JPH1174138A - High-voltage transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the insulating properties of the high-voltage coil of a high-voltage transformer. SOLUTION: A annular core 3 is enhanced in direct current superposing characteristic by providing a gap 6 to a magnetic path, the annular core 3 is sheathed with a first insulating resin case 4, the resin case 4 is wound regularly with a secondary coil 2 in a single layer, the secondary coil 2 is covered with a second case 5, and the sheath of case 5 is wound with a primary coil 1 for the formation of a high-voltage transformer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-voltage transformer used for lighting a cold cathode lamp or a metal halide lamp which requires a high voltage.

[0002]

2. Description of the Related Art Heretofore, generally known as high-voltage lighting is a cold cathode lamp mounted on the back side of a liquid crystal display such as a personal computer or a word processor. Was raised to several kV, and the cold cathode lamp was turned on to display the liquid crystal brightly. FIG.
2 is a sectional view of the high-voltage transformer. Bobbin 5 having hollow holes 55 with flanges 56 at both ends
4, a low-voltage-side primary coil 51 and a high-voltage-side secondary coil 52 are wound between the flanges 56, and an insulating wall 57a is provided between the primary-side coil 51 and the secondary-side coil 52. Are provided, and the secondary coil 52 is wound separately by an insulating wall 57b. The core 53 made of ferrite is incorporated in the hollow hole 55 of the bobbin 54 to constitute a high-voltage transformer.

In recent years, high-pressure discharge lamps such as metal halide lamps have appeared as headlights for automobiles. This high-pressure discharge lamp has a higher luminance than a conventional halogen lamp for a headlight and can illuminate brightly, but requires a high voltage of 20 kV or more at the start of lighting. As a high-voltage transformer used for the high-pressure discharge lamp, there is a high-voltage transformer disclosed in JP-A-8-130127 shown in FIG. In this high-voltage transformer, a cylindrical core 63 is housed in a spool 64 and a secondary coil 62 is wound. These are housed in a case 65 and integrated with a filling resin, so that the primary coil 61 in a holder shape covers the secondary coil 62 and the core 63 wound around a spool 64 integrated with the case 65. Mounted from above.

[0004]

However, in the above-mentioned conventional high-voltage transformers, although the secondary coil is divided and wound to suppress the interlayer voltage, the voltage of the secondary coil on the high voltage side is, for example, low. When the voltage is as high as 25 KV, the coil potential difference in each of the divided windings becomes extremely high, and there is a problem that reliability is lacking. Also, 2
Although the coil potential difference in the divided winding can be reduced by increasing the number of divisions of the secondary coil, there is a problem that the size as a high-voltage transformer increases.

[0005] In FIG. 13, the magnetic core as a transformer is composed of only a columnar core, and thus operates in an open magnetic path. Due to this open magnetic path structure, the required characteristics cannot be obtained unless the number of turns of the coil is increased or the core size is increased in order to generate the required voltage. There was a problem of becoming. Further, the method of mounting a transformer on an automobile is to be incorporated as a unit together with other elements, and since the transformer is constituted by a magnetic core of an open magnetic path, other elements in the unit are affected by leakage magnetic flux. Was something.

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a high-voltage transformer that is small and lightweight, has improved reliability with respect to a high voltage, and has little leakage magnetic flux.

[0007]

According to the present invention, there is provided a high-voltage transformer comprising a magnetic core made of a magnetic material and a primary coil and a secondary coil, wherein the magnetic core is an open magnetic path magnetic core made of a metallic magnetic material. The core is covered with an insulator, and a secondary coil is wound around the sheath of the insulator. Further, the secondary coil is again covered with the insulator together with the core, and a primary coil is wound around the sheath. This is a high-voltage transformer.

The present invention is a high-voltage transformer having one or more air gaps on a magnetic path of a magnetic core, and in a case where two or more magnetic cores are combined, an air gap is provided in an opposing portion of the combination of the magnetic cores. .

The present invention is a high-voltage transformer wherein the insulator is a case made of an insulating resin, an insulating tape or a coating made of an insulating resin.

Further, according to the present invention, a magnetic core made of a metal-based material is made of a microcrystalline alloy or an amorphous alloy, and is formed by molding a wound core formed by winding a ribbon, a laminated magnetic core formed by lamination, and powder. This is a high-pressure transformer that is a dust core. Also, the present invention provides a magnetic core made of a metal-based material
e-Al-Ni alloy, Mo-P alloy, pure iron, Fe-Si
A high-pressure transformer, which is a dust core formed by molding a powder, formed by winding a ribbon, winding a magnetic core made of an alloy, and laminating a laminated magnetic core.

Further, according to the present invention, the secondary coil is composed of two windings, each of which is wound at a symmetric position of the magnetic core, and the winding directions of the two windings are opposite to each other. This is a high-voltage transformer that connects the start and end of the winding to form a secondary coil of the transformer. Further, the present invention is a high-voltage transformer in which the secondary coil is wound in a single-layer arrangement.

Further, according to the present invention, the primary coil is a rectangular wire,
This is a high-voltage transformer using an electric wire having an insulating coating and an electric wire having a coaxial structure.

Further, according to the present invention, a ring-shaped magnetic core of an open magnetic circuit using a metal-based magnetic material is housed in a first case, and the first case armor is arranged and wound in a symmetrical positional relationship. A secondary coil composed of two windings is wound, and the secondary coil is housed in a second case together with a first case housing a magnetic core. A flat wire and an insulated wire are provided in a second case exterior. This is a high-voltage transformer in which a primary coil using a coaxial wire is wound, and the entire transformer is insulated by a third case or resin surrounding the primary coil.

Further, the present invention is a high voltage transformer in which an insulating resin for insulation or fixing is sealed in a case, and the resin sealed in the case is made of a different material for each case.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a high-voltage transformer according to the present invention. The ring-shaped magnetic core 3 is a magnetic core having a DC superposition characteristic in which an air gap 6 is provided in a part of a magnetic path and an inductance can be generated with respect to a DC current. The ring-shaped magnetic core 3 has a first case 4 made of an insulating resin.
And the exterior of the case 4 containing the magnetic core 3,
The secondary coil 2 is wound in a single-layer arrangement, and the secondary coil 2 is covered with a second case 5.
The primary side coil 1 is wound around the exterior. Note that a spacer 7 was inserted into the gap 6 to obtain a stable gap size.

Generally, a high-voltage transformer has a high voltage side 2
Since a voltage of several kV or more is generated in the secondary coil 2, it is necessary to insulate other conductive parts from the secondary coil 2 without fail. In the present invention, the case 4 and the case 5 shown in FIG. It is intended to provide insulation. By covering the core 3 with the case 4, the core 3 is wound around the exterior of the case 4 containing the core 3.
The secondary coil 2 is insulated. The primary side coil 1 is wound around the secondary side coil 2 so that the secondary side coil 2
The primary coil 1 wound around the case 5 is insulated by a case 5 covering the case.

That is, insulation is interposed between the magnetic core 3 and the secondary coil 2 and between the secondary coil 2 and the primary coil 1 to insulate the high-voltage secondary coil 2. Things. The cases 4 and 5 in FIG. 1 have a structure in which the magnetic core 3 and the secondary coil 2 are housed in a state close to sealing. Other methods include winding an insulating tape over each of them, or coating them with a coating, which are high voltage transformers suitable for sample and small volume production.

Further, some of the high-voltage transformers have a DC superposition characteristic of obtaining a high voltage required at the time of lamp operation and generating an inductance with respect to a DC current flowing through the high-voltage transformer after the lamp operation. is there. In a conventional high-voltage transformer using ferrite, the maximum saturation magnetic flux density of a Mn-based ferrite is about 500 mT. Therefore, a very large air gap is provided to suppress saturation with respect to DC current. As shown in the figure, the rod-shaped core was formed, and a large leakage magnetic flux was generated, which affected various peripheral elements. The high-voltage transformer of the present invention has a saturation magnetic flux density of about 2 to 4 times and a high magnetic permeability as compared with a conventional ferrite material by using a metal-based magnetic material as a magnetic core. It can have a DC superimposition characteristic equal to or higher than that of the material, and can reduce the magnetic flux leakage to the outside of the core.
Moreover, high inductance can be generated with a small number of turns.

Further, by winding the secondary coil 2 on the high voltage side in a single-layer arrangement, the potential difference between adjacent windings can be minimized. Because it is clear, the insulation distance between terminals of the coil can be easily set.

As shown in FIG. 2, the secondary coil has a coil 8 and a coil 9 wound at symmetric positions of a case 4 containing a magnetic core, and the winding directions of the coils 8 and 9 are reversed. And the winding start 8a, 9a and the winding end 8b, 9b are connected to form a secondary coil. Since the coils 8 and 9 are connected in parallel, the voltage rises or drops starting from the winding start 8a, 9a or the winding end 8b, 9b, and the secondary coil starts winding 8a, 9a. And the winding ends 8b and 9b can have a positional relationship of approximately 180 degrees, and the distance between the winding start and the winding end where the maximum potential difference occurs in the secondary coil can be greatly increased. In addition, since the secondary coil is configured by connecting the two coils 7 and 8 in parallel, the wire diameter of each coil can be reduced, and the number of coil turns on the bobbin can be increased. Although the winding start and end of the winding are connected to each other for easy understanding in the drawing, they are actually connected using other conductors or terminals, or connected by a pattern of an attachment circuit.

Since a larger current flows through the primary coil than the secondary coil, the sectional area of the coil becomes larger.
If a rectangular copper wire is used, winding can be performed without jumping out, so that the size of the high-voltage transformer can be reduced. In addition, since the primary-side coil is closest to the high-voltage transformer of the present invention, the insulating property of the high-voltage transformer is improved by using an electric wire having an insulating tube. Also, by using a coaxial cable type electric wire, the coupling as a high-voltage transformer is improved.

Further, by filling each case of the high-voltage transformer of the present invention with a resin, the magnetic core or the coil in the case can be fixed, and the heat radiation of the magnetic core and the coil can be improved. it can. Further, the gap generated in the fitting portion of the case can be filled with the filling resin, and the insulating property is improved.

When the material used for the magnetic core is weak against stress, the case of the magnetic core is filled with a soft resin such as silicone and the case for accommodating the secondary coil is provided in order to suppress the characteristic deterioration due to the stress. By filling a hard resin such as an epoxy resin, the strength as a high-voltage transformer can be obtained, and the characteristic deterioration of the magnetic core can be prevented.

3 to 6 show a method of manufacturing the high-voltage transformer according to the present invention. The magnetic core 3 is a wound magnetic core formed by winding a fine crystalline alloy ribbon. The magnetic core is hardened with a resin in order to form a gap in a magnetic path, and thereafter a gap 6 is provided. A spacer 7 of a resin sheet piece is inserted into the gap 6. Thus, the gap size was made constant. The magnetic core 3 is incorporated in the case 4a, 4b of a two-part structure located in the vertical direction to provide insulation. The microcrystalline alloy ribbon used for the magnetic core 3 has a predetermined magnetic property by heat treatment, and the same applies to a magnetic core using an amorphous alloy ribbon. The magnetic core 3 made of the microcrystalline alloy ribbon is a magnetic core having a magnetic permeability of 10,000 or more, a saturation magnetic flux density of 1 T or more, and low loss and excellent characteristics. A magnetic core with properties was obtained.

The insulation distance of the case fitting portion in FIG.
The thickness of the case is taken, but other methods such as wrapping an insulating tape around the inner and outer peripheries of the case fitting part, or filling it with silicone resin, which is easy to handle, so as to wrap the magnetic core in the case, and taking the insulation distance There is also.

The secondary coil 2 on the high voltage side is wound around a case 4 containing the magnetic core 3 manufactured according to FIG.
It is. The secondary coil 2 was wound in a single-layer alignment using a UEW wire, and a terminal distance for insulation was provided at the beginning and end of winding. In addition, what is located above and below in the figure is
Cases 5a and 5b for insulating the exterior of the secondary coil 2
It is. Since the secondary coil 2 has a single layer of aligned windings, the potential difference between adjacent windings is equal to the secondary voltage divided by the number of turns of the secondary coil, and the potential difference between the windings can be minimized. Was. For example, at a secondary output voltage of 20 kV,
If the number of coil turns on the secondary side is 80 turns, the potential difference between adjacent windings is 250 V, which is a voltage that can be insulated even by a UEW line.

The flat surface of one case 5a in FIG.
The secondary coil 2 has a lead extraction hole 10. Also, in the figure, the winding start and winding end of the secondary coil 2 have a distance between the terminals only in the space, but by providing the convex partition 11 shown in FIG. 5, the distance between the terminals can be reduced. And the coil winding frame can be expanded. Cases 5a and 5b for storing the secondary coil 2
By providing a groove or the like for fitting the convex partition 11 of the case 4, the secondary coil 2 and the case 4 can be stably fixed in the cases 5a and 5b.

At this time, the position of the air gap provided in the magnetic core is always fixed, so that the influence of the leakage magnetic flux when the high-voltage transformer is used can be minimized. At the same position or the partitions 11 and 18
For example, there is a method of setting the position to 0 degree, and the performance as a high-voltage transformer is improved.

FIG. 6 is a completed view of the high-voltage transformer of the present invention. Magnetic cores 3 and 2 produced according to FIGS. 3 and 4
The primary coil 1 is wound around the exterior of the case 5 in which the secondary coil 2 is built, and the high-voltage transformer is completed. The primary coil 1 uses a tube wire to increase the insulation as a high-voltage transformer, and also improves the insulation with respect to the secondary coil 2 in the case 5. Also, the primary coil 1
Even if the number of windings is small, the space winding around the case 5 can minimize the leakage magnetic flux from the primary coil 1. When an insulating film type such as a UEW wire or a PEW wire is used for the primary coil 1, a case for accommodating the primary coil 1 is further attached, or an outer insulating coat is applied, so that a high-voltage transformer is formed. Insulation can be strengthened.

The specifications and performance of the high-voltage transformer of the present invention in a prototype are shown below. 8 of Fe-based microcrystalline alloy ribbon
mm width, 18 μm, outer diameter 44 mm, inner diameter 28 m
A magnetic core having a height of 8 mm and a height of 8 mm was prepared, and heat treatment for obtaining predetermined characteristics was performed. After hardening the magnetic core with an epoxy resin, a gap of 0.5 mm was provided to obtain a magnetic core of a high-voltage transformer. The outer surface of the magnetic core was wrapped around the entire magnetic core with a powdered epoxy coating and was shielded from the outside. The secondary coil takes the form shown in FIG. 2, and turns the 0.18 mmφ UEW into a single-layer arrangement of 140 turns in opposite winding directions to the symmetrical positional relationship of the coated magnetic core. Are connected to each other to form a secondary coil.

The exterior insulation of the secondary side coil was performed in the case 5a, 5b shown in FIG. 4 made of PBT resin. At this time, in order to increase the insulation distance due to the gap between the case facing parts, the case is completely filled with silicone resin,
The gap between the case-facing portions was filled, and the heat dissipation from the secondary coil was improved. In addition, the primary side coil was wound around a 5 mm wide, 0.05 mmt polyester-coated rectangular copper wire for two turns in order to suppress the dimensions of the high voltage transformer, thereby completing the high voltage transformer of the present invention. The primary coil was space wound in order to minimize the leakage magnetic flux due to winding.

The performance of the high-voltage transformer according to the above-mentioned prototype can be reduced to a thin volume of 47 mm × 47 mm and a height of 12 mm. The characteristics are as follows: input voltage 400 V (primary side); A high-voltage transformer having an excellent DC superimposition characteristic capable of obtaining an output voltage and generating an inductance of 1.7 mH when a secondary coil has no-load inductance of 2 mH and a DC current of 1 A is applied. Could be produced. In addition, the potential difference between adjacent windings of the secondary coil could be reduced to about 142V.

FIG. 7 is a partial sectional view of a case for accommodating a magnetic core and a coil used in the high-voltage transformer of the present invention.
The insulation between the inside and the outside of the case is determined by the space distance and creepage distance of the case fitting portion, and the space distance is determined by the case thickness B shown in FIG. By increasing the number or increasing the vertical fitting dimension A, a sufficient insulation distance can be secured for a voltage of several tens of kV even if the case thickness B is small, and it is used in the high-voltage transformer of the present invention. The case was reduced in size.

FIGS. 8 to 11 show magnetic cores used in the high-voltage transformer of the present invention. When a microcrystalline alloy ribbon and an amorphous alloy ribbon having a high saturation magnetic flux density and good temperature characteristics are used in the present invention, a core wound in a ring shape, a substantially elliptical core shown in FIG. The laminated frame type shown in FIG. 9 can be used.

FIG. 8 shows a metal-based magnetic ribbon having a substantially elliptical shape and a gap 6 provided in a part of a magnetic path. This substantially elliptical core may be formed by deforming a ring-shaped core in addition to making it elliptical when the thin ribbon is wound.

FIG. 9 shows a frame-shaped magnetic core obtained by laminating sheet-shaped ribbons made by punching a metal-based magnetic ribbon.
The frame-shaped magnetic cores to be combined include a method in which U-shaped sheets are laminated in advance, or a method in which frame-shaped sheets are laminated and then cut and divided.

Further, as a magnetic core of a high-voltage transformer requiring a DC superimposition characteristic, there is a dust core shown in FIGS. 10 and 11 in which a metallic magnetic material is formed into powder.

FIG. 10 shows an example in which a ring-shaped magnetic core is provided with an air gap in a portion of the spacer 7 facing the core. When the outer surface of the spacer 7 is subjected to insulation coating treatment with an epoxy resin or the like, the spacer 7 plays a role of partitioning the coil of the secondary coil including the two windings shown in FIG.

FIG. 11 shows a frame-shaped dust core formed by combining a U-shaped member 12 and an I-shaped member 13 made of magnetic powder. The secondary coils of the dust core are respectively arranged on the side legs of the core and connected in parallel, and each of the bobbins 14 has a single-layer aligned winding 15 and a winding 16 opposite in winding direction. Forms a secondary coil. Note that U
A thin insulating coating was applied to the exteriors of the mold 12 and the I-type 13 to improve the insulation between the magnetic core and the secondary coils 15 and 16, and to reduce the bobbin thickness of the secondary coil. .

As the material of the dust core, Fe—Al—
There are Ni alloys, Mo-P alloys, pure iron, Fe-Si alloys, and the like, and the above-described microcrystalline alloys and amorphous alloys can be easily turned into dust cores by making them into powder.

[0041]

According to the high-voltage transformer of the present invention, the resin is provided for each of the magnetic core and the coil, thereby enabling insulation in a substantially sealed state, thereby improving reliability. In addition, the use of a metal-based magnetic material for the magnetic core has made it possible to reduce the size of the magnetic core compared to the prior art, to obtain a DC superimposition characteristic with a small air gap, and to obtain a high-voltage transformer with little leakage magnetic flux.

[Brief description of the drawings]

FIG. 1 is a sectional view of a high-voltage transformer according to the present invention.

FIG. 2 is another secondary coil specification diagram of the high-voltage transformer of the present invention.

FIG. 3 is a diagram illustrating a magnetic core incorporated in a high-voltage transformer according to the present invention.

FIG. 4 is a diagram showing a coil incorporated in a high-voltage transformer according to the present invention.

FIG. 5 is an external view of another magnetic core storage case of the high-voltage transformer of the present invention.

FIG. 6 is a diagram showing a completed high-voltage transformer according to the present invention.

FIG. 7 is a partial sectional view of a case used in the high-voltage transformer of the present invention.

FIG. 8 shows another magnetic core shape used in the high-voltage transformer of the present invention.

FIG. 9 shows another magnetic core shape used in the high-voltage transformer of the present invention.

FIG. 10 shows another magnetic core shape used for the high-voltage transformer of the present invention.

FIG. 11 is a view showing a secondary coil incorporated in a high-voltage transformer according to the present invention

FIG. 12 is a sectional view of a conventional high-voltage transformer.

FIG. 13 is an exploded perspective view of another conventional high-voltage transformer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Primary side coil 2 Secondary side coil 3 Magnetic core 4 Case 5 Case 6 Air gap 7 Spacer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01F 30/00 H01F 31/00 H 31/06 501G

Claims (12)

[Claims] 1. A high-voltage transformer comprising a magnetic core made of a magnetic material and a primary coil and a secondary coil, wherein the magnetic core is an open magnetic path magnetic core made of a metallic magnetic material, and the magnetic core is covered with an insulator. A secondary coil is wound around the outer sheath of the insulator, and the secondary coil is again covered with an insulator together with a magnetic core, and the primary coil is wound around the outer sheath. Trance. 2. The magnetic core has one or more air gaps on a magnetic path, and when two or more magnetic cores are combined, an air gap is provided in a combination facing portion of the magnetic cores. Item 1. The high-voltage transformer according to Item 1. 3. The high-voltage transformer according to claim 1, wherein the insulator is a case made of an insulating resin. 4. The high-voltage transformer according to claim 1, wherein the insulator is a coating made of an insulating tape or an insulating resin. 5. A magnetic core made of a metal-based magnetic material is made of a fine crystalline alloy or an amorphous alloy, and is formed by molding a wound core formed by winding a ribbon, a laminated magnetic core formed by laminating, and powder. 3. The high-voltage transformer according to claim 1, wherein the high-voltage transformer is a dust core. 6. A magnetic core made of a metal-based magnetic material,
It is a dust core formed by molding a powder using a Al-Ni alloy, a Mo-P alloy, pure iron, an Fe-Si alloy, and a wound core formed by winding a ribbon, a laminated core formed by lamination, and powder. 3. The high-voltage transformer according to claim 1, wherein: 7. The secondary coil comprises two windings, each of which is wound at a symmetric position of a magnetic core, wherein the winding directions of the two windings are opposite to each other, and 2. The high voltage transformer according to claim 1, wherein the winding start and the winding end are connected to form a secondary coil of the transformer. 8. The high-voltage transformer according to claim 1, wherein the secondary coil is wound in a single-layer arrangement. 9. The high-voltage transformer according to claim 1, wherein the primary coil uses a flat wire, a wire having an insulating coating, and a wire having a coaxial structure. 10. A ring-shaped magnetic core of an open magnetic circuit using a metal-based magnetic material is housed in a first case, and two windings in a symmetrical positional relationship are wound around the first case exterior. And the secondary coil is wound in the second case together with the first case containing the magnetic core,
A primary coil using a flat wire, an insulated wire, and a coaxial wire is wound around the second case exterior.
A high voltage transformer characterized in that the entire transformer is insulated by a third case or resin surrounding the entire secondary coil. 11. The high-voltage transformer according to claim 3, wherein an insulating resin for insulation or fixing is sealed in the case. 12. The high-voltage transformer according to claim 11, wherein the resin sealed in the case is made of a different material for each case.