JP6400522B2 - Electric filter - Google Patents

Description

  The present invention relates to an electrical filter.

  In an electromagnetic shield room that cuts off the electromagnetic environment between the room and the outside, measurement of weak unnecessary radiation (noise electromagnetic wave) generated from electric equipment or antenna performance is performed. In an electromagnetic shield room, it is necessary to provide a power line for supplying power or a signal line for transmitting a signal, that is, an electric line between the inside and the outside of the electromagnetic shield room, depending on the purpose of use. is there. The high frequency component contained in the electric signal passing through such an electric wire causes electromagnetic noise that leaks from the inside of the electromagnetic shield room to the outside of the room or from the outside to the room. For this reason, an electric filter is inserted into the electric wire for the purpose of cutting high frequency components contained in the electric signal. An example of such an electric filter is disclosed in Patent Document 1, for example.

  The electric filter is installed on a filter panel constituting a part of the shield wall of the electromagnetic shield room. An input terminal block and an electric filter connected to the input terminal block are mounted on the front surface of the filter panel, and an output terminal block is mounted on the rear surface. Between the electric filter and the output terminal block, a through pipe for passing an electric wire is provided, and the electric filter and the output terminal block are connected via an electric wire (penetrating cable) passing through the through pipe. (See FIG. 4). This electric filter enables power supply or signal transmission / reception between the inside and outside of the electromagnetic shield room while maintaining the shielding performance of the electromagnetic shield room.

Japanese Utility Model Publication 3-65298

  In a filter panel, a plurality of electric filters are generally installed together. There are various types of electrical filters depending on the shielding performance, current value, number of cores of the cable, etc., and the sizes and shapes are different. In particular, in an electric filter for a power source having a current value exceeding 200 A or an electric filter for a signal line having 100 cores or more, the installation area of the filter in the filter panel is increased, and the number of installed electrical filters is also increased. For this reason, when installing a plurality of electric filters on the filter panel, it is often difficult to secure an installation space for the electric filters.

  Moreover, since the electric filter is provided with a capacitor, it is recommended to replace the electric filter with a new one, for example, in about 15 years after installation. However, when the electromagnetic shield room is installed for the purpose of so-called Tempest (Transient Electromagnetic Pulse Surveillance Technology) to prevent the leakage of electromagnetic waves, the shielding performance does not deteriorate during the replacement of the electric filter. Such a device is required. For example, the entire through pipe is covered with a shield cloth, the gap is completely covered with a shield tape, and a preparatory work for pulling out the through cable is performed, and then the electric filter is replaced. Such preparatory work increases the burden on the operator and increases the time required for the entire replacement work.

  This invention is made in view of the said situation, and it aims at providing the electric filter which can perform an exchange operation | work efficiently, making the installation area of a filter smaller, and reducing a shield performance. To do.

  In order to achieve the above object, an electric filter according to the present invention is an electric filter inserted into an electric wire connecting the inside and the outside of an electromagnetic shield room, and is installed on one surface of a shield wall of the electromagnetic shield room, and has one end Is installed on the other surface of the shield wall opposite to the first filter circuit, one end of the other surface of the shield wall. A second filter circuit connected to the second wire, and a through portion that connects the other end of the first filter circuit and the other end of the second filter circuit through the shield wall.

  According to this invention, the first filter circuit is installed on one surface of the shield wall of the electromagnetic shield room, and one end is connected to the electric wire on the one surface side of the shield wall, and the second filter circuit However, it is installed on the other surface of the shield wall so as to face the first filter circuit, and one end is connected to the electric wire on the other surface side of the shield wall. For this reason, since it is not necessary to provide both the first and second filter circuits on one side of the shield wall of the electromagnetic shield chamber, the installation area of the filter can be further reduced. Further, even when one of the filter circuits is being replaced, electromagnetic wave noise that has passed through the wall surface can be attenuated by the other filter circuit, so that preparation work for preventing leakage of electromagnetic waves becomes unnecessary. As a result, it is possible to efficiently replace the filter without degrading the shielding performance.

It is sectional drawing of a part of electric shield room | chamber based on Embodiment 1 of this invention. 2 is a cross-sectional view illustrating a configuration of an electric filter according to Embodiment 1. FIG. 3 is an equivalent circuit of the electric filter according to the first embodiment. It is sectional drawing which shows the structure of the conventional electric filter. FIGS. 5A and 5B are a front view and a back view of a filter panel on which a conventional electric filter is mounted. FIGS. 6A and 6B are a front view and a back view of a filter panel on which the electrical filter according to Embodiment 1 is mounted. FIG. 7A and FIG. 7B are diagrams showing parts replacement work in a conventional electric filter. FIG. 5 is a diagram illustrating a component replacement operation in the electric filter according to the first embodiment. It is sectional drawing which shows the structure of the electrical filter which concerns on Embodiment 2 of this invention. 6 is an equivalent circuit of the electric filter according to the second embodiment.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent parts are denoted by the same reference numerals.

Embodiment 1 FIG.
FIG. 1 is a partial cross-sectional view of an electric shield chamber according to Embodiment 1 of the present invention. As shown in FIG. 1, the electric filter 100 according to the first embodiment of the present invention is installed between the inside and outside of the electromagnetic shield room 200 and is inserted into an electric wire connecting the inside and outside of the electromagnetic shield room 200. The electromagnetic shield chamber 200 is formed by a shield wall 50 having a thickness of 1.6 mm, for example. The shield wall 50 is made of a material including a conductive material (a metal thin plate, a metal net, a conductive fiber cloth, or the like), and is grounded. As a result, the shield wall 50 is given the property of not allowing electromagnetic waves across the wall surface to pass therethrough.

  Although only a part of the shield wall 50 is shown in FIG. 1, the shield wall 50 actually forms a closed space together with the filter panel 20 on which the electric filter 100 is installed. The shield wall 50 forms an electromagnetic shield room 200 that does not propagate electromagnetic waves radiated indoors to the outside and does not propagate external electromagnetic waves inside, that is, shields the electromagnetic environment between the room and the outside.

  Actually, an opening 60 is provided in a part of the shield wall 50. The filter panel 20 is attached to the shield wall 50 by bolts and nuts so as to close the opening 60. Similarly to the shield wall 50, the filter panel 20 is also made of a conductive material and is grounded. Therefore, the filter panel 20 constitutes a part of the shield wall of the electromagnetic shield chamber 200 that blocks electromagnetic waves that cross the panel surface. The thickness of the filter panel 20 is, for example, 3.2 mm, which is twice that of the shield wall 50. Thereby, the filter panel 20 is given a strength that can sufficiently support the electric filter 100.

  A plurality of electrical filters 100 are installed on the filter panel 20. Each electric filter 100 has various sizes, but the configuration is the same. As described above, each electric filter 100 is a front side filter installed on one surface of the filter panel 20 constituting the shield wall of the electromagnetic shield chamber 200, that is, the front side of the filter panel 20 (inside the electromagnetic shield chamber 200). 100A and the back side filter part 100B installed in the other side of the filter panel 20 which comprises the back side (outside of the electromagnetic shielding room 200) of the filter panel 20, ie, the shield wall of the electromagnetic shielding room 200, is provided. The front-side filter unit 100A and the back-side filter unit 100B are provided at positions facing each other with the filter panel 20 in between. In this embodiment, the front filter unit 100A corresponds to the first filter circuit, and the back filter unit 100B corresponds to the second filter circuit.

  The input terminal block 1 is installed on the indoor side of the filter panel 20. The input terminal block 1 is connected to a cable 71 connected to a transmission device 70 provided outside the electromagnetic shield room 200. An electrical signal is supplied to the input terminal block 1 from the transmitter 70 via the cable 71. An input cable 2, which is an electric wire on one side (front side) of the filter panel 20, is connected to the input terminal block 1. The input cable 2 is connected to one end of the front filter unit 100A. In the input cable 2, the electrical signal supplied to the input terminal block 1 is sent to the front filter unit 100 </ b> A via the input cable 2.

  FIG. 2 is a cross-sectional view showing the configuration of the electric filter according to Embodiment 1 of the present invention. FIG. 3 is an equivalent circuit of the electric filter according to Embodiment 1 of the present invention. As shown in FIGS. 2 and 3, the front-side filter unit 100A provided on the panel surface 13 of the filter panel 20 includes an input unit 3 that inputs an electrical signal, a π-type filter 4 that performs a filtering process on the electrical signal, And an input side through portion 5 for sending the filtered electric signal into the electromagnetic shield chamber 200. The back side filter unit 100B provided on the panel back surface 14 of the filter panel 20 includes an output side through unit 10 for sending an electrical signal sent from the input side through unit 5 to the π-type filter 9, and an output side through unit 10. A π-type filter 9 that performs a filtering process on the transmitted electrical signal, and an output unit 8 that outputs a power supply signal that has passed through the π-type filter 9 are provided.

  The input unit 3, the π-type filter 4 and the input-side through portion 5 are housed in different shield cases 3A, 4A and 5A, respectively, and the output-side through portion 10, the π-type filter 9 and the output unit 8 are different from each other. Cases 10A, 9A, and 8A are accommodated. Between the input unit 3 and the π-type filter 4, between the π-type filter 4 and the input-side through unit 5, between the output-side through unit 10 and the π-type filter 9, and between the π-type filter 9 and the output unit 8 are shielded. The cases 3A, 4A, 5A, 10A, 9A, and 8A are partitioned by shield walls. The shield cases 3A, 4A, 5A, 10A, 9A, and 8A can be opened and closed by an upper lid. The shield cases 3A, 4A, 5A, 10A, 9A, and 8A are made of a conductive material and are grounded through the filter panel 20. That is, the shield cases 3A, 4A, 5A, 10A, 9A, and 8A are subjected to a shield process for blocking the propagation of electromagnetic waves into and out of the case.

  The input unit 3 is connected to the input terminal block 1 via the input cable 2. An electric signal is supplied to the input unit 3 via the input terminal block 1 and the input cable 2. The electric signal supplied to the input unit 3 is supplied to the π-type filter 4.

  The π-type filter 4 includes two feedthrough capacitors 15A and 15B, two film capacitors 16A and 16B, and an inductor 17. The feedthrough capacitors 15A and 15B are three-terminal capacitors having two input / output terminals and one ground terminal. An input / output terminal on the input side of the feedthrough capacitor 15 </ b> A is connected to the input cable 2, and an input / output terminal on the output side of the feedthrough capacitor 15 </ b> A is connected to an input / output terminal on the input side of the inductor 17. The ground terminal of the feedthrough capacitor 15A is connected to the shield case 4A (ground).

  The film capacitor 16A is a two-terminal capacitor, and is inserted between the input / output terminal on the output side of the feedthrough capacitor 15A and the shield case 4A (ground).

  Inductor 17 is a cable having input / output terminals at both ends, and after firing a dust core (for example, iron or iron alloy metal powder) at a temperature of 1000 ° C. or less at which metal powder and other mixed materials do not dissolve. It is formed by winding a plurality of times. Thereby, the self-inductance necessary for removing the high frequency component contained in the electric signal can be obtained.

  The input / output terminal on the output side of the inductor 17 is connected to the input / output terminal on the input side of the feedthrough capacitor 15B. An input / output terminal on the output side of the feedthrough capacitor 15B (that is, the other end of the front filter unit 100A) is connected to the feedthrough cable 12. The ground terminal of the feedthrough capacitor 15B is connected to the shield case 4A (ground). The film capacitor 16A is inserted between the input / output terminal on the input side of the feedthrough capacitor 15B and the shield case 4A (ground).

  The π-type filter 4 having the above-described configuration is an LC composite type filter having a CLC configuration. The π-type filter 4 operates as a so-called low-pass filter that cuts a high-frequency component contained in a power signal flowing through the filter and passes a low-frequency component. Since the capacitors located at both ends of the π-type filter 4 need to be disposed so as to penetrate the partition surface of the shield case 4A, through capacitors 15A and 15B are used as these capacitors. The capacitances of the feedthrough capacitors 15A and 15B are small on the order of nF, and a necessary capacitance cannot be obtained by this alone. Therefore, film capacitors 16A and 16B having a capacitance of μF order are parallel to the feedthrough capacitors 15A and 15B, respectively. It is connected to the.

  The input side penetrating part 5 and the output side penetrating part 10 constitute a penetrating part. A through pipe 11 is provided in the filter panel 20 between the input side through portion 5 and the output side through portion 10. The through pipe 11 passes through the shield case 5A, the filter panel 20, and the shield case 10A. The through cable 12 is inserted through the through pipe 11 and extends from the input side through part 5 to the output side through part 10. The through pipe 11 is made of a conductive material and is grounded through the filter panel 20. That is, similarly to the shield cases 5A and 10A, the through pipe 11 is also shielded. The through cable 12 is covered with, for example, an insulating material and insulated from the through pipe 11.

  The through cable 12 extending to the output side through portion 10 is connected to the input side input / output terminal of the through capacitor 15A of the π-type filter 9 (that is, the other end of the back side filter portion 100B). In this way, the input-side through portion 5 and the output-side through portion 10 connect the other end of the front-side filter portion 100A and the other end of the back-side filter portion 100B through the filter panel 20.

  The configuration of the π-type filter 9 is the same as that of the π-type filter 4. In other words, the π-type filter 9 is an LC composite type filter having a CLC configuration having feedthrough capacitors 15A and 15B, film capacitors 16A and 16B, and an inductor 17. The π-type filter 9 operates as a so-called low-pass filter that cuts high-frequency components contained in the power supply signal flowing through the filter and passes low-frequency components.

  An input / output terminal on the output side of the feedthrough capacitor 15 </ b> B of the π-type filter 9 is connected to the output cable 7 in the output unit 8. An output terminal block 6 is provided on the panel back surface 14 of the filter panel 20. The electrical signal output from the π-type filter 9 is output to the output terminal block 6 via the output cable 7 which is an electric wire on the other surface side (back side) of the filter panel 20. The output cable 7 is connected to one end of the back filter unit 100 </ b> B and the other end is connected to the output terminal block 6. The back filter unit 100 </ b> B supplies an electrical signal to the output terminal block 6 through the output cable 7.

  As shown in FIG. 1, the output terminal block 6 is connected to a cable 72 connected to a processing device 73 provided inside the electromagnetic shield chamber 200. The electrical signal output from the output cable 7 to the output terminal block 6 is supplied to the processing device 73 via the cable 72.

  Next, an operation for removing a high frequency component contained in an electric signal in the electric filter 100 according to this embodiment will be described.

  In the π-type filter 4, the impedance of the inductor 17 is low for low frequency input signals, and the impedances of the feedthrough capacitors 15 </ b> A and 15 </ b> B and the film capacitors 16 </ b> A and 16 </ b> B are high. For this reason, the low frequency component of the electrical signal flows to the through cable 12 via the inductor 17.

  On the other hand, in the π-type filter 4, the impedance of the inductor 17 increases with respect to a high-frequency input signal, and the impedances of the feedthrough capacitors 15 </ b> A and 15 </ b> B and the film capacitors 16 </ b> A and 16 </ b> B decrease. For this reason, the high frequency component of the electric signal flows to the shield case 4A (ground) through the through capacitors 15A and 15B and the film capacitors 16A and 16B. By the above operation, high frequency components are removed from the electrical signal output from the π-type filter 4.

  The electrical signal from which the high frequency component has been removed is input to the π-type filter 9 through the through cable 12. In the π-type filter 9, the impedance of the inductor 17 is low for low frequency input signals, and the impedances of the feedthrough capacitors 15A and 15B and the film capacitors 16A and 16B are high. For this reason, the low frequency component of the electrical signal flows to the output cable 7 via the inductor 17.

  On the other hand, in the π-type filter 9, the impedance of the inductor 17 is high and the impedances of the feedthrough capacitors 15A and 15B and the film capacitors 16A and 16B are low for high-frequency electric signals. For this reason, the high frequency component of the electric signal flows toward the shield case 9A (ground) via the feedthrough capacitors 15A and 15B and the film capacitors 16A and 16B. Thereby, the high frequency component is removed from the electrical signal output from the π-type filter 9.

  Thus, the electrical filter 100 according to this embodiment has a two-stage configuration in which the π-type filters 4 and 9 are connected in series. If the π-type filter has a two-stage configuration, the shielding performance can be improved as compared with a single-stage configuration. If the one-stage configuration of the π-type filter 4 (that is, the state without the π-type filter 9), the attenuation amount of the high frequency component is 60 dB or less (voltage ratio 1/1000), whereas the π-type filters 4 and 9 When the two-stage configuration is adopted, the attenuation amount of the high frequency component is 80 dB or more (voltage ratio 1/10000).

  Here, the electric filter 100 according to this embodiment is compared with a conventional electric filter. First, the configuration of a conventional electric filter will be described. FIG. 4 is a cross-sectional view showing a configuration of a conventional electric filter. As shown in FIG. 4, a conventional electric filter 101 having a two-stage configuration of π-type filters 4 and 9 includes an input unit 3, a π-type filter 4, a π-type filter 9, and an output side through unit 10. The input unit 3, the π-type filter 4, the π-type filter 9, and the output side through portion 10 are installed on the panel surface 13 of the filter panel 20 and are partitioned by shield cases 3A, 4A, 9A, and 10A. The output side through portion 10 is provided with a through pipe 11 that penetrates the filter panel 20 and the shield case 10A.

  The π-type filter 4 includes feedthrough capacitors 15 </ b> A and 15, film capacitors 16 </ b> A and 16 </ b> B, and an inductor 17. The π-type filter 9 includes feedthrough capacitors 15 and 15B, film capacitors 16A and 16B, and an inductor 17. The feedthrough capacitor 15 is common to the π-type filters 4 and 9. The π-type filters 4 and 9 are LC composite type filters having a CLC configuration.

  The input cable 2 extends from the input terminal block 1 through the input unit 3 to the input / output terminal on the input side of the feedthrough capacitor 15 </ b> A of the π-type filter 4. The output cable 7 extends from the output side input / output terminal of the feedthrough capacitor 15 </ b> B of the π-type filter 9 to the output terminal block 6 through the through pipe 11.

  The electrical signal input to the input terminal block 1 is input to the π-type filters 4 and 9 through the input unit 3, and is output to the output cable 7 with the high frequency components removed, to the output terminal block 6. Sent.

  FIG. 5A is a surface view of a filter panel on which a conventional electric filter is mounted. FIG. 5B is a rear view of a filter panel on which a conventional electric filter is mounted. When the conventional electrical filters 101 are installed side by side on the panel surface 13 of the filter panel 20, the electrical filters 101 are densely arranged on the panel surface 13 of the filter panel 20 as shown in FIG. In this case, on the panel back surface 14 of the filter panel 20, only the output terminal block 6, the through pipe 11, and the output cable 7 are installed as shown in FIG. For this reason, the panel surface 13 of the filter panel 20 is in a state where there is not much free space, while most of the panel back surface 14 of the filter panel 20 is free space.

  However, if the electric filter 101 is installed on the panel back surface 14 of the filter panel 20, the cables connected to the electric filter 101 are complicated on the panel front surface 13 and the panel back surface 14, so that the electric filter is formed in an empty space on the panel back surface 14. It is difficult to install 101. Therefore, when the equipment in the electromagnetic shield room 200 is changed and the electric filter 101 is added to the electromagnetic shield room 200, it is necessary to find another free space for installing the electric filter 101.

  FIG. 6A is a surface view of a filter panel on which the electric filter according to Embodiment 1 of the present invention is mounted. FIG. 6B is a back view of the filter panel on which the electric filter according to Embodiment 1 of the present invention is mounted. As shown in FIGS. 6A and 6B, even when the plurality of electric filters 100 according to this embodiment are arranged densely on the filter panel 20, the installation area of the electric filter 100 is the same as that of the conventional example. Since the installation area of the electric filter 101 is smaller, empty spaces SA and SB in which the electric filter 100 can be newly installed can be secured. For this reason, more electrical filters 100 can be installed in the filter panel 20.

  Next, a case where the electric filter 100 is replaced will be described.

  FIG. 7A and FIG. 7B are diagrams showing parts replacement work in a conventional electric filter. When the conventional electric filter 101 is removed, as shown in FIG. 7A, first, the upper cover of the output side through portion 10 that is screwed first is removed, and then the output cable 7 is disconnected from the through capacitor 15B. There is a need. However, in the conventional electric filter 101, at the moment when the upper cover is removed, high frequency electromagnetic waves are induced in the output cable 7 by the electromagnetic waves (arrow E) that enter from the part where the upper cover of the shield case 10A is removed. It is transmitted to the opposite side of the filter panel 20 and the shielding performance of the electromagnetic shielding chamber 200 is temporarily deteriorated.

  In order to prevent such temporary deterioration of the shielding performance, the output cable 7 connected to the output terminal block 6 is disconnected as shown in FIG. It is necessary to confine the output cable 7 in the through portion 10. However, since the output cable 7 is often 10 m or more, and the nodes of the output cable 7 may be bundled, the work of confining the output cable 7 is not easy. For this reason, usually, using an electromagnetic shielding cloth formed with a large metal mesh, a preparatory work for covering the entire output cable 7 from the panel rear surface 14 of the filter panel 20 is performed, while preventing deterioration of the shielding performance. The filter is being replaced.

  FIG. 8 is a diagram showing part replacement work in the electric filter according to Embodiment 1 of the present invention. According to the electric filter 100 according to the first embodiment, as shown in FIG. 8, the upper cover of the shield case 10 </ b> A is removed from the output side through portion 10 of the back side filter portion 100 </ b> B, and the through cable 12 is connected to the π-type filter 9. Even when disconnected from the feedthrough capacitor 15A, the front filter unit 100A operates as it is, so that electromagnetic noise mixed in the feedthrough cable 12 is removed by the front filter unit 100A. For this reason, it becomes possible to avoid deterioration of the shielding performance during filter replacement.

  As described above in detail, according to this embodiment, the front-side filter portion 100A is installed on one surface of the shield wall (filter panel 20) of the electromagnetic shield chamber 200, and one end is one surface of the shield wall. The back side filter portion 100B is installed on the other surface of the shield wall (filter panel 20) so as to face the front side filter portion 100A, and one end is on the other side of the shield wall. Connected to the electric wire. For this reason, since it is not necessary to provide both the front-side filter part 100A and the back-side filter part 100B on one side of the shield wall (filter panel 20) of the electromagnetic shield room 200, the installation area of the filter can be further reduced. . In addition, even when one of the filter parts is being replaced, the electromagnetic wave noise that has passed through the wall surface can be attenuated by the other filter part, so that preparation work for preventing leakage of electromagnetic waves is not necessary. As a result, it is possible to efficiently replace the filter without degrading the shielding performance.

  Further, even when the part of the π-type filter on one side is being replaced, electromagnetic noise leaking to the other side of the filter panel 20 through the through pipe 11 can be attenuated by the π-type filter on the other side. Preparation work for preventing leakage of electromagnetic waves becomes unnecessary. As a result, it is possible to efficiently replace the filter parts without degrading the shielding performance.

Embodiment 2. FIG.
FIG. 9 is a cross-sectional view showing a configuration of an electric filter according to Embodiment 2 of the present invention. FIG. 10 is an equivalent circuit of an electric filter according to Embodiment 2 of the present invention. As shown in FIGS. 9 and 10, in the electric filter 100 according to Embodiment 2 of the present invention, a through portion is configured to connect the other end of the front-side filter portion 100A and the other end of the back-side filter portion 100B. A through capacitor 15 is used instead of the through tube 11 (see FIG. 2). The feedthrough capacitor 15 passes through the shield wall (filter panel 20) and the shield cases 4A and 9A. The feedthrough capacitor 15 functions as a feedthrough capacitor on the output side of the π-type filter 4 and also functions as a feedthrough capacitor on the input side of the π-type filter 9.

  A film capacitor 16B is inserted between the input / output terminal of the feedthrough capacitor 15 installed on the panel surface 13 side of the filter panel 20 and the shield case 4A (ground). A film capacitor 16A is inserted between the input / output terminal on the output side of the feedthrough capacitor 15 installed on the panel back surface 14 side of the filter panel 20 and the shield case 9A (ground). The film capacitor 16B plays the same role as the film capacitor 16B of the π-type filter 4 in the above embodiment. The film capacitor 16A plays the same role as the film capacitor 16A of the π-type filter 9 in the above embodiment.

  In the electric filter 100 according to this embodiment, the input side through portion 5, the output side through portion 10, and the through cable 12 are not provided. For this reason, the configuration of the filter can be further simplified. Further, the electric filter 100 according to the first embodiment can be further downsized. As a result, the empty space of the filter panel 20 can be made larger and the empty space can be used effectively.

  In addition, according to the electric filter 100 according to the second embodiment, even when the upper cover of the shield case 9A is removed and separated from the feedthrough capacitor 15 when replacing the parts of the back filter unit 100B, the front filter unit 100A remains as it is. Since it is operating, electromagnetic wave noise leaking to the opposite side of the filter panel 20 via the feedthrough capacitor 15 is removed by the front side filter unit 100A. For this reason, it becomes possible to avoid deterioration of the shielding performance during filter replacement.

  In the above embodiment, one stage of the π-type filter 4 is provided on the panel surface 13 of the filter panel 20 and one stage of the π-type filter 9 is provided on the panel back surface 14, but the present invention is not limited to this. For example, a π-type filter may be provided in a plurality of stages on at least one side of the filter panel 20. In this way, the high frequency component contained in the electrical signal can be removed more strongly.

  In the above embodiment, the π-type filter is used as the low-pass filter, but the present invention is not limited to this. For example, a T-type filter may be used, or another filter in which a coil and a capacitor are further added to a π-type filter and a T-type filter may be used. However, the T-type filter needs to connect the coils in a two-stage configuration, and is larger than the π-type filter. Therefore, the installation area of the entire filter can be further reduced when the π-type filter is adopted rather than the T-type filter.

  Moreover, in the said embodiment, although the front side filter part 100A and the back side filter part 100B were made into the low pass filter, it is not restricted to this. For example, a band pass filter or a high pass filter may be used.

  In the π-type filters 4 and 9, a capacitor component in which a feedthrough capacitor and a film capacitor are connected in parallel is used as a capacitor component, but the present invention is not limited to this. If the feedthrough capacitor has a sufficient capacity, only the feedthrough capacitor may be used.

  In the above embodiment, the case where an electrical signal is transmitted from the inside of the electromagnetic shield room 200 to the outside of the room has been described, but the present invention is not limited to this. The present invention can also be applied to the case where an electric signal is input from the outside of the electromagnetic shield room 200 into the room. Such an electric signal may be a power signal supplied from a power source or a data signal.

  Various embodiments and modifications can be made to the present invention without departing from the broad spirit and scope of the present invention. The above-described embodiments are for explaining the present invention and do not limit the scope of the present invention. In other words, the scope of the present invention is shown not by the embodiments but by the claims. Various modifications within the scope of the claims and within the scope of the equivalent invention are considered to be within the scope of the present invention.

  The present invention is applied to removing a high-frequency component contained in an electric signal passing through an electric wire between the inside and the outside of an electromagnetic shield room.

  1 input terminal block, 2 input cable, 3 input section, 3A shield case, 4π-type filter, 4A shield case, 5 input side through section, 5A shield case, 6 output terminal block, 7 output cable, 8 output section, 8A Shield case, 9π-type filter, 9A shield case, 10 output side through section, 10A shield case, 11 through tube, 12 through cable, 13 panel surface, 14 panel back surface, 15, 15A, 15B feedthrough capacitor, 16A, 16B film Capacitor, 17 Inductor, 20 Filter panel, 50 Shield wall, 60 Opening, 70 Transmitter, 71 Cable, 72 Cable, 73 Processing device, 100 Electrical filter, 100A Front side filter, 100B Back side filter, 101 Electrical filter, 200 Electromagnetic Sea De room.

Claims (5)

An electric filter inserted into an electric wire connecting the inside and outside of the electromagnetic shield room,
A first filter circuit installed on one surface of the shield wall of the electromagnetic shield chamber, one end connected to an electric wire on the one surface side of the shield wall;
A second filter circuit installed on the other surface of the shield wall so as to face the first filter circuit, and having one end connected to an electric wire on the other surface side of the shield wall;
An electrical filter comprising: a through portion that connects the other end of the first filter circuit and the other end of the second filter circuit through the shield wall. The penetrating part is
A conductive through pipe that penetrates the shield wall and is grounded;
The cable inserted through the through pipe, insulated from the through pipe, and connecting the other end of the first filter circuit and the other end of the second filter circuit. Electric filter. The penetrating part is
The electric filter according to claim 1, further comprising a feedthrough capacitor that passes through the shield wall and connects the other end of the first filter circuit and the other end of the second filter circuit. The first filter circuit, the second filter circuit, and the penetrating part are respectively housed in different shield cases that block electromagnetic waves.
The electric filter according to claim 1 or 2. The first and second filter circuits are
configure a π-type filter,
The electric filter according to any one of claims 1 to 4.

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