JPH10208956A - High-voltage transformer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a small size high-voltage transformer and improve its reliability. SOLUTION: The transformer comprises a closed magnetic path core having at least combined two cores 1, a bobbin 3 having a hollow hole 4 capable of mounting the closed magnetic path core, and coil wound round the bobbin 3. This core has at least two parallel bobbin mounting legs 2 on which at least two bobbins 3 are mounted parallel, each having a single-layer wound secondary coil 7 between flanges 5, 6 so that the adjacent sec. coils 7 are wound in mutually reverse directions. The core 1, bobbin 3 and coils 7, 8 are housed in a heat-resistive resin case 13 filled up with a heat-resistive resin.

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.
Is a sectional view of the high-voltage transformer. A bobbin 103 having a hollow hole 102 provided with a flange 101 at both ends is provided. Between the flanges 101, a low-voltage primary coil 104 and a high-voltage secondary coil 105 are wound, An insulating wall 106a is provided between the primary coil 104 and the secondary coil 105.
5 is divided and wound by the insulating wall 106b. And
A high-voltage transformer is configured by incorporating a core 107 made of ferrite into the hollow hole 102 of the bobbin 103.

In recent years, high-pressure discharge lamps such as metal halide lamps have appeared as headlights for automobiles. This high-pressure discharge lamp can illuminate brighter and brighter than conventional halogen lamps for headlights,
The voltage at the start of lighting requires a high voltage of 20 kV or more. 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 119 is accommodated in a spool 118, and a secondary coil 117a is wound therearound. These are housed in a case 120 and integrated with a filling resin, and the primary coil 122 in the form of a holder is mounted on the spool 1 integrated with the case 120.
18 and the secondary coil 117a wound around the core 11
9 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.

In Japanese Patent Application Laid-Open No. Hei 8-130127, since the magnetic core as a transformer is composed of only a cylindrical core, the operation is performed in an open magnetic circuit. 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, and the weight and mounting area are inevitably large. 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.

An object of the present invention is to provide a high-voltage transformer which is small, lightweight and has improved reliability against high voltage in consideration of the above.

[0007]

SUMMARY OF THE INVENTION The present invention provides at least two
In a high-voltage transformer comprising a closed magnetic circuit type core obtained by combining two cores, a bobbin having a hollow hole attachable to the closed magnetic circuit type core, and a coil wound around the bobbin, the closed magnetic circuit type core includes At least two parallel bobbin-mounted magnetic legs are provided, and at least two bobbins are mounted on the bobbin-mounted magnetic legs in parallel, and a single-layer aligned winding secondary coil is provided between flanges of the respective bobbins. Wound, and the adjacent secondary coils are wound in opposite directions,
The core, the bobbin, and the coil are a high-voltage transformer that is housed in an insulating resin case, and the case is filled with the insulating resin.

Further, in the present invention, the primary coil is formed as a one-turn coil on the flange of the bobbin.

Further, the secondary coil according to the present invention comprises:
This is a high-voltage transformer in which single-layer aligned winding coils are arranged in multiple layers, and winding start and winding end of each coil are connected to the same terminal.

In the present invention, the secondary coil includes:
This is a high-voltage transformer having a multilayer structure of a single-layer aligned winding coil in which multiple parallel wires are wound perpendicularly to a winding axis, and winding starts and winding ends of the respective coils are connected to the same terminal.

Further, the closed magnetic circuit type core according to the present invention comprises:
This is a high-voltage transformer having a non-linear DC superimposition characteristic.

Further, according to the present invention, the boosting ratio is 10 to 200,
It is desirable to apply the present invention to a high-voltage transformer having an output of 10 KV or more, and it is preferable to use it for a discharge lamp lighting circuit.

Further, the present invention is a high voltage transformer mounted in a metal halide lamp lighting circuit.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the core is a closed magnetic circuit type core, so that the number of windings is reduced and a high voltage can be obtained. Thereby, the insulation between the wires of the coil can be improved.

For example, when the number of turns is 100 turns when the secondary coil has a voltage of 25 kV, the potential difference between the individual lines is 250 V. This 250V
Is within a range that can be guaranteed by the withstand voltage of the electric wire. For example, if an electric wire having a withstand voltage of 400 V is used, the coating of the electric wire can sufficiently assure.

On the other hand, when the conventional secondary coil is divided into a plurality of flanges and divided into a plurality of flanges, for example, when divided into five, the withstand voltage of one division is 5 kV and the withstand voltage is 4 kV.
With a 00V electric wire, it cannot be guaranteed very much. Thus, it can be seen that the single-layer aligned winding is a winding having excellent withstand voltage characteristics.

Further, according to the present invention, a closed magnetic circuit type core, a bobbin,
Since the coil is housed in an insulating resin case and further filled with an insulating resin, not only the pressure resistance is improved, but also the reliability such as heat resistance and weather resistance is improved.

In the case of single-layer aligned winding, if the number of turns is the same, a long winding frame is required, and the transformer becomes large. However, in the present invention, by using the closed magnetic path core, the number of turns is reduced, and the size is prevented from increasing. That is, by using a closed magnetic circuit structure for the core, a high inductance can be obtained if the windings are the same. Therefore, compared to an open magnetic circuit structure, the same inductance can be achieved with a smaller number of turns in a closed magnetic circuit.

In the case of single-layer aligned winding, if a high current capacity is required or if it is desired to reduce the DC resistance value, a thick wire is used. When this thick wire is used, the length of the bobbin is inevitably increased, resulting in an increase in size. In the present invention, since the secondary coil is provided on the adjacent bobbin, the current capacity is twice as large and the DC resistance is half as compared with the case where only one side is provided. If a higher current capacity and a lower DC resistance are required, a single-layer aligned winding is composed of multiple layers and connected in parallel, so that even a thin wire can support a high current capacity and a low DC resistance. , It is possible to prevent an increase in size.

In order to structure the single-layer aligned winding into a multilayer, it is possible to simply form the single-layer aligned winding into a multilayer.
Alternatively, it may be configured by winding a multi-parallel wire formed integrally with a plurality of wires in a direction perpendicular to the winding shaft.

Further, the closed magnetic path core of the present invention may use a gap in a part thereof,
It may have a non-linear DC superimposition characteristic.

The high-voltage transformer of the present invention can constitute a highly reliable high-voltage transformer.
It can be seen that it is extremely effective when used in a lighting circuit such as a metal halide lamp that requires a high voltage such as KV.

[0023]

FIG. 1 is an exploded perspective view of an embodiment according to the present invention. In this embodiment, a pair of U-shaped cores 1 are butted, and a bobbin 3 is attached to a magnetic leg formed by butting each leg 2. Bobbin 3 is the core 1
Has a hollow hole 4 into which the leg 2 can be inserted, and has flanges 5 and 6 at both ends. Between the flanges 5 and 6 of the bobbin 3, a secondary coil 7 is wound in a single layer and aligned. The ends of the secondary coil 7 are connected to the terminals 10 respectively. The primary coil 8 is connected to one of the flanges 5.
, To form a one-turn coil. An end of the primary coil 8 protrudes from the other end of the flange 5 to form a terminal 9. A recess 12 for accommodating the core 1 is formed in the flanges 5 and 6 of the bobbin 3.

FIG. 2 is an exploded perspective view of this embodiment viewed from the terminal side. The bobbin 3 has a groove 14 for guiding the end of the secondary coil 7 to the terminal 10. Then, a pair of U-shaped cores 1 were inserted into the bobbin 3 on which the coil was mounted, housed in the insulating resin case 13, and filled with the insulating resin to form a high-voltage transformer. As this insulating resin,
For example, PBT, denatured PPO, or the like is preferable, and preferably has high withstand voltage characteristics.

In this embodiment, the primary coil 8 is made of a conductor having a diameter of 0.8 mm, and the secondary coil 7 is formed by winding a 0.2 mm UEW wire for 105 turns to obtain a primary voltage of 100 mm.
A secondary-side voltage of 20,000 V was obtained from 0 V. The high-voltage transformer of this example could be used as a high-voltage transformer for lighting a metal halide lamp. At this time, it was possible to obtain a high-voltage transformer having the overall dimensions of 25 mm × 40 mm × 25 mm in height. This made it possible to construct a high-voltage transformer with a volume of about 2/3 that of the conventional product.

The secondary coil 7 is wound in the opposite direction to each other, and is used by connecting the respective low voltage side and high voltage side.
This is shown in FIG. With this winding structure, for example,
Even if the voltage becomes 25 KV in the high voltage portion, the adjacent coil portions have the same potential, so that the discharge can be prevented even if the distance between the coils is shortened. Therefore, downsizing is achieved.

FIG. 4 is an explanatory view of a second embodiment according to the present invention. FIG. 4 shows a state in which two coils A and B are wound in a single layer on each bobbin 3. First one coil A
Is wound in a single layer and another coil B is wound in a single layer. Then, as shown in the circuit diagram of FIG. 5, the two single-layer aligned winding coils A and B are connected at the start of winding and at the end of winding to form a high-voltage transformer. By doing so, the current capacity can be doubled by making it two layers compared to one layer. At the same time, the DC resistance can be halved. In this case, the number of layers is two, but may be three or more. However, as the number of layers is increased, misalignment of aligned windings is more likely to occur, and three or less layers are desirable in terms of reliability.

FIG. 6 is an explanatory view of a third embodiment according to the present invention. In this embodiment, a parallel wire 15 in which two wires are integrally formed is used, and the parallel wire 14 is wound perpendicular to the winding axis of the coil. Thus, the same structure as the two-layer structure of the single-layer aligned winding shown in FIG. 4 can be configured.
Of course, three or more parallel lines may be used. In the case of these parallel lines, the possibility of misalignment is small and multilayering is possible.

In the present invention, the primary side coil is not limited to the one-turn structure provided on the flange as shown in FIG. 1, but may have, for example, an increased number of turns, or may have a coil at another location. May be provided. Further, the core is not limited to the UU type core as shown in FIG.
Any shape such as an EI type may be used. As a material of the core, a ferrite core having high pressure resistance is desirable, and a Ni—Zn ferrite core is desirable. Further, a gap may be provided in a part of the closed magnetic circuit type core, or the gap may have a multi-stage structure or the like and have a non-linear DC superimposition characteristic.

[0030]

According to the present invention, in a high-voltage transformer, the size of the transformer can be reduced by using a core having a closed magnetic circuit structure. To improve the pressure resistance characteristics of
In addition, because of the closed magnetic circuit structure, the leakage magnetic flux is small and the generation of electromagnetic noise can be greatly reduced, and the miniaturization of the high-voltage transformer can be achieved and the reliability can be improved. Is extremely useful.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of an embodiment according to the present invention.

FIG. 2 is an exploded perspective view of one embodiment according to the present invention as viewed from a terminal side.

FIG. 3 is a circuit diagram illustrating an embodiment according to the present invention.

FIG. 4 is an explanatory diagram of a second embodiment according to the present invention.

FIG. 5 is an explanatory circuit diagram of a second embodiment according to the present invention.

FIG. 6 is an explanatory perspective view of a third embodiment according to the present invention.

FIG. 7 is a sectional view of a conventional example.

FIG. 8 is an exploded perspective view of another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 U-shaped core 2 Leg part 3 Bobbin 4 Hollow hole 5, 6 Flange 7 Secondary coil 8 Primary coil 9, 10 Terminal 11 Mounting part 12 Depression 13 Heat resistant resin case 14 Groove 15 Parallel line

Claims (8)

[Claims] 1. A high-voltage transformer comprising a closed magnetic circuit type core formed by combining at least two cores, a bobbin having a hollow hole mountable on the closed magnetic circuit type core, and a coil wound around the bobbin. The closed magnetic circuit type core has at least two parallel bobbin mounting magnetic legs, at least two bobbins mounted on the bobbin mounting magnetic legs in parallel, and a single layer alignment between the flanges of each of the bobbins. The secondary coil of the winding is wound, and the adjacent secondary coils are wound in opposite directions. The core, bobbin and coil are housed in an insulating resin case, and are insulated in the case. High pressure transformer characterized by being filled with resin. 2. The high-voltage transformer according to claim 1, wherein the primary coil is formed as a one-turn coil on a flange of the bobbin. 3. The secondary coil, wherein single-layer aligned winding coils are arranged in multiple layers, and winding start and winding end of each coil are respectively connected to the same terminal. 2. The high-voltage transformer according to 1. 4. The secondary coil has a multilayer structure of a single-layer aligned winding coil in which multiple parallel wires are wound perpendicularly to a winding axis, and winding start and winding end of each coil are respectively set. 2. The high-voltage transformer according to claim 1, wherein the high-voltage transformer is connected to the same terminal. 5. The high-voltage transformer according to claim 1, wherein the closed magnetic circuit type core has a non-linear DC superimposition characteristic. 6. The boost ratio is 10 to 200 and the output is 10K.
The high-voltage transformer according to claim 1, wherein the voltage is V or more. 7. The high-voltage transformer according to claim 1, wherein the high-voltage transformer is used for a discharge lamp lighting circuit. 8. The high-voltage transformer according to claim 1, wherein the high-voltage transformer is mounted in a metal halide lamp lighting circuit.