JPS6029208B2 - Manufacturing method of resin molded coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION It is an object of the present invention to provide a method for manufacturing resin molded coils used in small transformers, ballasts, etc. that require molding at low cost and with excellent reliability.

Generally speaking, a method for inexpensively manufacturing resin molded coils used in small transformers, ballasts, etc. that do not require a high degree of heat resistance is to use oil-based enamel wire or polyester wire, which are easy to handle and inexpensive as insulated wires. However, after winding the electric wire around an iron core to form a coil, attaching a lead wire to the end of the coil and storing it in a case, the method often adopted is to inject molding resin and heat harden it. has been done.

As the molding resin, solvent-free polyester resin varnish or solvent-free epoxy resin varnish is usually used.

However, with the recent rationalization and mass production of resin molded coils, molding before resin molding,
The process of attaching the lead wire to the coil terminal was time consuming and became a bottleneck in mass production. Therefore, in order to particularly simplify the step of attaching the lead wire in the above process, it has been considered to extend the electric wire at the end of the molded coil as it is and use it as the lead wire.

However, in the case of ordinary oil-based enamel electric wires and polyester electric wires, when the ends of the wires are extended to form lead wires and then treated with mold resin, the mold resin and the electric wires firmly adhere to each other. The shrinkage and strain that occurs during curing results in large tensile and compressive forces, particularly in the lead wire region, resulting in cracks in the insulating layer in the lead wire region, exposing the conductor.

In particular, if the coil-forming wire is thin green, it may even break, which greatly affects the yield and reliability of the coil. As a way to improve this, it may be possible to apply silicone oil or the like to the part used as the IJ cord wire to ease the adhesion with the mold resin, but there may be a difference depending on the state of the silicone oil application, or the silicone If the oil diffuses into the mold resin and the mold resin is hardened by heating, the effectiveness of applying silicone oil will be significantly reduced, and
Since it required a silicone oil application process, it could not be called a revolutionary rationalization.

Although such a phenomenon can be prevented by using an esterimide wire or an amide-imide wire as an insulated wire, these wires are expensive and cannot be put to practical use from an economic standpoint.

The present invention aims to solve the problem in view of the current situation.As a result of intensive research, it has been found that when manufacturing such a resin molded coil, oil-based enamel paint or polyester paint is coated on the conductor as an insulated wire for forming the coil. By using an insulated wire with an insulating layer and a baked film layer of a thermosetting silicone mold release agent on top of that, the molded coil is extended and becomes a lead wire during the resin molding process. The inventors have discovered that the scale can significantly reduce the adhesiveness with the mold resin and protect the lead wire from the effects of shrinkage and distortion that occur when the mold resin hardens, leading to the present invention. After forming a coil using such an insulated wire, the terminal of the wire of the formed coil is extended as it is, and the lead wire is integrated with molded resin varnish. This solves the conventional problem and enables mass production. It has characteristics that make it possible to have sex.

In addition, in the method of the present invention, the thermosetting silicone template agent for forming the outermost layer of the insulated wire is one that hardens by heating to form a semi-permanent and strong film.
For example, SH671 (product name of Toray Silicon Co., Ltd.), K
S700 and KS701 (trade names of Shin-Etsu Chemical Co., Ltd.) are used.

When the insulated wire used in the method of the present invention was treated with a molding resin, the following experiment was conducted to measure the adhesion between the two.

Experimental example '1} Coat the copper wire on the 0.3 diameter side with oil-based enamel varnish and apply phosphor to form an insulating film with a thickness of 20mm, and then apply a thermosetting silicone mold release agent (product name: KS manufactured by Shin-Etsu Chemical Co., Ltd.) on top of it.
701) was coated once in a furnace with a furnace length of $h at a furnace temperature of 35,000 and a wire speed of h/min to obtain an insulated wire A.

Experimental example '2) Apply polyester varnish to the steel wire on the 0.3 diameter side to form an insulating film with a thickness of 20 mm, and then apply a thermosetting silicone mold release agent (product name: SH67 manufactured by Toray Silicon Co., Ltd.) on top of it.
1) was applied and baked under the same conditions as in Experimental Example 1 to obtain an insulated wire B.

The insulated wires A and B were placed vertically into a test tube with a diameter of about 10 mm, and a solvent-free polyester resin varnish (trade name: TVB manufactured by Toshiba Chemical Co., Ltd.) was applied as a molding resin inside the tube.
-2122, the product name TEL-962 manufactured by the same company as a curing agent
0) (hereinafter referred to as polyester resin varnish) or solvent-free epoxy resin varnish (Toshiba Chemical Co., Ltd. trade name TCGO022) (hereinafter referred to as epoxy resin varnish) and embedded electric wires to a height of 5 skins. ,
Polyester resin varnishes are cured by heating at 120 pm for 3 hours, and epoxy resin varnishes are cured at 120 pm.
After heating and curing at 10°C for 1 hour, the resin was cooled and the releasability of the electric wire embedded in the resin was measured.

The results are shown in Table 1. For comparison with the insulated wire of the present invention, conventional oil-based enamel wires and polyester wires were treated with polyester resin varnish and epoxy resin varnish in the same manner as above, respectively.
The releasability was measured and the results are also listed in Table 1.

As is clear from Table 1, the insulated wire used in the method of the present invention showed extremely low adhesion to the mold resin.

Next, examples of the present invention will be described.

The insulated wires used in this example were prepared as follows.

'1} Insulated wire C Coat the copper wire on the 0.26 diameter side with oil-based enamel varnish to form an insulating layer with a film thickness of 16 mm, and then apply a thermosetting silicone mold release agent (manufactured by Shin-Etsu Chemical Co., Ltd.) on the outside. Product name KS7
01) at a line speed of 12 in a dawn furnace with a furnace length of 3 hours and a furnace temperature of 350°C.
It was obtained by applying one coat at a rate of 1 h/min.

■ Insulated wire D A copper wire with a diameter of 0.26 mm is coated with polyester varnish and baked to form an insulating layer with a film thickness of 16 mm, and a thermosetting silicone mold release agent (product name S manufactured by Toray Silicon Co., Ltd.) is applied on the outside of the insulating layer.
H671) was coated once at a line speed of 12 m/min in a baking furnace with a furnace length of 3 hours and a furnace temperature of 350 oo.

'3; Insulated wire E This is a so-called oil-based enamel wire having an insulating layer with a thickness of 16 by coating and baking an oil-based enamel varnish on a 0.26 diameter willow copper wire.

■ Household wire F This is a so-called polyester electric wire that has an insulating layer with a coating thickness of 16 degrees by applying polyester varnish to a steel wire on the 0.26 diameter side and baking it.

As shown in Table 2 of Examples {1} to {4) and Comparative Examples (1} to (8), resin molded coils were manufactured by combining the above-mentioned insulated wire and molded resin varnish, and the insulated wire After winding the wire around an iron core to form a choke coil, the terminal 50 of the wire was extended and used as a lead wire portion.

Then, this coil was housed in a case, molded resin varnish was injected and filled, the lead wire part was buried in the resin varnish to a depth of 3 cm, the remaining 2 cm was exposed outside the resin varnish, and the terminal was connected. The resin molded coil was manufactured by attaching it and heating and hardening it in an oven. In addition, when polyester resin varnish is used as the resin mold once, it is heated at 120 qo for 3 hours, and when epoxy resin varnish is used, it is heated at 12000 qo for 1 hour.
It was heated for 0 hours.

Moreover, in Comparative Examples t5-[8)', silicone oil (product name: KF96, manufactured by Shin-Etsu Chemical Co., Ltd.) was particularly applied to the lead wire portion of the insulated wire.

The second expression is Examples (1} to (4) and Comparative Examples {1} to {8).
Table 3 shows the results of measuring the defective parts of the resin molded coil 5 obtained by the above method.

As detailed above in Table 3, according to the method of the present invention, the conventional complicated step of attaching a lead wire to the end of the coil can be omitted, and productivity can be significantly improved and a resin molded coil with a high degree of reliability can be obtained. It is also extremely useful in the field of manufacturing low voltage resin molded coils for transformers and other products.

Claims (1)

[Claims] 1. In the method for manufacturing a resin molded coil, after forming a coil using an insulated wire in which a thermosetting silicone mold release agent is further applied and baked on an insulating layer formed by applying and baking an oil-based enamel paint or a polyester paint on a conductor, the molding is performed. A method for manufacturing a resin molded coil, characterized in that the end of a coil electric wire is extended as it is and used as a lead wire, and then integrated with molded resin varnish.