire 3 into contact as shown in Figure 9, the arc 6 is generated by pulling them apart slightly, the heat melts the aluminum wire 1 and the Cp wire 3, and the two are butted together as shown in Figure 9. Iron on the boundary between the two. Copper, aluminum. This was a method of forming and joining a tin alloy part 6.

Problems to be Solved by the Invention In such a conventional bonding method, dissimilar metals such as iron and copper are scattered and attached to the aluminum wire 1 due to arc sputtering 7 during bonding as shown in FIG. As shown in Figure 9, iron,
copper. Since the alloy part 6 of aluminum, tin, etc. is exposed to the outside, fine powder of these metal fragments forms the capacitor electrode when assembling the capacitor.Aluminum foil or intercalating paper (electrolytic paper)
Fine powder that falls onto the top or rubs against each other in the vibrating transducer adheres to one part of the aluminum wire, causing leakage current defects and V w - t defects, which are important characteristics of electrolytic capacitors. etc., which have a huge negative impact.

As is well known, aluminum is a metal that quickly forms an oxide film, so the oxide film may remain inside the alloy part 6 or be mixed in, creating defects and preventing sufficient welding strength. The present invention solves these problems, and the bonding alloy layer of the aluminum wire and the CI wire is exposed to the outside. The object of the present invention is to provide a method for joining capacitor lead wires that is not exposed and has very stable welding strength.

Means for Solving the Problems In order to solve the above problems, the present invention provides a method for joining capacitor lead wires, in which an aluminum wire with a preheated chuck or a non-preheated chuck is connected to a Cp wire that is also preheated.
When bonding lea or unpreheated Cp wire, multiple gas burners are installed around the aluminum wire or around the aluminum wire's passing trajectory so that the multiple gas burners heat the aluminum wire from multiple directions at appropriate angles. arranged,
By repeatedly bringing the gas burner and the aluminum wire closer to each other and separating them at a constant tact or rotational speed depending on the machine timing, the heat required for the aluminum wire is generated within the range where the shape is maintained by the gas flame of the gas burner. By using the above configuration, the aluminum wire and gas burner can be brought close to each other in accordance with the timing of the overall machine. The Cp wire fed from one side is pushed into the aluminum wire at the optimal timing during the repeated separation, and as a result, an alloy layer is formed inside the aluminum wire and the bonding is completed one after another. , high quality capacitor lead wires can be obtained.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings. FIG. 1 shows a schematic diagram of a method for joining capacitor lead wires according to an embodiment of the present invention, in which an aluminum wire 12 is held by a preheated chuck 11, and an unpreheated Cp chuck 13 is used to hold an aluminum wire 12. Copper-undercoated tin wire (hereinafter referred to as Cp)
When the aluminum wire 14 is held, the combustible gas is burned in the gas burner 16, and the highest temperature core flame 161L of this gas flame 16 is applied to the round bar part, and the aluminum wire 12 is in a semi-molten state (the shape is Cp line 14'fr. Press and join.

Next, to explain the mechanism of joining the aluminum wire 12 and the Cp wire 14, in the first step, as shown in FIG. The aluminum wire 12 is heated to the extent that it does not lose its shape, and then a copper (Cu) wire is added to the iron (Fe) wire.
) plating and further tin (Sn) plating is pushed in. Since the tin (Sn) layer of the Op wire 14 has a melting temperature of 230°C, the tin (Sn) layer is
) layer melts instantly due to heat transfer from the aluminum wire 12 side, and as a result, as the Cp wire 14 is pushed and twisted, the second copper (Cu) layer transfers the temperature. As shown in the figure, tin (Sn) on the surface is pushed out.

At the same time, inside the aluminum wire 12, aluminum (▲l)
Since the atoms and the copper (Cu) atoms of the Cp wire 14 do not come into contact with the atmosphere at all, they come into contact with each other in a pure state without being oxidized.

In the second stage, as is clear from the general ▲l -Cu system equilibrium phase diagram shown in Figure 3, aluminum (▲l) and copper (Cu) undergo eutectic formation above the eutectic point of 648°C. A reaction occurs.

In the method for joining capacitor lead wires of the present invention,
When the temperature is raised to 648℃ or higher, aluminum (▲l) atoms and copper (Cu) atoms diffuse into each other at the contact area to form a eutectic structure, and the interface between aluminum (▲l) and copper (Cu) Once they become molten, they melt together.

In the third stage, the gas burner 15 is removed from the aluminum wire 12 to lower the temperature of the aluminum wire 12, but as a result, the eutectic structure melted at the contact area between aluminum (▲l,) and copper (On) After solidification, a eutectic alloy layer 1T is formed, and the bonding between the two is completed.

In the capacitor lead wire bonding method of the present invention, the changes in the ▲l-Cu-an interface of the alloy layer portion during the bonding process are as shown in FIGS. 4 to 6. In other words, Figures 4 to 6 are schematic diagrams examining how much each metal atom of ▲J, Cu, and 8n has moved quantitatively at the interface. (▲E) atoms, and it can be seen that these aluminum (▲l) atoms move from the aluminum (▲ll) layer part to the copper (On) layer part and exist in the alloy layer part. In addition, in Figure 6, the v mark is copper (
Cu) atom, and this copper (Ou) atom is copper (Cu) atom.
) It can be seen that it moves from part 71 to the aluminum (▲l) layer side and is present in the alloy layer part. Also in Figure 6, the mouthmark is a tin (in) atom, in this case,
It can be seen that a small amount of tin (Sn) atoms are scattered in the alloy layer.

The structure of the alloy layer produced in this way is mainly α phase (
▲II) containing up to 6% CU as a solid solution and 0 phase ((u
It consists of a eutectic structure of an intermetallic compound of Al2,
In this case, Curl2 is hard and brittle, and this eutectic structure may also contain a supersaturated solid solution depending on the cooling rate, but in any case, the structure of this alloy layer is It is assumed that it consists of a fairly complex organization.

The above is the mechanism of bonding the aluminum wire 12 and the Cp wire 14, but the biggest requirement for this bonding method is that the aluminum wire 12 must be uniformly and rapidly heated above the eutectic temperature (648°C). Various heating methods were investigated.

As a result of the investigation, as shown in FIG.
When the aluminum wire 12 is heated by irradiating it for a short time (about 0.4 seconds) and the temperature distribution is measured by the discoloration of thermocleon, etc., the temperature in the part ▲ has risen to about 660°C, whereas
Since the temperature of part B was 40° C., which was lower than the eutectic point (648° C.), the formation of the alloy layer was insufficient, and as a result, the bonding strength was unstable.

Therefore, as shown in FIG. 8a, two gas burners 6 are arranged at an angle C with respect to the aluminum wire 12.
When the aluminum wire 12 is irradiated with gas flame 16 from multiple directions by the gas burners 6, the gas flame 16 flows to surround the aluminum wire 12. As a result, the aluminum wire 12 is heated evenly, so that a good alloy layer 17 is formed.
As a result, a stable bond between the aluminum wire 12 and the Cp wire 14 can be obtained.

If two gas burners 16 are arranged in a straight line as shown in FIG. 8b, the two gas flames 16 will collide and abnormally heat the chuck 11. Since variations occur in the temperature of the aluminum wire 12, when the two gas burners 15 are shifted from each other as shown in FIG. It can be heated evenly.

Figure 9 a. b shows an embodiment in which the aluminum wire 12 is heated by three gas burners 16, and this embodiment also provides the same effects as the embodiments shown in FIGS. 8a and 8C above. It is something. In the case of three gas burners 16, heating can be performed more rapidly and uniformly than in the case of heating with two gas burners 16.

Effects of the Invention As is clear from the description of the above embodiments, according to the method for joining capacitor lead wires of the present invention, the aluminum wire is heated so that the plurality of gas burners heat the aluminum wire from multiple directions at appropriate angles. Multiple gas burners are placed around the periphery or around the aluminum wire passing track, and the gas burners and aluminum wire are brought relatively close to each other at a constant tact or rotational speed depending on the timing of the machine. By repeating the separation, the Cp wire is pushed in and joined while applying the necessary heat to the aluminum wire within the range where the shape is maintained by the gas flame of Siganuvarna, so the joint between the aluminum wire and the Cp wire is As a result, an alloy layer consisting of copper, aluminum, etc. is formed uniformly inside the aluminum wire, and as a result, an alloy layer consisting of copper, aluminum, etc. is formed uniformly inside the aluminum wire. Dissimilar metals such as tin are no longer exposed outside the aluminum wire. In addition, dissimilar metals such as iron and copper will not be scattered, so leakage current defects and seat defects, which are the electrical characteristics of electrolytic capacitors, will no longer occur. , and with little variation, it is possible to obtain a very stable lead wire.

[Brief explanation of drawings]

Figure 1 is a schematic diagram showing a method for joining capacitor lead wires in an embodiment of the present invention, Figure 2 is a longitudinal cross-sectional view of the joint of lead wires obtained by the same joining method, and Figure 3 is ▲
l-Ou system equilibrium state diagram, Figures 4 to 6 are schematic diagrams showing interface changes of ▲l-Cu-an in the alloy layer obtained by the same joining method, and Figures 7 a and b are the same joining method. This figure shows an example of the heating method using gas flame, and a is a top view. b is a longitudinal sectional view, Figures 8a, b, and c show an example of the heating method using a gas flame of the same joining method, a is a longitudinal sectional view, b and c are a top view, and Fig. 9 Figures a and b show another example of the same joining method using a heating method using a gas flame, and a is a top view. b is a longitudinal cross-sectional view, Fig. 10 is a partial perspective view of a welding device using the conventional welding method, Fig. 11 is a principle diagram showing the conventional welding method, and Fig. 12 is a lead made by the conventional welding method. FIG. 3 is a cross-sectional view of a line joint. 11...TEYAC, 12...Aluminum wire, 13...Cp chuck, 14...C
P-line, 16... Gas burner, 16...
Ganu flame, 17...eutectic alloy layer.

Claims (1)

[Claims] When joining an aluminum wire with a preheated chuck or an unpreheated chuck to a Cp wire that is also preheated or a Cp wire that is not preheated, multiple gas burners heat the aluminum wire from multiple directions at appropriate angles. Multiple gas burners are placed around the aluminum wire or around the aluminum wire's passing track, and the gas burners and the aluminum wire repeatedly approach and separate from each other at a constant tact or rotational speed depending on the timing of the machine. A method for joining lead wires for a capacitor, characterized in that a Cp wire is pushed in and joined while applying necessary heat to the aluminum wire within a range where the shape is maintained by the gas flame of a gas burner.