JPH04174911A - Extra fine electric wire - Google Patents

Abstract

PURPOSE:To reduce the work load by forming a metal layer with good solder elution resistance on the surface of a core wire. CONSTITUTION:A metal layer 1, which is made of nickel or nickel alloy such as nickel-iron or nickel-cobalt by spattering or ion plating, has a melting point higher than that of copper, has little elution to a solder bath, hardly generates an oxide film in electricity, and has good soldering property, is formed on the surface of an extra fine core wire S made of electric copper or oxygen-free copper. An electric insulating film Z is coated on the layer 1. The thickness of the layer 1 is desirably set to 1-3% of the diameter of an extra fine electric wire D to concurrently satisfy solder elution resistance and conductivity. The fusion of the wire D is prevented at the time of soldering, and the work load of a soldering worker can be reduced.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a watch motor, a magnetic head, and a relay.

The present invention relates to ultra-fine electric wires used as windings for ultra-small coils used in inductors, etc., and particularly to ultra-fine electric wires that are passed through for electrical connection by soldering.

[Conventional technology]

BACKGROUND ART Conventionally, ultrafine electric wires have been used as windings for ultra-small coils, etc., in which the core wire is made of electrolytic copper or oxygen-free copper, and the surface thereof is baked and coated with a resin such as polyurethane to form an electrically insulating coating.

In order to electrically connect the coil ends of the ultra-small coils made of these ultra-fine wires, soldering using lead-tin solder is carried out on boats.

However, when the wire diameter of ultra-fine wires becomes several hundred microns or less, the copper in the core wire diffuses and dissolves into the molten solder during soldering, resulting in so-called thinning (erosion).
As a result, there was a problem in that the ultra-fine electric wire itself was fused.

In addition, in the past, when trying to prevent melting due to soldering of ultra-thin wires, strict work management was carried out during the soldering work, and the temperature was constantly monitored and controlled to prevent the soldering temperature from becoming too high. Therefore, workers had to take precautions such as shortening the soldering time as much as possible, which placed an excessive burden on the workers.

Furthermore, since the temperature of the soldering bath cannot be raised with conventional ultrafine electric wires, there is also the drawback that the soldering workability is poor.

In addition, the thinner the ultra-fine wire is, the more likely it is that fusing occurs during soldering, so there is a certain limit to reducing the diameter of conventional ultra-fine wire (
(approximately several hundred micrometers), and this has been an obstacle to further miniaturization of coils and the like.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION Therefore, the present invention provides an ultra-fine electric wire in which the copper of the core wire will not be eroded by the solder and melted when soldering, thereby reducing the work burden of the person performing the soldering work, and The technical challenge is to improve the workability of attachment.

[Means to solve the problem]

In order to solve this problem, the present invention provides an ultra-fine electric wire in which an ultra-fine core wire made of copper or a copper alloy is coated with an electrically insulating coating, in which a metal layer with good solder corrosion resistance is formed on the surface of the ultra-fine core wire. , the metal layer is coated with the insulating film.

[Effect]

The ultra-fine electric wire according to the present invention has a metal layer with good solder corrosion resistance formed on the surface of the ultra-fine core wire made of copper or copper alloy, so that the copper of the ultra-fine core wire diffuses into the solder bath during soldering. It becomes difficult to elute, and there is no risk of melting due to thinning of the solder, which is the case with conventional ultra-fine wires.

Therefore, when performing the soldering work, there is no need to carry out strict work management as in the past, and the work burden on the person performing the soldering work is reduced.

Furthermore, since the ultra-fine wires are less susceptible to corrosion, the temperature of the soldering bath can be increased, and the workability of soldering is also improved.

Furthermore, by forming a metal layer with good solder corrosion resistance, we have been able to reduce the wire diameter limit that can melt during soldering. It becomes possible to put it to practical use, and the coil etc. can be further miniaturized.

In addition, if the ultra-fine core wire on which a metal layer with good solder corrosion resistance is formed is made thinner by drawing or rolling, the pinholes formed in the metal layer with good solder corrosion resistance will be crushed and the ultra-fine core wire will be made thinner. The quality of the coating on the core wire is improved, and corrosion of the ultra-fine core wire is more reliably prevented.

In addition, if a metal layer that improves solderability made of tin or lead wire diameter solder is formed on a metal layer that has good solder corrosion resistance, the solderability of ultra-fine electric wires will be significantly improved, and the solder resistance will also improve. Even if chromium or the like, which deteriorates solderability due to the formation of an oxide film, is used as the metal layer with good corrosion resistance, good soldering can be obtained.

〔Example〕

Hereinafter, the present invention will be specifically described based on embodiments shown in the drawings.

FIG. 1 is a sectional view showing an example of the ultrafine electric wire according to the present invention, and FIG. 2 is a sectional view showing another embodiment.

The ultra-fine electric wire shown in FIG. 1 has a metal layer 1 with good solder corrosion resistance formed on the surface of an ultra-fine core wire S made of electrolytic copper or oxygen-free copper, and an electrically insulating coating on the metal layer 1. Z is coated.

The metal layer 1 having good solder corrosion resistance is made of, for example, nickel or nickel-iron, which has a higher melting point than copper, is less eluted into the solder bath, is less likely to form an oxide film in the air, and has good solderability.

It is formed of a nickel alloy such as nickel-cobalt, and is coated on the surface of the ultrafine core wire S by electroplating, vacuum evaporation, sputtering, ion plating, or the like.

Here, an ultra-fine core wire S made of electrolytic copper and having a wire diameter of 0.5 mm,
To explain the case of coating nickel by the electroplating method, first, the ultrafine core wire S unwound from a feeding device such as a recoiler is immersed in a plating bath in an electroplating device to coat a metal made of nickel with a thickness of 0.1 wm. Form layer 1. The plating bath used in this case is a nickel boride bath or a nickel sulfamate bath, which has little internal stress on the ultrafine core wire S and can perform high-speed plating.

Next, the ultrafine core wire S on which the metal layer 1 was formed was annealed in a non-oxidizing atmosphere such as argon at 600°C to soften it and stabilize the electrical resistance value, and then subjected to drawing processing with a cross-sectional reduction rate of 60%. give

Then, the above-mentioned annealing process and drawing process are repeated several times to finally reduce the wire diameter to 0.05 mm, and then the wire is made into polyurethane or polyester depending on the purpose.

An electrically insulating film Z is coated by baking polyamide, polyesterimide, etc. to a thickness of 10 to 20 microns.

The above is an example of the configuration of the ultra-fine electric wire according to the present invention.Next, the ultra-fine electric wire according to the present invention having a wire diameter of 0.05fi and a conventional ultra-fine electric wire of the same diameter are immersed in a solder bath to prevent corrosion. To explain the results of a control experiment, 360℃
When a conventional ultra-fine electric wire is immersed in a 60% tin-40% lead solder bath heated to a temperature of It was confirmed that the formation of the metal layer 1 made of nickel is effective as a means for preventing corrosion caused by soldering the ultra-fine core wire S.

Further, subsequent experiments have revealed that in order to achieve both solder corrosion resistance and conductivity, it is desirable to set the thickness of the metal layer 1 to 1 to 3% of the wire diameter.

Further, as in the above embodiment, by forming the metal layer 1 on the surface of the ultrafine core wire S and then performing drawing or rolling, a desired wire diameter can be obtained, and the metal layer 1 can be By crushing pinholes etc. that occur during plating, it is possible to eliminate areas with poor adhesion of the metal layer 1, and the quality of coating on the ultra-fine core wire S of the metal layer 1 is improved.
Erosion can be more reliably prevented.

Note that the metal layer 1 may be formed thick with a wire diameter several to several tens of times larger than the wire diameter used for the ultra-fine electric wire, and the diameter may be reduced by drawing or rolling. .

In addition, the metal layer 1 made of nickel-based metal has a tensile strength about five times that of copper, so it is possible to strengthen the coil by about 10 to 20% compared to conventional ultra-fine wires of the same wire diameter. This makes it difficult for wires to break during automatic wire winding work, etc.

In addition, when strength is required for the ultra-fine wire, use tin-containing copper, chromium-containing copper, silver-containing copper, 1iJ nickel, etc. with a high tensile strength as the ultra-fine core wire S instead of electrolytic copper or oxygen-free copper. Large highly conductive copper alloys can also be used.

Next, another example shown in FIG. 2 will be described. In the ultra-fine electric wire, a metal N1 having good solder corrosion resistance similar to the above-mentioned example is formed on the surface of the ultra-fine core wire S, and the metal layer is A metal layer 2 for improving solderability is formed on the surface of the metal layer 1, and an electrically insulating film Z is coated thereon.

The metal layer 2 that improves solderability is formed of tin, lead-tin solder, copper metal, silver metal, gold thread metal, etc.
Like the metal layer 1, it is deposited by a method such as electroplating.

The metal layer 2 that improves solderability works to further improve the solderability when the metal layer 1 having good solder corrosion resistance is formed of a nickel-based metal. This makes it possible to use metals other than the metals in the series.

That is, in addition to nickel-based metals, chromium, etc., which has a higher melting point than copper, can be considered as a metal material for forming the metal layer 1 with good solder corrosion resistance, but chromium and the like form an oxide film in the air. However, as shown in the embodiment shown in Fig. 1, soldering must be performed directly on the metal layer l, which has good solder corrosion resistance. In some cases, it is not appropriate to form the metal layer 1 with chromium or the like because of its poor solderability.

However, as in this embodiment, tin or lead is added on the metal layer 1.
When forming a metal layer 2 that improves solderability made of tin-based solder, etc., regardless of whether the metal layer 1 has good solderability, the ultra-fine wire can be Since solderability is imparted to the metal layer 1, chromium or the like can now be used as the metal material for forming the metal layer 1.

Then, by forming the metal layer I with chromium or the like,
Further improvements in solder corrosion resistance, tensile strength, etc. of ultra-fine electric wires can be expected.

Note that after forming the metal layer 2 that improves solderability,
It is also possible to perform drawing or rolling to obtain a desired wire diameter in the same manner as in the above-mentioned embodiments, and then coat the wire with an electrically insulating film Z.

〔Effect of the invention〕

As described above, the ultra-fine electric wire according to the present invention has a metal layer made of 2.7 Kel, nickel alloy, etc. with good solder corrosion resistance formed on the surface of the ultra-fine core wire made of copper or copper alloy. , because the ultra-fine core wire is corroded during soldering.
This has an excellent effect in that there is no risk of melting due to thinning of the solder, unlike conventional ultra-thin wires.

In addition, there is no need to perform strict work management as in the past in order to prevent ultra-thin wires from melting during soldering work, which has the effect of reducing the work burden on those performing soldering work. .

Furthermore, since the ultra-fine electric wire is less likely to corrode, the temperature of the soldering bath can be increased, which has the effect of improving soldering workability.

Furthermore, by forming a metal layer with good solder corrosion resistance, the limit of the wire diameter that can be fused during soldering can be made smaller than before, and the tensile strength is also improved, making it even more effective than before. It becomes possible to put into practical use ultrafine electric wires with reduced diameters, and there is also the effect that coils and the like can be made more compact.

In addition, if the ultra-fine core wire on which a metal layer with good solder corrosion resistance is formed is made thinner by drawing or rolling, pinholes etc. that live in the metal layer with good solder corrosion resistance will be crushed. There is also the effect that the quality of coating on the ultra-fine core wire is improved and corrosion of the ultra-fine core wire is more reliably prevented.

In addition, on top of the metal layer with good solder corrosion resistance, tin or lead
By forming a metal layer that improves solderability made of assembled diameter solder, etc., the solderability of ultra-fine electric wires is significantly improved, and it is also possible to form a metal layer with good solder corrosion resistance using chromium or iron. It also has the effect of becoming

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example of the ultrafine electric wire according to the present invention, and FIG. 2 is a cross-sectional view showing another embodiment according to the present invention. Explanation of symbols D - Extra-fine electric wire, s - Extra-fine core wire, 2 - Electrical insulating coating, 1 - Metal layer with good solder corrosion resistance, 2 - Metal layer that improves solderability.

Claims (1)

[Scope of Claims] [1] In an ultra-fine electric wire (D) in which an ultra-fine core wire (S) made of copper or a copper alloy is coated with an electrically insulating film (Z), the surface of the ultra-fine core wire (S) is coated with a solder welding-resistant coating. An ultrafine electric wire characterized in that a metal layer (1) with good edibility is formed, and the metal layer (1) is coated with the insulating film (Z). [2] The ultrafine electric wire according to claim 1, wherein the metal layer (1) having good solder corrosion resistance is formed of nickel or a nickel alloy. [3] The above-mentioned patent, in which the ultrafine core wire (S) on which the metal layer (1) with good solder corrosion resistance is formed is reduced in diameter by drawing or rolling and then coated with an electrically insulating film (Z). The ultrafine electric wire according to claim 1. [4] In an ultra-fine electric wire (D) in which an ultra-fine core wire (S) made of copper or copper alloy is coated with an electrically insulating coating (Z), a metal layer with good solder corrosion resistance is provided on the surface of the ultra-fine core wire (S). (1) is formed, and a metal layer (2) for improving solderability made of tin, lead-tin solder, copper metal, silver metal, or gold metal is formed on the surface of the metal layer (1). , An ultrafine electric wire characterized in that the insulating film (Z) is coated thereon. [5] The ultrafine electric wire according to claim 4, wherein the metal layer (1) having good solder corrosion resistance is made of nickel, a nickel alloy, or chromium.