JPS60213015A - Noise intercepting transformer and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain a superiorly noise intercepting transformer generating no deterioration of a noise intercepting function by a method wherein the coil of the transformer is magnetically shielded completely. CONSTITUTION:Permeability of a ring-shape magnetic core 1 is favorable at a low-frequency current, and permeability at a high-frequency current is low. Permeability of a shield member 2 is high at a high-frequency current, and permeability at a low-frequency current is low. The shield member 2 is equipped as to fill up a gap part between ring-shape coils 3, 4 and the magnetic core 1, and moreover as to cover the whole of the outer peripheral surfaces of the coils 3, 4. A low-frequency component to be necessitated by an electric power source, etc. and a high-frequency component to be caused by high-frequency noise of various kinds are mixedly existing in a magnetic field generated according to a current flowed in the coils 3, 4. Energy of the low-frequency component is carried as electric energy again. The magnetic field of the high-frequency component is generated making the shield member 2 as a magnetic path, leaking into the magnetic core 1 is not generated, and a closed path having small magnetic resistance is constructed. Accordingly, propagation of noise between both the coils is not generated, and noise is intercepted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention intrudes into electronic equipment, etc., causes the equipment to operate w1,
In the worst case, the equipment may be destroyed. <This invention relates to a noise isolation transformer that isolates noise and a method for manufacturing the same.

[Prior Art] Conventionally, noise generated by various causes spans a wide frequency band and has various energies, so it is almost impossible to uniformly remove all noise.

Moreover, with the progress of semiconductor technology, the processing speed of electronic devices has become faster and the signals handled have become smaller, so measures against noise have become particularly important in recent years.

These noises can be roughly divided into radiated noise, which is emitted from the noise source into space and directly hits the electronic equipment, and radiated noise, which propagates from the noise source to the primary power supply and then propagates through the conductive paths of the electronic equipment. It becomes noise.

Among these, the most common method for dealing with radiation noise is to electrostatically and magnetically shield the entire electronic device individually, and countermeasures are taken depending on the usage status of the electronic device. However, electronic equipment must always supply power to the noise propagating through the conductor, so it is necessary to select only the necessary components from the electrical energy propagating through the conductor, and remove unnecessary noise. Blocking the noise component is complicated because the noise has a wide range of energy distribution in a wide frequency band as described above.

As a device for removing and covering the noise propagating through the conductive line, an effective method is to use a magnetic path-based shielding system for interference waves, which is disclosed in Japanese Patent Publication No. 56-35290.

However, the above device has a structure in which the same surfaces of the primary and secondary coils of the transformer are wrapped in different magnetic materials, resulting in a complex structure and problems such as a large number of manufacturing steps and high manufacturing costs. It had a

[Object of the Invention] An object of the present invention is to provide an excellent noise isolation transformer that does not have the above-mentioned drawbacks and whose noise isolation performance does not deteriorate, and a method for manufacturing the same.

[Structure of the Invention] In order to achieve the above object, the structure of 1f'F, bright, includes one shield member with high high frequency magnetic permeability, two annular = 1-ils installed inside the shield member, and the following. At least one of the two annular coils is placed between the two coils with the shield member interposed therebetween. The gist of the present invention is 18 noise-blocking lances, characterized by having a ring-shaped magnetic core having a lower high-frequency magnetic permeability and a higher low-frequency magnetic permeability than the shielding member, and the structure of the second invention. is formed by at least one of two annular coils fitted into an annular magnetic core having an air gap between the two annular coils and the magnetic core! - The lance is added to the curable fluid composition having low low frequency magnetic permeability and high high frequency magnetic permeability after curing at least the magnetic core J.
The gist of the present invention is a method for manufacturing a noise-blocking transformer, characterized in that two annular coils are buried so as to be connected through the curable fluid composition, and then the curable fluid composition is cured.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Embodiment] FIG. 1 is an overall perspective view of an embodiment of a noise isolation transformer according to the first invention.

In the figure, 1 is an annular magnetic core, which has good magnetic permeability at low frequencies and low magnetic permeability at 8 frequencies. Here, low frequency means at least 50Hz, which is the commercial power frequency.
A frequency band of tens to hundreds of Ml-IZ including ~60H2 is defined, and high frequency refers to a frequency band of several hundred KHz to several hundred kHz, which has a significant effect on equipment signals. Therefore, the structure of the magnetic core 1 is one in which thin silicon steel plates are laminated, which is often used as a magnetic core of a normal power transformer.

2 is a shield member that has high high frequency magnetic permeability and low low frequency magnetic permeability, contrary to the magnetic core 1. For example, it is constructed using a magnetic powdered iron plate or a thin sheet of fired metal oxide magnetic material, and as shown in the figure, it is constructed so as to completely enclose two annular coils 3.4 fitted into the magnetic core 1. Lead wires 3a and 4a are attached to the outside and constitute an annular coil 3.4.
stands out.

Figures 2 (A) and (0) show the magnetic cores 1 and 2 when only the shielding member 2 is removed from the noise isolation transformer of this embodiment.
The relationship between the two toroidal coils 3.4 is shown. (stomach)
The figure is its front view, and the (opening) figure is its plan view. As is clear from the figure, the inner hollow portion of the annular coil 3.4 has a similar cross-sectional shape to the fitted portion of the magnetic core 1, and is larger.

Therefore, there is a gap 6 between the annular coil 3.4 and the magnetic core 1.
exists. The shield member 2 is installed so as to fill the void 6 and cover the outer circumference of the coil 3.4. Therefore, as shown in the end view of the noise isolation transformer cut along the magnetic core 1 in FIG. be.

The noise blocking transformer of this embodiment having the above configuration has the following effects.

The magnetic field generated by the current flowing into the annular coil 3.4 includes a mixture of low frequency components required by a power source and the like and high frequency components caused by various high frequency noises. Of these, the magnetic field of low frequency components interlinks with both coils 3.4 through the magnetic core 1, most of which has high low frequency permeability, as a magnetic path. That is, only the energy of the low frequency component is once converted into magnetic energy, propagated to the other coil, and transformed into electric energy again to be transported.

On the other hand, the magnetic field of high frequency components generated by noise is generated using the shield member 2 with high high frequency magnetic permeability as a magnetic path,
There is almost no leakage into the magnetic core 1. The magnetic field generated in the shield member 2 in this manner creates a loop with low magnetic resistance, forming a closed circuit. Here, since the shield member 2 is made of a material with a uniform high frequency magnetic permeability, the magnetic resistance is naturally directly proportional to the length of the magnetic path, so the shield member 2 is passed through the shield member 2 very close to the coil that generates the magnetomotive force. Therefore, even if the coils 3.4 are shielded by the integrated shield member 2, high-frequency magnetic flux will not interlink between the two coils. Therefore, even if the shield member 2 is attached as in this embodiment, no noise is propagated between both coils, and the purpose of noise isolation can be achieved.

Furthermore, by integrally forming the shield part vJ2, there is an effect of suppressing noise caused by magnetostriction of the transformer, so that noise countermeasures are not required. In addition, if the power transmitted between the two coils becomes large, heat generation will occur, but since the volume of the shield member 2 becomes large and the heat capacity increases, it is possible to suppress the increase in humidity in the coils, and it is also possible to Because it is formed, mechanical strength against vibrations, shocks, etc. is improved.

Next, a method for manufacturing a noise isolation transformer according to the second invention will be explained based on FIG. The figure represents the principle of the manufacturing method. In the figure, 21 is the magnetic core, 23.24
1 and 2 respectively represent annular coils, which are made of the same material and have the same shape as the magnetic core 1 and coil 3.4 described in the previous embodiment. The dotted line in the figure represents a mold 25, which has an injection port 26 for injecting a fluid and an air vent hole 27, and has a hollow rectangular parallelepiped shape that can be separated into two parts. The size of the mold 25 is such that it can at least envelop both coils 23, 24 as one body.

Further, a spacer is inserted between the coils 23, 24 and the mold 25 and has the same magnetic permeability as the fluid composition after hardening.

This mold 25 is attached to the lance, which has a low frequency magnetic permeability lower than that of the magnetic core 21 at least after hardening.
A curable fluid composition exhibiting high high-frequency magnetic permeability is injected and filled through the injection port 26. As the curable fluid composition, a two-component heat-curable or heat-curable synthetic resin such as epoxy, urethane, or acrylic is mixed with a predetermined amount of fly light powder having high high frequency magnetic permeability. It will be done.

Further, in the case of the above-mentioned contamination, the contaminant and the amount of contamination can be appropriately determined depending on the frequency band of the desired noise to be blocked.

In order to inject a composition with good fluidity into the mold 25 as described above, the air gap between the magnetic core 21 and both coils 23.24, the surrounding area of both coils 23.24, and both coils 23.2 are
All spaces between 4 will be filled with the composition.

Next, the filled composition was cured and adhered to the magnetic core 21 and the two coils 23 and 24, and when they were integrated, the noise mK of the above-mentioned example was fixed (same characteristics,
It is possible to manufacture a transformer with high performance. The curing method may be carried out by an optimal method depending on the characteristics of the curable fluid composition, and techniques such as heat treatment or mixing with a curing agent may be used. If the material is made of a material with high magnetic flux, the step of removing the mold 25 after the fluid composition is cured becomes unnecessary, and the noise-blocking transformer can be manufactured by a simpler method.

Here, curing refers to making the hardness appropriate depending on the characteristics of the curable substance, and for example, a urethane-based composition may be used to cure the material while maintaining a certain degree of elasticity f1.

By manufacturing a noise-blocking transformer using the method described above, it becomes possible to easily and inexpensively manufacture a transformer that exhibits the excellent effects described in detail in the above-described embodiments with a small number of steps. Further, since magnetic shielding is performed using a fluid composition, complete shielding can be achieved even if the gap between the magnetic core 21 and the two coils 23 and 24 is only small.

Therefore, the coils 23 and 24 can be made into windings with a small diameter, and not only can the wires be used effectively, but also the magnetic coupling with the magnetic core 21 is strong, and the efficiency of the transformer can also be improved.

The two inventions have been described above with reference to examples, but the invention is not limited to the above structure. For example, at least one of the gaps between the magnetic core and the coil is filled with a shielding member. It is sufficient to form the coil for the coil. That is, if the noise intrusion route is unidirectional, it is only necessary to completely magnetically shield one of the coils connected to the ingress port. Therefore, to connect to an electronic device that does not have a noise source such as a switching transistor, connect one completely magnetically shielded coil to the power supply side and the other coil to the electronic device side.J:
stomach.

[Effect of the invention J As detailed above, the noise according to the present invention! l The transformer used and its manufacturing method have a structure in which at least one of the two coils of the transformer is completely magnetically shielded, and the shielding member integrally wraps the primary and secondary sides of the transformer, and its manufacturing method. .

Therefore, not only does it have all the 1:J effects of conventional noise isolation transformers, but it is also possible to suppress the noise caused by the magnetostriction of the transformer to a low level with the shielding member, and also to reduce the temperature rise of the transformer due to heat generation etc. It has excellent effects such as improving the presser foot and mechanical strength.

Furthermore, if the shield member is manufactured from a curable fluid composition, the transformer for blocking hemorrhoids, which exhibits the above-mentioned excellent effects, can be rotated at low cost with fewer steps.

In addition, since magnetically shielded compositions can have various properties depending on the substances mixed therein and their amounts, various products can be manufactured depending on the manner of use. Moreover, since the hardness of the composition after curing can be controlled, it is possible to make many variations of the product, such as making it elastic, especially for those used in places where there is a lot of mechanical impact.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a noise isolation transformer that is an embodiment of the first invention, Figure 2 (A) is its front view, Figure (B) is a plan view, and Figure 3 is a cut along the magnetic core. FIG. 4 is an end view showing the principle of the second invention. 1.21...Magnetic core 2...Shield member 3.4.23.24...Coil 25...Molding mold Fig. 2 Fig. 3

Claims (1)

[Claims] 1. One shield member with high 14-frequency magnetic permeability, two annular coils installed inside the shield member, and at least one of the two annular coils with the shield member in between, and both fills fitted. 1. A noise-blocking transformer comprising: a ring-shaped magnetic core having lower high-frequency magnetic permeability and higher low-frequency magnetic permeability than the shielding member. 2. A transformer in which at least 1 h of two annular coils fitted in an annular magnetic core has an air gap between them and the magnetic core is hardened at least more quickly than the magnetic core and has a low frequency magnetic permeability. In the curable fluid composition having low and high high frequency magnetic permeability, the above-mentioned 2
implanting two annular coils connected through the curable flow composition, and then curing the curable flow composition.