Coupling inductor

Abstract

Provided is a coupling inductor with which a coupling coefficient can easily be adjusted without changing the shape of two conductors to be electromagnetically coupled.　This coupling inductor comprises: a first conductor and a second conductor each having a U-shape in plan view along the main surface of a first core and each having two arm parts; and a second core sandwiching, with the first core, the first conductor and the second conductor. The second conductor is disposed between the arm parts of the first conductor such that the U-shaped opening of the second conductor faces in the same direction as the U-shaped opening of the first conductor. The two arm parts of the first conductor each have a proximity section where the arm parts of the second conductor approach and a separation section which is closer to the U-shape opening side of the first conductor than the proximity section and in which the interval between the separation section and the arm parts of the second conductor is wider than the interval in the proximity section. On the main surface of the first core, there are two projecting parts each provided between the separation part of each of the two arm parts of the first conductor and each of the arm parts of the second conductor.

Description

Coupling Inductor

[0001] The present invention relates to a coupling inductor.

[0002] As a coupling inductor used in a power supply circuit or the like, Patent Document 1 discloses a first conductor having a U-shape in plan view, a second conductor having a U-shape in plan view disposed inside the first conductor, a first core portion which is a magnetic body disposed inside the second conductor, and a second core portion which is a magnetic body disposed between the first conductor and the second conductor. In this coupling inductor, by changing the ratio of the length of the first core portion and the length of the second core portion measured along the extending direction of the arms of the U-shaped first conductor and second conductor, the coupling coefficient of the electromagnetic coupling between the first conductor and the second conductor can be adjusted.

[0003] Japanese Patent Application Laid-Open No. 2024-61638

[0004] In the coupling inductor of Patent Document 1, when adjusting the coupling coefficient, it may be necessary to change the length of the arms of the first conductor and / or the second conductor as the ratio of the length of the first core portion and the length of the second core portion is changed.

[0005] An object of the present invention is to provide a coupling inductor capable of easily adjusting the coupling coefficient by changing the size of a part of a magnetic core without changing the shapes of two conductors that are electromagnetically coupled.

[0006] One aspect of the present invention comprises a first core having a main surface, a first conductor having two arm portions that are U-shaped in plan view along the main surface of the first core, a second conductor having two arm portions that are U-shaped in plan view along the main surface of the first core and disposed between the two arm portions of the first conductor, and a second core that sandwiches the first conductor and the second conductor together with the first core, wherein on the main surface of the first core, the U-shaped opening of the second conductor is the same as the U-shaped opening of the first conductor The first conductor is arranged to face the same direction as the U-shaped opening, and each of the two arm portions of the first conductor has a proximity portion in which the arm portion of the second conductor is close, and a separation portion which is located on the U-shaped opening side of the first conductor and is wider than the distance between the arm portion of the second conductor and the proximity portion, and the first core has two projections on its main surface provided between the separation portions of each of the two arm portions of the first conductor and the arm portion of the second conductor. This specification includes all the contents of Japanese Patent Application No. 2025-018099, filed on February 6, 2025.

[0007] According to the present invention, a coupled inductor can be provided that allows for easy adjustment of the coupling coefficient without changing the shapes of the two electromagnetically coupled conductors.

[0008] Figure 1 is a perspective view of a coupled inductor according to one embodiment of the present invention, viewed from the top side. Figure 2 is a perspective view of the coupled inductor viewed from the bottom side. Figure 3 is a perspective view of the coupled inductor viewed from the wide side. Figure 4 is an exploded perspective view of the coupled inductor. Figure 5 is a plan view of the first core. Figure 6 is a plan view of the first core showing the arrangement of the first and second conductors. Figure 7 is a diagram showing the configuration of the bottom surface of the coupled inductor. Figure 8 is a diagram showing the configuration of the narrow side surface of the coupled inductor. Figure 9 is a simulation result of the coupling coefficient and mutual inductance of the coupled inductor. Figure 10 is a perspective view of a coupled inductor according to a modified example, viewed from the bottom side. Figure 11 is a plan view of the first core of the coupled inductor according to a modified example, with the arrangement of the first and second conductors.

[0009] Embodiments of the present invention will be described below with reference to the drawings. [1. Configuration of the coupled inductor] Figures 1, 2, and 3 show the configuration of a coupled inductor 1 according to one embodiment of the present invention. Figure 1 is a perspective view of the coupled inductor 1 as seen from the top surface 12 side, and Figure 2 is a perspective view of the coupled inductor 1 as seen from the bottom surface 10 side opposite the top surface 12. Figure 3 is a perspective view of the wide side surface 14 of the coupled inductor 1, and Figure 4 is an exploded perspective view of the coupled inductor 1.

[0010] In this embodiment, in the coupled inductor 1, the first main surface that faces the mounting substrate (e.g., a circuit board) not shown during mounting is defined as the bottom surface 10, and the second main surface opposite the bottom surface 10 is called the top surface 12. Furthermore, of the two pairs of main surfaces that are perpendicular to the bottom surface 10 and face each other, the pair with the larger area is called the wide side surface 14, and the pair of main surfaces with the smaller area that are perpendicular to the bottom surface 10 and the pair of wide side surfaces 14 are called the narrow side surface 16.

[0011] As shown in Figure 1, the distance from the bottom surface 10 to the top surface 12 is defined as the height H of the coupled inductor 1, the distance between the pair of wide sides 14 is defined as the width W of the coupled inductor 1, and the distance between the pair of narrow sides 16 is defined as the length L of the coupled inductor 1. Furthermore, the direction of height H is defined as the height direction DH, the direction of width W is defined as the width direction DW, and the direction of length L is defined as the length direction DL.

[0012] The coupled inductor 1 has a roughly plate-shaped first core 20 and a second core 21 made of a magnetic material, and a first conductor 30 and a second conductor 40 sandwiched between the first core 20 and the second core 21. The first core 20 and the second core 21, when combined so as to sandwich the first conductor 30 and the second conductor 40, form a roughly rectangular magnetic core 50.

[0013] The first conductor 30 and the second conductor 40 are electromagnetically coupled to each other via the first core 20 and the second core 21, which are magnetic materials. The magnetic material constituting the first core 20 and the second core 21 is, for example, ferrite. The ferrite may be, for example, Ni-Zn ferrite or Mn-Zn ferrite. Instead of ferrite, the first core 20 and the second core 21 may be made of a magnetic material obtained by compression molding a mixed powder of magnetic powder such as a metallic magnetic material and a resin.

[0014] The first core 20 has two opposing main surfaces 201 and 202, and the second core 21 has two opposing main surfaces 211 and 212 (see Figure 4, etc.). The first conductor 30 and the second conductor 40 are held between one main surface 201 of the first core 20 and one main surface 211 of the second core 21 (Figure 4). The first conductor 30 has a U-shape in plan view along the main surface 201 of the first core 20 (plan view of a plane parallel to the main surface 201) and has two arm portions 31, 31. Similarly, the second conductor 40 has a U-shape in plan view along the main surface 201 of the first core 20 and has two arm portions 41, 41. The second conductor 40 is smaller in size than the first conductor 30 and is positioned between the two arm portions 31, 31 of the first conductor 30.

[0015] The first conductor 30 and the second conductor 40 are formed, for example, by bending a wire having a rectangular cross-section. Alternatively, the first conductor 30 and the second conductor 40 may be formed by punching a conductor plate into a U-shape. Furthermore, the first conductor 30 and the second conductor 40 are not limited to wires with a rectangular cross-section, but may be formed by bending wires having any cross-sectional shape, such as circular or elliptical shapes.

[0016] In this embodiment, the conductor width T of each arm portion 31, 31 of the first conductor 30 in a plan view is, for example, wider than the conductor width t of each arm portion 41, 41 of the second conductor 40. Alternatively, the conductor width T of each arm portion 31, 31 of the first conductor 30 may be narrower than the conductor width t of each arm portion 41, 41 of the second conductor 40, or the same as the conductor width T of each arm portion 41, 41 of the second conductor 40. However, as in this embodiment, by making the conductor width T of the arm portions 31, 31 wider than the conductor width t of the arm portions 41, 41, the allowable current of the first conductor 30 can be increased compared to that of the second conductor 40. Note that the conductor thickness perpendicular to the conductor width T of the arm portions 31, 31 of the first conductor 30 and the conductor thickness perpendicular to the conductor width t of the arm portions 41, 41 of the second conductor 40 may be the same.

[0017] Figure 5 is a plan view of the main surface 201 of the first core 20. Figure 6 shows the state in which the first conductor 30 and the second conductor 40 are arranged on the main surface 201 of the first core 20. As shown in Figure 5, in this embodiment, the first core 20 is configured symmetrically with respect to the center line CL in the width direction (DL direction). As shown in Figure 6, the second conductor 40 is arranged on the main surface 201 of the first core 20 such that the U-shaped opening of the second conductor 40 faces in the same direction (downward in the example shown in Figure 6) as the U-shaped opening of the first conductor 30.

[0018] The two arm portions 31, 31 of the first conductor 30 each have a proximity portion 310 (hatched portion in the illustration) where the arm portions 41, 41 of the second conductor 40 are close together, and a separation portion 311 (hatched portion in the illustration) where the distance between the arm portions 41, 41 and the second conductor 40 is wider than that of the proximity portion 310. The proximity portion 310 is the portion where the arm portions 31, 31 of the first conductor 30 are close together along the arm portions 41, 41 of the second conductor 40. The separation portion 311 is located closer to the U-shaped opening of the first conductor 30 than the proximity portion 310, and the distance between the arm portions 41, 41 of the second conductor 40 and the separation portion 311 is wider than that in the proximity portion 310.

[0019] To prevent electrical contact between the arm portion 31 and the arm portion 41 at the proximity portion 310, at least one of the first conductor 30 and the second conductor 40 has an insulating film on its surface. In this embodiment, as an example, the first conductor 30 does not have an insulating film, and the surface of the second conductor 40 is protected by an insulating film (not shown).

[0020] When Mn-Zn ferrite is used as the magnetic material constituting the first core 20 and the second core 21, the insulation resistance of the first core 20 and the second core 21 becomes smaller compared to when Ni-Zn ferrite is used, so it is desirable to also apply an insulating film to the first conductor 30.

[0021] In this embodiment, as an example, each of the two arm portions 31, 31 of the first conductor 30 is bent in a crank shape toward the U-shaped opening of the first conductor 30, away from each other, from the proximity portion 310, thereby forming a separation portion 311. This makes it easy to form the proximity portion 310 and the separation portion 311 in the arm portion 31 of the first conductor 30.

[0022] The end faces 312 of the two arm portions 31, 31 of the first conductor 30 are exposed to the bottom surface 10 of the magnetic core 50. As a result, the end faces 312 of the first conductor 30 exposed to the bottom surface 10 can be used directly as external electrodes, thus simplifying the shape of the first conductor.

[0023] Furthermore, the sides of the two arm portions 31, 31 of the first conductor 30 are exposed from the two narrow sides 16, 16 of the magnetic core 50. As a result, when the coupled inductor 1 is soldered to a conductor pattern on a circuit board or the like, the solder also flows to the sides of the arm portions 31 that are exposed on the narrow sides 16 of the magnetic core 50, thereby further increasing the fixing strength to the circuit board and the like while further reducing the connection resistance with the conductor pattern.

[0024] The first core 20 has two projections 205, 205 on its main surface 201, which are provided between the respective separation portions 311 of the two arm portions 31, 31 of the first conductor 30 and the respective arm portions 41, 41 of the second conductor 40.

[0025] As shown in Figure 5, the main surface 201 of the first core 20 has a groove 206 (hatched area in the figure) in which the first conductor and the second conductor are arranged. Specifically, the main surface 201 of the first core 20 has a central core portion 203 and two outer wall portions 204, 204 that protrude from the main surface 201 in the direction normal to the main surface 201, so as to form the groove 206. The central core portion 203 is the part that is positioned between the arm portions 41, 41 of the second conductor 40 when the second conductor 40 is mounted. The two outer wall portions 204, 204 are protrusions that define the outer surface position of the arm portions 31, 31 (specifically, the adjacent portions 310, 310) of the first conductor 30 when the first conductor 30 is mounted, and are formed on a part of each of the two sides of the first core 20 that face each other in the DL direction.

[0026] Furthermore, two projections 205, 205 are provided on the bottom surface of the groove 206 (i.e., on the main surface 201) that separate the respective separation portions 311 of the two arm portions 31, 31 of the first conductor 30 from the respective arm portions 41, 41 of the second conductor 40.

[0027] In this embodiment, the second core 21 has the same shape as the first core 20. As a result, as shown in Figure 6, when the second core 21 is placed over the first core 20 on which the first conductor 30 and the second conductor 40 are mounted, the first conductor 30 and the second conductor 40 fit into grooves in the second core 21 that correspond to grooves 206 in the first core 20, and the first conductor 30 and the second conductor 40 are held between the first core 20 and the second core 21.

[0028] Figure 7 shows the configuration of the bottom surface 10 of the coupled inductor 1. Figure 8 shows the configuration of the narrow side surface 16 of the coupled inductor 1. On the bottom surface 10, the central core 203 and the two protrusions 205, 205 of the first core 20 face the central core 213 and protrusion 215 of the corresponding second core 21, respectively. On the narrow side surface 16, the outer wall 204 of the first core 20 faces the outer wall 214 of the second core 21.

[0029] On the bottom surface 10, the gap G2 between the core portion 203 of the first core 20 and the core portion 213 of the second core 21 is filled with adhesive to fix the core portions 203 and 213, forming an adhesive layer. Similarly, on the narrow side surface 16, the gap G3 between the outer wall portion 204 of the first core 20 and the outer wall portion 214 of the second core 21 is filled with adhesive to fix the outer wall portions 204 and 214, forming an adhesive layer.

[0030] The spacing d2 of gap G2 and the spacing d3 of gap G3 can be adjusted to set the mutual inductance of the first conductor 30 and the second conductor 40 to a desired value. The adhesive constituting the adhesive layer may be mixed with insulating particles such as silica. This makes it possible to bond the first core 20 and the second core 21 while setting the spacing d2 of gap G2 and the spacing d3 of gap G3 to a desired value.

[0031] On the other hand, the gap G1 between the upper surface of the projection 205 of the first core 20 and the projection 215 of the second core 21 is an air gap. In the above configuration, the first conductor 30 and the second conductor 40 are electromagnetically coupled by the magnetic flux generated in the first conductor 30 and the second conductor 40 passing through the central core portions 203 and 213. In the coupled inductor 1 of this embodiment, because of the projections 205 and 215 provided between the arm portion 31 of the first conductor 30 and the arm portion 41 of the second conductor 40, a portion of the magnetic flux generated by the first conductor 30 passes through the projections 205 and 215, and as a result, the amount of magnetic flux generated by the first conductor 30 that passes through the central core portions 203 and 213 is reduced.

[0032] This reduction depends on the magnetic resistance of the magnetic path including the protrusions 205 and 215, and the magnetic resistance depends on the area S of the opposing surfaces of the protrusions 205 and 215 (the upper surfaces of the respective protrusions) and the spacing d1 of the gap G1, which is the air gap. Therefore, in the coupled inductor 1 having the above configuration, the coupling coefficient K of the electromagnetic coupling between the first conductor 30 and the second conductor 40 can be easily adjusted by adjusting the spacing d1 of the gap G2, which is the air gap, and / or the area S, without changing the shapes of the first conductor 30 and the second conductor 40.

[0033] In this embodiment, the shape of the second core 21 is the same as that of the first core 20, and the main surface 211 of the second core 21, which faces the main surface 201 of the first core 20, is provided with another projection 215 at a position opposite to the projection 205 of the first core 20. Alternatively, the shape of the second core 21 may differ from that of the first core 20, as long as there is an air gap between the upper surface of the projection 205 of the first core 20 and the second core 21. For example, the height hp2 of the projection 215 of the second core 21 may differ from the height hp1 of the projection 205 of the first core 20, or the second core 21 may not have a projection 215 at all (i.e., hp2 = 0). In these cases as well, the coupling coefficient K can be easily adjusted by changing the height of the projection 205 of the first core 20 without changing the shapes of the first conductor 30 and the second conductor 40.

[0034] [2. Characteristics of Coupled Inductance] Figure 9 shows the simulation results for the coupling coefficient K and mutual inductance M of the coupled inductor 1. Figure 9 shows a graph showing the relationship between the heights hp1 and hp2 of the protrusions 205 and 215, the coupling coefficient K and mutual inductance M, with the area S of the protrusion 205 as a parameter. As the first core 20 and the second core 21 have the same shape as described above, in the above simulation, the height hp2 of the protrusion 215 was always assumed to be equal to the height hp1 of the protrusion 205. Also, in the above simulation, the width W, length L and height H of the coupled inductor 1 were fixed values ​​of 6 mm, 12 mm, and 12 mm, respectively. Therefore, changing the heights hp1 and hp2 of the protrusions 205 and 215 is equivalent to changing the spacing d1 of the gap G1. In addition, the area S of the opposing surfaces of the two protrusions 205 and 215 were all assumed to be the same value.

[0035] In Figure 9, the horizontal axis shows the heights hp1 and hp2 of the protrusions 205 and 215, while the left and right vertical axes show the mutual inductance M and coupling coefficient K, respectively. Also in Figure 9, the graphs indicated by the diamond, X-shape, triangle, and black circle plot marks represent areas S of 3.125 mm². ２ , 2.475 mm２ 1.6 mm ２ , and 0.8 mm ２ This shows the case where... The solid line is the graph of mutual inductance M, and the dashed line is the graph of coupling coefficient K.

[0036] When designing the coupled inductor 1, it is desirable that the coupling coefficient K can be adjusted independently of the mutual inductance M. In Figure 9, comparing the solid line graph showing the mutual inductance M with the dashed line graph showing the coupling coefficient K, it can be seen that the larger the area S, the smaller the change in mutual inductance associated with changes in heights hp1 and hp2, and the larger the change in the coupling coefficient K. In other words, the larger the area S, the easier it becomes to adjust the coupling coefficient K while suppressing fluctuations in the mutual inductance M, and the wider the adjustment range of the coupling coefficient K.

[0037] [3. Modified Examples] In the embodiment described above, the end faces of the two arm portions 31, 31 of the first conductor 30 are exposed to the bottom surface 10 of the magnetic core 50. However, the shape of the first conductor 30 exposed to the bottom surface 10 is not limited to this. Figures 10 and 11 show the configuration of a coupled inductor 1a, which is a modified example of the coupled inductor 1 with a different shape of the first conductor. Figures 10 and 11 correspond to Figures 2 and 6 of the coupled inductor 1, respectively. In Figures 10 and 11, components that are the same as those shown in Figures 2 and 6 are indicated using the same reference numerals as in Figures 2 and 6, and the explanation of Figures 2 and 6 described above will be used with reference.

[0038] The coupling inductor 1a has the same configuration as the coupling inductor 1, but has a first conductor 30a instead of the first conductor 30. The first conductor 30a has the same configuration as the first conductor 30, but at the ends of the two arm portions 31a, 31a of the first conductor 30a, the end faces 312, 312 of the arm portions 31a, 31a are bent in a direction facing each other. And the side surfaces of the two arm portions 31a, 31a are exposed on the narrow side surface 16 and the bottom surface 10. Thereby, in the coupling inductor 1a, since the side surface of the first conductor 30a exposed on the bottom surface 10 of the magnetic core 50a can be used as an external electrode, compared with the case where the end face 312 of the first conductor 30 is used as an external electrode, the area of electrical connection with the conductor pattern on the circuit board or the like can be increased, and the connection resistance can be reduced while increasing the fixing strength of the above electrical connection.

[0039] The two arm portions 31a, 31a of the first conductor 30a each have a proximity portion 310a where the arm portions 41, 41 of the second conductor 40 are close, similar to the arm portions 31, 31 of the first conductor 30, and a separation portion 311a where the distance from the arm portions 41, 41 of the second conductor 40 is wider than the proximity portion 310a.

[0040] The first core 20a that houses the first conductor 30a has the same configuration as the first core 20, and has two protrusions 205a, 205a provided between the respective separation portions 311a of the two arm portions 31a, 31a of the first conductor 30a and the respective arm portions 41, 41 of the second conductor 40. However, since the first core 20a houses the first conductor 30a having a different shape from the first conductor 30, the planar shape of the protrusion 205a is different from that of the protrusion 205.

[0041] Similar to the configuration of the coupling inductor 1, the second core 21a has the same shape as the first core 20a, and the first conductor 30a and the second conductor 40 are sandwiched and held between the first core 20a and the second core 21a. The first core 20a and the second core 21a constitute a substantially rectangular parallelepiped magnetic core 50a in a state of sandwiching the first conductor 30a and the second conductor 40.

[0042] [4. Other Embodiments]

[0043] In the embodiment described above, the first core 20 is configured symmetrically with respect to the center line CL in the width direction, and the second core 21 has the same shape as the first core 20. Alternatively, the first core 20 may be configured asymmetrically with respect to the center line CL. For example, in Figure 5, the first core 20 may not have the projection 205 on the left side shown. In this case, the bottom surface 10 shown in Figure 7 will lack the projection 205 on the left side and the projection 215 on the right side shown, respectively. Even in this case, the coupling coefficient K can be adjusted by adjusting the area S and height hp1, hp2 of the projections 205 and 215, each provided on the first core 20 and / or the second core 21.

[0044] Furthermore, when the first core 20 is configured asymmetrically with respect to the center line CL as described above, the second core 21 may be configured to have a shape that is a mirror image of the first core 20 in the left-right direction shown in Figure 5. For example, if the first core 20 does not have the projection 205 on the left side shown in Figure 5, then the first core 20 and the second core 21 will lack the projection 205 and projection 215 on the left side shown in Figure 7, respectively, on the bottom surface 10. In this case as well, the coupling coefficient K can be adjusted by adjusting the area S and height hp1, hp2 of the projections 205 and / or 215 provided on each of the first core 20 and / or the second core 21.

[0045] Alternatively, the second core 21 may not have two protrusions 215, while the first core 20 may have at least one protrusion 205. In this case as well, the coupling coefficient K can be adjusted by adjusting the area S and height hp1 of the at least one protrusion 205 provided on the first core 20.

[0046] In the above-described embodiment, the first core 20 and the second core 21 that constitute the magnetic core 50 are configured such that the first conductor 30 is exposed from the upper surface 12. Instead, the first core 20 and the second core 21 may be configured such that the first conductor 30 is not exposed from the upper surface 12. For example, in the first core 20 shown in FIG. 6, the height in the DH direction may be extended, and the left and right outer wall portions 204 may be configured to be connected on the upper surface 12.

[0047] In addition to being configured such that the end faces 312 face each other as in the first conductor 30a, the first conductor 30 may be configured to be bent such that the end faces 312 face in opposite directions.

[0048] In the above-described embodiment, it is assumed that the first conductor 30 has no insulating film and the surface of the second conductor 40 is protected by an insulating film. Instead, an insulating film may be provided only on the first conductor 30, or insulating films may be provided on both the first conductor 30 and the second conductor 40.

[0049] Note that the present invention is not limited to the configuration of the above-described embodiment, and can be implemented in various aspects without departing from the gist thereof.

[0050] [5. Configuration Supported by the Above Embodiment] The above-described embodiment (and its modification) supports the following configuration.

[0051] (Configuration 1) A first core having a main surface, a first conductor having two arm portions that are U-shaped in plan view along the main surface of the first core, a second conductor having two arm portions that are U-shaped in plan view along the main surface of the first core and disposed between the two arm portions of the first conductor, and a second core that sandwiches the first conductor and the second conductor together with the first core, wherein on the main surface of the first core, the U-shaped opening of the second conductor is the same as the U-shaped opening of the first conductor A coupled inductor is provided, wherein the first conductor and the second conductor are arranged to face the same direction as the opening, and the two arm portions of the first conductor each have a proximity portion in which the arm portion of the second conductor is close to the proximity portion, and a separation portion which is located on the U-shaped opening side of the first conductor and is wider in distance from the arm portion of the second conductor than the proximity portion, and the first core has two projections on its main surface provided between the separation portions of the two arm portions of the first conductor and the arm portion of the second conductor. According to configuration 1, the coupling coefficient between the first conductor and the second conductor can be easily adjusted by changing the height of the projections of the first core without changing the shape of the first conductor and the second conductor which are electromagnetically coupled via the first core and the second core.

[0052] (Configuration 2) The coupling inductor according to Configuration 1, wherein the main surface of the first core has grooves in which the first conductor and the second conductor are arranged, and the projection is provided on the bottom surface of the grooves. According to Configuration 2, the first conductor and the second conductor can be easily mounted on the main surface of the first core.

[0053] (Configuration 3) A coupled inductor according to Configuration 1 or 2, wherein, in a plan view, the conductor width of the arm portion of the first conductor is wider than the conductor width of the arm portion of the second conductor. According to Configuration 3, the allowable current in the first conductor can be made larger than that in the second conductor.

[0054] (Configuration 4) The coupled inductor according to any one of Configurations 1 to 3, wherein each of the two arm portions of the first conductor is bent in a direction away from each other from the proximity portion toward the U-shaped opening of the first conductor to form the separation portion. According to Configuration 4, the proximity portion and the separation portion can be easily formed in the arm portion of the first conductor.

[0055] (Configuration 5) A coupled inductor according to any one of Configurations 1 to 4, wherein there is an air gap between the upper surface of the projection of the first core and the second core. According to Configuration 5, the coupling coefficient can be effectively adjusted by adjusting the height of the projection.

[0056] (Configuration 6) A coupled inductor according to any one of Configurations 1 to 5, wherein the main surface of the second core facing the main surface of the first core is provided with other protrusions at a position facing the protrusions of the first core. According to Configuration 6, the coupling coefficient can be easily adjusted by adjusting the height of the protrusions of the first core and / or the height of the protrusions of the second core.

[0057] (Configuration 7) The coupling inductor according to any one of Configurations 1 to 6, wherein the first core and the second core form a substantially rectangular parallelepiped magnetic core with the first conductor and the second conductor sandwiched between them, the magnetic core has a bottom surface that faces the mounting substrate when mounted, and the end faces of the two arm portions of the first conductor are exposed on the bottom surface of the magnetic core that is perpendicular to the main surface of the first core. According to Configuration 7, the end faces of the first conductor exposed on the bottom surface can be used as external electrodes, so the shape of the first conductor can be simplified.

[0058] (Configuration 8) The coupling inductor according to any one of Configurations 1 to 6, wherein the first core and the second core form a substantially rectangular parallelepiped magnetic core with the first conductor and the second conductor sandwiched between them, the magnetic core has a bottom surface that faces the mounting substrate when mounted, the ends of the two arm portions of the first conductor are bent in a direction in which the end faces of the two arm portions face each other, and the sides of the two arm portions are exposed to the bottom surface. According to Configuration 8, the sides of the first conductor exposed to the bottom surface of the magnetic core can be used as external electrodes, so that the area of ​​electrical connection with the conductor pattern of a circuit board or the like can be increased compared to when the end face of the first conductor is used as an external electrode, and the connection resistance can be reduced while increasing the fixing strength of the electrical connection.

[0059] (Configuration 9) The coupling inductor according to any one of Configurations 1 to 8, wherein the first core and the second core form a substantially rectangular parallelepiped magnetic core with the first conductor and the second conductor sandwiched between them, the magnetic core has a bottom surface that faces the mounting substrate when mounted, and the sides of the separated portions of the two arm portions of the first conductor are exposed from two sides of the magnetic core that are perpendicular to the bottom surface. According to Configuration 9, when the coupling inductor is soldered to a conductor pattern such as a circuit board, the solder also flows to the sides of the arm portions of the first conductor that are exposed on the sides of the magnetic core, so that the fixing strength to the circuit board and the like can be further increased while the connection resistance with the conductor pattern can be further reduced.

[0060] 1, 1a...Coupled inductor, 10...Bottom surface, 12...Top surface, 14...Wide side surface, 16...Narrow side surface, 20, 20a...First core, 21, 21a...Second core, 30, 30a...First conductor, 31, 31a, 41...Arm portion, 40...Second conductor, 50, 50a...Magnetic core, 201, 202, 211, 212...Main surface, 203, 213...Core portion, 204, 214...Outer wall portion, 205, 205a, 215...Protrusion portion, 206...Groove, 310, 310a...Proximity portion, 311, 311a...Separation portion, 312...End surface, G1, G2, G3...Gap.

Claims

1. A first core having a main surface; a first conductor having two arm portions that are U-shaped in plan view along the main surface of the first core; a second conductor having two arm portions that are U-shaped in plan view along the main surface of the first core and disposed between the two arm portions of the first conductor; and a second core that sandwiches the first conductor and the second conductor together with the first core, wherein on the main surface of the first core, the second conductor is arranged such that the U-shaped opening of the second conductor faces the same direction as the U-shaped opening of the first conductor, and the two arm portions of the first conductor each have a proximity portion where the arm portions of the second conductor are close together, and a separation portion which is on the U-shaped opening side of the first conductor than the proximity portion and the distance between the arm portions of the second conductor and the proximity portion is wider than the distance in the proximity portion. The first core is a coupled inductor having two protrusions on its main surface, provided between the respective separation portions of the two arm portions of the first conductor and the arm portion of the second conductor.

2. The coupling inductor according to claim 1, wherein the main surface of the first core has grooves in which the first conductor and the second conductor are arranged, and the projection is provided on the bottom surface of the grooves.

3. In a plan view, the conductor width of the arm portion of the first conductor is wider than the conductor width of the arm portion of the second conductor, as described in claim 1 or 2.

4. The coupling inductor according to any one of claims 1 to 3, wherein each of the two arm portions of the first conductor is bent away from each other from the adjacent portion toward the U-shaped opening of the first conductor to form the separating portion.

5. The coupling inductor according to any one of claims 1 to 4, wherein there is a gap between the upper surface of the projection of the first core and the second core.

6. The coupled inductor according to any one of claims 1 to 5, wherein the main surface of the second core facing the main surface of the first core is provided with other protrusions at a position facing the protrusions of the first core.

7. The coupling inductor according to any one of claims 1 to 6, wherein the first core and the second core constitute a substantially rectangular parallelepiped magnetic core with the first conductor and the second conductor sandwiched between them, the magnetic core has a bottom surface that faces the mounting substrate when mounted, and the end faces of the two arm portions of the first conductor are exposed on the bottom surface of the magnetic core that is perpendicular to the main surface of the first core.

8. The coupling inductor according to any one of claims 1 to 6, wherein the first core and the second core constitute a substantially rectangular parallelepiped magnetic core with the first conductor and the second conductor sandwiched between them, the magnetic core has a bottom surface that faces the mounting substrate when mounted, and the ends of the two arm portions of the first conductor are bent in a direction in which the end faces of the two arm portions face each other, and the sides of the two arm portions are exposed to the bottom surface.

9. The coupled inductor according to any one of claims 1 to 8, wherein the first core and the second core constitute a substantially rectangular parallelepiped magnetic core with the first conductor and the second conductor sandwiched between them, the magnetic core has a bottom surface that faces the mounting substrate when mounted, and the respective side surfaces of the separation portions of the two arm portions of the first conductor are exposed from two side surfaces of the magnetic core that are perpendicular to the bottom surface.

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