JPH06120051A - Noiseless transformer - Google Patents

Abstract

PURPOSE:To contrive an accurate interruption of noise by a method wherein shielding cases, which are respectively formed of a suitable metal plate in such a way that they are made to fit to the formation of each coil, are respectively adhered to the respective whole peripheral surfaces of the input coil and the output coil, which are individually formed. CONSTITUTION:An input coil 1 and an output coil 2 are formed into the form of a doughnut of a necessary diameter and shielding cases 3 are made to adhere to the respective whole inner and outer peripheral surfaces, in which a core 4 is not made to insert internally, of the coils 1 and 2 in such a way that insulating films 5 are respectively applied on the insides of the coils. The cases 3 are formed using an aluminium thin plate or the like into a daughnut form by a draw processing, a press processing or the like in such a way that they are made to fit to the whole inner and outer peripheral surfaces of each coil. In the core 4, one pair of left and right cut cores 41 and 41, whose front forms are a longitudinally long square-shaped form and whose outer peripheral surfaces are flat, with a semicircular section are butted to each other on each one side of them and coil fitting parts of these cores have a circular sectional form to fit to the coils 1 and 2. Thereby, noise is prevented from intruding, the generation of radiant noise is prevented and a miniaturization and a lightening of a noiseless transformer, the improvement of the workability of the transformer, a reduction in the cost of the transformer and the like are made possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a noise restaurant used as a power source for various semiconductor devices.

[0002]

2. Description of the Related Art Since various semiconductor devices and the like dislike noise coming in from power supply lines, external devices and the like as much as possible, noise transformers for cutting off noise are used in transformers used for power supplies. The mainstream of conventional noise restaurants is an outer iron type, for a single phase, and the whole is wrapped with an iron cover or the outside of the coil is covered with an iron cover. An example of the case where the outer side of the coil is covered with an iron cover is as shown in FIG. 7, for example, the input coil 11 and the output coil 12 are separately attached to the core 14, and these coils are attached from the left and right sides. A pair of iron covers 13 and 13 (usually made of die casting or casting) are covered, and shielding plates 15 and 15 are integrally provided on the inner middle portions of both iron covers, respectively, to connect the input coil 11 and the output coil 12. By interposing between them, each coil is individually magnetically and electrostatically shielded to electrically block noise that intrudes from the power supply line, external equipment, etc. Prevents the generation of radiation noise.
However, in such a configuration, the space factor of the iron covers 13 and 13 becomes high, the outer shape becomes very large, the iron amount increases, the weight increases, and the cost becomes high. There is. Also, because such an iron cover is required,
It is difficult to construct a noise restaurant for three phases, and therefore, in reality, three three-phase noise restaurants are used.

[0003]

If a metal foil tape is wound around the inner and outer peripheral surfaces of each coil to form an electrostatic shield, the same electrical performance can be expected and the iron cover can be eliminated. It is considered possible. But,
Generally, the input coil and the output coil of this type of transformer are rectangular, and in particular, at each corner, as shown in FIG. 9, the inner corner is one point B, while the outer corner is a circle of radius r. Since it is an arc A of 1/4 of that, its ratio is infinite,
When the metal foil tape 16 is wound around the coil, as shown in FIG. 8, in the above-mentioned B portion of the inner corner, it is overlaid and piled up, and since the insulating film 17 is applied to the inside,
The inner corner bulges out, making it difficult to fit into the core 14. Further, it is necessary to make the bobbin larger, and the outer shape becomes larger accordingly. On the contrary, in the above-mentioned A portion of the outer corner, the portion becomes rough, wrinkles are more generated, and a gap is generated, so that radiation noise is easily generated. In addition, the winding of the metal foil tape is not easy, and the workability is greatly deteriorated. Therefore, it is almost impossible to put it to practical use as it is, and it is in the present situation that it has not been implemented. Therefore, in the present invention, in a noise restaurant such as an outer iron type, by attaching a shield case formed by drawing, pressing or the like of a metal plate to the coil, an electrostatic shield is provided on the entire inner and outer peripheral surfaces of the coil. It is possible to properly and easily equip the equipment, and by using the electrostatic shield, it is possible to reduce the size and weight, improve the workability, and reduce the cost without compromising the performance. ,
Therefore, it is intended to make it easy to obtain a three-phase one.

[0004]

In order to achieve the above object, the present invention forms an input coil and an output coil separately, and adapts the shape of each coil to the entire peripheral surface of each coil by appropriately using a metal plate. It is characterized in that a shield case formed by the above is attached.

[0005]

With the above-mentioned structure, the shield case made of a metal plate attached to the input coil and the output coil enables proper and easy mounting of the electrostatic shield on the entire inner and outer peripheral surfaces of each coil, and , The shield case appropriately blocks the intrusion of noise from the power line, external equipment, etc.,
At the same time, it prevents the generation of radiant noise and thus eliminates the conventional iron cover.
It enables downsizing and weight reduction, workability improvement, cost reduction, etc., and enables the realization of noise restaurants for three phases.
Achieve the intended purpose.

[0006]

【Example】

Part 1. FIGS. 1 to 3 show an example of the embodiment, in which 1 is an input coil, 2 is two output coils, and 3 is an output coil.
Is a shield case made of a metal plate adhered to the entire inner and outer peripheral surfaces of these coils, and 4 is a core into which the input coil 1 and the output coil 2 are fitted. The input coil 1 and the output coil 2 are formed in a toroidal shape having a required diameter, and the insulating film 5 is applied to the inner and outer circumferential surfaces of the core, respectively, into which the core is not inserted, and the shield case 3 is attached. The lead wire may be inserted through a cutout described later in the shield case 3 or may be inserted through a through hole.
The shield case 3 is formed into a donut shape by using a thin aluminum plate or the like by drawing, pressing, or the like so as to fit the entire inner and outer peripheral surfaces of each coil. Provided with the plate 32 and fitted,
An extremely narrow notch that makes the ring endless to end 33,34
To prevent short circuit current from occurring. In addition,
The metal plate of the material is not limited to aluminum and may be any appropriate one.
The shield case 3 is not limited to the cover-shaped main body 31 and the lid-shaped closing plate 32, but a pair of shallow cover-shaped ones may be butted, or four or eight.
It may be formed from a combination of appropriate divided bodies such as two. It may be designed as appropriate in consideration of workability and cost. The core 4 is composed of a pair of left and right cut cores 41, 41, each having a vertically-elongated front shape and a semicircular cross-section with a flat outer peripheral surface, abutting each other on one side. The part has a circular cross-sectional shape suitable for the coils 1 and 2.

2. FIG. 4 and FIG. 5 relate to a modification of the previous example. In the configuration of the previous example, the cut cores 41, 41 are formed by combining a plurality of plate-shaped cut core pieces 411, 411, 411 having different widths. There is. In the figure, 6 is an exterior material, 7 is a band, and 8 is a leg.

Part 3. FIG. 6 shows an embodiment of a three-phase noise restaurant. In this case, as in the previous example, the doughnut-shaped input coil 1 and output coil 2 to which the shield case 3 is attached are applied to the respective phases, one for each phase, and three for convenience, respectively, and fitted to the cores 4, respectively. , As in the previous example,
It is formed from three inner and outer cut cores 41, 41, 41 which are a combination of a plurality of plate-shaped cut core pieces 411, 411, 411 having different widths. Also in this case, 6 is an exterior material, 7 is a band, and 8 is
It is a leg.

In the above embodiment, the input coil 1 and the output coil 2 are formed in a donut shape, and the shield case 3 is adapted to the donut shape.
Can also be formed in a rectangular shape, and therefore, the input coil 1 and the output coil 2 may be formed in a rectangular shape and fitted to the core having a rectangular cross section.

[0010]

According to the present invention, the shield case formed by adapting the shape of each coil by a suitable metal plate is attached to the entire peripheral surfaces of the input coil and the output coil which are individually formed. Therefore, the electrostatic shield of the shield case allows the input coil 1 to be connected to the power line, external equipment, etc.
It is possible to properly block the noise that enters the output coil 2, and of course, to prevent the generation of radiation noise from itself, and the noise removal performance is not inferior.
It is possible to improve the common-mode noise elimination performance in the most practical frequency band, that is, in the region of 10 MHz or less, and it is possible to eliminate the conventional iron cover. Therefore, it is possible to reduce the external shape, weight and cost to about half or less of the conventional one, and it is possible to achieve a significant reduction in size and weight, which can not be expected from the conventional product, and cost reduction. Therefore, it can be made inexpensive. As a result, the magnetizing current and iron loss can be reduced by the remarkable reduction in size and weight, and the performance can be further improved. Further, a noise restaurant for three phases, which could not be achieved conventionally, can be easily manufactured in the same manner. Furthermore, the shield case can be manufactured very easily and inexpensively by appropriately drawing or pressing a metal plate, and furthermore, it can be easily fitted to the coil, resulting in extremely good workability. You can

[Brief description of drawings]

FIG. 1 is a cutaway front view showing an embodiment of a single-phase noise restaurant of the present invention.

FIG. 2 is a cutaway plan view of the same example.

FIG. 3 is an exploded perspective view showing a shield case of the same example.

FIG. 4 is a perspective view showing another embodiment of the single-phase noise restaurant of the present invention.

FIG. 5 is a cutaway plan view of a main part of the example.

FIG. 6 is a perspective view showing an embodiment of a three-phase noise restaurant of the present invention.

FIG. 7 is a cutaway front view showing an example of a conventional noise restaurant.

FIG. 8 is a cutaway plan view showing an example of preceding thinking.

FIG. 9 is an explanatory diagram of a main part of the same example.

[Explanation of symbols]

 1 Input coil 2 Output coil 3 Shield case 4 Core 5 Insulating film 6 Exterior material 7 Band 8 Leg 31 Cover-like body 32 Lid-like closing plate 33,34 Very narrow notch 41 Cut core 411 Plate cut core piece

Claims (1)

[Claims] 1. An input coil and an output coil are individually formed, and a shield case formed by appropriately matching the shape of each coil with a metal plate is attached to the entire circumferential surface of each coil. Noise restaurants.