JP2014138045A - Common mode choke - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a configuration suitable for the miniaturization of a common mode choke applicable even for large current use.SOLUTION: A common mode choke includes: a magnetic core part configured by making a plurality of magnetic cores to abut each other; and a coil part wound around the magnetic core part. The magnetic core part has an inner leg and a pair of outer legs arranged on both sides of the inner leg, the coil part has a plurality of edge-wise coils, and the edge-wise coils are wound around the inner leg so as to be placed side by side in the axial direction of the inner leg of the magnetic core part.

Description

  The present invention relates to a common mode choke used in various power supply devices, electronic devices, and the like.

  Conventionally, a common mode choke in which a conducting wire is wound around a toroidal core has been widely used as a noise filter for removing common mode noise (for example, Patent Document 1). Such a common mode choke is configured by dividing a toroidal core into a plurality of regions and winding each region.

  In the case of a common mode choke applied to a large current application such as a power supply device, it is advantageous to use a rectangular wire that can secure a large cross-sectional area as a conducting wire. However, it is difficult to wind a flat wire around the toroidal core as described above. Therefore, for example, as shown in Patent Document 2, an edgewise coil wound so as to overlap a rectangular wire in the thickness direction is applied to two opposing magnetic legs of a square-shaped (rectangular frame) core. Arranged configuration is used.

JP-A-6-36951 Japanese Patent Laid-Open No. 10-97927

  In patent document 2, it aims at providing the coil component which is small and has the favorable high frequency impedance characteristic by dividing the close_contact | adherence winding part of the coil comprised with the flat wire into several through the gap. However, in a common mode choke using a square-shaped (rectangular frame) core as shown in Patent Document 2, a coil using a flat wire occupies a large proportion of the entire common mode choke. There was a limit to the overall miniaturization.

  In view of the above problems, an object of the present invention is to provide a configuration suitable for downsizing a common mode choke that can be applied to a large current application.

  The common mode choke of the present invention is a common mode choke having a magnetic core portion configured by abutting a plurality of magnetic cores, and a coil portion wound around the magnetic core portion, the magnetic core portion including a middle leg, It has a pair of outer legs arranged on both sides of the middle leg, the coil part has a plurality of edgewise coils, and the plurality of edgewise coils are juxtaposed in the axial direction of the middle leg of the magnetic core part. It is wound around the middle leg as described above. According to such a configuration, it is not necessary to arrange a plurality of edgewise coils in a direction (radial direction) perpendicular to the winding axis direction, so that the common mode choke can be reduced in size.

  Further, in the common mode choke, it is preferable that a magnetic gap is provided in a middle leg of the magnetic core portion.

  Furthermore, in the common mode choke, the edgewise coil is preferably provided with a line gap every turn.

  Furthermore, in the common mode choke, the magnetic core portion and the coil portion are preferably housed in a case and sealed with resin.

  Furthermore, in the common mode choke, it is preferable that a support portion for supporting the pair of outer legs of the magnetic core portion from the bottom surface side of the case is provided inside the case.

  Further, in the common mode choke, the case is preferably provided with a group of protrusions for forming the gap between lines.

  Further, in the common mode choke, it is preferable in terms of assembly work that the height of each protrusion of the protrusion group is monotonously changed with respect to the winding axis direction of the edgewise coil.

  ADVANTAGE OF THE INVENTION According to this invention, the structure suitable for size reduction of the common mode choke applicable also to a heavy current use can be provided.

It is a figure which shows embodiment of the common mode choke which concerns on this invention. It is a figure which shows the example of the magnetic core part used for embodiment of the common mode choke which concerns on this invention. It is a figure which shows the example of the coil part used for embodiment of the common mode choke which concerns on this invention. It is a figure which shows other embodiment of the common mode choke which concerns on this invention. It is a figure which shows other embodiment of the common mode choke which concerns on this invention. It is an enlarged view which shows a part of other embodiment of the common mode choke which concerns on this invention. It is a figure which shows other embodiment of the common mode choke which concerns on this invention. It is a figure which shows other embodiment of the common mode choke which concerns on this invention. It is a figure which shows the impedance characteristic of a common mode choke. It is a figure which shows the impedance characteristic of a common mode choke.

  Hereinafter, embodiments of the common mode choke according to the present invention will be specifically described with reference to the drawings. However, the present invention is not limited thereto. Moreover, the structure demonstrated in each embodiment is applicable also in other embodiment, unless the meaning of other embodiment is impaired, In that case, the overlapping description is abbreviate | omitted suitably.

  FIG. 1 is a diagram showing an embodiment of a common mode choke according to the present invention. A common mode choke 100 shown in FIG. 1 includes a magnetic core portion 200 configured by abutting a plurality of magnetic cores 1 and 2, and a coil portion 300 wound around the magnetic core portion 200. 1A is a bottom view of the common mode choke 100 viewed from the desired direction (z direction) of the window of the magnetic core portion 200 (a space portion formed in the magnetic core portion), and FIG. It is the side view seen from the winding axis direction (x direction).

  The magnetic core portion 200 includes a middle leg 6 and a pair of outer legs 7 and 8 disposed on both sides of the middle leg 6. The coil part 300 has a plurality of edgewise coils 3 to 5, and the edgewise coils 3 to 5 are wound around the middle leg 6 so as to be juxtaposed in the axial direction (x direction) of the middle leg 6 of the magnetic core part 200. Has been. In the embodiment shown in FIG. 1, a three-phase common mode choke is configured using three edgewise coils.

  An edgewise coil using a rectangular wire can secure a large conductor cross-sectional area, and is therefore suitable for large current applications, but inevitably increases the width of the conductor. Therefore, the configuration in which a plurality of edgewise coils are juxtaposed in the radial direction of the coil as in Patent Document 2 is an obstacle to miniaturization of the common mode choke because the coils are juxtaposed in the wide width direction of the flat wire. On the other hand, the common mode choke using the edgewise coils can be miniaturized by arranging the plurality of edgewise coils 3 to 5 on the same axis as shown in FIG.

  Also, when configuring a three-phase common mode choke, as in Patent Document 2, if three coils corresponding to each phase are wound around two opposing cores, they are wound in a balanced manner without waste. Is difficult. On the other hand, if three edgewise coils are wound around one middle leg as in the embodiment shown in FIG. 1, the same winding shape of the edgewise coil can be used and the length of the middle leg is increased. The length can be set without waste according to the winding area of the coil portion.

  Although the coil part 300 can be wound around the magnetic core part 200 via the bobbin, in the embodiment shown in FIG. 1, the coil part 300 is wound around the magnetic core part 200 without using the bobbin. An edgewise coil using a rectangular wire has a shape maintaining ability, so the bobbin can be omitted and the common mode choke can be downsized and the structure can be simplified. In this case, it is preferable to wind the coil part 300 around the magnetic core part 200 via an insulating sheet. As shown in FIG. 1B, the winding ends 9 and 10 of the edgewise coil are led out to one side of the magnetic core portion 200 in the z direction. In FIG. 1B, only the winding ends 9 and 10 of the edgewise coil arranged at the end in the x direction are shown for convenience, but the winding ends are derived in the same manner for the edgewise coils at the center and the opposite side. Has been.

  FIG. 1C shows a form in which the common mode choke 100 is developed at the A-A ′ butt position in FIG. Reference numeral 13 represents the abutting surface of the middle leg, and reference numerals 11 and 12 represent the abutting surfaces of the outer leg portions 7 and 8 on both sides of the middle leg, respectively. As the edgewise coil, a coil wound in a circular shape as viewed from the winding axis direction is used in accordance with the shape of the columnar middle leg. The winding part of the coil part (edgewise coil 4) is accommodated between the middle leg and the outer leg in the y direction (the juxtaposition direction of the middle leg and the outer leg), and on both sides of the magnetic core part (magnetic core 2) in the z direction. Protruding. The outer leg is enlarged in the z direction so that the winding portion of the coil portion does not protrude from the magnetic core portion, so that stabilization at the time of assembling the common mode choke can be achieved. However, when priority is given to downsizing, it is preferable to employ a configuration in which the winding portion of the coil portion protrudes from the magnetic core portion as shown in FIG.

  Next, the magnetic core part 200 will be further described in detail with reference to FIG. 2A is a view of the magnetic core window 15 as viewed from the desired direction (z direction), and FIG. 2B is a view of the magnetic core 2 as viewed from the butting surface side. The magnetic core part 200 is configured by abutting the ER cores having the same shape at three parallel leg portions. The abutment surface shape (cross-sectional shape) of the middle leg is circular, and the abutment surface shape of the outer leg is substantially rectangular. However, the shape of the magnetic core constituting the magnetic core part 200 is not particularly limited. For example, in the embodiment shown in FIGS. 1 and 2, the cross-sectional shape of the outer leg is an arc shape on the middle leg side, following the shape of the coil portion, but may be a rectangle having no arc portion. Further, the cross-sectional shape of the middle leg may be an ellipse, or a square such as a square or a rectangle. In this case, it is preferable that the coil portion has the same shape in accordance with the cross-sectional shape of the middle leg. However, from the viewpoint of minimizing the coil length and improving the productivity of the edgewise coil, it is necessary to use an edgewise coil wound in a circle in accordance with the shape of the middle leg, with the cross-sectional shape of the middle leg being circular. More preferred.

  The magnetic core 1 and the magnetic core 2 can be abutted without providing a gap, but a configuration in which a magnetic gap is provided in the middle leg of the magnetic core portion 200 is more preferable. As shown in FIG. 2, by providing a magnetic gap 14 at the abutting portion of the middle leg, it is possible to provide a common mode choke that prevents magnetic saturation and can cope with a larger current. In the embodiment shown in FIGS. 1 and 2, the magnetic gap 14 is provided in the center of the middle leg in the axial direction, and is disposed so as to be inside the edgewise coil 4. With such a configuration, leakage of magnetic flux can be suppressed.

  The magnetic material used for the magnetic core is not particularly limited. For example, a ferrite such as Mn—Zn or Ni—Zn, a dust core, a laminated core, or the like can be used. Among these, ferrite is more preferable from the viewpoints of freedom of shape and cost.

  Next, the coil unit 300 will be further described in detail with reference to FIG. 3A is a view as seen from a direction perpendicular to the direction (z direction) in which the window 15 of the magnetic core part is desired and the winding axis direction (x direction) of the coil part 300, and FIG. It is the figure seen from 300 winding axis directions (x direction). As shown in FIGS. 1 and 3, the edgewise coils 3 to 5 are wound in a circular shape, and the winding ends are led out substantially parallel to one direction (upper side in the z direction). Since the winding ends of adjacent edgewise coils are led away so as to be located on the opposite side in the y-axis direction with the middle leg in between, the connection between the winding end and other devices, parts, etc. is easy . Further, the edgewise coils 3 to 5 are arranged apart from each other at a predetermined interval for ensuring insulation. Such a predetermined interval can be ensured by arranging a spacer between the edgewise coils.

  Each of the edgewise coils 3 to 5 can be formed by closely winding without any interval every turn, but as shown in FIGS. 1 and 3, each edgewise coil 3 to 5 has one turn. More preferably, a gap is provided for each. A conceptual diagram in which a part of the edgewise coil 3 is enlarged is shown in FIG. In FIG. 3 (c), for convenience of showing the positional relationship for each turn, the continuity of the coils is omitted and the respective turns are separated.

  The shape of the conductor cross section of the edgewise coil is substantially rectangular (width> thickness), the winding axis direction of the edgewise coil is the thickness, and the direction perpendicular thereto is the width. Each turn 3a-3d of the edgewise coil 3 is wound through a predetermined line gap d. Since the edgewise coil has a large facing area at each turn, the line-to-line capacitance tends to increase. Therefore, the impedance characteristics on the high frequency side are particularly likely to deteriorate. On the other hand, by providing a gap between lines in each edgewise coil 3 to 5 for each turn, the capacitance between lines can be reduced and the impedance characteristics can be improved. In order to provide a gap between lines, a spacer may be inserted between each turn. Details of how to form the gap between lines will be described later.

  Since the line-to-line capacitance decreases as the line-to-line gap for each turn increases, the size of the line-to-line gap is preferably 10% or more, more preferably 20% or more of the width of the flat wire. On the other hand, if this is too large, the entire common mode choke becomes large, and therefore, the gap d between lines is more preferably in a range smaller than the thickness t of the flat wire. Further, in order to take advantage of the downsizing of juxtaposing the edgewise coils in the winding axis direction, the thickness T in the winding axis direction (x direction) of each edgewise coil including the gap between the lines is used. Is more preferably smaller than the maximum dimension in the y-direction perpendicular to it (corresponding to the outer diameter in the case of a circular edgewise coil as shown in FIGS. 1 and 3). The dimension of the conductor cross section of each edgewise coil is not limited to this. However, since the edgewise coils are juxtaposed in the axial direction, the ratio of the width w to the thickness (flat wire thickness) t of the conductor cross section is preferably large. For example, the ratio of the width w to the thickness t is preferably 2 or more, and more preferably 3 or more.

  Next, a common mode choke according to another embodiment will be described with reference to FIG. In the common mode choke 400 shown in FIG. 4, the magnetic core portion 200 and the coil portion 300 are accommodated in the case 17 and sealed with resin. FIG. 4 is a perspective view of the magnetic core part 200 and the coil part 300 accommodated in the box-shaped case 17 as seen from the y direction (the direction in which the middle leg and the outer leg are juxtaposed). 200 and the coil unit 300 are indicated by dotted lines.

  The accommodated magnetic core part 200 and coil part 300 are arranged so that the winding end protrudes toward the opening side of the case, that is, the window part of the magnetic core part 200 is on the opening side of the case. It is sealed by. The resin 18 is loaded to such a height that the winding portion of the coil unit 300 is covered, and only the winding end portion of the edgewise coil is exposed on the surface of the resin 18. By sealing the magnetic core part 200 and the coil part 300 with the resin 18, the insulation between the edgewise coils and between the coil part / magnetic core part can be more reliably increased.

  As such a resin, for example, a resin having excellent insulating properties such as a silicone resin, a urethane resin, and an epoxy resin is used. Also, the material of the case is not particularly limited, and generally used resins such as PBT and PET can be used.

  Next, a common mode choke according to another embodiment will be described with reference to FIG. In the common mode choke 500 shown in FIG. 5, the magnetic core part 200 and the coil part 300 are accommodated in the case 19 and are resin-sealed, as in the embodiment shown in FIG. The portion related to the resin sealing is the same as that of the embodiment shown in FIG. The embodiment shown in FIG. 5 is different from that of the embodiment shown in FIG. 4 in the structure inside the case. FIG. 5 is a side view of the common mode choke 500 seen through from the axial direction (x direction) of the coil portion.

  Inside the case 19, a support portion 20 is provided in a state extending in the x direction for supporting the pair of outer legs of the magnetic core portion 200 from the bottom surface side of the case. The support 20 supports the surface formed by the middle leg and the outer leg of the magnetic core portion 200 so as to be parallel to the bottom surface 21 of the case 19, and the direction of the winding end protruding from the resin 18 is also stabilized. Even in the embodiment shown in FIG. 4 in which the support portion 20 is not provided, a certain degree of positioning between the magnetic core portion and the coil portion is possible by setting the clearance between the magnetic core portion and the side wall of the case within an appropriate range. It is. However, by providing the support portion 20 as described above, the positioning and fixing of the magnetic core portion 20 and the coil portion wound around the magnetic core portion 20 are further ensured.

  The support portions 20 provided on both sides in the case 19 may extend over the entire x direction in the case 19 or may be arranged in a plurality of locations. Further, in the embodiment shown in FIG. 5, the support portion 20 is formed so as to protrude from the bottom surface 21 and the side wall of the case 19, and its cross section viewed from the x direction is rectangular. It is not limited. For example, the support portion may be formed so as to protrude from the bottom surface at a position spaced from the side surface, or conversely, may be provided so as to protrude from the side wall at a position spaced from the bottom surface. Further, the cross-sectional shape of the support portion is not limited to a rectangle, and may be any shape that can support the magnetic core portion 200 such as a triangle. Further, the position where the support portion 20 supports the magnetic core portion 200 is more preferably a position where the lower end of the magnetic core portion 200 is separated from the bottom surface of the case 19.

  It is possible to prepare a structure corresponding to the support portion 20 separately from the case and insert it under the magnetic core portion 200 for positioning. However, in order to reduce the number of parts, as shown in FIG. More preferably, it is integral with the case.

  Next, another embodiment of the common mode choke will be described with reference to FIG. FIG. 6 shows a modification of the case portion of the common mode choke shown in FIGS. Since other parts are the same as those of the embodiment shown in FIG. FIG. 6 is an enlarged conceptual view of a part of the edgewise coil 3 and the bottom surface of the case adjacent to the edgewise coil 3, as in FIG.

  As described above, when each of the turns 3a to 3d of the edgewise coil 3 is wound via the predetermined gap d, a spacer is disposed between the turns. The spacer can be inserted from the side surface or the upper surface side of the coil portion. However, the insertion of the spacer is complicated and positioning is difficult to stabilize. On the other hand, in the embodiment shown in FIG. 6A, the case is provided with a projection group 23 for forming a gap between lines. By integrating the spacer with the case, the above problem relating to the insertion of the spacer can be solved.

  In FIG. 6A, a projection group 23 having the same height is provided upward from the bottom surface 22 of the case, and each projection is inserted between each turn to form a gap between lines. The cross-sectional shape of each protrusion viewed from the y direction is substantially rectangular, but its tip is rounded so that it can be easily inserted between turns. Instead of rounding, the tip portion may be triangular. In addition, although the cross-sectional shape of the protrusion is not limited to this, a substantially rectangular shape whose width does not change at a certain height from the bottom surface is preferable so that the coil portion is difficult to come off. The protrusion group 23 may extend over the entire y direction of the case bottom surface, or may be partially provided only in the lower end portion of the coil portion, that is, in the region straddling the center of the case bottom surface in the y direction. Further, the protruding portion can be formed so as to protrude from the side surface or the supporting portion as shown in FIG. 5 instead of or in addition to the bottom surface.

  In the embodiment shown in FIG. 6 (b), similarly to the embodiment shown in FIG. 6 (a), a protrusion group 25 is provided upward from the bottom surface 24 of the case, and each protrusion is inserted between each turn. A gap between lines is formed. In the embodiment shown in FIG. 6B, the height of each protrusion of the protrusion group 25 changes monotonously with respect to the winding axis direction of the edgewise coil. By adopting such a configuration, when inserting each protrusion between turns, it is possible to insert from the higher protrusion in order, so that the assembly work is more complicated than when the protrusions have the same height. Is greatly improved.

  In the above embodiment, the pair of E-shaped magnetic cores are abutted to form the magnetic core portion, but the configuration of the magnetic core portion is not limited to this. For example, as shown in FIG. 7, a magnetic core portion configured by abutting an E-shaped magnetic core 26 and an I-shaped magnetic core 27 may be used. When a magnetic gap is formed in such a configuration, the magnetic gap 28 is usually disposed outside the edgewise coil. It is also possible to arrange the edgewise coil so as to cover the magnetic gap 28 at the forefront of the middle leg.

  Moreover, although the above-described embodiment is intended for a three-phase common mode choke, it goes without saying that each of the above-described configurations can be similarly applied to a single-phase common mode choke. FIG. 8 shows an example. A magnetic core portion having a middle leg and a pair of outer legs arranged on both sides of the middle leg is configured by abutting E-shaped magnetic cores 29 and 30, and the coil portion is configured by two edgewise coils 31 and 32. The two edgewise coils 31, 32 are wound around the middle leg so as to be juxtaposed in the axial direction of the middle leg of the magnetic core portion. In such a case as well, the effect of downsizing the common mode choke can be obtained as in the case of the three-phase. In the case of the embodiment shown in FIG. 8, the magnetic gap is arranged outside the edgewise coil (between the two edgewise coils), but using two magnetic cores having different lengths of the middle leg and the outer leg. The magnetic gap can also be arranged inside the edgewise coil by a method such as shifting the position of the magnetic gap from the center.

  The common mode choke of the embodiment shown in FIG. 4 was produced in the following manner. An ER-shaped Mn—Zn ferrite core was abutted to form a magnetic core. The diameter of the middle leg was 14.0 mm, and the size of the magnetic gap was 0.15 mm. Further, a rectangular wire having a thickness t of 1.4 mm and a width w of 5.5 mm is wound four turns to form one circular edgewise coil, and the core portion is formed by three such edgewise coils. Configured. The inner diameter of the edgewise coil was 15.6 mm, and the outer diameter was 26.6 mm. After inserting the middle leg of the magnetic core part into the coil part, the coil part was accommodated in a case. A spacer was inserted between the turns to form a 1 mm line gap, and then sealed with silicon resin.

  The obtained common mode choke has a case external dimension of 45 mm in the vertical direction (y direction), 53 mm in the horizontal direction (x direction), and 40 mm in height (z direction). The outer diameter of the width coil could be reduced to less than twice. In addition, a common mode choke configured without a spacer gap was also produced.

  FIG. 9 shows the frequency characteristics of the impedance of the common mode choke in which the line gap is provided between the turns, and FIG. 10 shows the impedance frequency characteristics of the common mode choke in which the line gap is not provided between the turns. As is clear from FIGS. 9 and 10, the impedance characteristic on the high frequency side is improved by providing the line gap between the turns by the spacer, and the line gap is provided between the turns of the edgewise coil coil. The configuration has been confirmed to be particularly effective. In addition, it was confirmed that in the common mode choke in which no line gap was provided between the turns, the impedance characteristics on the high frequency side after resin sealing were deteriorated as compared with those before resin sealing. On the other hand, in the common mode choke with a line gap between turns, there is no change in the impedance characteristics on the high frequency side before and after resin sealing, and this configuration is particularly effective when resin sealing is used. I understand.

1, 2: Magnetic core 3-5: Edgewise coil 6: Middle leg 7, 8: Outer leg 9: Winding end 10: Winding end 11-13: Abutting surface 14: Magnetic gap 15: Window 16: Line gap 17: Case 18: Resin 19: Case 20: Support portion 21: Bottom surface 22: Bottom surface 23: Protrusion group 24: Bottom surface 25: Protrusion group 26, 27: Magnetic core 28: Magnetic gap 29, 30: Magnetic core 31, 32: Edgewise coil 33 : Magnetic gap 100: Common mode choke 200: Magnetic core part 300: Coil part 400, 500: Common mode choke

Claims (7)

A common mode choke having a magnetic core portion configured by abutting a plurality of magnetic cores, and a coil portion wound around the magnetic core portion,
The magnetic core has a middle leg and a pair of outer legs disposed on both sides of the middle leg,
The coil portion has a plurality of edgewise coils,
The plurality of edgewise coils are wound around the middle leg so as to be juxtaposed in the axial direction of the middle leg of the magnetic core portion.   The common mode choke according to claim 1, wherein a magnetic gap is provided in a middle leg of the magnetic core portion.   The common mode choke according to claim 1, wherein a line gap is provided in the edgewise coil every turn.   The common mode choke according to claim 1, wherein the magnetic core portion and the coil portion are accommodated in a case and sealed with resin.   5. The common mode choke according to claim 4, wherein a support portion is provided inside the case for supporting the pair of outer legs of the magnetic core portion from the bottom surface side of the case.   6. The common mode choke according to claim 4, wherein a projection group for forming the gap between the lines is provided in the case.   The common mode choke according to claim 6, wherein the height of each protrusion of the protrusion group changes monotonously with respect to the winding axis direction of the edgewise coil.

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