Coil component and method for assembling coil component

Abstract

The present invention facilitates adjustment to a desired leakage inductance value and prevents narrowing of a coil winding area.　The present invention comprises: first and second magnetic cores (not illustrated) combined such that three legs of each of the cores have leading-end parts that oppose each other and the middle leg is inserted into a hollow part 42C of a bobbin 4; and a ring-shaped third magnetic core 3 divided circumferentially and mounted on the outer circumferential surface of a winding shaft part 21 of the bobbin 4 so that a desired leakage inductance value is generated according to the positional relation to the two magnetic cores, wherein the mounting of the third magnetic core 3 on the winding shaft part 21 is achieved by the mutual engagement of a plurality of first engaging parts 64 arranged circumferentially on the outer circumferential surface of the winding shaft part 21 and a second engaging part 65 arranged circumferentially on the inner circumferential surface of the third magnetic core 3 (only one magnetic core portion 3A is illustrated) so as to correspond with the first engaging parts 64.

Description

Coil component and method for assembling the same

[0001] The present invention relates to coil components such as magnetically coupled inductors and transformers that are mounted in electronic circuits of various devices, and to a method for assembling coil components.

[0002] In coil components, such as magnetically coupled inductors, the two built-in inductors are operated in an interleaved manner to reduce ripple and improve DC superposition characteristics by canceling out the DC magnetic flux generated within the core. As a result, it is possible to reduce the size and increase the efficiency of the coupled inductor, and even to make the capacitor more compact.

[0003] Among such magnetically coupled inductors, one known structure that facilitates adjustment of leakage inductance is that described in Patent Document 1 listed below. As shown in Fig. 12 , for example, the magnetically coupled inductor shown in Patent Document 1 includes a pair of magnetic cores 101, 102 each having a center leg portion and a side wall portion, a bobbin 104 into which the center legs of the magnetic cores 101, 102 are inserted and disposed on the outside, and coil windings 106A, 106B wound around the bobbin 104 and magnetically coupled to each other (106B is not shown; Fig. 12 shows the state in which the coil winding 106B has been removed and only a winding shaft portion 121 that is part of the bobbin 104 is visible), a ring core (third magnetic core) 103 for adjusting leakage inductance between the coil windings 106A, 106B and the ring core 103, and a spacer 175 for insulating the coil windings 106A, 106B from the ring core 103 and for positioning the ring core 103.

[0004] International Publication No. WO2023 / 188026A1

[0005] However, as mentioned above, the above-mentioned conventional technology has a structure in which a spacer is interposed between the magnetic core and the ring core. The spacer is made of a material with low magnetic permeability, such as plastic, which increases magnetic resistance and reduces leakage inductance. Therefore, to maintain high leakage inductance, the ring core must be made wider, which narrows the coil winding area accordingly. This reduces the number of coil turns and the coil wire diameter, resulting in a decrease in the performance of the magnetically coupled inductor. Coil components such as transformers also require control of leakage inductance, and present similar challenges.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a coil component that can easily be adjusted to a leakage inductance value according to the situation, and that can ensure the performance of a magnetically coupled inductor by preventing the coil winding area from becoming narrower, and a method for assembling the coil component.

[0007] In order to achieve this object, the coil component of the present invention comprises: a first magnetic core and a second magnetic core each having a center leg portion, outer leg portions located on both sides of the center leg portion, and a back portion connecting the center leg portion and the outer leg portion, and arranged so that the tips of the center legs and the tips of the corresponding outer legs abut against each other; a bobbin through which the center legs of the first magnetic core and the second magnetic core are inserted and arranged around the outside of the center legs of these two magnetic cores; a third magnetic core of an annular shape attached to a winding shaft portion through which the center leg portion of the bobbin is inserted, divided in the circumferential direction; and a first coil winding wound around one region of the winding shaft portion divided by the third magnetic core, and a second coil winding wound around the other region of the winding shaft portion, The third magnetic core is divided and attached circumferentially to the outer surface of the winding shaft portion of the bobbin with predetermined elements set so that a desired leakage inductance value is generated depending on the positional relationship with the first magnetic core and the second magnetic core, and the attachment of the third magnetic core to the winding shaft portion is achieved by mutual engagement of a plurality of first engaging portions arranged circumferentially on the outer surface of the winding shaft portion with second engaging portions arranged circumferentially on the inner surface of the third magnetic core to correspond to the first engaging portions.

[0008] In the above coil component, the wire material of the first coil winding and the second coil winding is preferably insulated wire. The wire material of the first coil winding and the second coil winding is preferably insulated wire in which the outer periphery of a litz wire is covered with insulating tape. Furthermore, the predetermined element related to the third magnetic core, which is set to generate the desired leakage inductance value, is preferably the thickness of the third magnetic core. Furthermore, the predetermined element related to the third magnetic core, which is set to generate the desired leakage inductance value, is preferably the outer diameter of the third magnetic core. Furthermore, the predetermined element related to the third magnetic core, which is set to generate the desired leakage inductance value, is preferably the magnetic saturation characteristic of the material of the third magnetic core.

[0009] Preferably, at least one second engaging portion is provided for each core member of the circumferentially divided third magnetic core so as to correspond to a plurality of first engaging portions arranged in the circumferential direction on the outer circumferential surface of the winding shaft portion. Also, the first engaging portion may be a convex portion formed on the outer circumferential surface of the winding shaft portion, and the second engaging portion may be a concave portion formed on the inner circumferential surface of the third magnetic core and engaging with the first engaging portion.

[0010] Furthermore, a method for assembling a coil component of the present invention includes a first magnetic core and a second magnetic core, each having a center leg portion, outer legs located on both sides of the center leg portion, and a back portion connecting the center leg portion and the outer legs, butting together the tips of the center legs and the tips of the corresponding outer legs, and inserting the center legs of the first magnetic core and the second magnetic core into a hollow portion of a bobbin, and attaching a circumferentially divided annular third magnetic core to a winding shaft portion of the bobbin around the hollow portion into which the center leg portion is inserted, and then performing a second step of winding a first coil winding in one region and a second coil winding in the other region, the winding shaft portion being divided in the axial direction by the third magnetic core, In the first step, the third magnetic core is attached to the winding shaft portion of the bobbin by engaging a second engaging portion provided on the inner surface of the third magnetic core with a first engaging portion provided on the outer surface of the winding shaft portion of the bobbin, with predetermined elements set so that a desired leakage inductance value is generated depending on the positional relationship between the first magnetic core and the second magnetic core.

[0011] In the coil component and coil component assembly method of the present invention, the annular (ring-shaped) third magnetic core is positioned by engaging a first engaging portion provided on the outer surface of the winding shaft portion of the bobbin with a second engaging portion provided on the inner surface of the third magnetic core, without using the spacers used in the past. Eliminating the spacers improves magnetic coupling between the first and second magnetic cores and the third magnetic core, which is the ring core. This allows for the use of a smaller ring core, thereby avoiding the need for narrowing the coil winding area and improving the performance of the coil component. Furthermore, since the assembly of spacers is no longer necessary, the number of components can be reduced, and the labor and time required for assembly can be reduced. Furthermore, the coil component and coil component assembly method of the present invention can adjust the leakage inductance value in a transformer, making them useful not only for magnetically coupled inductors but also for coil components such as transformers.

[0012] It is a perspective view showing the main part of the coil component according to an embodiment of the present invention. It is a perspective view showing the magnetic core part (first magnetic core, second magnetic core, and third magnetic core) of the coil component according to an embodiment of the present invention. It is a perspective view showing a state in which one coil winding is removed from the coil component shown in FIG. 1A. It is a perspective view showing a state in which both coil windings, the first magnetic core, the second magnetic core, and one third magnetic core component are removed from the coil component shown in FIG. 1A. It is a schematic view showing the third magnetic core (A) and one third magnetic core component (B) of the coil component shown in FIG. 1A. It is a schematic view showing the spacer (A) and one third magnetic core component (B) of the coil component according to the prior art. It is a cross-sectional view (A) of the coil component shown in FIG. 1A and a partially enlarged view (B) thereof. It is a cross-sectional view (A) of the coil component according to the prior art and a partially enlarged view (B) thereof. It is a perspective view showing the first insulation mode (A) and the second insulation mode (B) of the coil winding among the coil components shown in FIG. 1A. It is a schematic cross-sectional view showing the flow of magnetic flux of the magnetic coupling inductor (coil component) according to an embodiment of the present invention. In the magnetic coupling inductor (coil component) according to an embodiment of the present invention, the mode of adjusting the leakage inductance value ((A) is the mode of changing the thickness of the third magnetic core (ring core), (B) is the mode of changing the outer diameter of the third magnetic core (ring core), (C) is the mode of changing the magnetic saturation characteristic of the third magnetic core (ring core)) is shown in a schematic view. It is a schematic view (part 1) showing the assembly method (A1, A3) of the coil component according to an embodiment of the present invention and the assembly method (B1 to B3) of the coil component according to the prior art. It is a schematic view (part 2) showing the assembly method (A4 to A7) of the coil component according to an embodiment of the present invention and the assembly method (B4 to B7) of the coil component according to the prior art. It is a perspective view showing a state in which one coil winding is removed from the coil component according to the prior art.

[0013] A coil component and an assembly method thereof according to one embodiment of the present invention will be described below with reference to the drawings. The coil component according to this embodiment is configured to function as a magnetically coupled inductor 100. <Magnetic Coupled Inductor (Coil Component)> Fig. 1A is a perspective view showing the main components of the coil component 100 according to this embodiment (hereinafter referred to as the magnetically coupled inductor 100), and Fig. 1B shows the magnetic core components (comprising a first magnetic core 1, a second magnetic core 2, and a third magnetic core 3) of the magnetically coupled inductor 100 assembled together. Fig. 2 is a perspective view showing the magnetically coupled inductor 100 shown in Fig. 1A with one coil winding 6B removed, and Fig. 3 is a perspective view showing the magnetically coupled inductor 100 shown in Fig. 1A with both coil windings 6A and 6B, and one third magnetic core component 6B of the first magnetic core 1, the second magnetic core 2, and the third magnetic core 3 removed.

[0014] That is, this magnetically coupled inductor 100 has center legs 14, 24, outer legs 12, 22 located on both sides of the center legs 14, 24, and back surfaces 13, 23 connecting the center legs 14, 24 and the outer legs 12, 22, respectively, and includes a first magnetic core 1 and a second magnetic core 2 that are arranged such that the tips of the center legs 14, 24 and the tips of the corresponding outer legs 12, 22 abut against each other, and a first magnetic core 1 and a second magnetic core 2 through which the center legs 14, 24 of the first magnetic core 1 and the second magnetic core 2 are inserted, and these two magnetic The coil winding includes a bobbin 4 disposed around the outer periphery of the middle legs 14, 24 of the cores 1, 2, a circular third magnetic core 3 (consisting of a combination of two third magnetic core portions 3A, 3B) divided in the circumferential direction of the winding shaft portion 21 into which the middle legs 14, 24 of the bobbin 4 are inserted, and attached to the winding shaft portion 21, and a coil winding 6A wound around one (42A) of the winding shaft regions 42A, 42B divided by the third magnetic core 3 in the axial region of the winding shaft portion 21, and a coil winding 6B wound around the other (42B).

[0015] The third magnetic core 3 is divided and attached to the outer peripheral surface of the winding shaft portion 21 of the bobbin 4 in a circumferential direction so as to generate a desired leakage inductance value depending on the positional relationship with the first magnetic core 1 and the second magnetic core 2. The third magnetic core 3 is attached to the winding shaft portion 21 by mutual engagement between a plurality of first engaging portions 64 (for example, four at 90-degree intervals) arranged in the circumferential direction on the outer peripheral surface of the winding shaft portion 21 and second engaging portions 65 arranged in the circumferential direction on the inner peripheral surface of the third magnetic core 3 so as to correspond to the first engaging portions 64.

[0016] 12 , in a coil device 200 (hereinafter referred to as magnetically coupled inductor 200) according to the prior art, in order to position the third magnetic core 103 with respect to the center legs of the first magnetic core 101 and the second magnetic core 102, a spacer 175 carrying the ring-shaped third magnetic core 103 is engaged with the winding shaft portion 121 of the bobbin 104 arranged around the center legs. However, the spacers 175 interposed between the center legs of the first magnetic core 101 and the second magnetic core 102 and the third magnetic core 103, and between the windings 106A, 106B and the third magnetic core 103, are made of a material with low magnetic permeability, such as plastic, and therefore increase the magnetic resistance, which causes a decrease in leakage inductance. For this reason, in the past, in order to maintain a high leakage inductance, it was necessary to set the width of the third magnetic core 103 wider, but this narrowed the space in which the windings could be arranged, which forced the number of coil turns and the diameter of the wire to be reduced, which had an adverse effect on the electrical characteristics.

[0017] Therefore, in this embodiment, the third magnetic core 3 is configured to directly engage with the winding shaft portion 21 of the bobbin 4 arranged around the center legs 14, 24 of the first magnetic core 1 and the second magnetic core 2 without using a spacer, bringing the third magnetic core 3 closer to the first magnetic core 1 and the second magnetic core 2, making it easier to ensure leakage inductance. This makes it possible to narrow the width of the third magnetic core 3, and due to the two effects of eliminating the spacer, it is possible to expand the space area (42A, 42B) in which the windings 6A, 6B are arranged, and it is possible to ensure the desired number of coil turns and the diameter of the coil wire, thereby improving the electrical characteristics.

[0018] Below, we will explain the structure for engaging the third magnetic core 3 with the bobbin 4 arranged around the center legs 14, 24 of the first magnetic core 1 and the second magnetic core 2. As shown in Figure 4 ((A) shows the assembled state of the third magnetic core 3, and (B) shows one third magnetic core part 3A that constitutes the third magnetic core 3), in this embodiment, a second engaging part 65 consisting of a plurality of recesses arranged in the circumferential direction is provided on the inner peripheral surface of the third magnetic core 3 of the magnetically coupled inductor 100. Meanwhile, near the center of the width direction of the outer peripheral surface of the winding shaft portion 21 of the bobbin 4, a plurality of first engagement portions 64 (for example, four at 90 degree intervals) which are convex portions are arranged circumferentially around this winding shaft portion 21, and each of the first engagement portions 64 which are convex portions is fitted into the corresponding second engagement portion 65 which is a concave portion, so that the third magnetic core 3 engages with the outer peripheral surfaces of the winding shaft portions 42A, 42B of the bobbin 4 arranged around the outer peripheries of the middle leg portions 14, 24 of the first magnetic core 1 and the second magnetic core 2, and is positioned.

[0019] It is preferable that at least one second engaging portion 65 is provided for each of the third magnetic core portions 3A and 3B. Furthermore, by configuring the third magnetic core 3 from two third magnetic core portions 3A and 3B that can be separated in the circumferential direction, it becomes possible to assemble the third magnetic core 3 around the winding shaft portion 21 of the bobbin 4. In this embodiment, the third magnetic core 3 is configured from two third magnetic core portions 3A and 3B, but the third magnetic core 3 can be configured from three or more third magnetic core portions.

[0020] In addition, in the above embodiment, the first engaging portion 64, which is a convex portion, is provided on the outer peripheral surface of the winding shaft portion 21 of the bobbin 4, and the second engaging portion 65, which is a concave portion, is provided on the inner peripheral surface of the third magnetic core 3. However, it is also possible to provide the first engaging portion, which is a concave portion, on the outer peripheral surface of the winding shaft portion 21 of the bobbin 4, and the second engaging portion, which is a convex portion, on the inner peripheral surface of the third magnetic core 3. However, if it is desired to set the thickness of the winding shaft portion 21 of the bobbin 4 thin, it is preferable to use the above embodiment in which the first engaging portion provided on the outer peripheral surface of the winding shaft portion 21 of the bobbin 4 is a convex portion. Note that in the above embodiment, the second engaging portion 65, which is a concave portion, is provided on the inner peripheral surface of the third magnetic core 3. In this case, it is preferable to mold the third magnetic core 3 using a vertical pressing machine (vertical pressing machine).

[0021] In contrast, in the case of a magnetically coupled inductor according to the prior art, as described above, in order to position the third magnetic core with respect to the center legs of the first and second magnetic cores, a spacer carrying the ring-shaped third magnetic core is engaged with a bobbin arranged around the center legs. To explain this using Figure 5 ((A) shows the assembled state of spacer 175, and (B) shows third magnetic core part 103A constituting one of the third magnetic cores 103), spacer 175 is shaped like a tape reel with flanges 175A and 175B (see Figure 5) on both sides, and its ring-shaped magnetic core mounting groove 175C has an inner diameter that allows it to be fitted along the outer circumferential surface of winding shaft part 121 of bobbin 104. A plurality of recesses 185 are arranged circumferentially on the inner surface of the magnetic core mounting groove portion 175C, and each of these recesses 185 engages with each of the engaging protrusions (not shown) arranged circumferentially on the winding shaft portion 121 of the bobbin 104 (see Figure 12) to position the third magnetic core 103 relative to the middle legs of the first magnetic core 101 and the second magnetic core 102.

[0022] In the above-described conventional technology, when the third magnetic core 3 is mounted on the magnetic core mounting portion 175C of the spacer 175, the third magnetic core 3 is basically sandwiched and positioned between the flange portions 175A and 175B of the spacer 175. Therefore, unlike the third magnetic core 3 according to this embodiment, the third magnetic core portions 103A and 103B constituting the third magnetic core 103 have no engaging portions for positioning and have a simple shape, as shown in FIG. 5B . Therefore, the third magnetic core 103 is molded using a horizontal pressing machine (horizontal pressing machine).

[0023] As described above, this embodiment eliminates the spacer 175 that has conventionally been used, thereby achieving the advantageous effect of enabling the winding shaft regions 42A, 42B in which the windings 6A, 6B are disposed to be enlarged, which will be explained in more detail below by comparing Fig. 6, which shows this embodiment, with Fig. 7, which shows the prior art. Fig. 6 is a cross-sectional view (A) and a partially enlarged view (B) of the magnetically coupled inductor 100 according to this embodiment shown in Fig. 1, and Fig. 7 is a cross-sectional view (A) and a partially enlarged view (B) of the magnetically coupled inductor 200 according to the prior art.

[0024] In the magnetically coupled inductor 100 according to this embodiment, as shown in FIGS. 6A and 6B, the third magnetic core 3 (3A, 3B) and the windings 6A, 6B are arranged so as to be in contact with each other without any separate member interposed therebetween. In contrast, in the magnetically coupled inductor 200 according to the prior art, as shown in FIGS. 7A and 7B, the flanges 175A, 175B of the spacer 175 are interposed between the third magnetic core 103 (103A, 103B) and the windings 106A, 106B. Therefore, the width b of the third magnetic core 3 (3A, 3B) according to this embodiment is allowed to be up to a value equivalent to the width d of the third magnetic core 103 (103A, 103B) according to the prior art plus the thickness of the flanges 175A, 175B of the spacer 175. As a result, in this embodiment, there are no restrictions on the number of turns or the wire diameter of the electric wires constituting the windings 6A, 6B, thereby improving the electrical characteristics.

[0025] 6A and 6B, in the magnetically coupled inductor 100 according to the present embodiment, the third magnetic core 3 (3A, 3B) faces the first magnetic core 1 and the second magnetic core 2 via the winding shaft portion 21 of the bobbin 4, which has a thickness a, whereas in the magnetically coupled inductor 200 according to the prior art, the third magnetic core 103 (103A, 103B) faces the first magnetic core 101 and the second magnetic core 102, separated by a thickness c, which is the sum of the thickness of the winding shaft portion 121 of the bobbin 4 and the thickness of the magnetic core mounting portion 175C of the spacer 175. In this way, in the magnetically coupled inductor 100 according to the present embodiment, the distance between the third magnetic core 3 (3A, 3B) and the first magnetic core 1 and the second magnetic core 2 can be reduced by the thickness of the magnetic core mounting portion 175C of the spacer 175, compared to the prior art. This reduces the magnetic resistance and makes it possible to use a third magnetic core 3 (3a, 3b) with a smaller width, thereby further avoiding narrowing of the coil winding area and further improving the performance of the magnetically coupled inductor 100.

[0026] In the above-described prior art, the spacer 175 is provided with an insulating function. That is, the spacer 175 is made of an insulating material such as plastic, and flanges 175A and 175B (see FIG. 5 ) of the spacer 175 are interposed between the windings 106A and 106B and the third magnetic core 3 to provide insulation between the windings 106A and 106B and the third magnetic core 3. However, in this embodiment, the spacer 175 is eliminated, and the electrical wires constituting the windings 6A and 6B are provided with an insulating function. That is, as shown in FIG. 8(A), the windings 6A and 6B may be, for example, a litz wire 91A insulated by covering it with insulating tape 92A (made of PET, PEN, PI, or the like), or as shown in FIG. 8(B), a litz wire 91B insulated by molding it with multiple layers of insulating coating 92B (made of ETFE, FEP, PFA, nylon, or the like).

[0027] This ensures insulation even when the windings 6A, 6B come into direct contact with the third magnetic core 3. At the same time, insulation between the wires constituting the windings 6A, 6B can also be ensured. The insulation performance (voltage resistance) of the wires constituting the windings 6A, 6B is set to satisfy, for example, 0.6 kV / s between the wires constituting the windings 6A, 6B and the third magnetic core 103, and 1.8 kV / s between the wires constituting the windings 6A, 6B. While the above example shows the use of litz wires 91A, 91B as the windings 6A, 6B to be insulated, other wires, such as a single copper wire, may be used instead of the litz wires.

[0028] Below, a supplementary structural description of each part of the magnetically coupled inductor 100 of this embodiment will be provided. In this magnetically coupled inductor 100, the length of the center legs 14, 24 of the first magnetic core 1 and the second magnetic core 2 is approximately half the distance between the opposing back portions 13, 23, and the outer legs 12, 22 have a planar plate shape. The three legs 12, 14 constituting the first magnetic core 1 and the corresponding three legs 22, 24 constituting the second magnetic core 2 are arranged to face each other with minute gaps 32, 34 between them. The third magnetic core 3 is made of, for example, a ferrite core and has a circular ring shape with a rectangular cross section. The third magnetic core 3 is formed by combining a pair of third magnetic core portions 3A, 3B.

[0029] 3, the bobbin 4 is made of insulating resin and has flanges 43A, 43B on both ends of the cylindrical winding shaft 21, tape suspension sections 45A, 45B for suspending an exterior tape on the outside of each flange 43A, 43B, and terminal blocks 41A, 41B below each flange 43A, 43B. A plurality of terminal pins 9 are provided on each terminal block 41A, 41B.

[0030] Meanwhile, a plurality of first engagement portions 64 (for example, four at 90-degree intervals) are provided at approximately the center of the axial direction of the outer peripheral surface of the winding shaft portion 21 of the bobbin 4, arranged in the circumferential direction of this outer peripheral surface, and a plurality of second engagement portions 65 of the third magnetic core 3 that engage with these first engagement portions 64 are arranged in the circumferential direction of the inner peripheral surface of the third magnetic core 3 (for example, four at 90-degree intervals), and when the first engagement portions 64 and the second engagement portions 65 engage with each other, the third magnetic core 3 is fitted onto the winding shaft portion 21 of the bobbin 4. The third magnetic core 3 is formed by combining two semi-annular third magnetic core portions 3A, 3B, and is fixed by winding a third magnetic core fixing tape 77 around the outer peripheral surface.

[0031] The magnetically coupled inductor 100 of this embodiment, which has the basic configuration described above, has a two-in-one (2-in-1) structure in which the core portion is formed in a zigzag shape in plan view, with the annular third magnetic core 3 sandwiched between the first magnetic core 1 and the second magnetic core 2. Thus, in the magnetically coupled inductor 100 whose core portion is formed in a zigzag shape in plan view, the magnetic flux 8 flows as shown by the arrows in Fig. 9, and the magnetic fluxes 8 passing through the third magnetic core 3, which are generated by the currents passing through the coil winding 6A and the coil winding 6B, flow in the same direction.

[0032] More specifically, as described above, the first magnetic core 1 and the second magnetic core 2 are separated by gaps 32, 34 formed between the center legs 14, 24 and the outer legs 12, 22, respectively. Therefore, in the first magnetic core 1, the magnetic flux 8 passing through the outer legs 12 and the back surface 13 on both sides joins at the center leg 14 and both flows toward the tip surface of this center leg 14. On the other hand, in the second magnetic core 2, the magnetic flux passing from the outer legs 22 on both sides to the back surface 23 joins at the center leg 24 and both flows toward the tip surface of this center leg 24.

[0033] The magnetic flux 8 flowing through these two center legs 14, 24 collides with each other at the tip surfaces of the center legs 14, 24 and is cancelled out. Meanwhile, the magnetic flux 8 branched toward the third magnetic core 3 before the collision passes through the third magnetic core 3 and reaches the outer legs 12, 22 of the first magnetic core 1 and the second magnetic core 2. As a result, a magnetic loop consisting of the magnetic flux 8 circulating in the direction of the arrows as shown in Figure 9 is formed in the first magnetic core 1, the second magnetic core 2, and the third magnetic core 3. As shown in Figure 9, a gap 33 of a predetermined distance is also formed between the third magnetic core 3 and the outer legs 12, 22 of the first magnetic core 1 and the second magnetic core 2.

[0034] As described above, the core portions (first magnetic core 1, second magnetic core 2, and third magnetic core 3) are formed as a whole in a square shape in a plan view, and the proportion of the magnetic flux 8 flowing through the center legs 14, 24 of the first magnetic core 1 and the second magnetic core 2 that branches toward the third magnetic core 3 and flows through the outer legs 12, 22 of the first magnetic core 1 and the second magnetic core 2 can be adjusted by changing the degree of ease with which the magnetic flux 8 flows from the center legs 14, 24 of the first magnetic core 1 and the second magnetic core 2 to the third magnetic core 3. In view of the above, the magnetically coupled inductor 100 of this embodiment is configured so that the degree of ease with which the magnetic flux 8 flows from the center legs 14, 24 toward the third magnetic core 3 can be adjusted to a desired leakage inductance (leakage magnetic flux) value by changing (selecting) at least one element from the thickness (width) of the third magnetic core 3, the outer diameter of the third magnetic core 3, and the magnetic saturation characteristics of the third magnetic core 3. These elements will be explained in detail below.

[0035] 10A, multiple types of third magnetic cores 3 with different thicknesses (widths) may be prepared, and the one that provides the desired leakage inductance value may be attached to the outer circumferential surface of the winding shaft portion 21 of the bobbin 4. This is because the thicker the third magnetic core 3 is, the greater the amount of magnetic flux 8 branched toward the third magnetic core 3, as shown in FIG. 9, i.e., the greater the amount of leakage inductance.

[0036] 10B, multiple types of third magnetic cores 3 with the same inner diameter but different outer diameters may be prepared, and the one that provides the desired leakage inductance value may be attached to the outer peripheral surface of the winding shaft portion 21 of the bobbin 4. This is because the greater the thickness of the third magnetic core 3 (the difference between the outer diameter and the inner diameter), the greater the amount of leakage inductance in the direction of the third magnetic core 3, as shown in FIG.

[0037] 10C, multiple types of third magnetic cores 3 with different magnetic saturation characteristics may be prepared, and the one that provides the desired leakage inductance value may be attached to the outer circumferential surface of the winding shaft portion 21 of the bobbin 4. This is because the higher the magnetic saturation characteristic of the third magnetic core 3, the greater the amount of leakage inductance in the direction of the third magnetic core 3, as shown in FIG.

[0038] According to the magnetically coupled inductor 100 of this embodiment, as described above, a plurality of third magnetic cores 3 with different leakage inductance values ​​are prepared, and the third magnetic core 3 that provides the desired leakage inductance value is attached to the outer peripheral surface of the winding shaft portion 21 of the bobbin 4, so that the leakage inductance value can be easily adjusted.

[0039] <Method of Assembling a Magnetically Coupled Inductor (Coil Component)> Next, the flow of the method of assembling the magnetically coupled inductor 100 according to this embodiment will be described with reference to FIGS. 11A (A1) to 11B (A7). For comparison, the flow of the method of assembling the magnetically coupled inductor described in the prior art (the above-mentioned Patent Document 1) is shown in FIGS. 11B (B1) to 11B (B7). Note that the components of the magnetically coupled inductor 200 shown in the drawings relating to the prior art are assigned reference numerals obtained by adding 100 to the reference numerals assigned to the corresponding components of the magnetically coupled inductor 100 shown in the drawings relating to this embodiment. First, as shown in FIG. 11A (A1), a bobbin 4 is fabricated and set in the assembly position (bobbin setting process). As described above, the bobbin 4 is made of insulating resin and is fabricated by molding. 3 again, winding shaft 21 around which coil windings 6A, 6B are wound is cylindrical with hollow portion 42C, and roughly disk-shaped flange portions 43A, 43B are provided on both ends of winding shaft 21. Furthermore, terminal blocks 41A, 41B are provided below each flange portion 43A, 43B, and tape suspension portions 45A, 45B for suspending exterior tape 79 (see FIG. 11B (A7)) are provided above each flange portion 43A, 43B, and six metal terminal pins 9, 9 are arranged in parallel on each terminal block 41A, 41B so that they face sideways and downward, respectively.

[0040] As described above, the first engaging portion 64, which is made up of four protrusions spaced at 90-degree intervals in the circumferential direction of the outer peripheral surface, is provided at approximately the center in the axial direction on the outer peripheral surface of the winding shaft portion 21 of the bobbin 4. Note that the method of assembling the magnetically coupled inductor 200 according to the prior art also produces a bobbin 104 provided with a first engaging portion 164 having approximately the same shape as the first engaging portion 64, as shown in FIG.

[0041] Next, as shown in Figure 11A (A3), the third magnetic core 3 provided with second engagement portions 65 (see Figures 3 and 4(A) and (B)) consisting of recesses is engaged with the outer circumferential surface of the winding shaft portion 21 of the bobbin 4 for each of the third magnetic core portions 3A and 3B (third magnetic core assembly process (hereinafter also referred to as ring core assembly process)). This engagement process is performed by fitting the second engagement portions 65 consisting of recesses of the third magnetic core 3 into first engagement portions 64 consisting of protrusions formed on the outer circumferential surface of the winding shaft portion 21 of the bobbin 4. With both third magnetic core portions 3A and 3B fitted onto the outer circumferential surface of the winding shaft portion 21 of the bobbin 4, the third magnetic core portions 3A and 3B are combined with each other to form a ring shape, as shown in Figure 4(A).

[0042] In contrast, in the prior art, as shown in FIG. 11A (B2), before performing the ring core assembly process, it is necessary to attach an annular spacer 175 to the outer peripheral surface of the winding shaft portion 21 of the bobbin 4 (spacer assembly process). The present embodiment has the advantage that such a spacer assembly process is not necessary. That is, in the prior art, it is necessary to engage the engaging portion provided on the inner peripheral surface of the spacer 175 with the engaging portion provided on the outer peripheral surface of the winding shaft portion 21 of the bobbin 4, and to mount and position the third magnetic core 103 on the magnetic core mounting portion 175C provided between the two flanges of the spacer 175 (see FIG. 5A). Furthermore, when mounting the third magnetic core 103 on the magnetic core mounting portion 175C, it is necessary to combine the semicircular third magnetic core portions 103A and 103B constituting the third magnetic core 103 on the magnetic core mounting portion 175C to form the annular shape shown in FIG. 11A (B3). The advantage of this embodiment is that it omits the processing steps involved in the conventional techniques and reduces the labor and time involved in those steps.

[0043] 11B (A4), the outer circumferential surface of each of the third magnetic core portions 3A, 3B is wound with third magnetic core fixing tape 77 around the third magnetic core 3 mounted on the outer circumferential surface of the winding shaft portion 21 of the bobbin 4 so that the third magnetic core portions 3A, 3B are combined together to maintain a circular shape (third magnetic core tape fixing process (hereinafter also referred to as ring core tape fixing process)). On the other hand, in the prior art, as shown in FIG. 11B (B4), the outer circumferential surface of each of the third magnetic core portions 103A, 103B is wound with third magnetic core fixing tape 177 around the third magnetic core 103 mounted on the magnetic core mounting portion 175C of the spacer 175 so that the third magnetic core portions 103A, 103B are combined together to maintain a circular shape.

[0044] Next, as shown in FIG. 11B (A5), approximately equal numbers of coil windings 6A and 6B are wound around the winding regions 42A and 42B of the winding shaft portion 21, which are divided by the third magnetic core 3 (winding installation process). Next, as shown in FIG. 11B (A6), the center leg 14 of the first magnetic core 1 is inserted into one end of the hollow portion 42C (see FIG. 3) of the cylindrical winding shaft portion 21 of the bobbin 4, and the center leg 24 of the second magnetic core 2 is inserted into the other end (main core assembly process). At this time, the bobbin 4 and the cores 1 to 3 are fixed together by wrapping a core fixing tape 78 around the circumferential surfaces of the sides of the first magnetic core 1 and the second magnetic core 2. Note that adhesives, fasteners, or the like may be used instead of the core fixing tape 78 to physically integrate the bobbin 4 and the cores 1 to 3.

[0045] 11B (A7), the bobbin 4 and each of the cores 1 to 3 are more firmly fixed by winding an exterior tape 79 in a direction perpendicular to the core fixing tape 78 so that the coil windings 6A, 6B are not exposed to the outside (exterior tape fixing process). Note that adhesives, fasteners, etc. may be used in addition to the exterior tape 79 as a means for physically integrating the bobbin 4 and each of the cores 1 to 3. Note that in the prior art, the winding attachment process, main core assembly process, and exterior tape fixing process described above are also performed in substantially the same manner as in the present embodiment, as shown in FIGS. 11B (B5 to B7).

[0046] The magnetically coupled inductor and its assembly method of the present invention are not limited to those described in the above embodiments and can be modified in various other ways. For example, the coil components described in the above embodiments are used as magnetically coupled inductors. However, the coil components of the present invention can also be used as transformers with the same configuration as the magnetically coupled inductors of the above embodiments. That is, when the present invention is applied to a transformer, it can achieve the same useful effects as when it is applied to a magnetically coupled inductor. Furthermore, while PQ cores are used as the first magnetic core 1 and the second magnetic core 2 in the above embodiments, various types of cores, such as EE cores and EER cores, can be used instead. Furthermore, various types of cores, such as EE cores and EER cores, can also be constructed by combining multiple I-core members or cylindrical core members.

[0047] In the above embodiment, the leakage inductance value is set to a desired value by setting any one or a combination of the thickness, outer diameter, and magnetic saturation characteristics of the third magnetic core 3 to the desired value. However, it is also possible to use other methods for setting a desired value to a shape element of the third magnetic core 3 or a material characteristic element of the third magnetic core 3. For example, it is also possible to use a method for setting the leakage inductance value to the desired value by the inner diameter of the third magnetic core 3 or a combination of the inner diameter of the third magnetic core 3 with other elements.

[0048] In the above embodiment, the winding direction of the coil windings 6A and 6B or the direction of the current flowing through the coil windings 6A and 6B can be adjusted so that the flow directions (directions of the arrows) of the magnetic flux shown in FIG. 9 are all reversed, achieving the same effect. The shape of the bobbin 4 is not limited to that of the above embodiment and can be other shapes. For example, the first engaging portion 64 on the outer circumferential surface of the winding shaft portion 21 can be a recessed portion rather than a protruding portion, and the second engaging portion 65 on the inner circumferential surface of the third magnetic core 3 that engages with the winding shaft portion 21 can be a protruding portion rather than a recessed portion. In the above embodiment, the coil windings 6A and 6B use round wire. However, this is not limited to this, and other windings may also be used. For example, edge-wound windings of rectangular wire are not excluded. Furthermore, the coil windings 6A and 6B may be formed by inserting a pre-wound air-core coil into the winding shaft portion 21. In the above embodiment, the third magnetic core 3 is divided into two parts, but it may also be divided into three or more parts.

[0049] 1, 101 First magnetic core 2, 102 Second magnetic core 3, 103 Third magnetic core (ring core) 3A, 3B, 103A, 103B Third magnetic core portion 4, 104 Bobbin 6A, 6B, 106A, 106B Coil winding 8 Magnetic flux 9 Terminal pin 12, 22 Outer leg portion 13, 23 Back portion 14, 24 Center leg portion 21, 121 Winding shaft portion 32, 33, 34 Gap 41A, 41B Terminal block 42A, 42B Winding shaft region 42C Hollow portion 43A, 43B Flange portion (of bobbin) 45A, 45B Tape suspension portion 64, 164 First engaging portion 65 Second engaging portion 77, 177 Third magnetic core fixing tape 78, 188 Core fixing tape 79, 179 Outer tape 91A, 91B Litz wire 92A Insulating tape 92B Insulating coating 100, 200 Magnetic coupling inductor 175 Spacer 175A, 175B (of spacer) flange 175C Magnetic core mounting groove 185 Recess

Claims

1. A first magnetic core and a second magnetic core each having a middle leg portion, outer leg portions located on both sides of the middle leg portion, and a back portion connecting the middle leg portion and the outer leg portions, wherein the tips of the middle leg portions and the tips of the corresponding outer leg portions are arranged to abut against each other; a bobbin through which the middle leg portions of the first magnetic core and the second magnetic core are inserted and which is disposed around the outer circumferences of the middle leg portions of these two magnetic cores; an annular third magnetic core which is detachably attached to the bobbin in the circumferential direction of a winding shaft portion through which the middle leg portions are inserted; a first coil winding wound around one region of the winding shaft portion divided by the third magnetic core, and a second coil winding wound around the other region; the third magnetic core is detachably attached to the outer circumferential surface of the winding shaft portion of the bobbin in a circumferentially divided state with predetermined elements set so as to generate a desired leakage inductance value according to the positional relationship with the first magnetic core and the second magnetic core; and the attachment of the third magnetic core to the winding shaft portion is achieved by engagement between a plurality of first engaging portions arranged in the circumferential direction on the outer circumferential surface of the winding shaft portion and second engaging portions arranged in the circumferential direction on the inner circumferential surface of the third magnetic core so as to correspond to the first engaging portions.

2. The coil component according to claim 1, wherein the wire materials of the first coil winding and the second coil winding are insulated wires.

3. The coil component according to claim 2, wherein the wire materials of the first coil winding and the second coil winding are insulated wires obtained by covering the outer circumference of a litz wire with an insulating tape.

4. The coil component according to any one of claims 1 to 3, wherein the predetermined element regarding the third magnetic core, which is set so as to generate the desired leakage inductance value, is the thickness of the third magnetic core.

5. The coil component according to any one of claims 1 to 3, wherein the predetermined element regarding the third magnetic core, which is set so as to generate the desired leakage inductance value, is the outer diameter of the third magnetic core.

6. The coil component according to any one of claims 1 to 3, wherein the predetermined element regarding the third magnetic core, which is set so as to generate the desired leakage inductance value, is the magnetic saturation characteristic of the material of the third magnetic core.

7. The coil component according to any one of claims 1 to 3, characterized in that at least one second engaging portion is provided for each core member of the third magnetic core divided in the circumferential direction so as to correspond to a plurality of first engaging portions arranged in the circumferential direction on the outer peripheral surface of the winding shaft portion.

8. The coil component according to any one of claims 1 to 3, characterized in that the first engaging portion is a convex portion formed on the outer peripheral surface of the winding shaft portion, and the second engaging portion is a concave portion formed on the inner peripheral surface of the third magnetic core and engaging with the first engaging portion.

9. A first step of abutting the tips of the middle legs and the tips of the corresponding outer legs of the first magnetic core and the second magnetic core, each having a middle leg, outer legs located on both sides of the middle leg, and a back surface connecting the middle leg and the outer legs, inserting the middle legs of the first magnetic core and the second magnetic core into the hollow portion of the bobbin, and attaching an annular third magnetic core divided in the circumferential direction to the winding shaft portion around the hollow portion through which the middle leg is inserted of the bobbin; a second step of winding a first coil winding around one region and a second coil winding around the other region, which are axially divided by the third magnetic core of the winding shaft portion; and in the first step, the attachment of the third magnetic core to the winding shaft portion of the bobbin is performed by engaging the second engaging portion provided on the inner peripheral surface of the third magnetic core with the first engaging portion provided on the outer peripheral surface of the winding shaft portion of the bobbin in a state where predetermined elements are set so as to generate a desired leakage inductance value according to the positional relationship with the first magnetic core and the second magnetic core. A method for assembling a coil component.

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