JP2975197B2 - Insulated wire for high-frequency transformer and high-frequency transformer using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulated wire such as a high-frequency transformer having a frequency of 100 to 500 kHz used as a power source of an electronic circuit, and a high-frequency transformer using the same as a coil.

[0002]

2. Description of the Related Art An enamel electric wire such as a polyurethane electric wire is used for a coil of a transformer used for a switching power supply which is often used as a power supply of an electronic circuit. Here, the operating frequency of the transformer for a switching power supply is 100 to 500 in order to make it as small as possible.
It is a high frequency such as kHz.

[0003] However, the enameled wire usually used for the coil of such a high-frequency transformer has a thin insulating film covering a conductor from several µm to several tens µm, and the insulating film is formed by using an insulating resin or an insulating resin. Since this method involves applying, drying and baking a varnish formed by dissolving a modifier in an organic solvent onto a conductor, such an enameled wire has a mechanical strength and a covering power that is formed by extrusion-coating a high-molecular-weight insulating resin onto the conductor. And the reliability of the insulation uniformity is inferior.

For these reasons, special consideration is given to the structure of the transformer using the enameled wire in order to enhance safety. For example, in standards such as IEC-950, the output voltage on the secondary side (low voltage side) of a transformer is 3
Even if the voltage is 0 V or less, if it is directly connected to the operator (classified as SELV), the inter-phase insulation between the primary coil and the secondary coil requires a total of two layers of basic insulation and one layer of auxiliary insulation. Provide three layers, or provide an insulation layer with a thickness of 0.4 mm or more. The enamel film of the coil is not considered to be an insulation film, and the insulation creepage distance between the primary and secondary coils is determined by the voltage between the coils. According to the requirements, it is required to provide several mm or more (in practice, about 5 mm or more).

[0005] In other high-frequency transformers, the loss due to the high frequency is significantly larger than that of the commercial frequency. For this reason, the primary coil and the secondary coil are alternately wound one by one so that the electromagnetic coupling between the primary coil and the secondary coil is further improved and the loss is reduced as much as possible. For example, FIG. 9 shows a concentric-wound small-sized transformer 1 generally used in a transformer such as a switching power supply.
The primary coil 3 and the secondary coil 4 are alternately wound one by one on an insulating bobbin 2 and housed in a ferrite core 5.

[0006]

By the way, in a high-frequency transformer such as a switching power supply, the output voltage on the secondary side is 30V.
As mentioned above, if the coil is an enameled wire, three layers of insulating layer or 0.4 mm or more between the phases of the primary coil and the secondary coil, even if they are directly connected to the operator, even if According to the IEC standard, it is necessary to provide the insulation and the creepage distance between phases of several mm to about 5 mm or more in accordance with the voltage between phases.

For this reason, as shown in FIG. 9, when winding an insulated wire around an insulated bobbin to form a coil, an interphase insulating layer and a creepage insulating layer must be provided for each layer. Therefore, there is a disadvantage that the transformer becomes extremely large, and it is difficult to automatically wind the coil, the productivity of the transformer is reduced, and the cost is significantly higher than that in the case of the commercial frequency.

[0008] The present invention has been made in view of the above points, by providing the insulated wire itself with the function of inter-phase insulation between the primary and secondary coils and the creepage insulation distance provided separately from the coil in the transformer, These insulation treatments can be omitted,
An object of the present invention is to provide an insulated electric wire for a high-frequency transformer and a high-frequency transformer using the same, which are capable of achieving cost reduction by improving manufacturing productivity by greatly reducing the size of a transformer and improving automatic coil winding. .

[0009]

According to the present invention, in order to achieve the above object, in an insulated wire for a high-frequency transformer according to the present invention, an insulated wire having an insulating layer on a conductor is interposed through a release layer. The configuration was such that an extruded coating insulating layer was provided. In the high-frequency transformer according to the present invention, an insulated wire for a high-frequency transformer in which an extruded insulation layer is provided on an insulated wire having an insulating layer on a conductor via a release layer is used as a coil wire.

The reason why the extruded insulation layer is provided on an insulated wire having an insulation layer on a conductor via a release layer is that, for example, when the same resin is multilayer-extruded and coated, the layers are adhered after extrusion and integrated. This is to prevent that. Since the insulating layer has a multi-layer structure as described above, it is possible to prevent the first insulation breakdown on the surface from affecting the entire insulating layer, so that the insulating layer can be thinned. IEC-950 and the like do not prescribe a minimum thickness to be ensured in the case of three-layer insulation. Furthermore, since the insulating layer is multilayered and the thickness can be reduced, the size of the coil is reduced, the flexibility required for the electric wire for this purpose is improved, and the high-frequency transformer using the coil can be reduced in size.

Examples of the insulated wire having an insulating layer on a conductor include an ordinary enamel-coated wire obtained by applying an enamel paint on a conductor and baking it, or an extrusion coating obtained by melting various resins and extruding and coating the conductor using an extruder. There are electric wires. As the resin that can be used for the extrusion coating, an engineering resin that is extrudable and has an insulating property higher than that of polyurethane for enameled wires of E class or more is used. Examples of such engineering resins include resins such as polyester, polyphenylene oxide, polyetherimide, and polyethersulfone.

As the release material that can be used for the release layer, any material can be used regardless of liquid or solid as long as it prevents adhesion between the extruded resin layers and does not hinder insulation.
Insulating mineral oil, synthetic insulating oil, paraffin, wax, Teflon dispersion and the like can be used. Here, those having a volatile dispersant, such as Teflon dispersion, need to be evaporated and dried after coating and before coating the upper insulating resin.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to FIGS. The high frequency transformer has the same structure as the transformer shown in FIG. Accordingly, in the following description, the transformer coil will be referred to as a high-frequency transformer. Example 1 An insulated wire having three layers of insulating coating was manufactured by one resin extruder having three heads as an extrusion head.

That is, a soft copper wire 12a for winding an electric device having a diameter of 1.0 mm is first passed through a first extrusion head to a thickness of 3 mm.
After extrusion-coating a 0 μm polyester resin 12b, it was cooled and solidified. Then, the soft copper wire 12a, which is extrusion-coated with a polyester resin, is returned to the second extrusion head entrance side, and as a release layer 12c, an insulating mineral oil is applied, passed through the second extrusion head, and placed thereon. A polyester resin 12d having a thickness of 30 μm was further coated, and was similarly cooled.

Next, this polyester resin-coated copper wire is
After being guided to the third extrusion head and forming the release layer 12e on the polyester resin extrusion coating layer again, the thickness was 40 μm.
The polyester resin 12f was extrusion-coated to produce a three-layer insulated wire 12 (hereinafter referred to as a 1.0-φ extruded insulated wire) having an outer diameter of 1.2 mm as shown in FIG. This extruded insulated wire 12
In the longitudinal direction, a cut was made in the insulating layer with a knife, and the insulating coating layer was peeled off. The insulating coating layer was easily divided into three layers.

Next, the 1φ extruded insulated wire (outer diameter: 1.2 m
m) Using a secondary coil 12 and a 0.16φ2 type polyurethane enameled copper wire (0.18 mm in outer diameter, 0.16 mm in conductor diameter) as a primary coil, a high frequency transformer 10 having a sectional shape shown in FIG. 2 was manufactured. That is, one layer (three turns) of the secondary coil 12 is provided on the insulating bobbin 13 in order from the inside, and then the primary coil 1
1 was alternately wound by approximately one layer (26 turns) to manufacture the high-frequency transformer 10 shown in FIG.

Here, the primary and secondary coils 11, 12 are:
The winding start terminal and winding end terminal of each layer were put out of the left and right flanges 13a, 13a of the bobbin 13, and the upper and lower primary and secondary coils 11, 12 were connected in parallel. The uppermost insulating layer 14 of the transformer 10 is formed by laminating three single-sided polyester tapes each having a thickness of 50 μm (total thickness of 0.1).
5 mm). The resulting transformer 10 had cross-sectional dimensions indicated by A and B in the figure of A ≒ 2.8 and B ≒ 3.6 mm, respectively.

[0018] Comparative Example 1 using a polyurethane enamel wire of Example 1φ extruded insulated wire 12 and the same conductor diameter was used in 1 (= 1.0 mm), section in a conventional manner the high-frequency transformer 20 shown in FIG. 3 Was manufactured. That is, the primary coil 21 has the same 0.16φ as that of the first embodiment.
Two types of polyurethane enameled copper wires (0.18 mm in outer diameter) and 1.0 mm type 1 polyurethane enameled copper wires (1.07 mm in outer diameter) are used for the secondary coil 22. Layer (26 turns), thickness 50μm
Three layers of insulating tape 24 made of a single-sided adhesive polyester tape and one layer (three turns) of the secondary coil 22 are alternately wound, and a creepage distance insulating layer 25 is provided on both sides of the coil of each layer.
A glass phenol spacer (divided into two parts in the bobbin axis direction) of 0.18 × 2.3 mm and 1.07 × 3.0 mm was arranged. Here, the terminals of the coils 21 and 22 were processed in the same manner as in the first embodiment. In addition, the obtained high frequency transformer 2
0 indicates that the cross-sectional dimensions indicated by A and B in the figure are A ≒ 3.0 and B, respectively.
≒ 9.3 mm.

Example 2 Two types of insulated wires having two insulating layers with conductor diameters of 0.37 mm and 1.8 mm, respectively, were prepared using one resin extruder having two extrusion heads. It was manufactured in the same manner as in Example 1. However, solid paraffin was used as the release agent, and the outer diameter of each extruded insulated wire was 0.5 mm (insulation thickness: lower layer 30 μm, upper layer 35 μm) and 2.0 mm (insulation thickness: 55 μm for both lower and upper layers).
m) (hereinafter referred to as 0.37φ extruded insulated wires, 1.8, respectively)
φExtruded insulated wire). As for the insulating layer, the extruded insulated wire of any conductor diameter was not adhered between the two insulating layers and was separated.

Using these two types of extruded insulated wires, 1.
8φ extruded insulated wire (outer diameter 2.0mm) with secondary coil, 0.37
φ extruded insulated wire (outer diameter 0.5mm) as primary coil
A high-frequency transformer 30 having a sectional shape shown in FIG. 4 was manufactured.
That is, the secondary coils 32 are sequentially placed on the insulating bobbin 33 from the inside.
For one layer (3 turns), then the primary coil 31
The layers (12 turns) were alternately wound, and three layers of a 50 μm thick single-sided adhesive polyester tape were arranged as the insulating layer 34 on the uppermost layer to obtain the transformer 30 shown in FIG. Here, the terminals of the coils 31 and 32 were processed in the same manner as in the first embodiment. In addition, the obtained high frequency transformer 30
Indicates that the cross-sectional dimensions indicated by A and B in the figure are A {5.0, B}, respectively.
6.0 mm.

Comparative Example 2 Using two types of enamel-coated electric wires having the same conductor diameter as the extruded insulated electric wires used in Example 2, a high-frequency transformer 40 shown in FIG. 5 was manufactured by a conventional method. That is, the primary coil 4
0.37φ2 class polyurethane enameled copper wire (outer diameter 0.4
0mm), 1.8mm class 1 polyester enameled copper wire (outer diameter 1.88mm) is used for the secondary coil 42, the primary coil 41 is one layer (12 turns) in order from the inside to the insulating bobbin 43, and single-sided adhesive of 50μm thickness Three layers of insulating layers 44 made of polyester tape are alternately wound, and the secondary coil 42 is alternately wound in one layer (three turns). On both sides of the coil of each layer, a creepage distance insulating layer 45 is formed as in Comparative Example 1. 0.40 × 2.7mm, 1.
An 88 × 2.3 mm glass phenol spacer was placed.

Here, the terminals of the coils 41 and 42 were processed in the same manner as in the first embodiment. The obtained high frequency transformer 40 is
The sectional dimensions indicated by A and B in the figure are A ≒ 5.1 and B１，10.
3 mm. Example 3 Outside diameter 1.07 coated with a polyurethane resin having a thickness of 35 μm
mm class 1 polyurethane enameled copper wire (conductor diameter 1.0mm) 5
2a is coated with an insulating mineral oil as a release layer 52b, passed through an extrusion head of a resin extruder, further coated with a 30 μm-thick polyester resin 52c, and solidified by cooling to obtain an outer diameter 1 shown in FIG. A .13 mm extruded insulated wire (hereinafter referred to as a 1.0φ extruded insulated wire) 52 was manufactured.

Next, the insulating layer of the 1.0-diameter extruded insulated wire 52 was cut in the longitudinal direction with a knife, and the extruded insulating coating layer was peeled off. The extruded insulating coating layer was easily peeled off.
Next, the 1.0φ extruded insulated wire (outer diameter: 1.13 mm) 52 is used as a secondary coil, and the 0.16φ2 type polyurethane enameled copper wire (0.18 mm in outer diameter, 0.16 mm in conductor diameter) is used as a primary coil. A high-frequency transformer 50 having a sectional shape shown in FIG. 7 was manufactured.

That is, the secondary coil 52 is wound around the insulating bobbin 53 in order from the inner side in one layer (3 turns), and then the primary coil 11 is alternately wound in about one layer (26 turns). 50 were produced. Here, the winding start terminal and winding end terminal of each layer of the primary and secondary coils 51 and 52 were processed in the same manner as in Example 1. In addition, the transformer 50
The uppermost insulating layer 54 is a laminate of three 50 μm-thick single-sided adhesive polyester tapes (0.15 mm in total thickness).
It is. In the obtained transformer 50, the cross-sectional dimensions indicated by A and B in the figure were A ≒ 2.6 and B ≒ 3.4 mm, respectively.

[0025] Using the polyurethane enameled wire 1.0φ extruded insulated wire 52 and the same conductor diameter used in Comparative Example 3 Example 3 (= 1.0 mm), high frequency transformer shown in FIG. 8 in a conventional manner 60 Was manufactured.

That is, the primary coil 61 has the same function as that of the third embodiment.
16φ2 class polyurethane enameled copper wire (0.18m outside diameter)
m), using a 1.0φ class 1 polyurethane enameled copper wire (outer diameter 1.07 mm) for the secondary coil 62, one layer of primary coil 61 (26 turns) in order from the inside of the insulating bobbin 63, and a thickness of 5
Three layers of insulating layers 64 made of a polyester tape of 0 μm single-sided adhesion and three layers of the secondary coil 62 are alternately wound, and a creeping distance insulating layer 65 is formed on both sides of each layer as a creeping distance insulating layer 65. A glass fiber / phenolic resin spacer (divided into two parts in the bobbin axis direction) of × 2.3 mm and 1.07 × 3.0 mm was arranged. Here, each coil 61, 6
The second terminal was processed in the same manner as in the first embodiment. Also, the obtained high-frequency transformer 60 has a cross-sectional dimension indicated by A and B in the figure.
A ≒ 4.0 and B ≒ 9.5 mm, respectively.

In the first and second embodiments and the first and second comparative examples, the winding order of the primary coil and the secondary coil is reversed. However, the winding order is not necessarily required. In order to increase the magnetic coupling efficiency of the secondary coils, they may simply be arranged alternately. In the application example, the secondary coil is arranged inside in order to make the state of coil winding above and below the primary coil the same.

[0028]

According to the present invention, the outer extruded insulating coating of the insulated wire for a high-frequency transformer according to the present invention is an extruded coating of a high-molecular-weight insulating engineering resin having a mechanical strength larger than that of the enamel film, and therefore, is used as an insulating layer rather than an enameled wire. High reliability. Also, since the insulating layer is a multi-layered composite insulating layer via a release layer, sufficient insulation reliability can be ensured even if the insulating layer is thinner than the integrated enamel insulating layer, and the flexibility of the electric wire is improved. improves.

Further, since the extruded coating layer is not an enamel coating, each layer of the insulating layer can be regarded as an insulating layer specified in IEC-950 or the like. Therefore, the high-frequency transformer of the present invention using the above-described extruded insulated wire has a role of interphase insulation between the primary and secondary coils, for example, a three-layered polyester tape, and a composite insulating layer of the extruded insulated wire itself of the present invention. In addition, the creepage insulation distance between the primary and secondary coils is infinite inside the insulation bobbin of the coil.
There is no need for an insulating spacer defined as 0 or the like.

Therefore, the compact high-frequency transformer using the insulated electric wire for the high-frequency transformer of the present invention can be remarkably downsized as compared with the conventional one using the enameled wire, and at the same time, winding the insulating tape between the primary and secondary coils and inserting the spacer. This eliminates the process of (1), which makes it possible to automatically wind the coil, which has been difficult in the past, and makes it possible to reduce the cost by greatly improving the manufacturing productivity.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of an insulated wire for a high-frequency transformer according to the present invention, and is a perspective view of a 1φ extruded insulated wire.

FIG. 2 is a longitudinal sectional view showing a first embodiment of the high-frequency transformer according to the present invention and showing an upper half of the high-frequency transformer using the 1φ extruded insulated electric wire of FIG. 1;

FIG. 3 is a longitudinal sectional view showing a comparative example with the above embodiment, and showing an upper half of a high frequency transformer manufactured by a conventional method.

FIG. 4 is a longitudinal sectional view showing an upper half of a high frequency transformer according to a second embodiment of the present invention.

FIG. 5 is a longitudinal sectional view showing an upper half of a high frequency transformer according to a comparative example with respect to the second embodiment.

FIG. 6 is a perspective view of a 1.0-φ extruded insulated wire, showing a third embodiment of the insulated wire for a high-frequency transformer according to the present invention.

7 is a longitudinal sectional view showing an upper half of a high-frequency transformer using the insulated wire of FIG. 6;

FIG. 8 is a longitudinal sectional view showing an upper half of a high frequency transformer according to a comparative example with respect to the third embodiment.

FIG. 9 is a longitudinal sectional view showing a conventional concentric winding type small transformer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 High frequency transformer 12 High frequency transformer insulated wire 12a Conductor 12b, 12d, 12f Extrusion coating insulating layer 12c, 12e Release layer 30 High frequency transformer 31, 32 Insulated wire for high frequency transformer 50 High frequency transformer 52 For high frequency transformer Insulated wire

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H01F 38/42 H01B 7/02 H01F 5/06 H01F 27/00 H01F 27/28

Claims (2)

(57) [Claims] 1. An insulated wire for a high-frequency transformer, wherein an insulated wire having an insulating layer on a conductor is provided with an extruded coating insulating layer via a release layer. 2. A high-frequency transformer characterized in that an insulated wire for a high-frequency transformer in which an insulated wire having an insulating layer on a conductor and an extruded insulating layer is provided via a release layer as a coil wire material.