JPH02308608A - Noise filter - Google Patents

Abstract

PURPOSE:To obtain a noise filter with ease of mount by providing an electrode terminal onto an insulating resin made base, incorporating a magnetic member in the base and penetrating the electrode terminals on both sides of the base through the magnetic member and connecting them together. CONSTITUTION:A noise filter 1 is supported by an insulating resin made base 2 and consists of electrode terminals 3 whose ends connect to connection terminals of power wires or the like and of a ferrite group magnetic member 4 with a desired frequency attenuation characteristic incorporated in the base 2 and to which the terminal 3 is penetrated. The base 2 is formed to a shape and a size coincident with each end face of the input and output side of a single phase line filter 10 and bosses 2a, 2b are provided to the support of the terminal 3. The terminal 3 is formed to be a screw with a prescribed length and penetrates through the base 2 and the core 4. Through the constitution above, the magnetic member 4 is penetrated through the power line and acts like a simple common coil and since number of the turn is one, the noise attenuation characteristic corresponding to the high frequency band is shown especially. Since the magnetic member is incorporated in the base, the filter is easily mounted anywhere of idle space of the device.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a noise filter that is installed in the middle of a circuit such as a power supply line and removes unnecessary noise such as conduction noise superimposed on the line.

(Prior Art) In general, in various electronic devices, an active or passive line filter is installed in the power supply line to remove unnecessary noise such as conduction noise and radiation noise. This has led to the World Noise Standard (
For example, the FCC, etc.) were aiming to achieve the specified values set as targets.

In addition, if the noise cannot be reduced to the desired specified level even with various line filters, a capacitor may be inserted between the power line and the frame ground or earth to form a so-called Y-conductor, or a common coil may be installed on the power line. By inserting them in series or by inserting a coated core through them, noise resistance has been improved and desired specified values have been achieved.

(Problem to be solved by the invention) However, when a Y-conductor is configured, current leakage occurs in the capacitor, and especially in the high frequency range, the leakage is large and the leakage current is large. Therefore, there is a problem in that it cannot be applied to electronic devices where leakage current values are strictly regulated in addition to noise.

Moreover, the leakage current also leaks noise and circulates to other parts, so the noise removal performance deteriorates as the leakage current increases, making it impossible to sufficiently remove noise in the high frequency range. .

In addition, capacitors, common coils, and coating cores are all mounted on circuit boards or in empty spaces within equipment, but each has shape constraints, so it is not possible to flexibly choose the mounting location and fixing method. However, there was also the problem that it was not easy to install.

On the other hand, some line filters are equipped with feed-through capacitors on their input and output terminals for noise removal, but since these also use capacitors, there are strict limits on the leakage current value. This method cannot be applied to certain electronic devices, and it has not been possible to sufficiently remove noise in a high frequency band.

This invention was made in view of the above-mentioned background, and its purpose is to have high noise removal performance in high frequency bands, no leakage current, and free space on circuit boards or equipment. To provide a noise filter that can be easily mounted anywhere.

(Means for Solving the Problems) In order to achieve the above object, the noise filter according to the present invention is a noise filter that is inserted in series in the middle of a circuit such as a power supply line, and is made of an insulating resin. A base, an electrode terminal supported by the base and connected to the circuit at each end, and a magnetic member having a desired frequency attenuation characteristic housed in the base, and arranged at both ends. The electrode terminals were connected to each other by penetrating the magnetic material.

(Function) With the above configuration, the magnetic member penetrated by the electrode terminal is connected to each connection end of the power line, etc., so that the magnetic member penetrates the power line. Become. As a result, the magnetic member acts as a simple common coil for the power supply line, and since the number of turns is one, it exhibits noise attenuation (removal) characteristics that are particularly suitable for high frequency bands. becomes.

In addition, since the magnetic member is internally housed in the base, there is no need to consider its fixation, and it can be easily attached to a circuit board or any empty space within the device.

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

FIG. 1 is a partially cutaway perspective view of a preferred embodiment of a noise filter according to the present invention. Also, Figure 2 shows
FIG. 2 is a cross-sectional view of the noise filter shown in FIG. 1 taken along arrows -■.

This noise filter 1 is arranged on the input side and output side of an active or passive type line filter 10, and when the line filter 10 is installed in series in the middle of a power supply line, etc. function as.

In other words, this noise filter 1 includes a base 2 made of insulating resin, an electrode terminal 3 supported by the base 2, and connected to each cut end of a power line or the like at each end of the base 2.
A magnetic member 4 made of ferrite or the like having a desired frequency attenuation characteristic is installed inside the magnetic member 4 and has an electrode terminal 3 passing through it.

The base 2 is shaped to have a shape and size that approximately matches the input and output end faces of the single-phase line filter 10 on which it is installed, and the portion supporting the electrode terminal 3 protrudes. The boss portions 2a and 2b are formed by molding.

The electrode terminals 3 are made of screws or the like having a predetermined length, and a desired number of the input and output lines of the line filter 10 (two since it is single phase) are buried and supported in a predetermined position of the base 2. Note that this electrode terminal 3 is buried through the base 2, and the cut ends of the power line etc. are connected to each of its ends protruding from the boss portions 2a and 2b of the base 2. In the case of the embodiment, since it is used as a terminal board for the input and output of the line filter 10, the boss portion 2b side is connected to the input or output of the line filter 10, and the boss portion 2a side is connected to the cut end of the power line, etc. .

The magnetic member 4 has a desired number of through holes 4a through which the electrode terminals 3 pass, and is formed at predetermined locations, and is adjusted to a desired frequency attenuation characteristic by appropriately changing the outer dimensions and material of the through holes 4a.

FIG. 3 is a circuit diagram showing application of the above-described noise filter.

That is, the noise filter 1 is arranged on the input side and the output side of the line filter 10, and as described above, the noise filter 1 is arranged on the input side and the output side of the line filter 10, and as described above,
The boss portion 2b side is connected to the input and output of the line filter 10. Thereby, the noise filter 1 is input to the line filter 10.

If the boss portions 2a sides of the electrode terminals 3 of both outputs are connected to each cut end of a power line, etc., and the line filter 10 is inserted into the power line, etc., the magnetic member 4 will be inserted through the line. As a result, the magnetic member 4 acts as a simple common coil. At this time,
Since the magnetic member 4 is only penetrated by the electrode terminal 3, the number of turns as a common coil is one turn.
In particular, it shows noise attenuation characteristics corresponding to high frequency bands.

Now, FIG. 4 is a circuit diagram showing application of the present invention to a three-phase circuit. Moreover, FIG. 5 is a sectional view showing another embodiment.

The noise filter 1a shown in FIG. 4 is applied to a three-phase circuit, so the number of electrode terminals 3 is increased from two to four in correspondence with the three-phase line filter 2o. Since it is the same as that, the same reference numerals are given and the explanation thereof will be omitted.

Further, the noise filter 1b shown in FIG.
0 and can be used as a terminal block.
The shape of each part has been changed as appropriate, and the bottom surface of the base 2 is flattened, and a collar 2c is formed on the top surface to serve as a partition between each electrode section, and the electrode terminal 3 is placed inside the base 2 on the bottom side. A constituting nut 3a is built in, and an electrode pin 3b protruding from the bottom surface of the base 2 is fixed to the nut 3a.

Moreover, FIG. 6 is a graph showing the frequency attenuation characteristics of the noise filter of FIG. 5. In the same figure, characteristic 4b shows the characteristic when Mn-Zn-based ferrite material is used as the magnetic member 4, and the frequency is -2,4b in the vicinity of 2MHz.
The maximum attenuation of about dB can be obtained, and the characteristic 4h is the magnetic member 4.
This shows the characteristics when using N1-Zn-based ferrite material, and the maximum attenuation of about dB near the frequency of 30 MHz to 0 MHz can be obtained.

7 and 8 are graphs showing the frequency attenuation characteristics of the noise filters shown in FIGS. 1 to 3.

The characteristic 1h (Fig. 7) is a circuit state in which the noise filter 1 is used together with the line filter 10 as shown in Fig. 3.
This is the characteristic when an N 1-Zn ferrite material is used as the magnetic member 4, similar to the characteristic 4h, and the characteristic 1 ((Fig. 8) is similar to the characteristic 4β when the magnetic member 4 is M n
-Z Characteristics when using n-based ferrite material.

Further, the characteristic 10f is a characteristic obtained by removing the noise filter 1 and using only the line filter 10. That is, property 1
Compared to 0f, the attenuation characteristics are significantly improved in the frequency band of approximately IMHz or higher in the characteristic 1 (with the characteristic 1h) and in the frequency band of approximately 4 MHz or higher with the characteristic 1h, and a remarkable effect can be seen.

Note that the Ni-Zn-based ferrite material may be changed to an iron-based amorphous alloy material, and the Mn-Zn-based ferrite material may be changed to a cobalt-based amorphous alloy material.

Further, a base 2 constituting the noise filter 1 according to the present invention
．． Electrode terminal 3. The shape of the magnetic member 4 and the like can be changed as appropriate, and is not limited to the embodiments described above.

(Effects of the Invention) According to the noise filter according to the present invention described in detail above, the following effects can be achieved.

Since the magnetic member penetrated by the electrode terminal is inserted into the power supply line, etc., the magnetic member acts as a simple common coil, and since the number of turns is 1, it is especially suitable for high frequencies. It shows noise removal characteristics corresponding to the band.

Furthermore, since the magnetic member is internally housed in the base, there is no need to consider its fixation, and it can be easily mounted anywhere on the circuit board or in the empty space within the device.

Furthermore, since no capacitors are used, of course,
There is no leakage current.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view of the present invention, Fig. 2 is a cross-sectional view taken along the -■ arrow in Fig. 1, Fig. 3 is a circuit diagram showing an application of the present invention, and Fig. 4 is a three-dimensional diagram. Circuit diagram showing application to phase circuit, No. 5
The figure is a sectional view of another embodiment, and FIGS. 6 to 8 are graphs showing frequency attenuation characteristics of the noise filter. 1, la, lb...Noise filter 2...Base 3...Electrode terminal 4...
Magnetic member patent applicant Fuji Electrochemical Co., Ltd. Representative
People Patent Attorney - Iro Ken Rinma
Patent Attorney Masatoshi Matsumoto Figure 1 Figure N3

Claims (1)

[Claims] A noise filter is installed in series in the middle of a circuit such as a power supply line, and includes a base made of insulating resin, and electrode terminals supported by the base and connected to the circuit at both ends. A noise filter comprising: a magnetic member having a desired frequency attenuation characteristic housed in the base; and electrode terminals disposed at both ends of the base are connected to each other by penetrating the magnetic material.