JPH07230923A - High-voltage transformer - Google Patents

Abstract

PURPOSE:To provide a high-voltage transformer of small size, by enlarging a barrier-layer length on a surface of an insulator without enlarging an insulation distance between a high-voltage winding and a core. CONSTITUTION:A transformer is made up of a wire 21, an interlayer insulator 25, and an outer-layer insulator 23 around a bobbin 22. flanges 31a, 31b, 32a, and 32b formed in a body with a bobbin 22 are put at an edge part of a high- voltage winding 10 of the transformer. Then, covers 41a, 41b, 42a, and 42b are inserted and fitted to the flanges to form insulation end parts 24a and 24b.

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 for an X-ray power supply device, etc., and relates to a structure for downsizing and improving reliability.

[0002]

2. Description of the Related Art In high voltage transformers, insulation of high voltage windings is an important issue. Generally, for example, Japanese Patent Laid-Open No. 4-2
As disclosed in Japanese Patent No. 62509, a method is used in which a wire is wound around a bobbin of a solid insulating material such as insulating paper and immersed in insulating oil to ensure a predetermined insulating performance. Further, as shown in, for example, Japanese Patent Laid-Open No. 3-250714, a structure in which a winding or a transformer is impregnated and filled with an insulating resin is also widely used.

[0003]

The X-ray power supply device requires a constant high voltage to output X-rays, which does not depend much on the magnitude of the output. Therefore, even for an X-ray power source having a relatively small capacity, a high insulation winding is required for the high voltage winding of the step-up transformer, and the smaller the capacity, the larger the ratio of the space required for insulation in the entire transformer.
For this reason, the constraint of reducing the insulation distance is a major impediment to the miniaturization of transformers.

In a conventional structure in which an electric wire is wound around a bobbin of a solid insulator and insulated with insulating paper, or a transformer using the same is immersed in insulating oil or kept in an insulating gas, Although the bobbin and insulating paper itself have a high dielectric strength, charged particles can move relatively freely in the insulating fluid.
A large insulation distance is required to prevent the breakdown along the surface of the solid insulator.

On the other hand, in the method of insulating a transformer or winding by impregnating it with a resin, the heat radiation depends on the heat conduction of the resin, so that the heat radiation efficiency is lower than that of the method using an insulating fluid, resulting in overheating. As a result of reducing the current density in order to prevent overheating, there is a drawback in that the transformer becomes large.

As a countermeasure against this, the above-mentioned Japanese Patent Laid-Open No. 3-25071
In the example of Publication No. 4, a method of winding a cooling duct around the winding is proposed, but there is a drawback that the structure becomes complicated.

It is an object of the present invention to reduce the insulation distance of the high voltage winding of a high voltage transformer and to downsize the transformer.

[0008]

According to the present invention, a plurality of collars are integrally formed with the bobbin at the end of an insulating resin bobbin of a high voltage winding of a high voltage transformer, and the space between the collars and the heights of the collar and the collar are increased. It is characterized in that a thin ring-shaped insulating eave is fitted between the coil windings.

[0009]

With the configuration of the present invention, the collar formed at the end of the insulating resin bobbin of the high voltage winding extends the axial creeping distance on the surface of the bobbin. The insulating eave fitted and arranged in the collar functions as a barrier for forming a short-circuit path that jumps over the gap between the collars. As a result, even if the linear distance between the high potential portion and the ground potential portion is small, the creepage distance is large.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of a high voltage transformer for an X-ray power supply device according to the present invention. The transformer 1 has the iron core 2 and the windings 3a and 3b as main constituent elements, and is wholly housed together with an insulating fluid (not shown) such as mineral oil or SF ₆ gas that also serves as insulation and cooling. In the configuration example of the winding 3a, as shown in the drawing, the low voltage electric wire 11 is wound around the bobbin 21, and the high voltage winding 10 is wound around the bobbin 22 with a predetermined insulating layer 20 therebetween.
End insulators 24a and 24b are provided at both ends of the high-voltage winding 10.
However, the outer layer insulator 23 is provided on the outer periphery.

FIG. 2 shows details of an example of the high voltage winding and its insulating structure. The bobbin 22 has a high-voltage wire 12 and an interlayer insulator 25.
Are wound alternately. An enamel-coated electric wire is often used as the high-voltage electric wire 12. In addition, a cellulosic insulating paper, a polymer film, or the like is used for the interlayer insulator 25, and often has a multilayer structure in which a plurality of thin strips are wound, rather than a single layer.
According to the present invention, a plurality of bobbins 22 are provided at one end of the bobbin 22,
As an example, two collars 31a and 31b are provided, and a collar 3 is further provided.
An insulating hood 41 formed in a thin ring shape between 1a and 31b.
Also, a similar insulating visor 41b is fitted and arranged between the flange 31a and the high voltage winding 10 to form the end insulator 24a. Collars 32a and 32b are similarly formed on the other end of the bobbin 22, and insulating eaves 42a and 42b are arranged to form an end insulator 24b. This insulation eaves 41
The a, 41b, 42a and 42b may be formed by cutting a press board into a predetermined shape, for example. In addition, it is not possible to fit the collar with an endless ring, so you may cut out a part or combine parts with a circular shape, but cut out multiple thin bodies to ensure insulation performance. The parts and joints are offset and overlapped.

The effect of this embodiment will be described with reference to FIG. The relationship between the high voltage winding 10 and the iron core 2 which is the ground potential is shown.
The high voltage electric wire 12 'wound on the outermost layer of the winding has the highest potential,
In the transformer for X-ray power supply, the voltage is several tens k to one hundred and several tens kV. The layer insulation distance between the winding and the iron core becomes the length of the discharge path 4, which is significantly longer than the linear distance between the high voltage electric wire 12 ′ and the iron core 1. Iron core 2 and high voltage electric wire 12 'in the conventional structure
According to the present embodiment, the collars 31a and 31b are attached to the bobbins 22 as compared with the method of ensuring the same level of insulation distance as the path 4 between the two.
Is provided and the insulating eaves 41a and 41b are fitted together, which has the effect of significantly reducing the size of the transformer.

The bobbin 22 of this embodiment is generally machined out of a laminated resin cylinder or the like by leaving a collar, but a large quantity and low cost can be obtained by injection molding a polymer resin material having high dielectric strength. Can be manufactured.

FIG. 4 shows another embodiment of the present invention. This is an example of a configuration in which two high voltage windings 10a and 10b arranged on one leg of an iron core are connected in series to obtain a predetermined voltage. When the voltage of the high voltage winding is E (V), the low potential side winding 10a
Of the lowest potential portion 10ax is 0, the highest potential portion 10ay
Potential is 0.5E, the lowest potential part 1 of the high potential side winding 10b
The potential of 0bx is 0.5E, the potential of the highest potential portion 10by is E, and the difference in the creeping potential at each winding end portion is different, so the required creeping insulation distance is also different. Therefore, in the embodiment of FIG. 4, the collars 31a, 31b formed on the ends of the bobbins 22a, 22b,
32a, 32b, 33a, 33b, 33c and insulating eaves 41a, 41b, 42a, 42b, 43 fitted to these
a, 43b, and 43c are formed and arranged according to the required creepage insulation distance in each part. According to this embodiment, a redundant insulating structure can be avoided, the transformer can be downsized, the amount of input material can be reduced, and an economic effect can be obtained.

Two high voltage windings 10 of the embodiment shown in FIG.
The a and 10b and the outer layer insulations 23a and 23b can be collectively formed on one bobbin 22 as shown in FIG. In this case, the bobbin 22 has a low pressure collar 31a, 31b,
Three flanges of the intermediate flange 32 and the high pressure flanges 33a, 33b, 33c are to be provided according to the insulation performance required for the respective parts.
1b, 42a, 42b in the middle part, 43a, 43 in the high pressure part
b, 43c, and the required number is provided. According to the present embodiment, one bobbin has a structure having the insulation performance required for each winding portion, so that the number of parts can be reduced and the man-hour required for assembling the transformer can be reduced.

[0016]

As described above, the present invention employs the end insulation structure in which the brim is formed at the end of the high-voltage winding bobbin and the eaves are fitted to the brim. Since the creeping distance on the surface of the insulator can be extended and the creeping withstand voltage can be improved without increasing the insulating distance between the high potential portion and the ground potential portion such as the iron core, the high voltage transformer can be miniaturized.

[Brief description of drawings]

FIG. 1 is a perspective view showing a partial cross-section of a high-voltage transformer having a high-voltage winding in which a collar is provided at an end of a bobbin and an insulating eave is combined, as an embodiment of the present invention.

FIG. 2 is a cross-sectional perspective view showing an internal structure of a high voltage winding and an end insulating structure as one embodiment of the present invention.

FIG. 3 is a cross-sectional view of a high voltage winding end structure for explaining the effect of the present invention.

FIG. 4 is a cross-sectional view showing an insulating structure of two high voltage windings arranged side by side in the axial direction of one leg of an iron core as another embodiment of the present invention.

FIG. 5 is a sectional view showing an insulating structure of two high voltage windings arranged side by side in the axial direction of one winding bobbin as still another embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transformer, 2 ... Iron core, 3a, 3b ... Winding, 4 ... Discharge path 10, 10a, 10b, 10ax, 10ay, 10
bx, 10by ... high-voltage winding, 11 ... low-voltage wire, 12, 1
2 '... high-voltage electric wire, 20 ... insulating layer 21, 22, 22a,
22b ... Bobbin, 23 ... Outer layer insulator, 24a, 24b ...
Edge insulator, 25 ... Interlayer insulator, 31a, 31b, 32
a, 32b, 32, 33a, 33b, 33c ... Tsuba, 41
a, 41b, 42, 42a, 42b, 43a, 43b, 4
3c ... insulating eaves.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keinobu Hatakeyama 1-1-14 Kanda, Chiyoda-ku, Tokyo Inside Hitachi Medical Co., Ltd.

Claims (6)

[Claims] Claims: 1. A winding bobbin around which an electric wire is wound, is provided with a flange integrally formed with the bobbin, and a winding body formed by fitting an eave of an insulator to the flange is used. High voltage transformer characterized by being 2. A high potential portion of the winding and a low potential or ground potential portion of the winding and other transformer components by a collar integrally formed with the winding bobbin and an insulating eave fitted and arranged with the collar. A high-voltage transformer characterized in that a creeping insulation distance along the surface of the insulator between and is longer than a penetration insulation distance penetrating the inside of the insulator. 3. A collar formed integrally with a winding bobbin at an end,
Having an end insulation structure consisting of an insulating eave fitted with this,
A high-voltage transformer characterized in that a plurality of windings having different insulation performance of their end insulation structures are arranged side by side in the axial direction and incorporated in the same iron core leg. 4. A winding formed by winding an electric wire between a collar and a collar of a winding bobbin having a collar integrally formed at both ends and in the middle, and using an insulating eave fitted and arranged on the collar. Characteristic high voltage transformer. 5. A brim integrally formed at an end of a winding bobbin, and a plurality of insulating thin bodies formed in a partially cut hollow disk shape or a partially hollow disk shape, and a joint part made of a disk. A high-voltage transformer characterized by using windings having an end insulating structure that is distributed in the circumferential direction and assembled in an eaves shape. 6. A high-voltage transformer characterized in that a winding bobbin integrally formed with the collar of the high-voltage transformer according to any one of claims 1 to 5 is made of a polymer resin.