JP5507974B2 - Noise filter - Google Patents

Description

The present invention relates to a noise filter that removes noise invading an electronic device or the like via a power line or the like, and in particular, has a structure that suppresses a temperature rise of a component having a low rated temperature and improves heat dissipation of a coil. The present invention relates to a noise filter.

  A noise filter composed of a choke coil and a capacitor is a device that prevents electronic devices from malfunctioning due to noise that enters the electronic device from the outside via a power line or communication line, and is indispensable for electronic devices. It is.

  Conventionally, as this type of noise filter, as shown in the external view of FIG. 7, an input terminal block 220 and an output terminal block 222 are provided at both ends on a metal bottom plate 212 provided with a ground terminal 214, synthetic resin, etc. In general, a case body 218 made of an insulating material is disposed, and a cover 224 is attached to the top of the case body 218.

  8 is an explanatory view of the conventional example shown in FIG. 7 as viewed from above. FIG. 8A is a plan view of the noise filter 210 with the cover 224 removed, and FIG. It is sectional drawing which showed the cross section of the center vicinity.

  As shown in FIG. 8A, the noise filter 210 includes a common mode choke coil 232, X as a component of the filter circuit between the input terminal block 220 and the output terminal block 222 provided at both ends of the case body 218. Capacitors 234 and 236 and Y capacitors 238 and 240 are provided.

The common mode choke coil 232 is placed at the bottom of the coil storage portion 242 provided in the case body 218, and is fixed by filling the coil storage portion 242 with a potting material 244 (shaded portion), the X capacitors 234, 236, and The Y capacitors 238 and 240 are assembled and wired at predetermined positions of the capacitor storage portions 246 and 248 provided in the case main body 218, respectively.

Japanese Utility Model Publication No. 2002-280234

  However, in the conventional noise filter 210 as shown in FIG. 8, the coil housing portion 242 of the case body 218 in which the common mode choke coil 232 is installed has a rectangular parallelepiped space that matches the product shape, from above. When viewed, it is a rectangular region as shown in FIG.

  As described above, since the cylindrical (circular) common choke coil 232 is disposed in the rectangular parallelepiped (rectangular) region of the coil storage portion 242, the distance between the common choke coil 232 and the outside air is increased.

  That is, the distance between the outer peripheral portion of the common choke coil 232 and the outer walls 242a and 242b that are in contact with the outside air of the coil storage portion 242 is closer to the capacitor storage portions 246 and 248, and when the noise filter 210 is used. The common choke coil 232 has a structure that hardly dissipates heat.

  Further, as shown in FIGS. 8A and 8B, the noise filter 210 includes a coil housing portion 242 and capacitor housing portions 246 and 248 separated by partition walls 246a and 248a. Since the potting material 244 filled in the coil housing portion 242 is in direct contact, the heat conduction from the common choke coil 232 to the X capacitors 234 and 236 and the Y capacitors 238 and 240 is large.

  Therefore, the conventional noise filter has a problem in performance that the heat generation of the common choke coil which is a heat generating component is poor and heat generation of the common choke coil is easily conducted to other components having a low rated temperature.

  Further, the noise filter 210 includes a rectangular common choke coil 232 disposed in a rectangular parallelepiped region of the coil storage portion 242, the four corners of the square of the coil storage portion 242, and the circular outer periphery of the common choke coil 232. There is a large space between them, and the amount of potting material 244 used is more than necessary.

  Therefore, the conventional noise filter has a manufacturing problem that potting material filling and curing takes time and a potting workability is lowered, and a use problem that a product weight is increased.

The present invention has been made to solve the above-described problems, and suppresses the temperature rise of components having a low rated temperature, has good heat dissipation of the common choke coil, and reduces the amount of potting material used. An object is to provide a noise filter which is reduced in weight.

In order to achieve this object, the present invention is configured as follows. The present invention relates to a noise filter in which a coil and a capacitor are housed in a case having an opening at the top, and the opening is closed with a cover so that the coil and the capacitor are isolated from the outside air. The coil storage part that is provided on the side, the capacitor storage part that is disposed adjacent to the side of the coil storage part and that has an outer wall in contact with the outside air, and the coil storage part and the capacitor storage part face each other. characterized in that it comprises a heat insulating portion made from the outside air which is formed on at least a part between the outer wall surface. The case has a capacitor storage part on both sides of the coil storage part, and includes heat insulating parts at two or four locations between the outer wall surfaces of the coil storage part and the capacitor storage part facing each other.

Here, the case includes a case main body in which a coil storage portion and a capacitor storage portion are integrally formed, and the case main body has a cylindrical shape along an outer shape in a radial direction of the coil with an outer wall contacting the outside air of the coil storage portion. To do.

Furthermore, the space formed between the coil storage part and the stored coil is filled with a filler having at least thermal conductivity.

  According to the present invention, by separating the space between the coil housing portion and the capacitor housing portion of the case body via the space outside the case body, a layer of outside air is formed between the choke coil and the capacitor having a low rated temperature, It is difficult for heat generated in the choke coil to be conducted to the capacitor, and the temperature rise of the capacitor can be suppressed.

  Further, according to the present invention, the outer wall of the coil housing portion that comes into contact with the outside air has a cylindrical shape along the outer shape in the radial direction of the coil, so that the distance between the choke coil and the outside air is reduced, and the heat dissipation of the choke coil is achieved. Will improve.

Furthermore, according to the present invention, by forming the outer wall of the coil housing part along the outer shape of the coil, the gap between the wall surface and the coil can be minimized, and the amount of potting material used to fill the coil housing part is used. As a result, the noise filter can be reduced in weight.

1 is an external view showing an embodiment of a noise filter according to the present invention. Circuit diagram of the embodiment shown in FIG. Explanatory drawing of the state which removed the cover of embodiment shown in FIG. Sectional drawing of the case main body of embodiment shown in FIG. Explanatory drawing which shows other embodiment of the noise filter by this invention. Sectional drawing of the case main body of embodiment shown in FIG. Explanatory drawing showing an example of a conventional noise filter Explanatory drawing of the conventional example shown in FIG.

  FIG. 1 is an external view showing an embodiment of a noise filter according to the present invention. In the present embodiment, a single-phase AC noise filter when the present invention is applied to the above-described conventional example will be described.

  As shown in FIG. 1, the noise filter 10 includes a case and a filter circuit provided in the case. The case includes a metal bottom plate 12 provided with a ground terminal 14 and an input terminal block 20 disposed on the bottom plate 12. And a case main body 18 provided with an output terminal block 22 and a cover 24 attached to the upper portion of the case main body 18, and a filter circuit is incorporated in the case main body 18.

  FIG. 2 is a circuit diagram of the embodiment of FIG. As shown in FIG. 2, the filter circuit 10a is a common circuit that attenuates low-frequency common mode noise formed by winding conductive wires 28 and 30 around a toroidal core 26 between input terminals 20a and 20b and output terminals 22a and 22b. Mode choke coil 32, X capacitors (across the line capacitors) 34, 36 connected between the input side and output side lines of common mode choke coil 32, high-frequency common mode noise and normal mode noise Y capacitors (line bypass capacitors) 38 and 40 connected between the output side line and ground are provided.

  In the present embodiment, one having a common mode choke coil 32 is shown. However, two common mode choke coils 32 may be provided. A bleeder resistor for discharging may be provided between the lines.

  3 is an explanatory view showing the internal structure of the case main body 18 of the embodiment of FIG. 1, FIG. 3 (A) is a plan view with the cover 24 removed, and FIG. 3 (B) is the case main body 18. It is a front view of the noise filter 10 which showed this by the cross section CC of FIG. 3 (A).

  As shown in FIGS. 3A and 3B, the case body 18 is formed by integrally forming an input terminal block 20 and an output terminal block 22 at both ends with an insulating material such as a synthetic resin, and the input terminal block 20 and the output terminal block. 22, a common mode choke coil 32, X capacitors 34 and 36, and Y capacitors 38 and 40 are disposed.

  The common mode choke coil 32 is placed at the bottom of the coil housing portion 42 provided at the center of the case body 18 and is potted in consideration of prevention of rattling due to vibration and heat dissipation, that is, good heat dissipation. A potting material 44 (shaded portion) such as an epoxy resin or a silicone resin is filled in the coil housing portion 42 and cured by being fixed.

  The X capacitor 34 is assembled to a capacitor housing 46 provided between the input terminal block 20 and the coil housing 42, and the X capacitor 36 and the Y capacitors 38, 40 are disposed between the coil housing 42 and the output terminal block 22. It is assembled at a predetermined position of the provided capacitor housing 48.

  The common mode choke coil 32 and the X capacitor 34 are connected to the connection portions of the terminal fittings 50 and 52 embedded in the input terminal block 20, the input side connection terminals of the conductive wires 28 and 30 wound around the toroidal core 26, and the X capacitor 34. Both lead terminals are fixed by caulking, soldering or the like, and are electrically connected to the terminal fittings 50 and 52.

  The common mode choke coil 32, the X capacitor 36, and the Y capacitors 38, 40 are connected to the connection portions of the terminal fittings 54, 56 embedded in the output terminal block 22, the output side connection terminals of the conductive wires 28, 30, and the X capacitor 36 These lead terminals and one lead terminal of the Y capacitors 38 and 40 are fixed by caulking, soldering or the like, and are electrically connected to the terminal fittings 54 and 56.

  Further, the Y capacitors 38 and 40 are electrically connected to the bottom plate 12 by fixing the other lead terminal to the connection terminal 16 rising from the bottom plate 12 disposed on the bottom surface of the case body 18 by means of carragage or soldering. doing.

  As shown in FIG. 3A, the outer walls 42a and 42b that come into contact with the outside air of the coil housing portion 42 are arcuate curved surfaces along the radial outer shape of the common mode choke coil 32. More specifically, the cross section is arcuate. The distance from the common mode choke coil 32 is a minimum necessary for potting.

  In the noise filter 10, the coil housing portion 42 is formed in such an arcuate wall shape, thereby reducing the distance between the common mode choke coil 32 and the outside air and increasing the contact area between the outside air and the common mode choke coil 32. The heat dissipation of the potting material is improved and the usage fee of the potting material is reduced.

  In addition, by forming the heat insulating portions 58, 60, 62, and 64, which are spaces made of outside air, between the outer walls 42a and 42b of the coil storage portion 42 and the capacitor storage portions 46 and 48, the common mode choke coil 32 Heat generation is difficult to conduct to the X capacitors 34 and 36 and the Y capacitors 38 and 40 having a low rated temperature.

  In the present embodiment, the common mode choke coil 32 is fixed to the coil housing portion 42 by potting. However, depending on the specifications of the noise filter 10, the amount of heat generated by the common mode choke coil 32 may be relatively small. In this case, since the distance between the common mode choke coil 32 and the outside air is short, the potting process can be omitted and the noise filter 10 can be further reduced in weight.

  When the potting process is omitted, the bottom of the common mode choke coil 32 is bonded to the coil housing portion 42, or other fixing such as fixing the common mode choke coil 32 by providing a fixing claw on the coil housing portion 42. Any method may be used, and since each method requires less labor than potting, the cost of the noise filter 10 can be reduced by reducing the number of assembly steps.

  In the present embodiment, the case main body 18 has a structure in which the X capacitors 34 and 36 are assembled from above the case main body 18 (on the cover 24 side), similarly to the common choke coil 32. The structure may be incorporated from below the main body 18 (from the bottom plate 12 side).

  In addition, the inventor of the present invention has confirmed that the temperature of the common choke coil is lowered by about 3 ° C. compared to the conventional example when used at room temperature in the experiment using the noise filter of the present embodiment.

  4 is a cross-sectional view of the case main body 18 of the embodiment of FIG. 1, FIG. 4 (A) shows the case main body 18 by a cross section DD of FIG. 3 (B), and FIG. It is explanatory drawing which compared the usage fee of the potting material of this embodiment shown to 4 (A), and the prior art example shown to FIG. 8 (B). In FIG. 4B, in order to compare this embodiment with the conventional example, the cross section of FIG. 4A and the cross section of FIG. ing.

  As shown in FIG. 4A, the capacitor storage portions 46 and 48 and the coil storage portion 42 are partially connected by partition walls 46a and 48a, and the capacitor storage portions 46 and 48 are connected from the coil storage portion 42 at this portion. There is heat conduction to.

  However, between the outer walls 46b, 46c of the capacitor housing part 46 on both sides of the partition wall 46a and the outer walls 42a, 42b of the coil housing part 42, there are heat insulating parts 58, 60 made of outside air, and the capacitor housing parts 48 on both sides of the partition wall 48a. Between the outer walls 48b and 48c of the coil and the outer walls 42a and 42b of the coil storage part 42, there are heat insulating parts 62 and 64 made of outside air.

  In the general use state of the noise filter, the outside air is air, and the heat conductivity of the air is much smaller than that of the potting material. Therefore, this embodiment is more common than the conventional example shown in FIG. The heat conduction from the capacitor to the capacitor is small.

  Further, as shown in FIG. 4B, the filling area of the potting material is smaller by the areas of the reduced portions 66 and 68 than in the conventional example shown in FIG. The amount of potting material to be used is reduced accordingly, and the noise filter 10 is reduced in weight.

  FIG. 5 is an explanatory view showing another embodiment of the noise filter according to the present invention, and shows the plane of the noise filter with the cover removed. The noise filter 110 of the present embodiment has the same circuit configuration as that of the embodiment shown in FIGS. 1-4, but has a structure in which the case width (vertical direction in the figure) is narrowed.

  As shown in FIG. 5, a case main body 118 is disposed on a metal bottom plate 112 provided with a ground terminal 114. The case main body 118 has an input terminal block 120 and an output terminal block 122 at both ends, and an insulating material such as a synthetic resin. The common mode choke coil 132, the X capacitors 134 and 136, and the Y capacitors 138 and 140 are disposed between the input terminal block 120 and the output terminal block 122.

  The common mode choke coil 132 is placed at the bottom of the coil housing part 142 provided at the center of the case body 118, and the potting material 144 (shaded part) is coiled in consideration of prevention of rattling due to vibration and heat dissipation. The storage unit 142 is filled and cured and fixed.

  The X capacitor 134 is assembled to a capacitor storage portion 146 provided between the input terminal block 120 and the coil storage portion 142, and the X capacitor 136 and the Y capacitors 138 and 140 are interposed between the coil storage portion 142 and the output terminal block 122. The capacitor storage portion 148 provided is assembled at a predetermined position.

  The common mode choke coil 132 and the X capacitor 134 are connected to the connection portions of the terminal fittings 150 and 152 embedded in the input terminal block 120, the input side connection terminals of the conductive wires 128 and 130 wound around the toroidal core 126, and the X capacitor 134. Both lead terminals are fixed by caulking, soldering or the like, and are electrically connected to the terminal fittings 150 and 152.

  The common mode choke coil 132, the X capacitor 136, and the Y capacitors 138 and 140 are connected to the connection portions of the terminal fittings 154 and 156 embedded in the output terminal block 122, the output side connection terminals of the conductive wires 128 and 130, and the X capacitor 136. These lead terminals and one lead terminal of the Y capacitors 138, 140 are fixed by caulking, soldering, or the like, and are electrically connected to the terminal fittings 154, 156.

  Further, the Y capacitors 138 and 140 are electrically connected to the bottom plate 112 by fixing the other lead terminal to the connection terminal 116 rising from the bottom plate 112 disposed on the bottom surface of the case body 118 by caulking or soldering. doing.

  As shown in FIG. 5, the outer wall 142a of the coil housing part 142 facing the outer circumference in the radial direction of the common mode choke coil 132 is cylindrical along the outer shape of the common mode choke coil 132, and the entire circumference is in contact with the outside air. Yes. Further, the distance between the cylindrical outer wall 142a of the coil housing part 142 and the common mode choke coil 132 is the minimum necessary for potting.

  In the noise filter 110, the coil housing portion 142 is formed in such a cylindrical wall shape, so that the distance between the common mode choke coil 132 and the outside air is shortened and the contact area between the outside air and the common mode choke coil 132 is increased. The heat dissipation of the potting material is improved and the usage fee of the potting material is reduced.

  Further, by forming the heat insulating portions 158 and 160, which are spaces made of outside air, between the outer wall 142a of the coil storage portion 142 and the capacitor storage portions 146 and 148, the heat generation of the common mode choke coil 132 has a rated temperature. It is difficult to conduct to the low X capacitors 134 and 136 and the Y capacitors 138 and 140.

  In the embodiment shown in FIGS. 1 to 4, a part of the opposing wall surfaces of the coil storage portion 42 and the capacitor storage portions 46 and 48 are in contact with each other (partition walls 46 a and 48 a), but in this embodiment, the heat insulating portions 158 and 160. Is over the entire area between the opposing wall surfaces of the coil storage part 142 and the capacitor storage parts 146 and 148, so that heat conduction from the coil storage part 142 to the capacitor storage parts 146 and 148 can be further suppressed.

  6 is a cross-sectional view of the case main body 118 of the embodiment shown in FIG. 5, FIG. 6A shows the case main body 118 by a cross-section EE of FIG. 5, and FIG. Is shown by a section FF in FIG.

  As shown in FIG. 6 (A), the capacitor storage portions 146 and 148 and the coil storage portion 142 are arranged in the height direction of the opposing wall surfaces 142a to 146a and 142a to 148a (the capacitor storage portions 146 and 148 and the coil storage portion. The case main body 118 is connected to the capacitor housing portions 146 and 148 and the coil housing portion 142 except for the outer walls 142a, 146a and 148a. They are connected and integrated at a location 118a.

  In the present embodiment, the connection location 118a is provided in the upper portions of the capacitor storage portions 146 and 148 and the coil storage portion 142. However, the connection location 118a is provided in the lower portion of the capacitor storage portions 146 and 148 and the coil storage portion 142, or in the middle portion. It doesn't matter.

  Further, as shown in FIG. 6B, the entire cylindrical outer wall 142a of the coil storage portion 142 is in contact with the outside air, and the heat insulating portions 158 and 160 are disposed on both sides of the case main body 118 (shown in the figure). Since it penetrates in the vertical direction), the heat dissipation is further improved by the convection of the outside air in this part.

The present invention is not limited to the above-described embodiment, and can be applied to any noise filter including a coil and a capacitor, such as a three-phase AC noise filter, and appropriate modifications that do not impair the object and advantages thereof. including.

10, 110, 210: Noise filters 12, 112, 212: Bottom plates 14, 114, 214: Ground terminals 16, 116: Connection terminals 18, 118, 218: Case bodies 20, 120, 220: Input terminal blocks 22, 122, 222: Output terminal blocks 24, 124, 224: Cover 26, 126: Toroidal cores 28, 30, 128, 130: Conductors 32, 132, 232: Common mode choke coils 34, 36, 134, 136, 234, 236: X Capacitors 38, 40, 138, 140, 238, 240: Y capacitors 42, 142, 242: Coil storage portions 44, 144, 244: Potting materials 46, 48, 146, 148, 246, 248: Capacitor storage portions 50, 52 , 54, 56, 150, 152, 154, 156: terminal fittings 58, 60, 6 , 64,158,160: the heat insulating section 66 and 68: reduction unit

Claims (5)

In a noise filter in which a coil and a capacitor are housed in a case having an upper opening , the opening is closed with a cover, and the coil and the capacitor are blocked from outside air .
A coil storage portion having an outer wall in contact with outside air on the side ;
A capacitor housing part disposed adjacent to the side of the coil housing part and having an outer wall on the side in contact with outside air ;
And the heat insulating portion made from the outside air which is formed on at least a part between the outer wall surface that faces with the coil receiving portion and the capacitor housing portion,
A noise filter comprising:
The noise filter according to claim 1, wherein the case includes:
A noise filter comprising: the capacitor housing portions disposed on both sides of the coil housing portion; and the heat insulating portions provided at two or four locations between the opposing outer wall surfaces.
The noise filter according to claim 1, wherein the case includes:
A noise filter comprising: a case main body in which the coil housing portion and the capacitor housing portion are integrally formed.
The noise filter according to claim 3, wherein the case body is
The noise filter according to claim 1, wherein an outer wall of the coil housing portion that comes into contact with the outside air has a cylindrical shape along a radial outer shape of the coil.
The noise filter according to claim 1, wherein the coil storage portion is
A noise filter comprising a space formed between the coil and a filler having at least thermal conductivity.

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