JP6673711B2 - Coil parts - Google Patents

Description

  The present invention relates to a coil component, and more particularly to a coil component having two types of cores.

  Patent Documents 1 to 3 each disclose a coil component having a coil and a core arranged around the coil. Patent Document 1 discloses that a plurality of cores may be formed using different alloy powders. Patent Document 2 discloses that two types of magnetic materials having different thermal conductivity are used as a core. Further, Patent Document 3 discloses that a core is composed of two portions having different filling rates of magnetic powder.

JP 2015-99902 A JP 2012-19087 A JP 2012-235051 A

  Patent Documents 1 to 3 disclose the use of two types of cores. However, these Patent Documents 1 to 3 all aim to provide coil components with enhanced heat dissipation, and use electric and magnetic properties such as AC copper loss and DC superposition characteristics due to the use of two types of cores. It does not disclose any effect on mechanical properties.

  On the other hand, the inventor has previously proposed a coil component that uses two types of cores to improve electrical and magnetic characteristics (Japanese Patent Application No. 2015-164925). However, the inventor has found that while studying the reduction in height of the proposed coil component, the proposed coil component has a problem that the AC copper loss increases with the reduction in height.

  An object of the present invention is to provide a coil component having a reduced height, and a coil component having reduced AC copper loss.

According to the present invention, as the first coil component,
A conductor that generates a magnetic flux when energized;
A core provided around the conductor to form a magnetic path through which the magnetic flux circulates;
A coil component having
The conductor has a cross section that forms a rectangular winding window in a plane including the magnetic path,
The core has a first core having a first magnetic permeability and a second core having a second magnetic permeability lower than the first magnetic permeability,
The first core is in contact with the entire side of the window in the plane, protrudes from both ends of the side in a direction in which the side extends, and is located on the opposite side of the window with respect to a straight line including the side. ,
As the second core, a coil component in contact with three sides other than the one side of the winding window in the plane is obtained.

Further, according to the present invention, as the second coil component,
A first coil component,
The conductor is a winding constituting one or more coils having an axis along a first direction,
The coil forms two or more winding windows on the plane,
The first core is a coil component that is in contact with at least one of the window windows in the plane.

According to the present invention, as the third coil component,
A second coil component,
The plane includes the axis,
The coil forms the three winding windows in the plane,
The winding window is arranged in a second direction orthogonal to the first direction,
The first core is a coil component that is in contact with at least one side extending in the second direction of the window located at the center of the window in the plane.

According to the present invention, as the fourth coil component,
A third coil component,
The first core is a coil component that is in contact with the entire one side of each of the winding windows located on both sides of the winding window in the plane.

Further, according to the present invention, as the fifth coil component,
A fourth coil component,
The first core is a coil component protruding outward from respective ends of the winding windows located on both sides of the winding window in the plane.

Further, according to the present invention, as the sixth coil component,
Any one of the third to fifth coil components,
A coil component is obtained in which the coil is two or two sets of coils arranged close to each other in a second direction orthogonal to the first direction.

According to the present invention, as the seventh coil component,
A second coil component,
The coil forms the two winding windows in the plane,
A coil component is obtained in which the first core is in contact with one side of at least one of the winding windows extending in the second direction.

According to the present invention, as the eighth coil component,
A second coil component,
The coil forms the two winding windows in the plane,
As the first core, a coil component in contact with two opposing sides of the winding window is obtained.

Further, according to the present invention, as a ninth coil component,
A seventh or eighth coil component,
As the coil, a coil component that is a single coil or a plurality of coils arranged close to each other in the first direction is obtained.

Further, according to the present invention, as a tenth coil component,
A second coil component,
The plane includes the axis,
The coil forms the four winding windows in the plane,
The winding window forms two pairs side by side in a second direction orthogonal to the first direction,
The first core is a coil component that is in contact with two opposite sides of each pair of the winding windows in the plane.

Further, according to the present invention, as an eleventh coil component,
Any one of the first to tenth coil components,
When the length of one side of the window in contact with the first core is A, and the length of the other side of the window perpendicular to the window is B, a coil component with A / B> 0.6 is obtained. .

Further, according to the present invention, as a twelfth coil component,
An eleventh coil component,
A coil component with A / B> 1 is obtained.

Further, according to the present invention, as a thirteenth coil component,
Any one of the first to twelfth coil components,
The coil component is a coil in which a flat wire is wound in a flatwise manner.

Further, according to the present invention, as a fourteenth coil component,
Any one of the first to thirteenth coil components,
A bottom portion, and a side portion extending in one direction from the bottom portion, further comprising a case for housing the coil and the core;
As the first core, a coil component in contact with the bottom is obtained.

  In a plane including the axis of the coil and the magnetic path in which the magnetic flux circulates, the first core is in contact with the entire side of at least one winding window, protrudes from both ends of the side, and is opposite to the winding window with respect to a straight line including the one side. Located on the side. As a result, it is possible to suppress an increase in AC copper loss caused by a reduction in height without deteriorating inductance characteristics.

It is a figure for explaining an operation principle of a coil part proposed by the inventor previously. FIG. 2 is a diagram for explaining a relationship between the coil component of FIG. 1 and a winding method of a winding. FIG. 2 is another diagram for explaining a relationship between the coil component of FIG. 1 and a winding method of a winding. FIG. 2 is a diagram for describing a problem that occurs in the coil component having the configuration of FIG. 1 as the height is reduced. FIG. 2 is another diagram for describing a problem that occurs in the coil component having the configuration of FIG. 1 with a reduction in height. FIG. 4 is a diagram for explaining intrusion of magnetic flux into a coil, which is a coil component in which the core is entirely formed of a cast core, and which is generated in the reduced-height coil component. It is a figure for explaining the coil component by a 1st embodiment of the present invention, and is a sectional view in the plane containing the axis of a coil, and the magnetic path which a core forms. It is a figure showing the result of having calculated the characteristic of the coil component by a 1st embodiment of the present invention, and the coil component from which it differs. It is a figure for explaining the modification of the coil part by a 1st embodiment of the present invention. The illustration of the casting core and the case is omitted. It is a perspective view showing the schematic structure of the coil component by a 2nd embodiment of the present invention. The casting core and the case are partially removed. It is a perspective view which cuts and shows the coil component of FIG. 10 along the XI-XI line. It is a figure for demonstrating the coil component of FIG. 10, Comprising: It is sectional drawing of the principal part in the plane containing the axis | shaft of a coil, and the magnetic path which a core forms. It is a sectional view for explaining the modification of the coil component by a 2nd embodiment of the present invention. It is a figure for explaining the coil component by a 3rd embodiment of the present invention, and is a sectional view of the principal section in the plane containing the axis of the coil, and the magnetic path which the core forms.

  Referring to FIG. 1, an example of a coil component previously proposed by the inventor is a coil (winding) 11 and a pair of dust cores (high μ cores) 13 and 15 which are arranged to face each other with the coil 11 interposed therebetween. And A casting core (low μ core) (not shown) is provided between the pair of dust cores 13 and 15, that is, on both sides of the coil 11. The "compact core" is obtained by compression-molding a soft magnetic alloy powder and a binder, and the "cast core" is obtained by curing a slurry containing a soft magnetic alloy powder and a binder (resin). In general, a dust core can have a higher magnetic permeability (μ) than a cast core.

  As shown by a broken line in FIG. 1, when a current flows through the coil 11, a magnetic flux 17 around the coil 11 is generated. Since the magnetic flux 17 tends to pass through the inside of the dust cores 13 and 15 which are high μ cores, strong magnetic poles N and S are formed at both ends of the dust cores 13 and 15. In other words, a magnetic field (vertical magnetic field) directed in one direction is formed between both end portions of the dust cores 13 and 15. As a result, the magnetic flux 17 passing through the casting core is compressed from near one end of the dust core 13 to near one end of the dust core 15 and from near the other end of the dust core 15. The powder core 13 is guided to go straight near the other end. As a result, the magnetic flux 17 travels straight along a path away from the coil 11, so that the penetration of the magnetic flux 17 into the coil 11 is suppressed. Thus, the eddy current generated by the magnetic flux 17 entering the coil 11 is reduced, and the AC copper loss is reduced. Even if a magnetic gap is provided in the middle of the casting core, the leakage of the magnetic flux 17 in the magnetic gap can be suppressed by the action of the vertical magnetic field.

  The above-described effect of reducing the AC copper loss by using the dust cores 13 and 15 differs depending on the winding method of the coil 11. That is, there is a difference in the effect of inducing the magnetic flux 17 by the vertical magnetic field between the edgewise coil using a rectangular wire as the winding of the coil 11 and the flatwise coil. As shown in FIG. 2, the edgewise coil in which the flat wire is wound in the direction along the vertical magnetic field is, as shown in FIG. 3, the flat wire in which the flat wire is wound in the direction perpendicular to the vertical magnetic field. The entry of the magnetic flux 17 into the coil 11 can be suppressed more than the wise coil, and the AC copper loss can be reduced. 2 and 3, the sizes of the coils 11 in the horizontal direction are different, but these sizes are assumed to be equal.

  The inventor studied a reduction in the height of a coil component having the configuration shown in FIG. Here, the reduction in height assumes that the height of the coil component is set to 1/3 or less of its width, and that the height is 30 mm or less. When the height of the coil component as shown in FIG. 1 is reduced, the strong magnetic poles N and S formed on the dust cores 13 and 15 approach each other to generate a strong magnetic field. On the other hand, the magnetic resistance of the coil 11 decreases due to the reduction in height. As a result, the magnetic flux 17 passing through the coil 11 increases as shown by the arrow in FIG. In FIG. 4, the character size of the magnetic poles N and S indicates the strength of the magnetic field. For coil components with a reduced height, the use of flat wise coils is desired. This is because in order to reduce the height of the edgewise coil having a predetermined number of turns, the thickness of the winding must be reduced, which makes winding (production) difficult. As shown in FIG. 5, when a flatwise coil is used, the magnetic flux 17 passing through the coil 11 further increases. The magnetic flux 17 passing through the coil 11 generates an eddy current in the winding of the coil 11 and increases the AC copper loss. As shown in FIG. 6, when the entire core is formed of the cast core 19, the magnetic flux 17 passing through the coil 11 is relatively large because there is no dust core for inducing the magnetic flux 17.

  The coil component of the present invention is configured as follows in order to solve the above problem. That is, the coil component has a conductor that generates a magnetic flux when energized, and a core that is provided around the conductor and forms a magnetic path through which the magnetic flux circulates. The conductor has a cross section that forms a rectangular winding window in a plane that includes the magnetic path. The core has a first core having a first magnetic permeability and a second core having a second magnetic permeability lower than the first magnetic permeability. The first core is in contact with the entire side of the winding window on a plane including the magnetic path, and protrudes from both ends of the side. Further, the first core is located on the opposite side of the winding window with respect to a straight line including one side that is in contact. The second core is in contact with three sides other than the one side with which the first core of the winding window is in contact with the plane including the magnetic path.

(First Embodiment)
Referring to FIG. 7, a coil component 20 according to the first embodiment of the present invention accommodates a coil 21, a dust core (first core) 23, a cast core (second core) 25, and these. And a case 27.

  The coil 21 is a coil having a rectangular wire (conductor) having a substantially rectangular cross section as a winding. As the rectangular wire, for example, a polyamide-imide wire (AIW) in which a copper wire is covered with an insulating film can be used. Further, the outer peripheral surface of the coil 21 may be further covered with an insulating coating (not shown). As can be understood from FIG. 7, the coil 21 has an axis along a first direction (vertical direction in the figure), and is formed by winding a winding along a direction orthogonal to the axis. Coil. The coil 21 has a pair of end surfaces 211 and 213, and an inner peripheral surface 215 and an outer peripheral surface 217 connecting them. The shape of the end face is an annular polygon or a circle. The coil 21 generates a magnetic flux when energized.

  As shown in FIG. 7, the dust core 23 and the casting core 25 are arranged around the coil 21. Specifically, the dust core 23 is arranged on the lower surface 211 side of the coil 21, and the casting core 25 is arranged on the dust core 23 and the coil 21. Specifically, the coil 21 is disposed on the dust core 23. As a result, the dust core 23 exists only below the lower surface 211 of the coil 21 and does not exist above the lower surface 211 (on the upper surface 213 side). The dust core 23 has an outer shape larger than the outer shapes of the end faces 211 and 213 of the coil 21, and the coil 21 is arranged on one surface of the dust core 23 inside the outer peripheral surface. Thus, the dust core 23 covers the entire lower surface 211 of the coil 21 and protrudes outward from the outer peripheral surface of the coil 21. On the other hand, the casting core 25 is in contact with all of the inner peripheral surface 215, the outer peripheral surface 217, and the upper surface 213 of the coil 21 and covers the coil 21. Here, the dust core 23 has a first magnetic permeability, and the casting core 25 has a second magnetic permeability lower than the first magnetic permeability. In other words, the dust core 23 is a high μ core, and the casting core 25 is a low μ core.

  As understood from FIG. 7, the magnetic flux generated by the coil 21 mainly passes through the inside of the dust core 23 and the casting core 25. That is, the dust core 23 and the casting core 25 form a magnetic path through which the magnetic flux circulates. The magnetic flux passes through the magnetic path formed by the dust core 23 and the casting core 25 from the outer peripheral surface 217 side of the coil 21 to the inner peripheral surface 215 side through one end surface (upper surface) 213 side. And circulates from the inner peripheral surface 215 side to the outer peripheral surface 217 side through the other end surface (lower surface) 211 side. In the present embodiment, the dust core 23 is not disposed across the corner of the coil 21 (the boundary between the inner peripheral surface 215 or the outer peripheral surface 217 and each of the end surfaces 211 and 213). Therefore, at the corners of the coil 21 where the direction of the magnetic flux changes greatly, the penetration of the magnetic flux into the coil 21 is suppressed.

  As shown in FIG. 7, the case 27 is a lidless case having a bottom portion 271 and a side portion 273 protruding from the periphery of the bottom portion 271 in one direction (first direction). The case 27 houses the coil 21, the dust core 23, and the casting core 25 with the dust core 23 facing the bottom 271. With the coil 21 housed in the case 27, the dust core 23 is located between the coil 21 and the bottom 271 and is in contact with the bottom 271. In the present embodiment, by arranging the dust core 23 between the coil 21 and the bottom 271, heat generated in the coil 21 can be efficiently transmitted to the case 27 via the dust core 23. Usually, the case 27 is connected to a heat dissipation mechanism or the like.

  As shown in FIG. 7, the coil 21 has two cross sections in a plane including the axis of the coil 21 and including a magnetic path through which magnetic flux circulates. Both cross sections of these two coils 21 form a winding window. When the coil 21 has an insulating coating or the like covering the outer periphery, the cross section of the insulating coating or the like is also included in the window. That is, the winding window includes not only the conductor portion but also the insulator portion forming the coil 21. In the present embodiment, the cross section of the coil 21 in which the magnetic flux circulating around is formed is referred to as a window. Therefore, when the coil 21 is a single unit, each cross section forms a winding window. On the other hand, when a plurality of coils are superimposed or arranged in close proximity, a plurality of cross sections may form one winding window. For example, when two or more coils of the same shape are stacked one on top of the other with their axes aligned, the cross section of the two coils that overlap one another forms one winding window. That is, in this case, the coil has four cross sections, but has two winding windows. In this case, the dust core 23 is in contact with one of the two end faces of one of the two coils, and is not in contact with the other coil. Note that the plurality of coils that are stacked or arranged in close proximity do not need to be in contact with each other, and there may be a gap between them.

  As shown in FIG. 7, in the present embodiment, the shape of each winding window is substantially a square. That is, each winding window has two sides extending in the first direction and two sides extending in the second direction. The dust core 23 is in contact with the whole one side (corresponding to the lower surface 211 of the coil 21) of each winding window, and protrudes from both ends of the one side in the second direction. Further, the dust core 23 is located on the opposite side of the winding window with respect to a straight line including one side of the winding window that is in contact. The casting core 25 is in contact with the remaining three sides of each winding window.

  As can be understood from FIG. 7, when a current is applied to the coil 21 to generate a magnetic flux, strong magnetic poles N and S are formed in the dust core 23. This is because the dust core 23 extends outside both ends of one side of each winding window. The formed magnetic poles N and S have no strong magnetic poles facing each other. Therefore, no strong vertical magnetic field is generated in the casting core 25. Therefore, the magnetic flux passing through the coil 21 is reduced as compared with the coil component having the configuration shown in FIG. As a result, AC copper loss can be reduced. On the other hand, since the thickness of the coil component 20 itself is thin, induction of magnetic flux by the dust core 23 can still be expected. Thus, the inductance L can be improved while maintaining a low loss. Note that such an effect is that the aspect ratio K = A / B is 0 when the length of the side of the window core in contact with the dust core 23 is A and the length of the side orthogonal to the side is B. This is remarkable when it is larger than 0.6, especially when it is larger than 1. Therefore, the shape of the coil 21 is set so that K> 0.6, preferably, K> 1.

  Referring to FIG. 8, coil component 20 (No. 1) according to the present embodiment, coil component (No. 2) having the configuration shown in FIG. 1, and coil component (No. 3) in which all the cores are dust cores. ) And results obtained by calculating various characteristic values of the coil component (No. 4) in which all the cores are cast cores by the finite element method (FEM). As can be understood from FIG. 8, the coil component 20 (No. 1) according to the present embodiment has a lower resistance loss Rac and lower AC copper loss than the coil component (No. 2) having the configuration of FIG. Few. Further, the coil component 20 (No. 1) according to the present embodiment has a higher inductance L and a lower loss resistance Rac than the coil component (No. 3) in which the entire core is a dust core. Further, the coil component 20 (No. 1) according to the present embodiment has a slightly higher loss resistance Rac but a higher inductance L (0A) than the coil component (No. 4) in which all the cores are cast cores. , Thermal resistance is small.

  In the above embodiment, the dust core 23 is disposed so as to cover the entire lower surface 211 of the coil 21 and protrude further outward, but the present invention is not limited to this. For example, a part surrounding the coil 21 such as an EI core or a UI core may be used. At least, as in the coil component 20A shown in FIG. 9, the dust core 23A that is in contact with a part of the end surface (lower surface) 211 of the coil 21 may be arranged. In this case, the dust core 23 </ b> A is arranged so that its longitudinal direction is orthogonal to the tangential direction on the outer peripheral surface 217 of the coil 21. The dust core 23 </ b> A is arranged such that the ends in the longitudinal direction protrude outside the inner peripheral surface 215 and the outer peripheral surface 217 of the coil 21. In other words, the dust core 23A is arranged so as to form a part of a magnetic path through which the magnetic flux generated by the coil 21 circulates. Further, the dust core 23A is in contact with the entire side of the winding window (corresponding to the lower surface 211 of the coil 21) on a plane including the axis of the coil 21 and the magnetic path formed by the dust core 23A. One side protrudes in the extending direction. Further, the dust core 23A is located on the opposite side of the winding window with respect to a straight line including one side of the winding window that is in contact. Also in this case, the casting core 25 is in contact with the remaining three sides of the winding window with which the dust core 23A is in contact. Thus, even when the dust core 23A is provided so as to cover a part of the lower surface 211 of the coil 21, the AC copper loss can be reduced as compared with the case where a pair of dust cores is used.

(Second embodiment)
Referring to FIG. 10, a coil component 50 according to the second embodiment of the present invention has two coils 51A and 51B, a dust core 53, a casting core 55, and a case 57. Referring to FIG. 11, the coil component 50 further includes an alumina plate 61 covering the lower surfaces of the coils 51A and 51B, an insulating film 63 covering the upper surfaces, the inner and outer peripheral surfaces of the coils 51A and 51B, and the coils 51A and 51B. It has a gap member 65 arranged on the dust core 53 on the inner peripheral side.

  As understood from FIGS. 10 and 11, the two coils 51A and 51B are each configured similarly to the coil 21 of the first embodiment. That is, the coils 51A and 51B have the same configuration as each other. Each of the coils 51A and 51B is covered by an alumina plate 61 and an insulating film 63. The coils 51A and 51B are connected to each other so that currents flow in opposite directions. The coils 51A and 51B have axes parallel to each other, and are arranged close to each other in a second direction orthogonal to a direction along the axis (first direction).

  The dust core 53 and the casting core 55 have a first magnetic permeability and a second magnetic permeability, respectively. The first magnetic permeability is higher than the second magnetic permeability. The dust core 53 is disposed so as to be in contact with one (lower surface) of a pair of end surfaces of the coils 51A and 51B via the alumina plate 61. In other words, the coils 51A and 51B are provided on one surface (upper surface) of the dust core 53 via the alumina plate 61. On the inner peripheral side of each of the coils 51A and 51B, a gap material 65 is disposed on one surface of the dust core 53. The casting core 55 is provided on the dust core 53 so as to cover the coils 51A and 51B, the alumina plate 61, and the gap material 65. The case 57 has a bottom part 571 and a side part 573 extending in one direction (first direction) from the bottom part 571. The case 57 accommodates therein the coils 51A and 51B, the dust core 53, the casting core 55, and the like. When housed in the case 57, the dust core 53 is located between the coils 51A and 51B and the bottom 571 of the case 57, and is in contact with the bottom 571. The casting core 55 is formed so as not to form a gap in the case 57.

  Referring to FIG. 12, on a plane including the axes of the coils 51A and 51B and the magnetic path (the magnetic path through which the circulating magnetic flux passes) formed by the cores (the dust core 53 and the casting core 55), the coils 51A and 51B. Has four cross sections arranged in the second direction. 12, the alumina plate 61, the insulating coating 63, the gap material 65, and the case 57 are omitted. In the following description, the coil 51A or 51B including the alumina plate 61 and the insulating coating 63 is also referred to. The four cross sections of the coils 51A and 51B constitute three winding windows. The cross sections of the coils 51A and 51B located on the center side constitute one winding window, and the cross sections of the coils 51A and 51b located on both sides constitute one winding window. The shape of each winding window is substantially square.

  As shown in FIG. 12, the dust core 53 is located on the opposite side of each winding window (coils 51A, 51B) with respect to a straight line including one side of each of the three winding windows (corresponding to the lower surfaces 511A, 511B of the coils 51A, 51B). It is located in. Further, the dust core 53 is in contact with the entire one side (corresponding to the lower surface 511A or 511B of the coil 51A or 51B) of each winding window, and protrudes outward (in the direction along the second direction) from both ends of the one side. . In the present embodiment, the dust core 53 projects outward from both sides of the two coils 51A and 51B in the second direction. In other words, when viewed along the axes of the coils 51A and 51B, the outer shape of the dust core 53 is larger than the outer shape of the two coils 51A and 51B. The casting core 55 is in contact with the remaining three sides except for one side of the window core in contact with the dust core 53.

  Among the magnetic fluxes generated by energizing the coils 51A and 51B, the magnetic flux circulating around the centrally located winding window is from the inner peripheral surface 515A of one coil 51A to the upper surfaces 513A and 513B of the coils 51A and 51B. To the inner peripheral surface 515B side of the other coil 51B, and goes out to the lower surface 511B side of the other coil 51B. It returns to the inner peripheral surface 515A side of one coil 51A. The magnetic flux circulating around each of the winding windows located on both sides passes from the outer peripheral surface 517A, 517B side of each coil 51A, 51B to the inner peripheral surface 515A, 515B side through the upper surface 513A, 513B side. It goes out to the opposite side, and returns to the inner peripheral surface 515A, 515B side of the coils 51A, 51B from the inner peripheral surface 515A, 515B side, passes through the lower surface 511A, 511B side. The magnetic flux generates strong magnetic poles N and S in the dust core 53. In FIG. 11, the strength of the magnetic pole is represented by the size of the character.

  Also in the present embodiment, the strong magnetic poles N and S formed on the dust core 53 have no strong magnetic poles facing each other. Therefore, no strong vertical magnetic field is generated in the casting core 55. As a result, penetration of magnetic flux into the coils 51A and 51B is suppressed, and AC copper loss can be reduced. On the other hand, since the thickness of the coil component 50 itself is thin (K> 0.6), induction of magnetic flux by the dust core 53 can be expected. Thereby, the leakage flux can be reduced.

  In the second embodiment, when viewed along the axial direction, the outer shape of the dust core 53 is larger than the outer shape of the combination of the coils 51A and 51B. Although it protrudes from both sides of 51B, the present invention is not limited to this. The dust core 53 only needs to be provided in contact with any one of the winding windows, and it is sufficient that the dust core 53 protrudes outward from both ends of one side in contact with the window. For example, like the coil component 50A shown in FIG. 13, the dust core 53 only needs to be in contact with the centrally located winding window and protrude from both sides thereof. In the example of FIG. 13, the dust core 53 is also in contact with the window located on both sides, but need not be in contact with the window located on both sides.

  In the second embodiment, the case where the coil component has the two coils 51A and 51B has been described, but the present invention is not limited to this. For example, instead of the two coils 51A and 51B, two coils in which a plurality of coils are layered in the first direction (disposed in close proximity) may be disposed close to each other in the second direction. In this case, the dust core 53 only needs to be in contact with at least one side of the central winding window among the three winding windows formed by the two sets of coils. In this case, the dust core 53 contacts one end face of any one of the coils included in each set and does not contact the other coils.

(Third embodiment)
Referring to FIG. 14, a coil component 70 according to the third embodiment of the present invention includes a coil 71, a dust core 73, and a casting core 75. The coil 71, the dust core 73, and the casting core 75 are housed in a case (not shown) similar to the case 27 of the first embodiment. Further, the coil 71 is configured similarly to the coil 21 of the first embodiment. That is, the coil 71 is a flatwise coil in which a rectangular wire having a substantially rectangular cross section is wound in a flatwise manner. The outer periphery of the coil 71 may be covered with an insulating film (not shown). The dust core 73 and the casting core 75 have a first magnetic permeability and a second magnetic permeability, respectively. The first magnetic permeability is higher than the second magnetic permeability. The dust core 73 is arranged on the inner peripheral side of the coil 71 and protrudes outward from both end surfaces 711 and 713 of the coil 71. One end of the dust core 73 is in contact with the bottom of a case (not shown). The casting core 75 is formed so as not to form a gap in the case.

  As shown in FIG. 14, on a plane including a shaft of the coil 71 and a magnetic path (a magnetic path through which a circulating magnetic flux passes) formed by the cores (the dust core 73 and the casting core 75), It has two rectangular winding windows (cross sections) arranged in the second direction. The dust core 73 is located on the opposite side of the winding window with respect to a straight line including one side of each winding window (corresponding to the inner peripheral surface of the coil 71). Further, the dust core 73 is in contact with the entire one side (corresponding to the inner peripheral surface 715 of the coil 71) of each winding window, and protrudes outward (in the direction along the first direction) from both ends of the one side. Also in the present embodiment, when the length of one side of the window in contact with the dust core 73 is A, and the length of the side of the window perpendicular to it is B, the aspect ratio K = A / B is as follows: Greater than 0.6, preferably greater than 1.

  The magnetic flux generated by energizing the coil 71 circulates around each of the two winding windows. That is, the magnetic flux goes from the inner peripheral surface 715 side to the outer peripheral surface 717 side of the coil 71 on the upper surface 713 side of the coil 71 and turns to the lower surface 711 side. Then, on the lower surface 711 side, the magnetic flux goes from the outer peripheral surface 717 side to the inner peripheral surface 715 side and turns to the upper surface 713 side. At this time, the magnetic flux generates strong magnetic poles N and S in the dust core 73. Also in the present embodiment, the strong magnetic poles N and S formed in the dust core 73 have no strong magnetic poles facing each other. Therefore, no strong vertical magnetic field is generated in the casting core 75. As a result, penetration of magnetic flux into the coil 71 is suppressed, and AC copper loss can be reduced. On the other hand, since the thickness of the coil component 70 itself is thin (K> 0.6), induction of magnetic flux by the dust core 73 can be expected. Thereby, the leakage flux can be reduced.

  In the third embodiment, the case where the coil component has the single coil 71 has been described, but the present invention is not limited to this. For example, the coil component may include a coil in which a plurality of coils are layered in the first direction (disposed in close proximity). In this case, the dust core 73 may be in contact with any one of the two opposing sides of the two winding windows formed by the plurality of coils. In this case, the dust core 73 is in contact with all of the inner peripheral surface (all or part) or the outer peripheral surface (all or part) of the plurality of coils. Further, the coil component may include two or two sets of coils arranged in a second direction orthogonal to the first direction. In this case, the coil forms four (two pairs) winding windows arranged in the second direction on a plane including the axis and the circulating magnetic flux. The dust core 73 contacts two opposing sides of each pair of two winding windows. In other words, the dust core 73 is arranged on the inner peripheral side so as to be in contact with the inner peripheral surface of each (set) of coils. The casting core 75 is in contact with the other side of the window.

  Although several embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, in each of the above embodiments, the core constituting the magnetic path through which the magnetic flux circulates is continuous, but a magnetic gap (air gap or gap material) may be arranged in the middle of the magnetic path. Further, in each of the above embodiments, the dust core and the casting core are each single, but may be composed of a plurality of divided portions.

11 coil (winding)
13,15 Dust core (high μ core)
17 Magnetic flux 19 Casting core 20 Coil component 21 Coil 211 End face (lower face)
213 End surface (upper surface)
215 Inner peripheral surface 217 Outer peripheral surface 23, 23A Dust core (first core)
25 Casting core (second core)
27 Case 271 Bottom 273 Side 50, 50A Coil component 51A, 51B Coil 511A, 511B End surface (lower surface)
513A, 513B End surface (upper surface)
515A, 515B Inner peripheral surface 517A, 517B Outer peripheral surface 53 Dust core 55 Casting core 57 Case 571 Bottom 573 Side 61 Alumina plate 63 Insulating coating 65 Gap material 70 Coil component 71 Coil 711 End surface (lower surface)
713 End surface (upper surface)
715 Inner peripheral surface 717 Outer peripheral surface 73 Dust core 75 Casting core

Claims (8)

A conductor that generates a magnetic flux when energized;
A core provided around the conductor to form a magnetic path through which the magnetic flux circulates;
A case accommodating the conductor and the core;
A coil component having
The conductor is a winding constituting one or more coils having an axis along a first direction,
The conductor has a cross section that forms a rectangular winding window in a plane including the magnetic path,
The plane includes the axis,
The coil forms two or more winding windows on the plane,
The winding window is arranged in a second direction orthogonal to the first direction,
The core has a first core having a first magnetic permeability and a second core having a second magnetic permeability lower than the first magnetic permeability,
Wherein the first core is in the plane, the one side across the contact extending into the winding window of each of the second direction, protrude from both ends of the one side in at least one of said Makimado the second direction, and wherein about the line containing the one side of each of Makimado located on the opposite side of the winding window,
The second core is in contact with three sides other than the one side of each of the winding windows in the plane,
The case has a bottom and side portions extending in one direction from the bottom,
A coil component in which the first core is in contact with the bottom. The coil component according to claim 1 ,
The coil forms the three winding windows in the plane,
The first core is continuously in contact with the winding window in the second direction,
The coil component, wherein the first core projects outward from respective ends of the winding windows located on both sides in the plane. The coil component according to claim 2 ,
A coil component, wherein the coil is two or two sets of coils arranged close to each other in the second direction . The coil component according to claim 1 ,
The coil forms the two winding windows in the plane,
A coil component in which the first core is continuously in contact with the window in the second direction and projects outward from an end of the window . The coil component according to claim 4,
A coil component, wherein the coil is a single coil or a plurality of coils arranged close to each other in the first direction . A coil component according to any one of claims 1 to 5 , wherein:
A coil component that satisfies A / B> 0.6, where A is the length of one side of the window in contact with the first core, and B is the length of the other side of the window perpendicular to the first window. The coil component according to claim 6 ,
A coil component where A / B> 1. A coil component according to any one of claims 1 to 7 ,
The coil component is a coil in which a flat wire is wound in a flatwise manner.

Images