Magnetically coupled inductor and method for assembling same

Abstract

[Problem] In a magnetic coupling inductor in which two installed inductors are caused to operate in interleave, to facilitate adjustment of a leakage inductance value and, in such adjustment, to ensure the dimensional accuracy of terminal pin intervals of both terminal blocks and the rigidity of a winding shaft part of a bobbin. [Solution] The present invention comprises a ring-shaped spacer member 5 which is split in the circumferential direction and attached to a bobbin 4 in a circumferential direction of a winding shaft part (42) through which a middle leg part (11, 21) is inserted. The spacer member comprises: a cylinder section (5C) on which an annular third core 3 (3A, 3B) is placed; and flange sections 5A, 5B provided at both ends thereof. The third core 3 is split in the circumferential direction and mounted on the outer periphery of the cylinder section (5C) of the spacer member 5 in a state in which, of elements of the shape of the third core 3 and the material characteristic of the third core 3, the magnitude of at least one of the elements is set so that a desired leakage inductance value is generated.

Description

[Technical Field]

[0001] The present invention relates to a magnetically coupled inductor mounted in the electronic circuits of various devices, and to an assembly method thereof. [Background technology]

[0002] In magnetically coupled inductors, the two built-in inductors are operated in an interleaved manner, which reduces ripple and improves 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. As shown in Patent Document 1 (particularly FIG. 1) below, a conventional magnetically coupled inductor is known in which a ring-shaped third core 102 is sandwiched between flanges 112, 112' of two split bobbins 110, 110', through which the center legs of a first core 101 and a second core 101' are inserted. Each of the split bobbins 110, 110' is provided with a winding shaft 111, 111' around which a coil winding is wound. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 4-014487 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the above-described conventional technology, because the third core 102 is sandwiched between two divided bobbins 110, 110', it is difficult to ensure the dimensional accuracy of the spacing between the two terminal rows 115, 115' that protrude from the bottom of each bobbin 110, 110' and are attached to a substrate, and it is difficult to ensure the rigidity of the bobbins 110, 110'. Furthermore, the shape (e.g., thickness) of the third core 102 is limited to modes in which a preset shape is used, making it difficult to adjust the leakage inductance value according to the situation.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a magnetically coupled inductor in which two built-in inductors operate in an interleaved manner, in which the leakage inductance value can be easily adjusted to suit the situation, and in which the dimensional accuracy of the terminal pin spacing between terminal blocks and the rigidity of the winding shaft portion of the bobbin can be easily ensured during the adjustment, and a method for assembling the same. [Means for solving the problem]

[0006] The magnetically coupled inductor 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 portions, the first magnetic core and the second magnetic core being arranged such that the tips of the center leg portions and the tips of the corresponding outer leg portions abut against each other; a bobbin through which the center legs of the first magnetic core and the second magnetic core are inserted and which is disposed outside the center legs of these two magnetic cores; an annular spacer member that is divided and attached to a winding shaft portion of the bobbin through which the center leg portion is inserted, the spacer member comprising a cylindrical portion on which an annular third magnetic core is mounted and flange portions disposed on both ends of the cylindrical portion; an axial region of the winding shaft portion is divided by the spacer member, with a first coil winding wound in one region of the winding shaft portion and a second coil winding wound in the other region; The third magnetic core is characterized in that it is divided and attached circumferentially to the outer periphery of the cylindrical portion of the spacer member, with at least one element of the shape of the third magnetic core and the material properties of the third magnetic core being set to a predetermined size so as to generate a desired leakage inductance value depending on the positional relationship with the first magnetic core and the second magnetic core.

[0007] Preferably, the at least one element is the thickness of the third magnetic core. In this case, it is preferable that the width of the cylindrical portion of the spacer member is adjusted to a size corresponding to the thickness of the third magnetic core. Preferably, the at least one element is the inner diameter of the third magnetic core. In this case, it is preferable that the outer diameter of the cylindrical portion of the spacer member is adjusted to a size corresponding to the inner diameter of the third magnetic core.

[0008] Preferably, the at least one element is the outer diameter of the third magnetic core. Furthermore, it is preferable that the at least one factor is the magnetic saturation characteristics of the material of the third magnetic core. Furthermore, it is preferable that the attachment of the spacer member to the winding shaft portion be achieved by mutually engaging a plurality of first engaging portions arranged in the circumferential direction on the outer circumferential surface of the winding shaft portion with second engaging portions arranged in the circumferential direction on the inner circumferential surface of the cylindrical portion so as to correspond to the first engaging portions.

[0009] It is also preferable that at least one second engaging portion is provided for each of the spacer members divided in the circumferential direction so as to correspond to the plurality of first engaging portions arranged in the circumferential direction on the outer circumferential surface of the winding shaft portion. It is also preferable that the spacer members divided in the circumferential direction each have a spacer assembly engaging portion that engages with and is integrated with the spacer members when attached to the winding shaft portion. Furthermore, it is preferable that the outermost peripheral portions of the flange portions arranged at both ends of the winding shaft portion of the bobbin are configured to have a height close to that of the outermost peripheral portions of the flange portions arranged at both ends of the cylindrical portion of the spacer member.

[0010] Furthermore, the method for assembling a magnetic coupled inductor of the present invention includes the steps of: 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, with the tips of the center legs and the tips of the corresponding outer legs butted against each other; inserting the center leg portions of the first magnetic core and the second magnetic core into a hollow portion of a bobbin; After performing a first step of attaching an annular spacer member divided in the circumferential direction to a winding shaft portion of the bobbin through which the center leg portion is inserted, the spacer member includes a cylindrical portion on which an annular third magnetic core is mounted and flange portions disposed on both ends of the cylindrical portion, a second step of winding a first coil winding in one of the regions axially divided by the spacer member and winding a second coil winding in the other region; setting at least one element of the shape of the third magnetic core and the material characteristics of the third magnetic core to a predetermined size so that the leakage inductance value of the third magnetic core can be set to a desired value; a third step of mounting the third magnetic core, at least one element of which is set to a predetermined size, on the outer periphery of the cylindrical portion of the spacer member in a circumferentially divided manner; It is characterized in that it is performed in a predetermined order. [Effects of the Invention]

[0011] According to the magnetically coupled inductor of the present invention, the annular third magnetic core is configured so that it can be mounted on a spacer member attached to the winding shaft portion of a bobbin in a state in which the leakage inductance value is adjusted to a desired value by selecting at least one element from among the elements of the shape of the third magnetic core and the material properties of the third magnetic core. This makes it easy to adjust the leakage inductance value of the magnetically coupled inductor, and because the length and rigidity of the winding shaft portion of the bobbin do not change during the adjustment, it is easy to ensure the dimensional accuracy of the terminal pin spacing between terminal blocks and the rigidity of the winding shaft portion of the bobbin. [Brief explanation of the drawings]

[0012] [Figure 1] 1A and 1B are perspective views showing a magnetically coupled inductor according to an embodiment of the present invention ((A) shows a state in which the bobbin and spacer member are removed, and (B) shows a state in which the bobbin, spacer member, and coil winding are removed). [Figure 2] 1 is a perspective view showing a magnetically coupled inductor (with coil windings removed) according to an embodiment of the present invention. [Figure 3] 1 is a schematic cross-sectional view showing the flow of magnetic flux in a magnetically coupled inductor according to an embodiment of the present invention. [Figure 4] 1A and 1B are schematic diagrams showing ways to adjust the leakage inductance value in a magnetically coupled inductor according to an embodiment of the present invention ((A) is a way to change the thickness of the spacer member and the ring core, (B) is a way to change the outer diameter of the central groove of the spacer member and the inner diameter of the ring core, (C) is a way to change the outer diameter of the ring core, and (D) is a way to change the magnetic saturation characteristics of the ring core). [Figure 5] 1A and 1B are perspective views showing an assembly process 1 ((A) and (B)) of a magnetically coupled inductor according to an embodiment of the present invention. [Figure 6] 10A and 10B are perspective views showing assembly steps 2 ((C), (D)) of the magnetically coupled inductor according to the embodiment of the present invention. [Figure 7] 10A and 10B are perspective views showing assembly steps 3 ((E), (F)) of the magnetically coupled inductor according to the embodiment of the present invention. [Figure 8] FIG. 10 is a perspective view showing an assembly step 4 ((G)) of the magnetically coupled inductor according to the embodiment of the present invention. [Figure 9] 1A and 1B are perspective views showing a spacer member of a magnetically coupled inductor according to an embodiment of the present invention ((A) is a state in which the spacer member is integrated, and (B) is a state in which the spacer member is disassembled into two). [Figure 10] FIG. 1 is a schematic diagram for explaining a conventional technique. DETAILED DESCRIPTION OF THE INVENTION

[0013] A magnetically coupled inductor according to an embodiment of the present invention and an assembly method thereof will be described below with reference to the drawings. Figure 1(A) is a perspective view of the magnetically coupled inductor 100 according to this embodiment with the bobbin and spacer member removed, Figure 1(B) is a perspective view of the magnetically coupled inductor 100 according to this embodiment with the bobbin, spacer member and coil winding removed, and Figure 2 is a perspective view of the magnetically coupled inductor 100 according to this embodiment with the coil winding removed.

[0014] As shown in Figures 1(A) and 1(B), the magnetically coupled inductor 100 of this embodiment comprises, as its main elements, a first core 1 and a second core 2, each of which is made of a PQ core, a third core 3 (3A, 3B) made of a ring core, and a first coil winding 6A and a second coil winding 6B. The first core 1 and the second core 2 are made of, for example, a ferrite core, and each have a cylindrical center leg portion 11, 21, outer leg portions 12, 12, 22, 22 arranged on both sides of the center leg portion 11, 21, and a back portion 13, 23 connecting the center leg portions 11, 21 and the outer leg portions 12, 12, 22, 22, and the first core 1 and second core 2 are arranged opposite each other so as to have symmetrical shapes.

[0015] The length of the middle legs 11, 21 is approximately half the distance between the opposing back sections 13, 23, and the outer legs 12, 12, 22, 22 are plate-shaped with arc-shaped inner surfaces and flat outer surfaces. The three legs 11, 12, 12 constituting the first core 1 and the corresponding tips of the three legs 21, 22, 22 constituting the second core 2 are arranged to face each other with minute gaps 31, 32, 32 between them. The third core 3 is made of, for example, a ferrite core and has a circular ring shape with a rectangular cross section. The third core 3 is formed by combining a pair of semicircular ring core members (semicircular ring cores) 3A and 3B.

[0016] 2 shows the bobbin 4 and spacer member 5 combined with the first core 1, second core 2, and third core 3, which are not shown in FIG. 1(B). However, in order to show the inside of the bobbin 4, the coil windings 6A and 6B have been removed. 5(A), the bobbin 4 is made of insulating resin and has flanges 43A, B on both ends of a cylindrical winding shaft 42, with terminal blocks 41A, B below each flange 43A, B. Each terminal block 41A, B is provided with a plurality of terminal pins 9, 9.

[0017] In addition, the middle leg portion 11 of the first core 1 is inserted through one end of the hollow portion 42C of the cylindrical winding shaft portion 42 of the bobbin 4, and the middle leg portion 21 of the second core 2 is inserted through the other end of the hollow portion 42C, so that the bobbin 4 is arranged outside each of these middle leg portions 11, 21. The first core 1 and the second core 2 have corresponding center legs 11, 21 and outer legs 12, 12, 22, 22 abutted against each other, and gaps 31, 32, 32 are provided between the corresponding legs (see FIG. 1(B)).

[0018] 5(A), a plurality of engaging protrusions 44a (for example, four at 90-degree intervals) are provided around the circumferential direction of the outer peripheral surface of the winding shaft portion 42 of the bobbin 4 at approximately the center in the axial direction of the outer peripheral surface of this outer peripheral surface, and the spacer member 5 is attached at this position. The spacer member 5 has a ring core mounting groove 5C between the spacer flanges 5A and 5B in which the third core 3 is mounted, and the ring core mounting groove 5C has an inner diameter that allows it to be fitted along the outer peripheral surface of the winding shaft portion 42 of the bobbin 4.

[0019] In addition, the ring core mounting groove portion 5C is provided with the same number of engagement holes 5Ca as the number of engagement protrusions 44a provided on the outer peripheral surface of the winding shaft portion 42 (see Figures 9(A) and (B)). 9(B), in order to be mountable on the winding shaft 42, the cylindrical spacer member 5 is configured to have two semicircular ring portions 51, 52, and is configured so that when each engagement hole 5Ca is engaged with a corresponding engagement protrusion 44a and these two semicircular ring portions 51, 52 are mounted on the winding shaft 42, these two semicircular ring portions 51, 52 engage with each other and become one body. The configuration that contributes to the engagement of these two semicircular ring portions 51, 52 will be described later.

[0020] As described above, each engaging protrusion 44a is provided at approximately the center in the axial direction on the outer circumferential surface of the winding shaft portion 42, and each engaging hole 5Ca is also provided at approximately the center in the axial direction of the ring core mounting groove portion 5C. Therefore, when this spacer member 5 is attached to the winding shaft portion 42, winding shaft regions 42A, 42B of the winding shaft portion 42 have approximately the same area on both axial sides of the spacer member 5. The first coil winding 6A is wound around one winding shaft region 42A, and the second coil winding 6B is wound around the other winding shaft region 42B, which are separated by the spacer member 5. Both ends of the first coil winding 6A are connected to corresponding terminal pins 9 on the terminal block 41A side, and both ends of the second coil winding 6B are connected to corresponding terminal pins 9 on the terminal block 41B side.

[0021] As shown in Fig. 2, semicircular ring cores 3A and 3B, which are divided into two semicircular rings, are mounted in the ring core mounting groove 5C of the spacer member 5, and in this mounted state, a third core is arranged along the entire outer circumferential surface of the ring core mounting groove 5C. In addition, with the semicircular ring cores 3A and 3B mounted on the outer circumferential surface of the ring core mounting groove 5C, the outer circumferential surfaces of the semicircular ring cores 3A and 3B are wound with ring core fixing tape 71 to prevent the semicircular ring cores 3A and 3B from falling off (see Fig. 6(D)).

[0022] The magnetically coupled inductor 100 of this embodiment, which has the basic configuration described above, has a 2-in-1 structure in which the core portion is formed in a zigzag shape in plan view, with the third core 3, which is an annular magnetic core, sandwiched between the first core 1 and the second 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. 3, and the magnetic fluxes 8 which pass through the third core 3 and are generated by the currents passing through the first coil winding 6A and the second coil winding 6B flow in the same direction.

[0023] More specifically, as described above, the first core 1 and the second core 2 are separated by gaps 31, 32, 32 formed between the center legs 11, 21 and the outer legs 12, 12, 22, 22. Therefore, in the first core 1, the magnetic flux 8 passing from the outer legs 12, 12 on both sides through the back surface 13 joins at the center leg 11 and both flow toward the tip surface of this center leg 11. On the other hand, in the second core 2, the magnetic fluxes passing from the outer legs 22, 22 on both sides to the back surface portion 23 join at the center leg 21 and both flow toward the tip surface of this center leg 21.

[0024] The magnetic flux 8 flowing through these two center legs 11, 21 collides with each other at the tip surfaces of the center legs 11, 21 and is cancelled out. On the other hand, the magnetic flux 8 that branches off toward the third core 3 before the collision passes through the third core 3 and reaches the outer legs 12, 12, 22, 22 of the first core 1 and the second core 2. As a result, a magnetic loop is formed in the first core 1, the second core 2, and the third core 3, which is made up of a magnetic flux 8 circulating in the direction of the arrow as shown in FIG. As shown in FIG. 3, a gap 33 of a predetermined distance is also formed between the third core 3 and the outer legs 12, 12, 22, 22 of the first core 1 and the second core 2.

[0025] As described above, the core portions (first core 1, second core 2, and third core 3) are formed as a whole in a square shape when viewed from above, and the proportion of the magnetic flux 8 that flows through the middle legs 11, 21 of the first core 1 and the second core 2 and branches off toward the third core 3 to flow through the outer legs 12, 12, 22, 22 of the first core 1 and the second core 2 can be adjusted by changing the ease with which the magnetic flux 8 flows from the middle legs 11, 21 of the first core 1 and the second core 2 to the third core 3. In the magnetically coupled inductor of this embodiment, taking into consideration the above points, the degree of ease of flow of magnetic flux 8 from center legs 11 and 21 toward third core 3 can be adjusted to a desired leakage inductance (leakage magnetic flux) value by changing (selecting) at least one element from among the thickness (width) of third core 3 (ring core), the inner diameter of third core 3 (ring core), the outer diameter of third core 3 (ring core), and the magnetic saturation characteristics of third core 3 (ring core). Note that when the thickness of third core 3 (ring core) is changed, it is desirable to change the width of ring-core mounting groove 5C of spacer member 5 accordingly. Also, when the inner diameter of third core 3 (ring core) is changed, it is desirable to change the outer diameter of ring-core mounting groove 5C of spacer member 5 accordingly.

[0026] For example, as shown in Figure 4(A), several types of third cores 3 with different thicknesses (widths) are prepared, and the one that provides the desired leakage inductance value is mounted in the ring core mounting groove 5C. This is because the thicker the third core 3 is, the greater the amount of magnetic flux 8 branched toward the third core 3, as shown in Figure 3, i.e., the amount of leakage inductance. In order to ensure stable retention of the third core 3, it is desirable to replace the spacer member 5 with one having a ring core mounting groove 5C width that corresponds to the selected thickness (width) of the third core 3.

[0027] 4(B), several types of third cores 3 with the same outer diameter but different inner diameters are prepared, and the one that provides the desired leakage inductance value is mounted in the ring core mounting groove 5C. This is because the greater the thickness of the third core 3 (the difference between the outer diameter and the inner diameter), the greater the leakage inductance in the direction of the third core 3, as shown in FIG. 3. In terms of holding the third core 3 stably, it is desirable to replace the spacer member 5 with one having an outer diameter of the ring core mounting groove 5C that corresponds to the inner diameter of the selected third core 3.

[0028] 4(C), multiple types of third cores 3 with the same inner diameter but different outer diameters are prepared, and the one that provides the desired leakage inductance value is mounted in the ring core mounting groove 5C. This is because, as in the case of FIG. 4(B), the greater the thickness of the third core 3 (the difference between the outer diameter and the inner diameter), the greater the leakage inductance in the direction of the third core 3, as shown in FIG. 3. Note that, since the inner diameter of any selected third core 3 can be the same, the spacer member 5 can be the same.

[0029] Furthermore, as shown in Figure 4(D), several types of third cores 3 with different magnetic saturation characteristics are prepared, and the one that provides the desired leakage inductance value is mounted in the ring core mounting groove 5C. This is because the higher the magnetic saturation characteristic of the third core 3, the greater the leakage inductance in the direction of the third core 3, as shown in Figure 3. Note that the selected third cores 3 can have the same shape, so the spacer member 5 can be the same for all of them.

[0030] According to the magnetically coupled inductor 100 of this embodiment, as described above, a plurality of third cores 3 with different leakage inductance values ​​are prepared, and the third core 3 that provides the desired leakage inductance value is mounted on the spacer member 5 attached to the outer peripheral surface of the winding shaft portion 42 of the bobbin 4. Therefore, unlike the prior art (Patent Document 1) described above, it is not necessary to change the axial length of the winding shaft portion 42 in response to a change in the thickness of the third core 3, and it is also not necessary to change the spacing of the terminal pins 9 between the two terminal blocks 41A and B in response to a change in the third core 3. This makes it easy to ensure the dimensional accuracy of the spacing between the terminal pins 9 between the two terminal blocks 41A and 41B and the rigidity of the winding shaft portion 42 of the bobbin 4 when adjusting the leakage inductance value.

[0031] Next, the flow of the method for assembling the magnetically coupled inductor according to this embodiment will be described with reference to FIGS. 5(A) to 8(G). First, a bobbin 4 as shown in FIG. 5(A) is produced. As described above, bobbin 4 is made of insulating resin and is produced by molding. Winding shaft 42 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 42. Furthermore, terminal blocks 41A, 41B are provided below each flange portion 43A, B, and tape suspension portions 45A, 45B for suspending exterior tape 73 (see FIG. 8(G)) are provided above each flange portion 43A, B. Each terminal block 41A, B has six metal terminal pins 9, 9 arranged in parallel, facing sideways and downward, respectively.

[0032] As described above, four engagement protrusions 44a are provided at 90-degree intervals around the circumferential direction of the outer peripheral surface of the winding shaft portion 42 of the bobbin 4, approximately at the center in the axial direction of the outer peripheral surface. These engagement protrusions have a rectangular parallelepiped shape that is elongated in the circumferential direction, and are shaped to exactly engage with the engagement holes 5Ca of the spacer member 5 (see Figures 9(A) and (B)).

[0033] Next, as shown in Fig. 5(B), spacer member 5 is attached to the outer peripheral surface of winding shaft portion 42 of bobbin 4. As shown in Fig. 9(B), this spacer member 5 is composed of two semicircular ring portions 51 and 52. Semicircular ring portion 51 is brought close to winding shaft portion 42 of bobbin 4 from above, and semicircular ring portion 52 is brought close to winding shaft portion 42 of bobbin 4 from below, and semicircular ring portions 51 and 52 are attached to winding shaft portion 42 so that engaging holes 5Ca formed in each semicircular ring portion 51 and 52 engage with engaging protrusions 44a provided on the outer peripheral surface of winding shaft portion 42. Then, when attached to winding shaft portion 42, semicircular ring portions 51 and 52 are combined into an annular shape as shown in Fig. 9(A). 5(B), the spacer member 5 assembled into an annular shape has a cylindrical ring core mounting groove 5C for mounting the third core 3, and spacer flanges 5A and 5B disposed on both sides of the ring core mounting groove 5C to stably hold the side surfaces of the third core 3. Therefore, the width of the ring core mounting groove 5C is set to a size corresponding to the thickness (width) of the third core 3 to be mounted.

[0034] 9(A) and 9(B), in view of the fact that the spacer member 5 is composed of two semicircular ring portions 51 and 52, the portion of the spacer flange portion 5A facing the semicircular ring portion 51 is referred to as the spacer flange portion 5A1, the portion of the spacer flange portion 5A facing the semicircular ring portion 52 is referred to as the spacer flange portion 5A2, the portion of the flange portion 5B facing the semicircular ring portion 51 is referred to as the flange portion 5B1, the portion of the flange portion 5B facing the semicircular ring portion 52 is referred to as the flange portion 5B2, and further, the portion of the ring core mounting groove portion 5C facing the semicircular ring portion 51 is referred to as the ring core mounting groove portion 5C1, and the portion of the ring core mounting groove portion 5C facing the semicircular ring portion 52 is referred to as the ring core mounting groove portion 5C2.

[0035] The two semicircular ring portions 51, 52 of the spacer member 5 are provided with spacer assembly engaging portions 51A, B, 52A, B which are engaged with each other and integrated together when attached to the outer circumferential surface of the bobbin 4. Spacer assembly engaging portion 51A and spacer assembly engaging portion 52B have the same shape, and inner portions of both spacer flanges 5A1, 5B1 at one end (spacer assembly engaging portion 51A) of semicircular ring portion 51 and inner portions of both spacer flanges 5A2, 5B2 at the other end (spacer assembly engaging portion 52B) of semicircular ring portion 52 are cut out. On the other hand, spacer assembly engaging portion 51B and spacer assembly engaging portion 52A have the same shape, and outer portions of both spacer flanges 5A1, 5B1 at the other end (spacer assembly engaging portion 51B) of semicircular ring portion 51 and outer portions of both spacer flanges 5A2, 5B2 at one end (spacer assembly engaging portion 52A) of semicircular ring portion 52 are cut out.

[0036] As a result, when the two semicircular ring portions 51, 52 are combined as shown in Figure 9(A), the spacer assembly engagement portion 51A and the spacer assembly engagement portion 52A are fitted together, while the spacer assembly engagement portion 51B and the spacer assembly engagement portion 52B are fitted together.

[0037] Furthermore, the cut-out spacer flange portions 5A1, 5B1, 5A2, 5B2 of the spacer assembly engagement portions 51A, 52B have radially extending engagement recesses 51Q, 52Q (51Q is not shown) formed on the inward-facing surfaces (only one of the engagement recesses of the spacer assembly engagement portion 52B is shown in Figure 9(B)), and the cut-out spacer flange portions 5A1, 5B1, 5A2, 5B2 of the spacer assembly engagement portions 51B, 52A have radially extending engagement protrusions 51P, 52P formed on the outward-facing surfaces (only one of the engagement protrusions of the spacer assembly engagement portions 51B, 52A is shown in Figure 9(B)). When the spacer assembly engagement portion 51A and the spacer assembly engagement portion 52A are fitted together, and when the spacer assembly engagement portion 51B and the spacer assembly engagement portion 52B are fitted together, the corresponding engagement recesses 51Q, 52Q (51Q not shown) and the engagement protrusions 51P, 52P engage with each other, so that the two semicircular ring portions 51, 52 of the spacer member 5 are stably engaged with each other.

[0038] The spacer member 5 is made of resin, and in the spacer assembly engagement portions 51A, 51B, 52A, 52B, the portions of the spacer flange portions 5A1, 5B1, 5A2, 5B2 where the engagement recesses 51Q, 52Q (51Q not shown) and the engagement protrusions 51P, 52P are formed are thin-walled, so these portions are easily elastically deformed, and therefore the engagement operation of the engagement recesses 51Q, 52Q (51Q not shown) and the engagement protrusions 51P, 52P can be easily performed.

[0039] Next, as shown in Figure 6(C), the inner peripheral surfaces of the semicircular ring cores 3A and 3B of the third core 3 are fitted to the outer peripheral surface of the ring core mounting groove portion 5C of the spacer member 5, which has been attached to the outer peripheral surface of the winding shaft portion 42 of the bobbin 4 as described above, and the semicircular ring cores 3A and 3B are mounted in the ring core mounting groove portion 5C. 6(D), the outer circumferential surfaces of the semicircular ring cores 3A and 3B of the third core 3 are wound with ring core fixing tape 71 so that the semicircular ring cores 3A and 3B are held by the spacer member 5.

[0040] Next, as shown in FIG. 7(E), the first coil winding 6A and the second coil winding 6B are wound in approximately equal numbers around the winding shaft regions 42A and 42B of the winding shaft portion 42 divided by the spacer member 5. Next, as shown in FIG. 7(F), the center leg portion 11 of the first core 1 is inserted into the hollow portion 42C of the cylindrical winding shaft portion 42 of the bobbin 4 from one end side, and the center leg portion 21 of the second core 2 is inserted from the other end side.

[0041] As a result, the first core 1 and the second core 2 are arranged so that the corresponding center legs 11, 21 and the outer legs 12, 12, 22, 22 on both sides are butted against each other. Also, the corresponding legs are arranged so that gaps 31, 32, 32 of predetermined intervals are provided between each other. The bobbin 4 and the cores 1 to 3 are fixed together by winding core-fixing tape 72 around the circumferential surfaces of the sides of the first core 1 and the second core 2. Instead of the core-fixing tape 72, adhesive, fastening metal fittings, or the like may be used as a means for physically integrating the bobbin 4 and the cores 1 to 3.

[0042] 7(E), the first coil winding 6A and the second coil winding 6B are configured to be wound to positions approximately equal to the outer circumferential positions of the flange portions 5A and 5B of the spacer member 5. In this case, the outer circumferential positions of the coil windings 6A and 6B are adjusted taking into consideration both the wire diameter and the number of turns of the coil windings 6A and 6B, making it possible to balance the magnetic flux and heat generated by the coil windings 6A and 6B (the larger the wire diameter, the more likely it is that the amount of heat will be reduced). 7(E), the outermost peripheral portions of both flanges 43A, 43B of the bobbin 4 and the outermost peripheral portions of both flanges 5A, 5B of the spacer member 5 are set to be close to each other in height. This makes it possible to align the height of the upward component protrusions in the upper opening region surrounded by the first core 1 and the second core 2 shown in FIG. 7(F), which allows for smooth winding of the exterior tape 73 shown in FIG. 8(G) and ensures the integration of the product.

[0043] Next, as shown in FIG. 8(G), the bobbin 4 and each of the cores 1 to 3 are more firmly fixed by winding an exterior tape 73 in a direction perpendicular to the core fixing tape 72 so that the coil windings 6A and 6B are not exposed to the outside.

[0044] In the above assembly process, the step of setting the leakage inductance value to the desired value is performed by placing and fixing the third core 3 selected using any of the methods shown in Figures 4(A) to (D) on the ring core mounting groove portion 5C of the spacer member 5, as shown in Figure 6(C). That is, this process is performed by selecting the desired third core 3 by selecting the thickness (width) of the third core 3 (see FIG. 4(A)), selecting the inner diameter of the third core 3 (without changing the outer diameter) (see FIG. 4(B)), selecting the outer diameter of the third core 3 (without changing the inner diameter) (see FIG. 4(C)), or selecting the magnetic saturation characteristics of the third core 3 (see FIG. 4(D)), and then attaching this to the spacer member 5. Note that it is also possible to use a combination of these methods.

[0045] However, in this embodiment, as described above, the third core 3 is mounted on the spacer member 5 to form a magnetically coupled inductor having a core portion that is shaped like a square in plan view. Therefore, when using the method shown in FIG. 4(A) above, it is essential to mount on the winding shaft portion 42 a spacer member 5 having a ring core mounting groove portion 5C with a width corresponding to the thickness of the third core 3. Furthermore, when using the method shown in FIG. 4(B) above, it is essential to mount on the winding shaft portion 42 a spacer member 5 having a ring core mounting groove portion 5C with an outer diameter that matches the inner diameter of the third core 3.

[0046] The magnetically coupled inductor and its assembly method of the present invention are not limited to the above-described embodiment, but can be modified into various other forms. For example, in the above embodiment, PQ cores are used as the first core 1 and the second core 2, but instead, various types of cores such as EE cores and EER cores can be used. Furthermore, various types of cores such as EE cores and EER cores can also be constructed by combining a plurality of I-core members or cylindrical core members. In addition, in the above embodiment, a method for setting the leakage inductance value to a desired value is shown in which any one or a combination of the thickness of the third core 3, the inner diameter of the third core 3, the outer diameter of the third core 3, and the magnetic saturation characteristics of the third core 3 is set to a desired value, but it is also possible to use other methods for setting elements of the shape of the third core 3 or elements of the material characteristics of the third core 3 to a desired value.

[0047] In addition, in the above embodiment, the same effect can be obtained by adjusting the winding direction of the coil windings 6A and B and the direction of the current flowing through the coil windings 6A and B so that the flow directions (directions of the arrows) of the magnetic flux shown in Figure 3 are all reversed. Furthermore, the shape of the bobbin 4 is not limited to that of the above embodiment, but can be other forms. For example, it is possible to form an engagement hole instead of the engagement protrusion 44a provided on the outer peripheral surface of the winding shaft portion 42, and to form an engagement protrusion that engages with the engagement hole of this winding shaft portion on the inner peripheral surface of the ring core mounting groove portion 5C of the spacer member 5 instead of the engagement hole 5Ca. Furthermore, in the above embodiment, round wire is used for the coil windings 6A and B, but the coil windings 6A and B are not limited to this and other windings may be used. For example, edge coil winding of rectangular wire is not excluded.

[0048] In the above embodiment, the third core 3 is divided into two parts, but it may also be divided into three or more parts. Furthermore, in the above embodiment, the spacer member 5 is composed of two semicircular ring portions 51 and 52, but it is also possible to compose the spacer member 5 from three or more partial circular ring portions. However, it is essential that each partial circular ring portion has an engagement portion (engagement hole, engagement protrusion, etc.) formed therein for mounting on the winding shaft portion 42.

[0049] In addition, in the above embodiment, engagement recesses 51Q, 52Q (51Q not shown) are formed in the spacer assembly engagement portions 51A, 52B, and engagement protrusions 51P, 52P are formed in the spacer assembly engagement portions 51B, 52A, but it is also possible to form the engagement recesses 51P, 52P and the engagement protrusions 51Q, 52Q in positions that are interchangeable with each other. Furthermore, in the assembly method according to the above embodiment, the process of selecting the third core 3 and attaching it to the spacer member 5 is performed before the process of winding each of the coil windings 6A and B around the winding shaft portion 42, but the order may be reversed, or the process of winding the coil windings 6A and B may be performed during the process of selecting and attaching the third core 3. [Explanation of symbols]

[0050] 1, 101 1st Core 2, 101´ 2nd core 3, 102 3rd core (ring core) 3A, B Semicircular ring core 4, 110, 110´ bobbins 5 Spacer member 5A, B, 5A1, 5A2, 5B1, 5B2 Spacer flange 5C, 5C1, 5C2 Ring core mounting groove 5Ca engaging hole 6A 1st coil winding 6B Second coil winding 8 Magnetic Flux 9, 115, 115´ terminal pins 11, 21 Middle leg 12, 22 External legs 13, 23 Back part 31, 32, 33 Gap 41A, B terminal block 42, 111, 111´ Winding shaft part 42A, B reel area 42C Hollow part 43A, B, 112, 112´ Tsuba 44a Engagement protrusion 45A, B Tape suspension section 51, 52 Semicircular ring 51A, B, 52A, B Spacer assembly engagement part 51P, 52P Engagement protrusion 52Q(51Q) Engagement recess 71 Ring core fixing tape 72 Core fixing tape 73 Exterior tape 100 Magnetically Coupled Inductor

Claims

1. 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 portions, the first magnetic core and the second magnetic core being arranged such that the tips of the center leg portions and the tips of the corresponding outer leg portions abut against each other; a bobbin through which the center legs of the first magnetic core and the second magnetic core are inserted and which is disposed outside the center legs of these two magnetic cores; an annular spacer member attached to a winding shaft portion of the bobbin through which the center leg portion is inserted, the spacer member comprising a cylindrical portion on which an annular third magnetic core is mounted and flange portions disposed on both ends of the cylindrical portion; an axial region of the winding shaft portion is divided by the spacer member, with a first coil winding wound in one region of the winding shaft portion and a second coil winding wound in the other region; A magnetically coupled inductor characterized in that the third magnetic core is divided and attached circumferentially to the outer periphery of the cylindrical portion of the spacer member, with at least one element of the shape of the third magnetic core and the material characteristics of the third magnetic core being set to a predetermined size so that a desired leakage inductance value is generated depending on the positional relationship with the first magnetic core and the second magnetic core.

2. The magnetically coupled inductor according to claim 1 , wherein the at least one element is a thickness of the third magnetic core.

3. 3. The magnetically coupled inductor according to claim 2, wherein the width of the cylindrical portion of the spacer member is adjusted to a size corresponding to the thickness of the third magnetic core.

4. 2. The magnetically coupled inductor according to claim 1, wherein the at least one element is an inner diameter of the third magnetic core.

5. 5. The magnetically coupled inductor according to claim 4, wherein the outer diameter of the cylindrical portion of the spacer member is adjusted to a size corresponding to the inner diameter of the third magnetic core.

6. 2. The magnetically coupled inductor according to claim 1, wherein the at least one element is an outer diameter of the third magnetic core.

7. 2. The magnetically coupled inductor according to claim 1, wherein the at least one factor is a magnetic saturation characteristic of the material of the third magnetic core.

8. The magnetically coupled inductor according to any one of claims 1 to 7, characterized in that the attachment of the spacer member to the winding shaft portion is achieved by mutually engaging a plurality of first engaging portions arranged in a circumferential direction on the outer circumferential surface of the winding shaft portion with second engaging portions arranged in a circumferential direction on the inner circumferential surface of the cylindrical portion so as to correspond to the first engaging portions.

9. The magnetically coupled inductor according to any one of claims 1 to 8, characterized in that at least one second engaging portion is provided for each of the spacer members divided in the circumferential direction 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.

10. The magnetically coupled inductor according to any one of claims 1 to 9, characterized in that each of the spacer members divided in the circumferential direction has a spacer assembly engagement portion that engages with and integrates with each other when attached to the winding shaft portion.

11. The magnetically coupled inductor according to any one of claims 1 to 10, characterized in that the outermost peripheries of the flanges arranged at both ends of the winding shaft portion of the bobbin are configured to have a height close to that of the outermost peripheries of the flanges arranged at both ends of the cylindrical portion of the spacer member.

12. 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, with the tips of the center legs and the tips of the corresponding outer legs butted against each other; inserting the center leg portions of the first magnetic core and the second magnetic core into a hollow portion of a bobbin; a first step of attaching an annular spacer member divided in the circumferential direction to a winding shaft portion of the bobbin through which the center leg portion is inserted, the annular spacer member including a cylindrical portion on which an annular third magnetic core is mounted and flange portions disposed on both ends of the cylindrical portion; a second step of winding a first coil winding in one of the regions axially divided by the spacer member and winding a second coil winding in the other region; setting at least one element of the shape of the third magnetic core and the material characteristics of the third magnetic core to a predetermined size so that the leakage inductance value of the third magnetic core can be set to a desired value; a third step of mounting the third magnetic core, at least one element of which is set to a predetermined size, on the outer periphery of the cylindrical portion of the spacer member in a circumferentially divided manner; A method for assembling a magnetically coupled inductor, characterized in that the method is performed in a predetermined order.

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