JP2015207574A - Common mode noise filter and manufacturing method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a common mode noise filter that can enhance the function of removing a common mode noise.SOLUTION: A common mode noise filter has a non-magnetic portion 12 formed to be sandwiched by a first lamination portion 13a and a second lamination portion 13b, and coils 14, 15 formed in the non-magnetic portion 12. In the non-magnetic portion 12, the winding shaft portions of the coils 14, 15 are provided with a first magnetic portion 11a whose area increases gradually towards the upper side in the non-magnetic portion 12 which is constructed by non-magnetic layers excluding a non-magnetic layer located at the lowermost layer out of plural non-magnetic layers, and a second magnetic portion 11b formed in the non-magnetic layer located at the lowermost layer out of the plural non-magnetic layers. In top view, the area of the second non-magnetic portion 11b is set to be larger than that of a portion of the first magnetic portion 11a which has the smallest area.

Description

  The present invention relates to a common mode noise filter used in various electronic devices such as digital devices, AV devices, and information communication terminals, and a method for manufacturing the same.

  As shown in FIG. 5 (a), a conventional method for manufacturing a common mode noise filter of this type is first formed with a first laminated portion 1a and a nonmagnetic portion 4 in which coils 2 and 3 are built. As shown in FIG. 5B, after forming the concave portion 5 by irradiating the winding shaft portions of the coils 2 and 3 of the non-magnetic portion 4 with a laser, as shown in FIG. To form the magnetic body portion 6, and then, as shown in FIG. 5D, the second laminated portion 1 b is laminated on the nonmagnetic portion 4 and fired, and further external electrodes are formed. It was like that.

  Further, the magnetic field portion 6 is intensified by the magnetic body portion 6 to increase the impedance of the common mode component so as to remove common mode noise.

  As a prior art document related to the invention of this application, for example, Patent Document 1 is known.

JP 2006-229105 A

  In the above-described conventional common mode noise filter, the concave portion 5 formed by irradiating the laser has a taper shape, so that the diameter of the lower portion of the concave portion 5 is reduced, so that the magnetic flux passing through the magnetic body portion 6 is reduced. As a result, the magnetic field that intersects the coils 2 and 3 cannot be increased, and as a result, the impedance of the common mode component cannot be increased, resulting in a problem that the common mode noise removal function is deteriorated. It was.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a common mode noise filter capable of improving a common mode noise removal function.

  In order to solve the above-mentioned object, the present invention provides a first magnetic body portion whose area gradually increases as it goes upward, and a nonmagnetic layer located at the lowest layer among the plurality of nonmagnetic layers. A second magnetic body portion formed on the body layer, and the area of the second magnetic body portion is larger than the area of the smallest area of the first magnetic body portion in a top view. It has the structure of.

  The common mode noise filter of the present invention can strengthen the magnetic field crossing the coil by increasing the area of the magnetic part in the nonmagnetic layer located at the bottom layer, thereby removing common mode noise. The effect is that the function can be improved.

  Further, the first magnetic body part and the second magnetic body part are formed in line symmetry when viewed from the cross section, and the symmetry axis of the first magnetic body part and the symmetry axis of the second magnetic body part are substantially coincided with each other. Thus, it is possible to stabilize the magnetic flux passing through the magnetic part, thereby strengthening the magnetic coupling of the coils and increasing the impedance of the common mode component.

Sectional drawing of the common mode noise filter in one embodiment of this invention Perspective view of the common mode noise filter Sectional drawing which shows the manufacturing method of the common mode noise filter Sectional drawing which shows the manufacturing method of the common mode noise filter Sectional drawing which shows the manufacturing method of the conventional common mode noise filter

  FIG. 1 is a sectional view of a common mode noise filter according to an embodiment of the present invention, and FIG. 2 is a perspective view of the common mode noise filter.

  As shown in FIGS. 1 and 2, the common mode noise filter according to the embodiment of the present invention includes a first magnetic body portion 11a and a second magnetic body portion 11b filled with a magnetic material. 12, first and second laminated portions 13 a and 13 b having magnetic materials laminated on the top and bottom of the nonmagnetic portion 12, and first and second coils 14 and 15 formed on the nonmagnetic portion 12. The first coil 14 is composed of two spiral coil conductors, the second coil 15 is composed of two spiral coil conductors, and the coil conductor constituting the first coil 14 is The two coil conductors constituting the two coils 15 are arranged so as to be sandwiched between them.

  That is, the first and second laminated portions 13a and 13b made of a magnetic material are sandwiched between the first laminated portion 13a and the second laminated portion 13b in the vertical direction, and a plurality of nonmagnetic layers are laminated. The non-magnetic portion 12 formed by the first magnetic coil 12, the first and second coils 14 and 15 formed inside the non-magnetic portion 12, and the first and second coils 14 and 15 in the non-magnetic portion 12. And magnetic body portions 11a and 11b formed on 15 winding shaft portions.

  Then, the area of the magnetic body portions 11a and 11b gradually increases as it becomes higher in the portion constituted by the nonmagnetic material layer that is not located at the lowest layer among the plurality of nonmagnetic material layers (tapered). A first magnetic body portion 11a and a second magnetic body portion 11b formed in the nonmagnetic body layer 12a located at the lowest layer among the plurality of nonmagnetic body layers. The area of the second magnetic body portion 11b is larger than the area of the smallest area of the first magnetic body portion 11a.

  At this time, the second magnetic body portion 11b completely covers at least the lowest portion of the first magnetic body portion 11a having the smallest area when viewed from above. Further, the first magnetic body portion 11a and the second magnetic body portion 11b are brought into contact with each other so as to be integrated. Further, the first magnetic body portion 11a and the second magnetic body portion 11b are formed symmetrically with respect to each other as viewed from the cross section, and the symmetry axis of the first magnetic body portion 11a and the symmetry axis of the second magnetic body portion 11b. Are substantially matched.

  In the above configuration, the nonmagnetic portion 12 is formed by laminating a plurality of nonmagnetic layers, and the nonmagnetic portion 12 is configured in a sheet shape with a nonmagnetic material such as Cu-Zn ferrite or glass ceramic. Has been.

  Furthermore, first and second coils 14 and 15 are formed inside the nonmagnetic portion 12, and the coil conductors constituting the first and second coils 14 and 15 are each made of a conductive material such as silver. Is formed by plating or printing in a spiral shape.

  At this time, the two coil conductors constituting the second coil 15 are laminated so as to sandwich the coil conductor constituting the first coil 14. Here, a part of coil conductor which comprises the 1st coil 14 is arrange | positioned in the substantially same position by the top view, and the winding direction is also made into the same direction. Similarly, the coil conductors constituting the second coil 15 are arranged at substantially the same position in top view, and the winding direction is also the same direction.

  The coil conductors constituting the first coil 14 are connected to each other via a via electrode 14a, and the coil conductors constituting the second coil 15 are connected to each other via a via electrode 15a. The via electrodes 14a are provided at the same position when viewed from above, and the via electrodes 15a are also provided at the same position when viewed from above. The via electrodes 14a and 15a are formed by drilling holes in a predetermined portion of each non-magnetic layer with a laser and filling the holes with silver.

  The upper and lower layers of the nonmagnetic portion 12 are provided with first and second laminated portions 13a and 13b made of a magnetic material, respectively, and the first and second laminated portions 13a and 13b are configured in a sheet shape. The magnetic layer is made of a magnetic material such as Ni-Cu-Zn ferrite.

  Note that the number of sheets of the non-magnetic layer constituting the non-magnetic portion 12 and the magnetic layer constituting the first and second laminated portions 13a and 13b is not limited to the number shown in FIG. . In addition, the arrangement of the coil conductor constituting the first coil 14 and the coil conductor constituting the second coil 15 may be alternated, the coil conductor constituting the first coil 14, A part of the coil conductor constituting the second coil 15 may be an extraction electrode.

  And the main-body part 16 of a common mode noise filter is formed by the above-mentioned structure. In addition, four external electrodes 17 are provided on both end faces of the main body 16, and the external electrodes 17 are connected to both ends of the first coil 14 and both ends of the second coil 15, respectively. . Further, the external electrode 17 is formed by printing silver on the end face of the main body portion 16, and a nickel plating layer is formed on these surfaces by plating, and tin, solder, etc. A low melting point metal plating layer is formed.

  Hereinafter, a method for manufacturing a common mode noise filter according to an embodiment of the present invention will be described with reference to FIGS.

  First, as shown in FIG. 3A, the coil winding is performed on the inner side of the innermost portions of the first and second coils 14 and 15 of the nonmagnetic layer 12a made of glass ceramic, Cu—Zn ferrite, or the like. A through hole 18 that penetrates the nonmagnetic layer 12a is formed in a portion that becomes the axis center.

  The nonmagnetic layer 12a is laminated in the lowermost layer among the plurality of nonmagnetic layers constituting the nonmagnetic portion 12, and the through hole 18 is provided by a laser irradiation method.

  Next, as shown in FIG. 3B, the magnetic layer 12a in which the through holes 18 are formed is laminated on the laminated portion 13a.

  Next, as shown in FIG. 3C, a plurality of nonmagnetic layers are stacked on the top surface of the nonmagnetic layer 12 a in which the through holes 18 are formed to form the nonmagnetic portion 12. At this time, the nonmagnetic layer and the spiral coil conductor are alternately laminated, and the first and second coils 14 and 15 are constituted by the coil conductor. Further, the first and second coils 14 and 15 are formed by connecting coil conductors to each other via via electrodes 14 a and 15 a provided in a predetermined nonmagnetic material layer, and are built in the nonmagnetic portion 12. The The nonmagnetic layer is made of a nonmagnetic material made of glass ceramic, Cu—Zn ferrite, or the like.

  Next, as shown in FIG. 3 (d), the winding shaft portions of the first and second coils 14, 15 are irradiated with laser from above the nonmagnetic portion 12 to form other through holes 18. Here, the winding shaft portion is a portion located on the inner side of the innermost portions of the first and second coils 14 and 15 in a top view. Then, the laser conditions are adjusted so that the through-hole 18 does not penetrate at least the lower first laminated portion 13a and is connected to the through-hole 18 formed in the lowermost nonmagnetic layer 12a. Further, the central axes of the two through holes 18 are coincident with each other, and the shape in a top view is similar. In addition, the area of the other through-holes 18 is gradually increased toward the upper side (tapered).

  Next, as shown in FIG. 4A, the insides of the two through holes 18 are filled and printed with a magnetic material made of Ni—Cu—Zn ferrite or the like, and the first magnetic body portion 11a and the second magnetic material are printed. The body part 11b is formed. The through hole 18 that penetrates the lowermost nonmagnetic layer 12a may be filled with a magnetic material first, but after all the through holes 18 are formed as in the present embodiment, the magnetic Filling the material is preferable because productivity is improved and the first magnetic body portion 11a and the second magnetic body portion 11b are integrated. That is, since there is no gap between the first magnetic body portion 11a and the second magnetic body portion 11b, it is possible to prevent a decrease in magnetic flux.

  Next, as shown in FIG. 4B, a magnetic layer made of Ni—Cu—Zn ferrite or the like is laminated on the upper surface of the nonmagnetic portion 12 to form an upper second laminated portion 13b. Part 16 is configured.

  Further, the first laminated portion 13a and the second laminated portion 13b are brought into contact with the magnetic body portions 11a and 11b. Thereafter, the main body 16 is fired at a predetermined temperature.

  Finally, silver is printed on the end portion of the main body 16 to form the external electrode 17 connected to the first and second coils 14 and 15.

  If necessary, a plating layer made of Ni or Sn is formed on the surface of the external electrode 17 thereafter.

  Further, the first and second laminated portions 13a and 13b may be constituted by alternately arranging the nonmagnetic material layer and the magnetic material layer instead of the magnetic material layer alone. You may comprise only a nonmagnetic material layer, without forming 13a, 13b.

  However, cracks may occur when the shrinkage rates during firing of the magnetic layer constituting the first and second laminated portions 13a and 13b and the nonmagnetic layer constituting the nonmagnetic portion 12 are greatly different. Therefore, as described above, it is preferable that the first and second stacked portions 13a and 13b are constituted by both the magnetic layer and the nonmagnetic layer to absorb the difference in shrinkage ratio between them. Moreover, you may make the 1st, 2nd laminated parts 13a and 13 and a coil conductor contact.

  As described above, in the common mode noise filter according to the embodiment of the present invention, the area of the second magnetic body portion 11b is the smallest portion of the first magnetic body portion 11a in the top view. Since the area of the second magnetic body portion 11b formed in the nonmagnetic material layer 12a located at the lowermost layer is made larger than the area of the lower portion, the magnetic flux passing through the magnetic body portion 11b can be increased. As a result, since the magnetic field intersecting the first and second coils 14 and 15 can be strengthened, the impedance of the common mode component can be increased, and the common mode noise removal function can be improved. An effect is obtained.

  That is, the area in the top view can be made larger than the conventional magnetic body portion tapered to the nonmagnetic layer 12a positioned at the lowermost layer as in the prior art, and the magnetic flux passing through the magnetic body portion is correspondingly increased. Can do a lot.

  In addition, since the area of the second magnetic body portion 11b is larger than the area of the lowermost portion, which is the smallest area of the first magnetic body portion 11a, an anchor effect that prevents the magnetic material from being brought back is achieved. Can be provided.

  Further, the first magnetic body portion 11a and the second magnetic body portion 11b are formed symmetrically with respect to each other as viewed from the cross section, and the symmetry axis of the first magnetic body portion 11a and the symmetry axis of the second magnetic body portion 11b. Since the magnetic fluxes passing through the magnetic parts 11a and 11b can be stabilized, the magnetic coupling of the coils 14 and 15 can be strengthened, and the impedance of the common mode component can be increased. it can.

  And since the 2nd magnetic body part 11b is formed in the nonmagnetic material layer 12a located in the lowest layer, the penetration distance by the laser irradiation for forming the 1st magnetic body part 11a can be shortened. Since this reduces the taper, the volume of the first magnetic body portion 11a can be increased, and as a result, the magnetic flux passing through the magnetic body portions 11a and 11b can be increased.

  In this case, another magnetic body portion having an area larger than the area of the uppermost portion, which is the largest area in the top view of the first magnetic body portion 11a, is provided on the nonmagnetic layer located on the uppermost layer. If formed, the penetration distance in the laser irradiation for forming the first magnetic body portion 11a can be further shortened, and therefore the height direction (lamination direction) of the tapered first magnetic body portion 11a. Thus, the volume of the first magnetic body portion 11a can be further increased.

  Further, by forming the second magnetic body portion 11b in the nonmagnetic layer 12a located at the bottom layer, the contact area between the lower first laminated portion 13a and the second magnetic body portion 11b is increased. Therefore, a decrease in magnetic flux can be prevented.

  If the area of the second magnetic body portion 11b is larger than the area of the uppermost portion, which is the largest area of the first magnetic body portion 11a, when viewed from above, a larger magnetic flux can be passed. Further, the anchor effect is improved, and the contact area with the lower first stacked portion 13a is further increased.

  The method for manufacturing a common mode noise filter according to the present invention has an effect of improving the function of removing common mode noise, and is particularly used for digital devices, AV devices, information communication terminals, and the like. This is useful in noise filters and the like.

11a 1st magnetic body part 11b 2nd magnetic body part 12 Nonmagnetic part 13a, 13b 1st, 2nd laminated part 14 1st coil 15 2nd coil 18 Through-hole

Claims (3)

Nonmagnetic formed by laminating a plurality of nonmagnetic layers sandwiched between the first laminated portion and the second laminated portion in the vertical direction and the first and second laminated portions having a magnetic material. Part, a coil formed inside the non-magnetic part, and a magnetic part integrally formed on a winding shaft portion of the coil in the non-magnetic part, and the magnetic part is Among the plurality of nonmagnetic layers, a first magnetic body portion that gradually increases in area as it rises in a nonmagnetic portion formed of a nonmagnetic layer that is not positioned at the lowest layer among the nonmagnetic layers. The second magnetic body portion formed in the nonmagnetic material layer located in the lowermost layer, and the area of the second magnetic body portion in the top view is the portion with the smallest area of the first magnetic body portion Common mode noise filter that is larger than the area. The first magnetic body portion and the second magnetic body portion are formed in line symmetry when viewed from the cross section, and the symmetry axis of the first magnetic body portion and the symmetry axis of the second magnetic body portion are substantially aligned. The common mode noise filter according to claim 1. 2. The common mode noise filter according to claim 1, wherein a through-hole is provided in a nonmagnetic material layer located on a lowermost layer formed on an upper surface of the first laminated portion, and then another nonmagnetic material layer is formed thereon. A non-magnetic part and a coil inside the non-magnetic part, and then a through-hole in another non-magnetic layer so that the diameter gradually increases toward the upper part of the winding axis of the coil. And a method of manufacturing a common mode noise filter in which the through hole is filled with a magnetic material.

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