JPH01213911A - Conductor for ultrafine coil - Google Patents

Abstract

PURPOSE:To obtain a conductor with a high degree of reliability and superior insolubility against solder by using, as a central wire, a wire rod made of a material having greater heat resistance than copper, while covering the surface of the wire rod with copper and specifying the resultant diameter of the wire rod. CONSTITUTION:A wire rod made of a material having greater heat resistance than copper is used as a central wire whose surface is covered with copper, while the resultant diameter of the wire rod is prepared to be less than 0.05mm. The transmission factor of the wire rod as a conductor should be 40% IACS or more and the surface of the conductor may be covered with Sn, Ag, Ni or their alloys, preferably. Steel wire, stainless steel wire, nichrome wire, tungsten wire or molybdenum wire may be used as the central wire made of a material having greater heat resistance than copper. This process can yield a conductor for ultrafine coil, having so-called excellent insolubility against solder with good solder adhesion and almost no occurrence of thinning of the conductor even in case of solder application directly on the conductor's enamel membrane.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is applicable to wire diameters of 0.05. The present invention relates to the following conductor for ultrafine windings, and particularly has improved solder melting resistance and solder wettability.

(Prior Art) Conventionally, a copper wire or a copper alloy wire is used as a winding conductor, and the wire is coated with enamel.

When used, the film on the terminal is removed and soldering is performed. Recently, the diameter of this winding wire has been reduced, and the demand for ultra-fine winding wire with a wire diameter of 0.05 mJX or less is increasing. And it is expected that the current diameter will continue to become smaller. As the winding becomes ultra-thin, it becomes difficult to peel off the coating, and in order to automate terminal processing, ultra-fine windings are soldered directly onto the enamel coating.

[Problem to be solved by the invention]

When soldering directly onto the enamel film, the solder temperature must be high because the solder removes the enamel. However, in the case of ultra-fine winding wires, the ratio of surface area to volume per unit length (surface area/volume) is quite large, so the conductor becomes thinner during soldering, and the conductor may break off from the soldering part. Happens frequently. Furthermore, in the case of heat-resistant enamel, the soldering temperature becomes high, making soldering unreliable.

(Means for Solving the Problems) In view of this, as a result of various studies, the present invention has been developed to provide a so-called solder melt resistant material that has good solderability and has almost no thinning of the conductor even when soldered over the enamel film. We have developed a conductor for m-pole windings with excellent properties.

That is, the conductor of the present invention has a central wire made of a material with better heat resistance than copper, the surface of which is coated with copper, and the wire diameter @
It is characterized by having the following characteristics: the conductivity of the conductor is 40% IACS or more, and the surface of the conductor is preferably coated with 3N, Ag, Ni, or an alloy thereof. In addition, the center wire is made of steel wire, which is made of a material with better heat resistance than copper.

Stainless steel wire, nichrome wire, tungsten wire or molybdenum wire can be used.

(Function) In the present invention, the center wire is made of a material with better heat resistance than copper, and the surface of the wire is coated with copper, so that it can be soldered without deteriorating its properties as a conductor for ultrafine windings, and can be coated with enamel. This is to prevent the conductor from thinning when soldering is performed from above the film.
The reason why the wire diameter is limited to 0.058 mm or less is that when the wire diameter is larger than 0.058 mm, thinning of the conductor during soldering does not pose a problem. Further, it is desirable that the conductivity of the conductor of the present invention is 40% IACS or more, because if it is less than 40% IACS, a large amount of heat will be generated when used as a winding wire, and the temperature will become high, which could be dangerous. Furthermore, the conductor surface is coated with Sn, Ag, N
The purpose of coating with i or its alloy is to improve the wettability with solder and increase the reliability of soldering.

〔Example〕

Using the center line shown in Table 1, coat it with copper and make the outer diameter 1. OIMl, which is wire-drawn to have a diameter of 0.0
A 25 m conductor of the present invention was produced. In addition, a part of the conductor is used, and the surface is coated with 3n, 3n-Pb alloy, Ag, N! A conductor of the present invention was prepared by coating the material. These conductors were coated with polyurethane to form windings, and the solder wettability and melting time of the conductors were measured. The results are also listed in Table 1 in comparison with the case of tough pitch steel, which is a conventional conductor.

Measurement of solder wettability and conductor dissolution time was performed at 50% 3n-
Using 50% Pb alloy solder and maintaining it at 380°C,
The above winding was placed vertically in a solder bath at a speed of 25 s/SeC.
2. The conductivity was determined by measuring the time until surface wetting and the solder source load at a dipping time of 2 seconds.

As for the dissolution time, the thinning of the wire diameter after 1 second of immersion and the time required for dissolution were investigated.

As is clear from Table 1, the conductors Nα1 to Nα15 of the present invention have much better solder melting resistance than the conventional conductor Nα16. In particular, copper is coated, and further 3n, 3n-Pb, Ag, N
It can be seen that the conductor of the present invention coated with i has better solder wettability and solder wetting load than the conventional conductor.

〔Effect of the invention〕

As described above, according to the present invention, the wire diameter is 0. In a conductor for ultra-fine winding of o5s or less, a highly reliable conductor with excellent resistance to solder melting can be obtained, and other industrially significant effects can be achieved.

Claims (4)

[Claims] (1) The center wire is made of a material with better heat resistance than copper, the surface is coated with copper, and the wire diameter is 0.05 m.
An ultra-fine winding conductor characterized by having a diameter of less than m. (2) The conductor for ultrafine winding according to claim (1), wherein the conductivity of the conductor is 40% IACS or more. (3) The conductor for ultrafine winding according to claim (1) or (2), wherein the conductor surface is further coated with Sn, Ag, Ni, or an alloy thereof. (4) Claims (1) and (2) wherein the center line is a steel wire, stainless steel wire, nichrome wire, tungsten wire or molybdenum wire.
) or (3) the ultrafine winding conductor.