JP3307435B2 - Three-layer insulated wire and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-layer insulated wire having three insulating layers and a method of manufacturing the same.
When immersed in a solder bath, the insulating layer is removed in a short time and the solder can be attached to the conductor, so that the soldering properties are excellent, and the insulating properties of the insulating layer are hardly deteriorated with time. The present invention relates to a three-layer insulated wire that can reduce the space factor of a coil when used as a winding, and is useful as a winding or a lead of a transformer to be incorporated in electric or electronic equipment.

[0002]

2. Description of the Related Art The structure of a transformer conforms to the IEC standard (Internat
ional Electrotechnical Communication Standard) Pu
b.950,65,335,601, etc. That is, in these standards, the enamel coating covering the conductor in the winding is not recognized as an insulating layer. At least three insulating layers are formed between the primary winding and the secondary winding, or The thickness is 0.4 mm or more, and the edge distance between the primary winding and the secondary winding depends on the applied voltage, but is 5 mm or more, and 300 mm on the primary and secondary sides.
It is specified that the device can withstand 1 minute or more when 0 V is applied.

[0003] For this reason, in the transformer currently occupying the mainstream seat, a cross-sectional structure as exemplified in FIG. 1 is adopted. That is, a bobbin 2 provided with a flange
Is wound, and an enamel-coated primary winding 4 is wound in a state where insulating barriers 3 for securing an edge surface distance are arranged on both sides of the peripheral surface of the bobbin 2.
, At least three layers of insulating tape 5 are wound thereon, and an insulating barrier 3 for securing an edge surface distance is further disposed on the insulating tape layer. Then, a secondary winding 6 also coated with enamel is wound. It is a turned structure.

In recent years, instead of the transformer having the cross-sectional structure shown in FIG. 1, a transformer having a structure not including the insulating barrier 3 and the insulating tape layer 5, as shown in FIG. 2, has begun to appear. This transformer is different from the transformer having the structure of FIG.
Since the space factor of the winding is reduced, the overall size can be reduced, and the winding of the insulating tape can be omitted.

When the transformer shown in FIG. 2 is manufactured, in the primary winding 4 and the secondary winding 6 to be used, at least three insulating layers 4b (on the outer periphery of one or both conductors 4a (6a)) are used. 6b), 4c (6c), and 4d (6d) are formed, and it is possible to achieve delamination between these insulating layers to satisfy the IEC standard described above. Is required.

As such a winding, first, an insulating tape is wound around the outer periphery of the conductor to form a first insulating layer, and then an insulating tape is wound thereon to form a second insulating layer. It is known that an insulating layer having a three-layer structure in which a third insulating layer is sequentially formed and the layers are separated from each other is formed. Further, there is known a winding in which a fluororesin is sequentially extruded around an outer periphery of a conductor which is enameled with polyurethane, and an extruded coating layer having a three-layer structure is used as an insulating layer as a whole (see Japanese Unexamined Utility Model Publication No.
-5612).

[0007]

However, in the case of the former winding, there is a problem that the productivity is remarkably reduced because the winding work of the insulating tape is inevitable, and the manufacturing cost is increased. In addition, the latter winding has the advantage that the insulating layer is formed of a fluorine-based resin and thus has good heat resistance, but on the other hand, the insulation between the layers is poor and the reliability as an insulated wire is poor. There is a problem of lack of sex.

Furthermore, since this insulating layer cannot be removed by immersion in a solder bath, the terminal insulating layer has low reliability, for example, at the time of processing a terminal when connecting an insulated wire to a lead wire. There is a problem that it must be peeled off by mechanical means. In order to solve such a problem, the first and second insulating layers are formed of an extruded coating layer of a polyester resin, and the outermost third insulating layer is formed of a polyamide resin. Insulated wires are being considered.

However, this three-layer insulated wire has the following problems. That is, since the polyester-based resin is relatively soft, the second and first insulating layers (polyester-based resin layer) receive a compressive force due to the winding tension applied to the outermost layer when the electric wire is coiled. Slightly deforms in the thickness direction. When a current is applied to the manufactured coil, the polyester resin is softened by the heat generated by the conductor, and the winding tension is constantly applied. Therefore, the compressive deformation in the second and first layers further progresses. As a result, the thickness of the insulating layer is reduced, and the insulating layer is crushed as a whole. In such a state, the electrical insulation of the insulating layer is reduced.

Therefore, in order to ensure the required electrical insulation, it is necessary to increase the thickness of the insulating layer, especially the second and first insulating layers, in consideration of the above-mentioned phenomenon of the thickness. become. However, the above-described measure is to increase the diameter of the electric wire, and therefore, when used as a winding of a transformer, the space factor of the coil is increased, and the transformer is enlarged.

[0011] The present invention solves the above-described problems and, of course, satisfies the IEC standard. In addition, it is possible to make the insulating layer thinner and realize a smaller coil space factor when used as a coil winding. And a method for manufacturing the same.

[0012]

According to the present invention, there is provided a three-layer insulated wire comprising a conductor and three insulating layers covering the surface of the conductor.
The first insulating layer is an extruded coating layer of a thermoplastic polyamide resin or a resin mixture containing a thermoplastic polyamide resin as a main component, and the second and third insulating layers are both thermoplastic linear resins. An extrusion coating layer of a resin admixture comprising 5 to 40 parts by weight of an ethylene copolymer having a carboxylic acid or a metal salt of a carboxylic acid in a side chain with respect to 100 parts by weight of a polyester resin. A method for producing a three-layer insulated wire is provided, wherein a three-layer insulated wire is provided, and the surface of each of the extruded coating layers is cooled to 100 ° C. or lower when the extrusion coating of each insulating layer is completed. Is done.

First, the first insulating layer in the three-layer insulated wire of the present invention is an extrusion coating layer of a thermoplastic polyamide resin or a resin mixture containing the same as a main component. This first insulating layer has good adhesion to the conductor, has better mechanical strength than polyester resin, and has a high softening temperature. Therefore, even if the second and third insulating layers are crushed by the winding tension during coil processing and the heat generated by the conductor when the coil is used, the first insulating layer has a small deformability, The collapse phenomenon is effectively prevented from spreading to the conductor, and a decrease in insulation properties is suppressed.

Examples of the thermoplastic polyamide resin forming the first insulating layer include 4-nylon, 6-nylon, 10-nylon, 11-nylon, 12-nylon, 4,6-nylon, 6, 6-nylon, 6,10-
Nylon, 6,12-nylon, or their copolymerized nylon (both are trade names manufactured by DuPont) can be mentioned.

Further, these polyamide resins include, for example,
One or more of ethylene-methacrylic acid copolymer, ethylene-acrylic acid copolymer, polyethylene, the above-mentioned thermoplastic linear polyester resin and polyurethane resin may be mixed. In this case, the mixing ratio is
The amount is preferably 3 to 50 parts by weight based on 100 parts by weight of the polyamide resin.

Among these materials, 4,6-nylon has a melting point higher by 20 to 30 ° C. than other nylons.
Since the temperature is about 90 ° C., thermal deformation during use of the coil hardly occurs, so that it is suitable as a material for the first insulating layer. The resin admixture, which is the material of each of the second and third insulating layers, contains, as essential components, a thermoplastic linear polyester resin and an ethylene copolymer, which will be described later.

Among these, as the thermoplastic straight-chain polyester resin, those obtained by an ester reaction between an aromatic dicarboxylic acid or a dicarboxylic acid in which a part thereof is substituted by an aliphatic dicarboxylic acid and an aliphatic diol are used. Can be
For example, polyethylene terephthalate resin (PET),
Representative examples include polybutylene terephthalate resin (PBT) and polyethylene naphthalate resin.

Examples of the aromatic dicarboxylic acid used in synthesizing the thermoplastic linear polyester resin include, for example, terephthalic acid, isophthalic acid, terephthaldicarboxylic acid, diphenylsulfondicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylethercarboxylic acid, and methyl terephthalic acid. Acid and methyl isophthalic acid. Of these, terephthalic acid is particularly preferred.

Examples of the aliphatic dicarboxylic acid which partially substitutes the aromatic dicarboxylic acid include succinic acid, adipic acid, sebacic acid and the like. The substitution amount of these aliphatic dicarboxylic acids is 3
It is preferably less than 0 mol%, especially 20 mol%
It is preferably less than. On the other hand, examples of the aliphatic diol used in the ester reaction include ethylene glycol, trimethylene glycol, tetramethylene glycol, hexanediol, and desanediol. Of these, ethylene glycol and tetramethyl glycol are preferred. Further, a part of the aliphatic diol may be oxyglycol such as polyethylene glycol or polytetramethylene glycol.

Another essential component of the resin mixture, which is a material of each of the second and third insulating layers, is, for example, an ethylene copolymer in which a carboxylic acid or a metal salt of a carboxylic acid is bonded to a side chain of polyethylene. It is a polymer. This ethylene-based copolymer functions to suppress the crystallization of the thermoplastic linear polyester resin described above, thereby suppressing the deterioration with time of the electrical characteristics of the formed insulating layer and at the same time as the first layer. 2
It contributes to ensuring good releasability between the insulating layers of the layer.

As the carboxylic acid to be bound, for example,
Examples thereof include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and phthalic acid. These metal salts include Zn, Na , K, Mg and the like. As such an ethylene-based copolymer, for example, a part of a carboxylic acid of an ethylene-methacrylic acid copolymer is converted into a metal salt, and a resin generally called an ionomer (for example, Himilan; trade name, Mitsui Polychemicals, Inc.) )), An ethylene-acrylic acid copolymer (for example, EAA; trade name, manufactured by Dow Chemical Company), an ethylene graft polymer having a carboxylic acid in a side chain (for example,
Admer; trade name, manufactured by Mitsui Petrochemical Industry Co., Ltd.).

In this resin mixture, the mixing ratio of the thermoplastic linear polyester resin and the ethylene copolymer is as follows:
For the former 100 parts by weight, the latter is set in the range of 5 to 40 parts by weight. When the amount of the latter is less than 5 parts by weight, there is no problem with the heat resistance of the formed insulating layer, but the effect of suppressing the crystallization of the thermoplastic linear polyester resin is small, and therefore, the surface of the insulating layer is not coated during coiling. At the same time as the occurrence of minute cracks, that is, the so-called crazing phenomenon, frequently occurs, and the aging of the insulating layer proceeds to cause a significant decrease in dielectric breakdown voltage. On the other hand, when the amount is more than 40 parts by weight, the heat resistance of the insulating layer is significantly deteriorated. The preferred mixing ratio of the two is 100 parts by weight of the former and 7 to 25 parts by weight of the latter.

The three-layer insulated wire of the present invention is formed by extrusion-coating the outer periphery of a conductor with a thermoplastic polyamide resin for the first layer or a resin mixture containing the same as a main component, thereby forming a first insulating layer having a desired thickness. Is formed, and then a second layer is formed around the outer periphery of the first insulating layer.
The resin mixture for the second layer is extrusion-coated to form a second insulating layer having a desired thickness.
It is manufactured by extrusion-coating a resin mixture for a layer to form a third insulating layer having a desired thickness.

At this time, the resin admixture used in the extrusion coating of the second layer and the third layer may have the same composition for each layer, or may have the same composition within the above-mentioned allowable mixing ratio. The composition may be changed. The total thickness of the formed three insulating layers is 100 μm.
It is preferable to manage the following. It is preferable to use 4,6-nylon as the material of the first insulating layer because the insulating properties of the IEC standard can be satisfied even if the thickness of the entire insulating layer is reduced to about 60 μm. .

Further, at the time when the second extruded coating layer is formed, the surface thereof is cooled to 100 ° C. or less by, for example, water cooling or air cooling, and then the third extruded coating layer is formed. The delamination property of the third and third layers is improved.

[0026]

In the three-layer insulated wire according to the present invention, since each of the insulating layers is formed by the extrusion coating method of the resin, the productivity at the time of production becomes very high. Since the first insulating layer is made of polyamide resin with high mechanical strength and softening temperature, the crushing phenomenon of the insulating layer due to the winding tension during coil processing and the heat generated by the conductor when using the coil extends to the conductor surface. Will not spread. Therefore, the thickness of the insulating layer can be reduced as compared with the conventional case, and the space factor of the coil can be reduced when used as a coil winding.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Examples 1 to 4 and Comparative Examples 1 to 5 The components shown in Table 1 were kneaded at the indicated ratios (parts by weight) to prepare resin blends for each extrusion coating layer. A soft copper wire having a wire diameter of 0.6 mm is prepared as a conductor, and the outer periphery thereof is extrusion-coated with a polyamide resin or a resin mixture containing the same as a main component to form a first extruded coating layer having the indicated thickness. Then, a second extruded coating layer was formed, the surface thereof was water-cooled, and the outer periphery of the second layer was extruded and coated with the above resin mixture to produce a three-layer insulated wire.

In Example 1, after each extruded coating layer was formed, its surface was water-cooled to 100 ° C. or less. Each insulating layer of the electric wire of Comparative Example 3 was obtained by winding the indicated insulating film.

[0029]

[Table 1]

With respect to the above nine types of three-layer insulated wires, various characteristics were measured according to the following specifications. Solderability: 400 ° C at the end of about 40mm of the wire
Immersed in the molten solder and measured the time (seconds) until the solder adhered to the immersed 30 mm portion. The shorter this time, the better the solderability.

Electrical insulation: Immediately after production, each of the two-layer and three-layer coated electric wires was measured for the dielectric breakdown voltage at that time using a bare copper wire in accordance with the two-strand method specified in JISC3003. . Further, the electric wire with the three layers was left in the air for one year, and then the dielectric breakdown voltage was measured in the same manner as described above, and the change with time of the electrical insulation was examined.

Heat resistance: The three-layer coated electric wire and the bare copper wire are JISC
Twist two in accordance with 3003
After a heat treatment at 0 ° C. for 7 days, the dielectric breakdown voltage was measured. The larger the value, the better the heat resistance. Crazing resistance: After leaving the electric wire in the air for 6 months, the electric wire was mechanically wound around a coil winding having a diameter of 12 mm, and it was observed whether or not crazing occurred on the electric wire surface at that time.

Delamination property: about 50 cm in the longitudinal direction of the insulating layer
After cutting with a cutter knife, one end of the electric wire was sandwiched between mandrels, and the mandrel was rotated to measure the number of mandrel rotations until the three insulating layers were separated from each other. This test is a test for examining whether or not the individual layers of the insulating layer can be distinguished from each other. The lower the number of revolutions, the better the delamination property of each layer.

Softening resistance: The short-circuit temperature at a load of 600 g and 3 kg was measured according to the crossing method specified in JIS C3003. The higher this value is, the better the softening resistance of the insulating layer is and the harder the collapse phenomenon is to occur. The above results are shown in Table 2 collectively.

[0035]

[Table 2]

[0036]

As is apparent from the above description, the three-layer insulated wire of the present invention has a high productivity at the time of manufacture because all of its insulating layers are formed by extrusion coating. It has excellent adhesion, heat resistance, crazing resistance, delamination, and electrical insulation, and has little deterioration over time.
Further, since the softening resistance is excellent, the thickness of the insulating layer can be reduced, and the coil space factor when used as a coil winding can be reduced. This is an effect brought about by the fact that the first insulating layer is formed of a polyamide resin in the three-layer insulated wire of the present invention, as is apparent from comparison between the results of the example and comparative example 5.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a transformer having a conventional structure.

FIG. 2 is a cross-sectional view illustrating an example of a transformer having a structure in which a three-layer insulated wire is wound.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ferrite core 2 Bobbin 3 Insulating barrier 4 Primary winding 4a Conductor 4b, 4c, 4d Insulating layer 5 Insulating tape 6 Secondary winding 6a Conductor 6b, 6c, 6d Insulating layer

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI H01B 13/14 H01B 13/14 Z // B29L 31:34 B29L 31:34 (72) Inventor Mitsuru Inoue 2 Marunouchi, Chiyoda-ku, Tokyo No. 6-1, Furukawa Electric Co., Ltd. (56) References JP-A-59-130008 (JP, A) JP-A-4-10305 (JP, A) JP-A-3-110721 (JP, U) ( 58) Field surveyed (Int.Cl. ⁷ , DB name) H01B 7/02 B29C 47/02 C09D 167/02 C09D 177/00 H01B 3/30 H01B 13/14

Claims (2)

(57) [Claims] 1. A three-layer insulated wire comprising a conductor and three insulating layers covering the surface of the conductor, wherein the first insulating layer mainly comprises a thermoplastic polyamide resin or a thermoplastic polyamide resin. It is an extrusion coating layer of a resin mixture,
The second and third insulating layers each contained 5 to 40 parts by weight of an ethylene copolymer having a carboxylic acid or a metal salt of a carboxylic acid in a side chain, based on 100 parts by weight of a thermoplastic linear polyester resin. A three-layer insulated wire, characterized in that it is an extruded coating layer of a blended resin mixture. 2. A method for producing a three-layer insulated wire, wherein three insulating layers are formed on a surface of a conductor by extrusion coating, and when the extrusion coating of each layer is completed, the surface of each extruded coating layer is kept at 100 ° C. or lower. A method for producing a three-layer insulated wire, comprising: