JPH0418253Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a noise filter, for example,
The present invention relates to a noise filter suitable for use by being attached to the case of a male device equipped with a switching power supply or the like.

(Prior Art) Conventionally, this type of noise filter has, for example,
A coil and a capacitor are combined in one conductive case to form an equivalent circuit as shown in FIG.

(Problem that the invention aims to solve) However, in order to remove high-frequency noise in a wide band, conventional noise filters with such a configuration combine a coil and a capacitor in one conductive case. Since it forms an equivalent circuit as shown in Figure 4, if the size of the coil changes depending on the required current capacity, etc., the case itself will change depending on the change in the size of the coil. The size of the area must also be changed each time, which complicates the work and increases costs.

Further, as shown in FIG. 5, such a conventional noise filter 1 is housed inside a case 2 of an electronic device to which a switching power supply or the like is attached, and is connected to a fuse 3, a switch 4, and a socket 5 with leads. When used in an electrically connected manner through the wires 6 and 7, high frequency noise generated by the switching power supply, etc. generated inside the case 2 is directly transmitted to the lead wires 6 and 7 without passing through the noise filter 1.
This causes the inconvenience of spatial propagation and leakage to the AC current side. Therefore, in order to solve this inconvenience, for example, as disclosed in Utility Model Application Laid-open No. 56-134820, the fuse 3, switch 4, socket 5, etc. are connected to the noise filter 1 in one conductive case. It is conceivable to store it inside the case. However, if you do this,
It is true that a considerable amount of unnecessary noise is removed, but these fuses 3 and switches 4
There are cases where they are not necessarily required, and cases where either one of them is required, and these must be selectively stored in the conductive case of the noise filter 1 according to each need. , the size of this case will also have to be changed. Moreover, in this case, in order to configure the combination of selectively housing the fuse 3 and switch 4 and the countless possible combinations of coil sizes, etc. within the same case of the noise filter 1, the number of combinations of these is required. In addition, the case must be prepared, which further complicates the work and increases costs.

The present invention has been made in view of these points, and aims to provide a noise filter that is easy to combine according to the purpose of use, simplifies assembly work, and does not increase costs. It is something.

(Means for solving the problem) The noise filter of the present invention has a high frequency block that removes noise in high frequency bands, and a low frequency block electrically connected to this high frequency block that removes noise in low frequency bands. The noise filter is composed of a high-frequency block, the high-frequency block housing a capacitor connected between the line and ground in a conductive case having an inlet socket, and the low-frequency block is characterized in that it comprises a coil disposed outside the conductive case and a capacitor connected between lines.

(Function) The noise filter of the present invention consists of a high-frequency block consisting of a capacitor connected between the line and ground housed in a conductive case with an inlet socket, and a coil and line block arranged outside the case. -The low-frequency block consists of a capacitor connected between the lines, so even if coils of different sizes are used depending on the purpose, the coil is used for the low-frequency block. Furthermore, there is no need to change the case of the high-frequency block each time the coil size changes. Furthermore, even if either a fuse, a switch, or both are housed in the case, the case only includes the filter element,
It is only necessary to prepare four types of storable items: a filter element and a fuse, a filter element and a switch, and a filter element and a fuse and a switch.

(Embodiment) A noise filter according to an embodiment of the present invention houses a three-terminal capacitor, a fuse, and a switch, which are the filter elements forming the equivalent circuit indicated by a in Fig. 1, in a metal case fitted with an inlet socket. a high-frequency block suitable for removing high-frequency noise in a high frequency band of, for example, 30 MHz or more; A low-frequency block suitable for removing high-frequency noise in a low frequency band of, for example, 30 MHz or less, which is composed of a coil and a capacitor as filter elements forming an equivalent circuit, is arranged. The three-terminal capacitor used in the high frequency block has a dielectric substrate 11 as shown in FIG.
A pair of capacitor electrodes 12 and 13 are formed on both sides of the electrode 12, and a lead wire 14 formed in a roughly U-shape is connected to the electrode 12 on the front side by solder or the like, and ferrite beads are attached to both legs of the lead wire 14, respectively. 15,
16 is inserted, and an earth lead 17 is connected to the electrode 13 on the back side by soldering or the like.
The entire structure is covered with an insulating resin 18.

A noise filter according to an embodiment of the present invention having such a configuration is, for example, as shown in FIG.
When used while being housed inside a conductive case 21 of an electronic device such as a switching power supply, a three-terminal capacitor 24 as a filter element, a fuse 25, and a switch 26 are placed in a metal case 23 having an inlet socket 22. A high frequency block 27 containing a cable 28 is inscribed in the side wall of the case 21 so that the inlet socket 22 can be connected to the outside.
Low-frequency block 2 consisting of a coil and a capacitor, which are filter elements, electrically connected by
9 may be formed directly on a substrate constituting a switching power supply or the like.

It goes without saying that the noise filter of the present invention is not limited to that of the above-mentioned embodiments, and may be modified as appropriate without changing the gist.

For example, the filter elements used in the high frequency block may be other types such as feedthrough capacitors.

Furthermore, it is not necessarily necessary to house fuses, switches, etc. in the high frequency block, but they can be selectively housed as needed. Therefore, high frequency blocks include those that house only the filter element, those that house the filter element and a fuse, those that house the filter element and a switch, and those that house the filter element, fuse, and switch. Four types are possible. Note that it is also possible to selectively use other electrical components in the metal case, so in such a case, the number of types of high-frequency blocks will increase accordingly.

Furthermore, the equivalent circuit formed within the high-frequency block and the low-frequency block is not limited to that shown in FIG. 1, but may be other circuits.

(Effects of the invention) Since the noise filter of the invention has the above configuration, it can be easily combined according to the purpose of use, and the assembly work is simplified and there is no increase in cost. be effective.

[Brief explanation of the drawing]

Fig. 1 is an equivalent circuit diagram of one embodiment of the noise filter of the present invention, Fig. 2 is a front view of a three-terminal capacitor used in the high frequency block, and Fig. 3 is:
FIG. 4 is an equivalent circuit diagram of a conventional noise filter, and FIG. 5 is a conceptual diagram showing an example of the mounting state. 21... Case of electronic equipment, 22... Inlet socket, 23... Metal case, 24... Filter element (3 terminal capacitor), 25... Fuse, 26... Switch, 27... High frequency block,
28...cable, 29...low frequency block.

Claims (1)

[Claims for Utility Model Registration] A noise filter consisting of a high-frequency block that removes noise in a high frequency band and a low-frequency block that is electrically connected to the high-frequency block and removes noise in a low frequency band. The high-frequency block is configured by housing a capacitor connected between the line and the ground in a conductive case having an inlet socket, and the low-frequency block is arranged outside the conductive case. 1. A noise filter comprising a coil and a capacitor connected between lines.