JPS6412161B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improvement in a method for removing the wire insulation film at the end portion of a twisted conductor made by twisting insulated wires together. Generally, in order to connect the terminals of stranded insulated conductors, it is necessary to remove the insulation coating of each strand at the terminal end of the conductor. The method for removing the wire insulation film of the composite conductor is, for example, by directly immersing the end portion of the wire conductor to be removed in a wire insulation film removal solution, or by removing it by mechanical polishing such as sandblasting. It was on. However, when these methods are applied, the following problems arise, particularly when removing the insulation coating of large conductor stranded wires. In other words, if a stranded wire conductor is directly immersed in a wire insulation removal solution, the liquid will penetrate into the inside of the conductor due to capillary action, so-called water running inside the conductor cannot be prevented, and the film must be removed. It was not possible to remove the oxidized insulating film even from the parts where the insulating film was not removed, and to achieve the purpose of providing the insulating film on the wire. In addition, in the case of mechanical polishing by sandblasting, etc., the abrasive material hits the sample surface and removes the film due to the physical impact force, so the wire conductors in each layer of the stranded wire conductor are spread out and polished. It was necessary to make the material collide with the inside of the wire conductor. Therefore, in order to remove the oxide insulation film on the surface of the wire, it is necessary to widen the distance between the wires as much as possible, but on the other hand, after the insulation film is removed, the original state must be restored by sleeve compression. , which required complicated means to operate. The present invention prevents the liquid from entering the inside of the wire by capillary action when removing the wire insulation film by a solution method, and immerses the film removal solution only in the part where the insulation film needs to be removed. They discovered a method to remove the insulating film. That is, the method of the present invention is a method of twisting insulated wires having an insulating film made of copper oxide and removing the insulating film at the terminal connection portion of the stranded conductor, in which the gaps between the insulating wires of each layer forming the stranded conductor are removed. The method is characterized in that the swellable polymer material is pressed and filled into the container and then immersed in a reducing solution. The reason why a swelling polymer substance is used in the present invention is to prevent the reducing solution for removing the insulation film from entering through the gaps between the wires and from progressing into the inside of the wires. The purpose is to prevent the necessary liquid from entering the area.
Therefore, the swelling polymeric substance must be capable of absorbing a solution several hundred times its own weight and must not release water from the absorbed liquid even when subjected to some pressure, and its water absorption capacity is Items that are small and release water when pressure is applied are not targeted. Examples of this polymeric substance include natural products such as starch and cellulose, and synthetic polymers such as polyacrylic acid, polyacrylamide, polyvinyl alcohol polyoxide, as well as polyvinylpyrrolidone, polystyrene sulfonic acid, and poly-2-acrylamide-2-methylpropanesulfonic acid. It is a bridge body etc. These materials may be used alone or in a sheet formed by superimposing them on a plastic film having a desired coating, and are press-fitted into the gaps between the strands of the stranded conductor under pressure. Thereafter, a wire insulation film removing solution such as hypophosphorous acid aqueous solution, hydrazine aqueous solution, or dilute hydrochloric acid aqueous solution is dropped or immersed in the part filled with the swelling polymeric substance. This removes the insulating film at the terminal connection part of the wires in the stranded conductor, so this part can be heated and dried, and if necessary, the swelling polymer substance filled between the wires can be removed. . In addition, when compressing a stranded wire conductor by covering it with a sleeve, the swellable polymer material can be destroyed and removed by the compressive force. There is no need to remove it. Next, examples of the method of the present invention will be described. Examples (1) to (3) Stranded wire conductor consisting of 2000 mm ² 6-segment insulated wire (CuO coating, average coating thickness 1.5μ), where the insulation film needs to be removed (terminal part) After filling the mutual gap with a swellable polymeric substance as shown in Table 1, an insulating film removing solution was dropped to remove the insulating film.

[Table] Also, for comparison with the method of the present invention, the insulation film was removed by dropping only the insulation film removal solution mentioned above onto the stranded wire conductor without using a swelling polymer substance. As a result of measuring the presence or absence of an insulating film at the end portion of the stranded wire conductor obtained by the method of the present invention and the method of the comparative example, it was found that in the case of the method of the present invention, the insulating film up to the point where the swelling polymer substance was filled was completely removed. This indicated that the insulation film removal liquid had penetrated into the inside of the wire. However, in the case of the comparative method, the insulating film was removed to the inside of the wire, indicating that the removal liquid ran through the water due to capillary action. As described in detail above, the method of the present invention is extremely useful in practice, as it prevents the insulating film removal liquid from running into the inside of the strand and allows the insulating film to be easily removed.

Claims (1)

[Scope of Claims] 1. In a method for removing an insulating film from a terminal connection portion of a stranded conductor made of strands having an insulating film made of copper oxide, the gap between the insulating strands of each layer forming the stranded conductor A method for removing an insulation film from a stranded insulated wire conductor, which comprises pressing and filling a swellable polymeric substance into a conductor, and then immersing the conductor in a reducing solution. 2. Use of starch, natural cellulose substances, polyacrylic acid, polyacrylamide, polyvinyl alcohol, or cross-linked products of polyvinylpyrrolidone, polystyrene sulfonic acid, and poly-2-acrylamide-2-methylpropanesulfonic acid as the swelling polymeric material. A method for removing an insulation film from an insulated stranded wire conductor according to claim 1, characterized in that: 3. A method for removing an insulation film from an insulated stranded wire conductor according to claim 1, characterized in that a hypophosphorous acid aqueous solution, a hydrazine aqueous solution, or a dilute hydrochloric acid aqueous solution is used as the reducing solution.