Magnetic coupled inductor

Abstract

The magnetic coupling inductor has a 2in1 structure actually serving as two independent inductors, so that the size of the inductor can be reduced; the magnetic coupling inductor comprises a first magnetic core (1) and a second magnetic core (2) respectively having a middle leg (11), (21), an outer leg (12), (22) and a connecting portion (13), (23), a coil former (4), (5) for the middle leg (11), (21) to pass through and arranged outside the middle leg (11), (21), a first coil winding (6) and a second coil winding (7) wound on the coil former (4), (5) respectively, and a third magnetic core (3) in the form of a ring clamped by the two coil formers (4), (5) and embedded with the middle leg (11), (21); the corresponding legs of the first magnetic core (1) and the second magnetic core (2) are mutually butted via a gap; the directions of the magnetic flux generated by the currents flowing through the first coil winding (6) and the second coil winding (7) and passing through the third magnetic core (3) are the same; when the thickness of the third magnetic core (3) is a, and the gap between the outer legs (12), (22) of the first magnetic core (1) and the second magnetic core (2) is b, the condition a >= b is established.

Description

TECHNICAL FIELD

[0001] The present application relates to a magnetic coupled inductor configured as a coupled inductor of a 2inl structure in which a toroidal magnetic core is sandwiched between a pair of PQ magnetic cores (including E-type magnetic cores and the like). BACKGROUND

[0002] In recent years, a PFC magnetic coupled inductor of a 2inl structure in which two independent high-voltage transformers actually function has been proposed as disclosed in Patent Document 1, and the product can be miniaturized in external dimensions.

[0003] In addition, in Patent Document 2, a transformer configured such that a toroidal magnetic core is sandwiched between a pair of PQ magnetic cores is disclosed.

[0004]

Prior Art Documents

[0005]

Patent Documents

[0006] Patent Document 1: Japanese Patent No. 5062439

[0007] Patent Document 2: Japanese Patent No. 4-14487

[0008] However, in the configurations of these patent documents, there is a problem in that in the structure of the combination of the pair of PQ magnetic cores and the magnetic core sandwiched therebetween, the cross-sectional area of the magnetic core becomes large in order to pass the synthesized magnetic flux, and thus the magnetic coupled inductor becomes large, and thus the miniaturization of the external dimensions cannot be sufficiently achieved. SUMMARY

[0009] The present application is completed in view of the above-described circumstances, and aims to provide a magnetic coupled inductor having a 2inl structure in which two independent inductors actually function, and thus the optimization of the arrangement conditions involved in the combination of the magnetic cores is sought, and thus further miniaturization of the external dimensions can be achieved.

[0010] In order to solve the above-described problems, the magnetic coupled inductor of the present application has the following features.

[0011] The magnetic coupling inductor of the present application has: first and second magnetic cores each having a middle leg portion, outer leg portions on at least two sides of the middle leg portion, and a connecting portion connecting the middle leg portion and the outer leg portions; coil forms through which the middle leg portions of the first and second magnetic cores are inserted and outside the middle leg portions; first and second coil windings wound on the coil forms, respectively; and a third magnetic core in the shape of a ring and sandwiched by the coil forms with the middle leg portions inserted in the third magnetic core.

[0012] The corresponding leg portions of the first and second magnetic cores are butted against each other with a gap between the corresponding leg portions, the directions of the magnetic flux generated by the currents flowing through the first and second coil windings and passing through the third magnetic core are the same, and the magnetic coupling inductor is configured so that when the thickness of the third magnetic core is a and the gap between the outer leg portions of the first and second magnetic cores is b, condition (1) a ≥ b is satisfied.

[0013] Here, it is preferable that condition (2) a ≥ c is satisfied when the thickness of the third magnetic core is a and the thickness of the connecting portion of the first and second magnetic cores is c.

[0014] Further, it is preferable that the magnetic coupling inductor has a positioning and fixing member that fixes the middle portion of the third magnetic core in the thickness direction at a middle position between the front end surfaces of the two middle leg portions.

[0015] Further, it is preferable that the positioning and fixing member has a longitudinal piece extending upward at the center of a flat base portion, engagement grooves in the shape of slits are formed on both sides of the inner side of the base portion, and the extended portions of the two inner flange portions of the coil forms can be engaged in the engagement grooves.

[0016] (EFFECTS OF THE INVENTION)

[0017] According to the magnetic coupling inductor of the present application, the outer dimensions of the magnetic core assembly composed of a plurality of magnetic cores can be reduced, and a 2in1 structure in which two independent inductors actually function can be realized.

[0018] Further, by optimizing the arrangement conditions involved in the combination of the magnetic cores, further reduction in the outer dimensions can be achieved, and thus the installation space can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 is a perspective view of the magnetic coupling inductor according to the first embodiment of the present application.

[0020] Figure 2 is a perspective view of the magnetic core after the adhesive tape is omitted. Figure 1

[0021] Figure 3 is a sectional view for explaining a magnetic core portion of the magnetic circuit.

[0022] Figure 4 is a partial plan view for explaining a configuration condition of the magnetic core structure.

[0023] Figure 5 is a partial plan view for explaining another configuration condition of the magnetic core structure.

[0024] Figure 6 is a sectional view for explaining a dimensional relationship of the magnetic core structure of the first embodiment.

[0025] Figure 7a is a front view showing a magnetic core portion of another embodiment.

[0026] Figure 7b is a perspective view of Figure 7a

[0027] Figure 7c is a perspective view showing one PQ magnetic core of Figure 7a after being omitted.

[0028] Figure 8 is a perspective view showing a combination of two coil forms and a positioning and fixing member.

[0029] Figure 9 is a perspective view showing a combined structure of two coil forms.

[0030] Figure 10 is a perspective view showing a combined structure of one PQ magnetic core and a positioning and fixing member.

[0031] Figure 11 is a middle sectional front view of a main portion.

[0032] Figure 12a is an overall perspective view of the magnetic coupled inductor viewed from above.

[0033] Figure 12b is a perspective view of a process of winding a coil on a coil form.

[0034] Figure 12c is a perspective view of a process of fixing a positioning and fixing member.

[0035] Figure 12d is a partial perspective view of a process of combining a magnetic core member and a coil form.

[0036] Figure 12e ​​is a bottom view illustrating the final bonding process.

[0037] (Symbol explanation)

[0038] 1 First magnetic core

[0039] 2 Second magnetic core

[0040] 3, 31 Third magnetic core

[0041] 4, 5 Coil former

[0042] 6 First coil winding

[0043] 7 Second coil winding

[0044] 8 Position fixing member

[0045] 9 Terminal pin

[0046] 10 Fixing tape

[0047] 11, 21 Middle leg portion

[0048] 12, 22 Outer leg portion

[0049] 13, 23 Connecting portion

[0050] 41, 51 Terminal plate

[0051] 42, 52 Barrel portion

[0052] 43, 53 Outer flange portion

[0053] 44, 54 Inner flange portion

[0054] 81 Base portion

[0055] 82 Longitudinal piece

[0056] 83 Click groove

[0057] 100 Magnetic coupled inductor

[0058] G1, G2 Gap DETAILED DESCRIPTION

[0059] Hereinafter, the structure of a magnetic coupled inductor according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0060] Figure 1 is an appearance perspective view of the magnetic coupled inductor 100 as a product, Figure 2 is an exploded perspective view of the magnetic coupled inductor 100 after the fixing tape is omitted. Figure 1

[0061] ​The magnetic coupling inductor 100 of the present embodiment is provided with: a first magnetic core 1 and a second magnetic core 2 made of PQ magnetic cores, a third magnetic core 3 made of a ring core, two bobbin 4, 5, a first coil winding 6 and a second coil winding 7, two positioning and fixing members 8, 8, eight terminal pins 9 on both sides, and a fixing tape 10 wound around the outer periphery.

[0062] As for the pair of PQ magnetic cores of the first magnetic core 1 and the second magnetic core 2, for example, they are made of ferrite cores and have the same outer dimensions, and the first magnetic core 1 has a middle leg portion 11, outer leg portions 12 on both sides of the middle leg portion 11, and a flat plate-shaped connecting portion 13 connecting the middle leg portion 11 and the outer leg portions 12, and the second magnetic core 2 has a middle leg portion 21, outer leg portions 22 on both sides of the middle leg portion 21, and a flat plate-shaped connecting portion 23 connecting the middle leg portion 21 and the outer leg portions 22, and the first magnetic core 1 and the second magnetic core 2 are arranged in opposition.

[0063] The middle leg portions 11, 21 are formed in a cylindrical shape, and have a length of approximately 1 / 2 of the interval distance between the opposing connecting portion 13 and the connecting portion 23, and the outer leg portions 12, 22 are formed in a plate shape in which the inner side surface is in a circular arc shape and the outer side surface is in a flat surface shape.

[0064] The third magnetic core 3 is made of a ferrite core, for example, and is formed in a circular ring shape (circular plate shape) having a rectangular cross section.

[0065] Figure 8 The two bobbin 4, 5 shown in the middle are made of insulating resin, are formed in a symmetrical shape, and are combined into one body as shown in the middle, and the two bobbin 4, 5 are respectively provided with terminal boards 41, 51 on the end portions thereof, and four terminal pins 9, 9 are respectively provided on each of the terminal boards 41, 51. Figure 9

[0066] The two bobbin 4, 5 shown in the middle are made of insulating resin, are formed in a symmetrical shape, and are combined into one body as shown in the middle, and the two bobbin 4, 5 are respectively provided with terminal boards 41, 51 on the end portions thereof, and four terminal pins 9, 9 are respectively provided on each of the terminal boards 41, 51. Figure 9 ​). In addition, butterfly-shaped protrusions 45, 55 are provided on the upper and lower ends of the outer flange portions 43, 53 of the coil forms 4, 5, respectively, and abut against the upper and lower inclined surfaces of the connecting portions 13, 23 of the first and second magnetic cores 1, 2, respectively.

[0067] Thus, by providing the butterfly-shaped protrusions 45, 55 on the upper and lower ends of the outer flange portions 43, 53 of the coil forms 4, 5, respectively, the insulation between the first coil winding 6 (including the lead wire) and the first magnetic core 1 and the insulation between the second coil winding 7 (including the lead wire) and the second magnetic core 2 are improved, and each of the magnetic cores 1, 2, 3 and each of the coil forms 4, 5 are stably fixed to each other.

[0068] The end portions of the cylindrical portions 42, 52 of the coil forms 4, 5 are configured such that the recessed portion 42b of one coil form 4 and the protruded portion 52a of the other coil form 5 (see FIG. 6) are engaged as one coil form 4 is symmetrically provided in a concave-convex shape for engagement, thereby aligning the axial centers of the cylindrical portions 42, 52. Figure 8

[0069] The middle leg portions 11, 21 of the first and second magnetic cores 1, 2 are inserted into the connected cylindrical portions 42, 52 of the coil forms 4, 5 from one end side and the other end side, respectively, and thus the coil forms 4, 5 are disposed outside the middle leg portions 11, 21, respectively.

[0070] Further, the corresponding middle leg portions 11, 21 of the first and second magnetic cores 1, 2 are butted against each other, and the corresponding outer leg portions 12, 22 on both sides are butted against each other, and gaps G1, G2 (see FIG. 6) are provided between these corresponding leg portions, respectively. Figure 3 The sizes b of these gaps G1, G2 (which are substantially the same size) are defined by the positioning and fixing member 8 (so-called spacer) described later.

[0071] In the structure of the coil forms 4, 5, the first coil winding 6 is wound between the outer flange portion 43 and the inner flange portion 44 of one coil form 4, and the second coil winding 7 is wound between the outer flange portion 53 and the inner flange portion 54 of the other coil form 5 (see FIG. 6). Figure 2 The end of the first coil winding 6 is connected to the prescribed terminal pin 9, and the end of the second coil winding 7 is also connected to the prescribed terminal pin 9.

[0072] ​Further, between the inner flange portion 44 of one coil former 4 and the inner flange portion 54 of the other coil former 5, a ring-shaped third magnetic core 3 is arranged. The third magnetic core 3 is sandwiched by the two coil formers 4, 5, and the majority of the middle leg portions 11, 21 of the first and second magnetic cores 1, 2 are inserted into the inner ring of the third magnetic core 3, and the gap G1 is formed between the front end faces of the middle leg portions 11, 21.

[0073] When the first to third magnetic cores 1 to 3 and the two coil formers 4, 5 are assembled, positioning and fixing members 8, 8 are arranged on both sides of the lower portions of the two coil formers 4, 5. As shown in FIGS. 1 to 3, Figure 8 、 Figure 10 and Figure 11 The positioning and fixing members 8, 8 are configured such that a vertical piece 82, 82 extending upward is erected at the center of a flat plate-shaped base 81, 81, and a slit-shaped engagement groove 83, 83 is formed on both sides of the inner side of the base 81.

[0074] The extended portions 44a, 54a of the two inner flange portions 44, 54 of the coil formers 4, 5 are engaged in the engagement grooves 83, 83. Thus, the positions in the axial direction and the center positions of the inner flange portions 44, 54 of the two coil formers 4, 5 are defined.

[0075] Further, the vertical pieces 82, 82 are sandwiched between the front end faces of the outer leg portions 12 of the first magnetic core 1 and the front end faces of the outer leg portions 22 of the second magnetic core 2, and the size b of the gap G2 between the front end faces of the outer leg portions 12 of the first magnetic core 1 and the front end faces of the outer leg portions 22 of the second magnetic core 2 is defined by the thickness dimension of the vertical pieces 82, 82 of the positioning and fixing members 8, 8.

[0076] As shown in FIGS. 1 to 3, Figure 10 The shapes of the vertical pieces 82, 82 of the positioning and fixing members 8, 8 are similar to the cross-sectional shapes of the outer leg portions 12, 22, and the two are in full contact without deviation. In addition, triangular openings 84 are formed in the upper and lower portions of the vertical pieces 82, 82, and an adhesive is filled in the openings 84 when the assembly is performed, whereby the vertical pieces 82, 82 are fixed to the front end faces of the outer leg portions 12, 22 of the first and second magnetic cores 1, 2.

[0077] Thus, by combining positioning and fixing components 8, 8 and third magnetic core 3 between the first magnetic core 1 and the second magnetic core 2, the position of the gap G1 between the middle legs 11, 21 can be accurately set at the middle position of the first coil winding 6 and the second coil winding 7 respectively wound on each coil frame 4, 5. Therefore, in a 2in1 type magnetic coupling inductor, the inductance of each inductor can be set to be equal to each other.

[0078] Therefore, the following undesirable situation in the prior art can be eliminated: due to the deviation in the distance from each inductor to the magnetic gap, any one of the inductors will become magnetically saturated.

[0079] In addition, such as Figure 9 As shown, the front ends of the protrusions 44b and 54b formed on the lower ends of the inner flange portions 44 and 54 of the two coil frames 4 and 5 respectively abut against the substrate surface, thereby stabilizing the posture during manufacturing processes such as assembly.

[0080] As described above, the magnetically coupled inductor 100 of this embodiment is configured as a coupled inductor with a 2-in-1 (2-in-1) structure. This 2-in-1 coupled inductor is constructed by sandwiching a third magnetic core 3, which is made of a toroidal magnetic core, between a coil frame 4 assembled to a first magnetic core 1 and a coil frame 5 assembled to a second magnetic core 2. Furthermore, the magnetic flux generated by the currents flowing in the first coil winding 6 and the second coil winding 7 and passing through the third magnetic core 3 is in the same direction.

[0081] Specifically, such as Figure 3 As shown, the first magnetic core 1 and the second magnetic core 2 are separated from each other by forming a gap G1 between the middle legs 11 and 21 and a gap G2 between the outer legs 12 and 22. Therefore, in the first magnetic core 1, the magnetic flux from the outer legs 12 and 12 on both sides through the connecting parts 13 and 13 converges at the middle leg 11 and flows toward the front end face of the middle leg 11.

[0082] On the other hand, in the second magnetic core 2, the magnetic flux from the outer legs 22, 22 on both sides through the connecting parts 23, 23 converges at the middle leg 21 and flows toward the front end face of the middle leg 21. The magnetic flux flowing in the two middle legs 11, 21 collides with each other at the front end face of the middle legs 11, 21 and then flows to the left and right, and after passing through the third magnetic core 3, it reaches the outer legs 12, 22 of the first and second magnetic cores 1, 2 respectively.

[0083] As a result, in the first and second magnetic cores 1 and 2 and the third magnetic core 3, an orientation as shown is formed. Figure 3magnetic loops Ll, L2 shown in FIG. 1.

[0084] The magnetic coupled inductor 100 of the embodiment described above is configured so that when the thickness of the third magnetic core 3 is set to a, and the gap amount of the gap G2 between the outer leg portions 12 and 22 of the first and second magnetic cores 1, 2 is set to b, as shown in FIG. 1, the following condition (1) is satisfied. Figure 4

[0085] a > b (1)

[0086] By being configured so that the above condition (1) is satisfied, the magnetic coupled inductor can be made smaller.

[0087] That is, when a < b, the coupling coefficient, which is an important parameter of the coupled inductor, becomes small. When the coupling coefficient becomes small, if the coupled inductor is not made larger, a large current cannot be allowed.

[0088] Therefore, it is preferable to be configured so that the condition (1) of a > b is satisfied, thereby achieving the miniaturization of the product.

[0089] In addition, the above magnetic coupled inductor 100 is configured so that when the thickness of the third magnetic core 3 is set to a, and the thickness of the connecting portions 13, 23 of the first and second magnetic cores 1, 2 is set to c, as shown in FIG. 1, the following condition (2) is satisfied. Figure 5 a > c (2)

[0090] By being configured so that the above condition (2) is satisfied, the magnetic coupled inductor can be made smaller.

[0091] That is, when a < c, generally, the circulating magnetic flux is saturated at the position to which a relates (the gap Gl position between the front end surfaces of the middle leg portions 11, 21 of the first and second magnetic cores 1, 2), not at the position to which c relates (the positions of the connecting portions 13, 23 of the first and second magnetic cores 1, 2), and thus it is difficult to secure the function as a coupled inductor.

[0092] In addition, when the duty (switching ON·OFF ratio) is set to a predetermined value, the magnetic flux flowing in the first and second magnetic cores 1, 2 flows into a (the gap Gl) after merging, and thus the third magnetic core 3 easily saturates, and thus it is set so that a is greater than or equal to c (the cross-sectional area of the third magnetic core 3 is greater than or equal to the cross-sectional area of the above connecting portions 13, 23) (when the output voltage Vout / input voltage Vin > 2).

[0093] Therefore, it is most preferable to configure the circuit so that the condition (2) of a = c is satisfied, thereby achieving the miniaturization of the product.

[0094] Therefore, it is most preferable to configure the circuit so that the condition (2) of a = c is satisfied, thereby achieving the miniaturization of the product.​

[0095] In the above condition (2), even if there is a tolerance of c (around ±5%), the effect of miniaturizing the inductor can be confirmed. Therefore, the actual numerical range can be the range that satisfies the following condition (2').

[0096] a≥0.95c(2')

[0097] Furthermore, the aforementioned magnetically coupled inductor 100 is configured such that: when... Figure 6 As shown, when the gap between the inner circumferential surface of the annular core in the third magnetic core 3 and the outer circumferential surface of the middle legs 11, 21 is set to f, or the gap between the outer circumferential surface of the annular core in the third magnetic core 3 and the inner circumferential surface of the outer legs 12, 22 is set to g, the total gap amount b of the gap G1 between the middle legs 11, 21 of the first and second magnetic cores 1, 2 and the two gaps G2, G2 between the outer legs 12, 22 on both sides (which is basically 3b) and the above f, g, the following conditions (3) or (4) are met.

[0098] 3b≥f (3)

[0099] or

[0100] 3b≥g (4)

[0101] By configuring the magnetically coupled inductor to meet the above conditions (3) or (4), the magnetically coupled inductor can be miniaturized.

[0102] That is, when 3b < f and 3b < g, similarly to when condition (1) is not met, the coupling coefficient, which is an important parameter of the coupled inductor, becomes smaller. When the coupling coefficient becomes smaller, a large current cannot be allowed unless the coupled inductor is made larger.

[0103] Therefore, the preferred configuration is to satisfy the condition (3) that 3b ≥ f or the condition (4) that 3b ≥ g, thereby achieving product miniaturization.

[0104] It should be noted that, regarding the physical integration of each magnetic core 1, 2, and 3, in the above embodiment, a fixing tape 10 is used. However, adhesives, adhesive tapes, clamps, etc., can also be used for integration.

[0105] The direction of the current flowing through the first coil winding 6 and the second coil winding 7, as well as the winding direction of the coil, can be configured as follows, and can be arbitrarily selected as long as the following effects are achieved.

[0106] That is, when Figure 3When the two magnetic cores 1, 2 are arranged to face each other as shown in the figure, magnetic flux from the outer leg portions 12, 12 on both sides of the first magnetic core 1 through the middle leg portion 11 based on the first coil winding 6 and magnetic flux from the outer leg portions 22, 22 on both sides of the second magnetic core 2 through the middle leg portion 21 based on the second coil winding 7 collide with each other in reverse directions between the front end faces of the middle leg portions 11, 21.

[0107] Further, when so configured, in Figure 3 the magnetic circuit L1 formed by the magnetic flux from the outer leg portions 12, 22 on both sides of the first magnetic core 1 through the middle leg portion 11 based on the first coil winding 6 and the magnetic circuit L2 formed by the magnetic flux from the outer leg portions 22, 22 on both sides of the second magnetic core 2 through the middle leg portion 21 based on the second coil winding 7 cancel each other in reverse directions between the front end faces of the middle leg portions 11, 21, thereby functioning to form a magnetic structure (flow of magnetic flux) that allows a large current.

[0108] Note that, according to the present embodiment, the first magnetic coupled inductor portion formed by the first coil winding 6 and the magnetic core portion around it and the second magnetic coupled inductor portion formed by the second coil winding 7 and the magnetic core portion around it are configured in a state of being coupled to each other, and thus, compared to the case where two independent inductors are provided, a magnetic structure (flow of magnetic flux) that allows a large current can be formed.

[0109] Figures 7a-7c Another embodiment is shown in the figure, which is an example in which a portion of the outer periphery of the third magnetic core 31 is removed, thereby reducing the size in the up-down direction in the figure. That is, it is an example in which the upper and lower arc-shaped portions of the donut shape of the third magnetic core 31, which do not face the inner peripheral surfaces of the outer leg portions 12, 22 of the first and second magnetic cores 1, 2, are removed by the cut surface 3A (see Figure 7a , Figure 7b ).

[0110] In this case, it is preferable to be configured such that when the surface area of the circular arc surface 3B in the outer peripheral surface of the third magnetic core 31, which faces the circular arc-shaped inner surfaces of the outer leg portions 12, 22 through a slight gap, is set as d, and the surface area of the front end face of the outer leg portion 12, 22 of the first or second magnetic core 1, 2 is set as e (see Figure 7c ), the following condition (5) is satisfied.

[0111] d ≥ e (5)

[0112] By being configured to satisfy the above condition (5), the magnetic coupled inductor can be miniaturized.

[0113] Since d in condition (5) can be replaced with a in condition (2) or e in condition (5) can be replaced with c in condition (2), when d < e, the coupling coefficient, which is an important parameter of the coupled inductor, becomes smaller, just as when condition (2) is not satisfied.

[0114] That is, when the coupling coefficient becomes smaller, a large current cannot be allowed without increasing the size of the coupled inductor. Therefore, when d < e, it is difficult to achieve product miniaturization.

[0115] Next, refer to Figures 12a-12e The manufacturing process of the magnetically coupled inductor 100 according to the above embodiment will be described.

[0116] first, Figure 12a The finished product status is shown in the image. When manufacturing this finished product, firstly, as... Figure 12b As shown, the second coil winding 7 is wound onto the coil frame 5. Although not shown, similarly, the first coil winding 6 is wound onto another coil frame 4. Then, the ends of each coil winding 6, 7 are soldered to the designated terminal pins 9 on the terminal blocks 41, 51, respectively.

[0117] Next, as Figure 12c As shown, to prepare the positioning and fixing components 8, 8, adhesive is filled and applied into each opening 84 of the longitudinal piece 82. Then, as... Figure 12d As shown, the coil frames 4 and 5, each wound with coil windings 6 and 7, are assembled in a monoaxial manner, with the third magnetic core 3 clamped between the two coil frames 4 and 5, and the concave and convex shapes of the ends of the cylindrical portions 42 of one coil frame 4 and the cylindrical portions 52 of the other coil frame 5 aligned (see reference). Figure 9 ).

[0118] Meanwhile, the lower extensions 44a and 54a of the inner flanges 44 and 54 of the coil frame are respectively engaged in the engaging grooves 83 of the positioning and fixing members 8 and 8 on both sides. Further, the first magnetic core 1 and the second magnetic core 2 are respectively positioned opposite the two ends of the coil frames 4 and 5 to be assembled, and the middle legs 11 and 21 are respectively inserted into the cylindrical parts 42 and 52, with the outer legs 12 and 22 located on the outer sides of the coil frames 4 and 5, thereby performing the assembly (see reference). Figure 8 , Figure 9 ).

[0119] At this point, the positioning and fixing components 8 and 8 are clamped by the front ends of the outer feet 12 and 22 of the two magnetic cores 1 and 2, and fixed using the previously applied adhesive. It should be noted that... Figure 12d The illustration of the first magnetic core 1 is omitted in the text.

[0120] Next, as described above, with the first to third magnetic cores 1 to 3 assembled on the coil frames 4 and 5, as follows... Figure 12e As shown, the fixing tape 10 is wrapped around the outer periphery of the first magnetic core 1 and the second magnetic core 2 to temporarily fix the whole. Additionally, at the bottom surface, adhesive is applied to the contact portion P between the base 81 of the positioning and fixing members 8, 8 and the outer peripheral surface of the third magnetic core 3, thereby fixing both and allowing them to dry, thus completing the manufacturing process. It should be noted that in this case, it is preferable to check the electrical characteristics before applying the adhesive.

[0121] Alternatively, EE-type magnetic cores, EER-type magnetic cores, or a pair of pot cores (with the outer foot surrounding the middle foot) can be used instead of the pair of PQ cores used in the above embodiments.

[0122] In addition, various shapes can be used for the shape of the coil frame.

Claims

1. A magnetic coupled inductor characterized by comprising: first and second magnetic cores each having a middle leg portion, outer leg portions on at least both sides of the middle leg portion, and connecting portions connecting the middle leg portion and the outer leg portions; coil forms through which the middle leg portions of the first and second magnetic cores are inserted, and which are disposed outside the respective middle leg portions; first and second coil windings wound around the respective coil forms; and a third magnetic core in the shape of a ring and sandwiched by the two coil forms with the middle leg portions inserted in the third magnetic core, the corresponding leg portions of the first and second magnetic cores are butted against each other with a gap provided between the corresponding leg portions, whereby the middle leg portions are separated from each other and the outer leg portions are separated from each other, the directions of magnetic flux generated by the respective currents flowing through the first and second coil windings and passing through the third magnetic core are the same direction, the magnetic coupled inductor is configured so that when the thickness of the third magnetic core is a, and the gap between the outer leg portions of the first and second magnetic cores is b, condition (1) a > b is satisfied.

2. The magnetic coupled inductor according to claim 1, characterized by comprising: the magnetic coupled inductor is configured so that when the thickness of the third magnetic core is a, and the thickness of the connecting portions of the first and second magnetic cores is c, condition (2) a > c is satisfied.

3. The magnetic coupled inductor according to claim 1 or 2, characterized by comprising a positioning and fixing member that fixes a middle portion in the thickness direction of the third magnetic core at a middle position between the front end surfaces of the two middle leg portions.

4. The magnetic coupled inductor according to claim 3, characterized by comprising: the positioning and fixing member is configured so that a longitudinal piece extending upward is erected at the center of a flat base, engagement grooves in the shape of slits are formed on both sides of the inner side of the base, and the extended portions of the two inner flange portions of the coil forms can be engaged in the engagement grooves. ​ ​ ​

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