Inductor, and DC-DC converter

Abstract

To provide an inductor capable of obtaining stable magnetic characteristics, and a DC-DC converter.SOLUTION: In an inductor 1, a terminal part 14B and a conductor part 11B include first recesses 21 and 22 which are recessed from the inside to the outside at positions adjacent with a connection conductor 15. A dimension of the first recesses 21 and 22 in a Y-axis direction (third direction) is equal to or more than a dimension of a conductor in the Y-axis direction at one of the conductor part 11B and the terminal part 14B having a shorter dimension in the Y-axis direction. Therefore, even in a case where a blur 50 occurs in a resin member 6C, the blur 50 can be stored in at least any one of the first recesses 21 and 22. In such a case, a principal surface 2Ca of a magnetic body 2C can be stably brought into contact with a side face 3Bb of the conductor part 11B. Therefore, positional displacement of the magnetic body 2C with respect to the conductor part 11B can be suppressed. Thus, stable magnetic characteristics can be obtained.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to an inductor and a DC-DC converter.

Background Art

[0002] Conventionally, an inductor described in Patent Document 1 is known. This inductor includes a coil conductor and a magnetic body serving as a core. The coil conductor has a bent portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, in an inductor, a resin member as an insulating member may be disposed between the coil conductor and the magnetic body. Such a resin member may have burrs protruding from the end of the conductor of the coil conductor. When the burrs of the resin member are interposed in the bent portion of the coil conductor, the positional relationship between the coil conductor and the magnetic body may shift. There is a problem that stable magnetic characteristics cannot be obtained due to the shift in the positional relationship between the coil conductor and the magnetic body.

[0005] Therefore, an object of the present disclosure is to provide an inductor and a DC-DC converter capable of obtaining stable magnetic characteristics.

Means for Solving the Problems

[0006] An inductor according to one aspect of the present disclosure includes a first conductor extending in a first direction, a second conductor extending in a second direction intersecting the first direction, and a connection conductor connecting one ends of the first conductor and the second conductor. A coil conductor, a magnetic body having a corner portion disposed so that the corner portion faces the connection conductor of the coil conductor, and a resin member disposed between the magnetic body and the first conductor of the coil conductor. At least one of the first conductor and the second conductor has a first recess that is recessed from the inside to the outside at a position adjacent to the connection conductor, and the dimension of the first recess in a third direction intersecting the first and second directions is the dimension of the shorter one of the one conductor and the other conductor in the third direction. It is equal to or greater than the dimension in the third direction of the conductor.

[0007] A DC-DC converter according to one aspect of the present disclosure includes the above-described inductor.

Effects of the Invention

[0008] According to one aspect of the present disclosure, it is possible to provide an inductor and a DC-DC converter that can obtain stable magnetic characteristics.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Embodiments for Carrying Out the Invention

[0010] Hereinafter, some embodiments of the present disclosure will be described in detail. However, the present disclosure is not limited to the following embodiments.

[0011] First, with reference to FIGS. 1 and 2, the schematic configuration of the inductor 1 in the present embodiment will be described. FIG. 1 is a perspective view of the inductor 1 in the present embodiment. FIG. 2 is a developed view of the inductor 1. Note that in FIG. 1, a state where the inductor 1 is mounted on the substrate 101 is shown. The inductor 1 in the present embodiment is formed by laminating magnetic bodies 2A, 2B, 2C, and coil conductors 3A, 3B in the X-axis direction. In the present embodiment, the X-axis direction, the Y-axis direction, and the Z-axis direction are orthogonal to each other. In the present embodiment, the X-axis direction corresponds to the "first direction" in the claims, the Z-axis direction orthogonal to the X-axis direction corresponds to the "second direction" in the claims, and the Y-axis direction orthogonal to the X-axis direction and the Z-axis direction corresponds to the "third direction" in the claims.

[0012] As shown in Fig. 1, the inductor 1 includes a magnetic body 2A, a magnetic body 2B, a magnetic body 2C, a coil conductor 3A, a coil conductor 3B, a resin material 5, a resin member 6A, a resin member 6B, and a resin member 6C. For easy understanding of the features, the resin material 5 is shown by a virtual line in Fig. 1. The inductor 1 can be adopted as the choke coil of the circuit of the DC-DC converter 100 shown in Fig. 3.

[0013] The magnetic body 2A and the magnetic body 2B are arranged in a state of being opposed to each other with a gap therebetween in the X-axis direction. The magnetic body 2B and the magnetic body 2C are arranged in a state of being opposed to each other with a gap therebetween in the X-axis direction. The magnetic bodies 2A, 2B, and 2C are arranged in this order from the positive side in the X-axis direction. The magnetic bodies 2A, 2B, and 2C have a rectangular parallelepiped shape. The magnetic bodies 2A, 2B, and 2C have the same shape. The magnetic bodies 2A, 2B, and 2C can be formed of, for example, a magnetic material such as a sintered core of MnZn ferrite, NiZn ferrite, etc., or a laminated core formed by laminating soft magnetic metal plates. The magnetic permeability of the magnetic bodies 2A, 2B, and 2C may be 1000 or more. Also, the magnetic characteristics of the magnetic bodies 2A, 2B, and 2C may be substantially the same or different.

[0014] The pair of coil conductors 3 (3A and 3B) included in the inductor 1 can be adopted for each choke coil in the circuit of the DC-DC converter 500 shown in FIG. 3. The DC-DC converter 500 includes a pair of switching elements SW1 and SW2, choke coils 520A and 520B, and a pair of diodes D1 and D2, and is a multi-phase converter in which these conversion units are connected in parallel. The inductor 1 can be adopted as the choke coils 520A and 520B of each conversion unit. More specifically, the DC-DC converter 500 includes a pair of input terminals A1 and A2, a pair of output terminals B1 and B2, a switching element SW1 and a choke coil 520A connected in series in this order between the input terminal A1 and the output terminal B1, a switching element SW2 and a choke coil 520B connected in series in this order between the input terminal A1 and the output terminal B1, and a capacitor C1 connected between the output terminals B1 and B2. The circuit including the switching element SW1 and the choke coil 520A and the circuit including the switching element SW2 and the choke coil 520B are connected in parallel between the input terminal A1 and the output terminal B1. The input terminal A2 and the output terminal B2 form a ground line. A diode D2 is connected in the reverse direction between the connection point of the switching element SW1 and the choke coil 520A and the ground line, and a diode D1 is connected in the reverse direction between the connection point of the switching element SW2 and the choke coil 520B and the ground line. The switching elements SW1 and SW2 are alternately turned on and off by a control circuit (not shown), thereby generating an output voltage obtained by stepping down the input voltage. By configuring the pair of choke coils 520A and 520B in the DC-DC converter 500 with the pair of coil conductors 3A and 3B of the inductor 1, it is possible to reduce the number of components constituting the DC-DC converter 500.

[0015] As shown in Fig. 2, the magnetic body 2A has main surfaces 2Aa and 2Ab, end surfaces 2Ac and 2Ad, and side surfaces 2Ae and 2Af. The main surfaces 2Aa and 2Ab are surfaces facing each other in the X-axis direction. The main surface 2Aa is arranged on the positive side in the X-axis direction, and the main surface 2Ab is arranged on the negative side in the X-axis direction. The end surfaces 2Ac and 2Ad are surfaces facing each other in the Y-axis direction. The end surface 2Ac is arranged on the positive side in the Y-axis direction, and the end surface 2Ad is arranged on the negative side in the Y-axis direction. The side surfaces 2Ae and 2Af are surfaces facing each other in the Z-axis direction. The side surface 2Ae is arranged on the positive side in the Z-axis direction, and the side surface 2Af is arranged on the negative side in the Z-axis direction.

[0016] The magnetic body 2B has main surfaces 2Ba and 2Bb, end surfaces 2Bc and 2Bd, and side surfaces 2Be and 2Bf. The magnetic body 2C has main surfaces 2Ca and 2Cb, end surfaces 2Cc and 2Cd, and side surfaces 2Ce and 2Cf. These surfaces have the same configuration as the main surfaces 2Aa and 2Ab, end surfaces 2Ac and 2Ad, and side surfaces 2Ae and 2Af of the magnetic body 2A.

[0017] The main surface 2Ab of the magnetic body 2A and the main surface 2Ba of the magnetic body 2B are arranged to face each other in a state of being separated from each other in the X-axis direction. The main surface 2Bb of the magnetic body 2B and the main surface 2Ca of the magnetic body 2C are arranged to face each other in a state of being separated from each other in the X-axis direction. Thereby, the magnetic body 2A is arranged to sandwich in the X-axis direction a portion (region 17A) located between the conductor portions 11A and 12A, which will be described later, with the magnetic body 2B. The magnetic body 2C is arranged to sandwich in the X-axis direction a portion (region 17B) located between the conductor portions 11B and 12B, which will be described later, with the magnetic body 2B. In the present embodiment, when viewed from the X-axis direction, the end surfaces 2Ac and 2Ad, the end surfaces 2Bc and 2Bd, and the end surfaces 2Cc and 2Cd are arranged at the same position within the Y-Z plane so as to overlap each other. Therefore, the magnetic bodies 2A, 2B, and 2C may have the same area when viewed from the X-axis direction. Also, the thicknesses of the magnetic bodies 2A, 2B, and 2C in the X-axis direction may be the same. That is, the magnetic bodies 2A, 2B, and 2C may have the same size. Note that in this specification, "the same position" includes a positional deviation within a range caused by manufacturing errors or the like, and "the same", "the same size" include errors within a range caused by manufacturing variations.

[0018] The coil conductor 3A includes a conductor part 11A (second conductor), a conductor part 12A (third conductor), a connecting part 13A (fourth conductor), a terminal part 14A (first conductor), and a terminal part 16A (fifth conductor). The material of the coil conductor 3A is composed of a metal selected from, for example, Cu, Ag, Au, Al, Ni, Sn, etc.

[0019] The conductor parts 11A and 12A extend in the Z-axis direction and are arranged between the magnetic bodies 2A and 2B in the X-axis direction. The conductor part 11A is arranged on the positive side in the Y-axis direction, and the conductor part 12A is arranged on the negative side in the Y-axis direction. The connecting part 13A is a member that connects the conductor part 11A and the conductor part 12A. The connecting part 13A is connected to the ends on the positive side in the Z-axis direction of the conductor parts 11A and 12A and extends in the Y-axis direction. The terminal part 14A is provided at the end on the negative side in the Z-axis direction of the conductor part 11A and extends to the positive side in the X-axis direction and the positive side in the Y-axis direction. The terminal part 14A is formed by widening a part near the end on the negative side in the Z-axis direction of the conductor part 11A to the positive side in the Y direction and bending the widened part to the positive side in the X direction. The terminal part 16A is provided at the end on the negative side in the Z-axis direction of the conductor part 12A and extends to the positive side in the X-axis direction and the negative side in the Y-axis direction. The terminal part 16A is formed by widening a part near the end on the negative side in the Z-axis direction of the conductor part 12A to the negative side in the Y direction and bending the widened part to the positive side in the X direction. The terminal parts 14A and 16A are joined to the electrodes 102 (see FIG. 1) of the substrate 101. Thereby, the inductor 1 is mounted on the substrate 101. Note that the conductor parts 11A and 12A do not have to be parallel to the Z-axis direction as long as they extend in the Z-axis direction. Also, the connecting part 13A does not have to be parallel to the Y-axis direction as long as it extends in the Y-axis direction.

[0020] The coil conductor 3A has a positive-side surface 3Aa in the X-axis direction and a negative-side surface 3Ab in the X-axis direction. The surface 3Aa is formed by arranging the positive-side surfaces in the X-axis direction of the conductor portions 11A, 12A, and the connecting portion 13A on the same plane. The terminal portions 14A, 16A protrude further in the positive direction of the X-axis than the surface 3Aa. The surface 3Aa faces the main surface 2Ab of the magnetic body 2A in the X-axis direction and is in contact with each other. The surface 3Ab is formed by arranging the negative-side surfaces in the X-axis direction of the conductor portions 11A, 12A, and the connecting portion 13A on the same plane. The surface 3Ab faces the main surface 2Ba of the magnetic body 2B in the X-axis direction and is in contact with each other. By arranging the magnetic bodies 2A, 2B, 2C and the coil conductors 3A, 3B in contact with each other, the positional relationship of the magnetic bodies 2A, 2B, 2C in the X-axis direction in particular is stabilized, so that the variation in inductance can be reduced. In this specification, "contact" includes not only the case where the magnetic bodies 2A, 2B and the coil conductor 3A are in direct contact, but also the case where they are in indirect contact via an insulating layer, an adhesive layer, or the like. The same applies to the contact between the magnetic bodies 2B, 2C and the coil conductor 3B described later.

[0021] As shown in FIG. 2, the coil conductor 3B includes a conductor portion 11B (second conductor), a conductor portion 12B (third conductor), a connecting portion 13B (fourth conductor), a terminal portion 14B (first conductor), and a terminal portion 16B (fifth conductor). The material of the coil conductor 3B may be the same as that of the coil conductor 3A.

[0022] The conductor portions 11B and 12B extend in the Z-axis direction and are arranged between the magnetic bodies 2B and 2C in the X-axis direction. The conductor portion 11B is arranged on the positive side in the Y-axis direction, and the conductor portion 12B is arranged on the negative side in the Y-axis direction. The connecting portion 13B is a member that connects the conductor portion 11B and the conductor portion 12B. The connecting portion 13B is connected to the ends of the conductor portions 11B and 12B on the positive side in the Z-axis direction and extends in the Y-axis direction. The terminal portion 14B is provided at the end of the conductor portion 11B on the negative side in the Z-axis direction and extends in the negative side in the X-axis direction and the positive side in the Y-axis direction. The terminal portion 14B is formed by widening a part near the end of the conductor portion 11B on the negative side in the Z-axis direction toward the positive side in the Y-axis direction and bending the widened portion toward the negative side in the X-axis direction. The terminal portion 16B is provided at the end of the conductor portion 12B on the negative side in the Z-axis direction and extends in the negative side in the X-axis direction and the negative side in the Y-axis direction. The terminal portion 16B is formed by widening a part near the end of the conductor portion 12B on the negative side in the Z-axis direction toward the negative side in the Y-axis direction and bending the widened portion toward the negative side in the X-axis direction. The terminal portions 14B and 16B are joined to the electrodes 102 (see FIG. 1) of the substrate 101. Thereby, the inductor 1 is mounted on the substrate 101. Note that the conductor portions 11B and 12B do not have to be parallel to the Z-axis direction as long as they extend in the Z-axis direction. Also, the connecting portion 13B does not have to be parallel to the Y-axis direction as long as it extends in the Y-axis direction.

[0023] The coil conductor 3B has a side surface 3Ba on the positive side in the X-axis direction and a side surface 3Bb on the negative side in the X-axis direction. The side surface 3Ba is formed by arranging the side surfaces of the conductor portions 11B and 12B and the connecting portion 13B on the positive side in the X-axis direction on the same plane. The side surface 3Ba faces the main surface 2Bb of the magnetic body 2B in the X-axis direction and is in contact with each other. The side surface 3Bb is formed by arranging the side surfaces of the conductor portions 11B and 12B and the connecting portion 13B on the negative side in the X-axis direction on the same plane. The terminal portions 14B and 16B protrude further to the negative side in the X-axis direction than the side surface 3Bb. The side surface 3Bb faces the main surface 2Ca of the magnetic body 2C in the X-axis direction and is in contact with each other.

[0024] The coil conductor 3A and the coil conductor 3B have a plane-symmetrical structure with respect to the ZY plane. Therefore, they are formed in the same shape so as to overlap each other when viewed from the X-axis direction. Note that "plane symmetry" includes positional deviations within a range caused by manufacturing errors or the like, and "the same shape" includes errors within a range caused by manufacturing variations.

[0025] The resin member 6A is arranged so as to cover the negative-side side surface 2Af of the magnetic body 2A in the Z-axis direction. The resin member 6B is arranged so as to cover the negative-side side surface 2Bf of the magnetic body 2B in the Z-axis direction. The resin member 6C is arranged so as to cover the negative-side side surface 2Cf of the magnetic body 2C in the Z-axis direction. The resin members 6A, 6B, and 6C are sheet-like members that cover substantially the entire surfaces of the side surfaces 2Af, 2Bf, and 2Cf. The material of the resin members 6A, 6B, and 6C is not particularly limited, and polyimide, polyamideimide, fluororesin, or the like may be adopted. As the resin members 6A, 6B, and 6C, for example, Kapton (registered trademark) tape or the like may be adopted.

[0026] The negative-side side surfaces 2Af and 2Cf (the other-side surfaces) of the magnetic bodies 2A and 2C in the Z-axis direction are placed on the upper surfaces 14a and 16a of the terminal portions 14A, 16A, 14B, and 16B via the resin members 6A and 6C. Thereby, the resin member 6A is arranged between the magnetic body 2A and the terminal portions 14A and 16A. The resin member 6C is arranged between the magnetic body 2C and the terminal portions 14B and 16B. In the present embodiment, the negative-side side surface 2Bf of the magnetic body 2B in the Z-axis direction is arranged at the same height as the negative-side side surfaces 2Af and 2Cf of the other magnetic bodies 2A and 2C in the Z-axis direction. Note that "the same height" includes errors within a range caused by manufacturing variations.

[0027] Next, the resin material 5 will be described. The resin material 5 covers the assembly by the magnetic bodies 2A, 2B, 2C and the coil conductors 3A, 3B. The resin material 5 exposes at least the lower surfaces of the terminal portions 14A, 16A, 14B, 16B. Therefore, the resin material 5 covers at least the positive-side side surfaces 2Ae, 2Be, 2Ce in the Z-axis direction of the magnetic bodies 2A, 2B, 2C. The resin material 5 may contain magnetic powder. Specifically, as the material of the resin material 5, a thermosetting resin such as epoxy is adopted. When the resin material 5 contains magnetic powder, a mixture of soft magnetic metal powder and resin may be adopted. As the soft magnetic metal powder, an iron-silicon alloy, permalloy, sendust, amorphous, nanocrystalline alloy or a mixture thereof can be used. Also, when the resin material 5 contains magnetic powder, the magnetic permeability of the resin material 5 may be 5 or more, and may be 20 or more. Further, the magnetic permeability of the resin material 5 may be 100 or less, and may be 50 or less. The resin material 5 may have a lower magnetic permeability than the magnetic bodies 2A, 2B, 2C. The resin material 5 is disposed within the regions 17A, 17B. That is, the resin material 5 is formed to cover the inner parts 11Aa, 11Ba, 12Aa, 12Ba, 13Aa, 13Ba.

[0028] Next, with reference to FIG. 4, the structure near the negative-side side surface 2Cf in the Z-axis direction of the magnetic body 2C will be described in detail. FIG. 4 is a cross-sectional view taken along the line IV-IV shown in FIG. 1. Note that FIGS. 1 and 2 are schematic configuration diagrams in which the thicknesses of the magnetic bodies 2A, 2B, 2C in the X-axis direction are drawn thinly, but as shown in FIG. 4, the thickness in the X-axis direction may be increased.

[0029] At the location shown in Fig. 4, the coil conductor 3B has a connection conductor 15. The connection conductor 15 is a portion that connects the end 11a on one side (negative side in the Z-axis direction) of the conductor portion 11B and the end 14c on one side (positive side in the X-axis direction) of the terminal portion 14B. In the structure near the corner between the terminal portion 14B and the conductor portion 11B, there is a switching portion P1 where the outside (lower surface 14b side) of the terminal portion 14B switches from extending in the X-axis direction to the Z-axis direction. Also, there is a switching portion P2 where the outside (side surface 3Ba side) of the conductor portion 11B switches from extending in the Z-axis direction to the X-axis direction. The connection conductor 15 is a portion existing between these switching portions P1 and P2. In Fig. 4, a pair of two-dot chain lines extending the surfaces 14a and 14b of the terminal portion 14B in the positive X-axis direction are drawn, and a pair of two-dot chain lines extending the surfaces 3Ba and 3Bb of the conductor portion 11B in the negative Z-axis direction are drawn. The region set by these four two-dot chain lines is defined as region E. The portion of the coil conductor 3B existing within region E corresponds to the connection conductor 15. The outside of the connection conductor 15 has a curved shape 15a. The curved shape 15a draws an arc that bulges outward with a predetermined radius of curvature between the switching portions P1 and P2. Note that when the surfaces of the conductor portion 11A and the terminal portion 14B are extremely small wavy surfaces or uneven surfaces, the two-dot chain line extending from the surface of the terminal portion 14B in the positive X-axis direction and the two-dot chain line extending from the surface of the conductor portion 11A in the negative Z-axis direction may be regression lines (linear approximations).

[0030] The magnetic body 2C has a corner 25 between the main surface 2Ca on the positive side in the X-axis direction and the side surface 2Cf on the negative side in the Z-axis direction. As described above, the main surface 2Ca of the magnetic body 2C contacts the side surface 3Bb of the conductor portion 11B. The side surface 2Cf of the magnetic body 2C contacts the upper surface 14a of the terminal portion 14B via the resin member 6C. Due to such a positional relationship, the corner 25 of the magnetic body 2C is arranged to face the connection conductor 15 of the coil conductor 3B. The corner 25 of the magnetic body 2C and the connection conductor 15 of the coil conductor 3B face each other in an oblique direction including the direction components in the X-axis direction and the Z-axis direction.

[0031] The terminal portion 14B has a first recessed portion 21 that depresses from the inside to the outside at a position adjacent to the connection conductor 15. The first recessed portion 21 depresses from the upper surface 14a, which is the inner surface of the terminal portion 14B, toward the negative side in the Z-axis direction. The end portion 14c on the positive side in the X-axis direction is at a position adjacent to the connection conductor 15 on the negative side in the X-axis direction. Therefore, the terminal portion 14B has the first recessed portion 21 at least at the position of the end portion 14c. Note that the position adjacent to the connection conductor 15 includes a position slightly separated from the connection conductor 15 (e.g., within the range of manufacturing errors).

[0032] The conductor portion 11B has a first recessed portion 22 that depresses from the inside to the outside at a position adjacent to the connection conductor 15. The first recessed portion 22 depresses from the side surface 3Bb, which is the inner surface of the conductor portion 11B, toward the positive side in the X-axis direction. The end portion 11a on the negative side in the Z-axis direction is at a position adjacent to the connection conductor 15 on the positive side in the Z-axis direction. Therefore, the conductor portion 11B has the first recessed portion 22 at least at the position of the end portion 11a.

[0033] As described above, in the present embodiment, the terminal portion 14B and the conductor portion 11B each have first recessed portions 21 and 22 that depress from the inside to the outside at positions adjacent to the connection conductor 15. Also, in the present embodiment, the connection conductor 15 has a second recessed portion 23 that depresses from the inside to the outside. The second recessed portion 23 depresses toward the positive side in the X-axis direction from the position of the end portion 14c of the terminal portion 14B and depresses toward the negative side in the Z-axis direction from the position of the end portion 11a of the conductor portion 11B. The second recessed portion 23 of the connection conductor 15 communicates with the first recessed portions 21 and 22. Note that when referred to as the "recessed portion 20" in the following description, it indicates a combination of the recessed portions 21, 22, and 23. In the present embodiment, the coil conductor 3B has a recessed portion 20 with an L-shaped cross section. The method of forming the recessed portion 20 is not particularly limited, and a known method for providing a recess in the conductor may be adopted.

[0034] The resin member 6C may have burrs 50 (a part of the resin member) formed during cutting or the like. The burrs 50 protrude to the positive side in the X-axis direction from the main surface 2Ca of the magnetic member 2C. Such burrs 50 are accommodated in the recessed portion 20 of the coil conductor 3B. In particular, the burrs 50 may be accommodated in the first recess 22 that is recessed to the positive side in the X-axis direction without bending. Further, the burrs 50 may be bent and accommodated in the second recess 23. Further, the burrs 50 may be bent (folded) and accommodated in the first recess 21 that is recessed to the negative side in the Z-axis direction. Also, depending on the shape of the burrs 50, they may be accommodated in a plurality of recesses 21, 22, 23. Also, the shape of the burrs 50 does not have to be constant in the Y-axis direction, and the recesses 21, 22, 23 in which they are accommodated may be different depending on the location in the Y-axis direction. The burrs 50 of the resin member 6B protrude to the negative side in the X-axis direction from the main surface 2Bb of the magnetic member 2B. The burrs 50 of the resin member 6B are deformed so as to bend to the negative side in the Z-axis direction along the curved shape 15a outside the connection conductor 15.

[0035] Next, the dimensions of each part of the recessed portion 20 will be described. The length dimension in the Z-axis direction of the first recessed portion 22 of the conductor portion 11B may be larger than the thickness (dimension in the Z-axis direction) of the resin member 6C. Also, the length dimension in the Z-axis direction of the first recessed portion 22 of the conductor portion 11B may be smaller than the radius of curvature of the curved shape 15a outside the connection conductor 15. Further, the length dimension in the Z-axis direction of the first recessed portion 22 of the conductor portion 11B may be smaller than half of the length dimension in the Z-axis direction of the conductor portion 11B. The depth (dimension in the X-axis direction) of the first recessed portion 22 of the conductor portion 11B may be smaller than half of the thickness dimension (dimension in the X-axis direction) of the conductor portion 11B. Also, the depth (dimension in the X-axis direction) of the first recessed portion 22 of the conductor portion 11B may be larger than the length dimension (dimension in the X-axis direction) of the burrs 50. Since the length dimension of the burrs 50 is a value that can be predicted at the design stage, the depth of the first recessed portion 22 may be set based on that value.

[0036] The length dimension of the first recessed portion 21 of the terminal portion 14B in the X-axis direction may be larger than the thickness dimension (dimension in the Z-axis direction) of the resin member 6C. Further, the length dimension of the first recessed portion 21 of the terminal portion 14B in the X-axis direction may be smaller than the radius of curvature of the outer curved shape 15a of the connection conductor 15. Furthermore, the length dimension of the first recessed portion 21 of the terminal portion 14B in the X-axis direction may be smaller than half of the length dimension of the terminal portion 14B in the X-axis direction. The depth (dimension in the Z-axis direction) of the first recessed portion 21 of the terminal portion 14B may be smaller than half of the thickness dimension (dimension in the Z-axis direction) of the terminal portion 14B. Furthermore, the depth of the first recessed portion 21 of the terminal portion 14B may be smaller than half of the thickness dimension of the terminal portion 14B in the Z-axis direction.

[0037] The dimension of the second recessed portion 23 of the connection conductor 15 in the Z-axis direction may be set to a dimension similar in purport to the depth of the first recessed portion 21 of the terminal portion 14B in the Z-axis direction. The dimension of the second recessed portion 23 of the connection conductor 15 in the X-axis direction may be set to a dimension similar in purport to the depth of the first recessed portion 22 of the conductor portion 11B in the X-axis direction. The inner radius of curvature of the connection conductor 15 may be smaller than the thickness of the resin member 6C. In the present embodiment, since the connection conductor 15 has the second recessed portion 23, the corner R of the second recessed portion 23 serves as the inner radius of curvature. In the example shown in FIG. 4, since the second recessed portion 23 has no corner R and is substantially right-angled, the inner radius of curvature is smaller than the thickness of the resin member 6C.

[0038] The dimensions of the first recessed portions 21 and 22 in the Y-axis direction (the third direction) are equal to or greater than the dimension in the Y-axis direction of the conductor with the shorter dimension in the Y-axis direction among the conductor portion 11B and the terminal portion 14B. In the present embodiment, the dimension of the conductor portion 11B in the Y-axis direction is shorter than the dimension of the terminal portion 14B in the Y-axis direction. Therefore, the dimensions of the first recessed portions 21 and 22 in the Y-axis direction only need to be equal to or greater than the dimension of the shorter conductor portion 11B in the Y-axis direction. In the present embodiment, the first recessed portion 21 may extend from one end portion 14d (see FIG. 2) to the other end portion 14e (see FIG. 2) of the terminal portion 14B in the Y-axis direction (the third direction). In this case, the dimension of the first recessed portion 21 in the Y-axis direction becomes larger than the dimension of the shorter conductor portion 11B in the Y-axis direction. However, the dimension of the first recessed portion 21 in the Y-axis direction may be equal to the dimension of the shorter conductor portion 11B in the Y-axis direction. At this time, the first recessed portion 21 may be formed in the region CE shown in FIG. 2. That is, the first recessed portion 21 extends from the position corresponding to one end portion 11Ba (see FIG. 2) of the conductor portion 11B in the Y-axis direction to the position corresponding to the other end portion 11Bb (see FIG. 2). The first recessed portion 22 may extend from one end portion 11Ba (see FIG. 2) to the other end portion 11Bb (see FIG. 2) of the conductor portion 11B in the Y-axis direction.

[0039] The size of the connection conductor 15 in the Y-axis direction is determined by the size of the portion where the terminal portion 14B and the conductor portion 11B overlap in the Y-axis direction. In the example shown in FIG. 2, the conductor portion 11B is connected to the terminal portion 14B throughout the width direction. Therefore, the second recessed portion 23 of the connection conductor 15 may extend from one end portion 11Ba (see FIG. 2) to the other end portion 11Bb (see FIG. 2) of the conductor portion 11B in the Y-axis direction.

[0040] Here, the recessed portion 20 is not limited to the structure shown in FIG. 4. At least one of the conductors of the terminal portion 14B and the conductor portion 11B may have a first recessed portion that recesses from the inside to the outside at a position adjacent to the connection conductor 15. For example, each configuration as shown in FIG. 5 may be adopted. As shown in FIG. 5(a), the recessed portion 20 may have only the first recessed portion 22 of the conductor portion 11B. As shown in FIG. 5(b), the recessed portion 20 may have the first recessed portion 22 of the conductor portion 11B and the second recessed portion 23 of the connection conductor 15 that communicates with the first recessed portion 22. As shown in FIG. 5(c), the recessed portion 20 may have only the first recessed portion 21 of the terminal portion 14B. As shown in FIG. 5(d), the recessed portion 20 may have the first recessed portion 21 of the conductor portion 11B and the second recessed portion 23 of the connection conductor 15 that communicates with the first recessed portion 22. As shown in FIG. 5(e), the recessed portion 20 may have the first recessed portion 22 of the conductor portion 11B and the first recessed portion 21 of the terminal portion 14B. In the forms shown in FIGS. 5(a), (b), and (e), the burr 50 may be accommodated in the first recessed portion 22 that recesses in the positive X-axis direction without bending. In the forms shown in FIGS. 5(c) and (d), the burr 50 may be bent in the negative Z-axis direction and accommodated in the first recessed portion 21 that recesses in the negative Z-axis direction.

[0041] Note that, as shown in FIG. 2, the coil conductor 3B has a terminal portion 16B and a conductor portion 12B on the negative side in the Y-axis direction. The coil conductor 3B may have a recessed portion 20 with the same gist as FIG. 4 near the connection conductor that connects the terminal portion 16B and the conductor portion 12B. The magnetic body 2C is placed on the terminal portion 14B and the terminal portion 16B via a resin member 6C. At this time, the burr 50 (see FIG. 4) of the resin member 6C provided on the magnetic body 2C is accommodated in the recessed portion 20 of the terminal portion 14B and the conductor portion 11B, and the recessed portion 20 of the terminal portion 16B and the conductor portion 12B. Further, the coil conductor 3A may have a recessed portion 20 with the same gist as FIG. 4 near the connection conductor that connects the terminal portion 14A and the conductor portion 11A, and may have a recessed portion 20 with the same gist as FIG. 4 near the connection conductor that connects the terminal portion 16A and the conductor portion 12A.

[0042] In the coil conductor 3B, when the terminal portion 14B is regarded as the "first conductor" in the claims, the conductor portion 11B can be regarded as the "second conductor", the conductor portion 12B can be regarded as the "third conductor", the connecting portion 13B can be regarded as the "fourth conductor", and the terminal portion 16B can be regarded as the "fifth conductor". In the coil conductor 3B, when the terminal portion 16B is regarded as the "first conductor" in the claims, the conductor portion 12B can be regarded as the "second conductor", the conductor portion 11B can be regarded as the "third conductor", the connecting portion 13B can be regarded as the "fourth conductor", and the terminal portion 14B can be regarded as the "fifth conductor". In the coil conductor 3A, when the terminal portion 14A is regarded as the "first conductor" in the claims, the conductor portion 11A can be regarded as the "second conductor", the conductor portion 12A can be regarded as the "third conductor", the connecting portion 13A can be regarded as the "fourth conductor", and the terminal portion 16A can be regarded as the "fifth conductor". In the coil conductor 3A, when the terminal portion 16A is regarded as the "first conductor" in the claims, the conductor portion 12A can be regarded as the "second conductor", the conductor portion 11A can be regarded as the "third conductor", the connecting portion 13A can be regarded as the "fourth conductor", and the terminal portion 14A can be regarded as the "fifth conductor".

[0043] Next, the operations and effects of the inductor 1 and the DC-DC converter 100 according to the present embodiment will be described. Unless otherwise noted, the operations and effects of the inductor 1 according to the present embodiment will be described with reference to FIG. 4 in the structure near the connection conductor 15 that connects the terminal portion 14B and the conductor portion 11B. However, the same operations and effects can be obtained for the structures near the connection conductors 15 in other portions as well.

[0044] In the inductor 1 according to the present embodiment, the corner portion 25 of the magnetic body 2C is arranged to face the connection conductor 15 of the coil conductor 3B. Further, the inductor 1 includes a resin member 6C disposed between the magnetic body 2C and the terminal portion 14B of the coil conductor 3B. Therefore, the magnetic body 2C is disposed on the terminal portion 14B in a state of being insulated from the terminal portion 14B, and is disposed in a state of being positioned in the X-axis direction with respect to the conductor portion 11.

[0045] Here, with reference to FIG. 6, the inductor 200 according to the comparative example will be described. The inductor 200 shown in FIG. 6 has a curved shape 55 with a corner R between the conductor portion 11B and the terminal portion 14B. In this case, as shown in FIG. 6(a), when the side surface 2Cf of the magnetic body 2C is brought into contact with the upper surface 14a of the terminal portion 14B, the corner portion 25 of the magnetic body 2C interferes with the curved shape 55. As a result, a gap is formed between the magnetic body 2C and the side surface 3Bb of the conductor portion 11B. As shown in FIG. 6(b), when the magnetic body 2C is brought closer to the conductor portion 11B, the corner portion 25 rides on the curved shape 55. As shown in FIG. 6(c), when the main surface 2Ca of the magnetic body 2C is brought into contact with the conductor portion 11, a gap is formed between the side surface 2Cf of the magnetic body 2C and the upper surface 14a of the terminal portion 14B.

[0046] With reference to FIG. 7, the inductor 300 according to another comparative example will be described. The inductor 300 shown in FIG. 7 has no corner R formed between the conductor portion 11B and the terminal portion 14B, and the side surface 3Bb rises substantially vertically from the upper surface 14a. In this case, as shown in FIGS. 7(a), (b), and (c), a burr 50 of the resin member 6C is interposed between the main surface 2Ca of the magnetic body 2C and the side surface 3Bb of the conductor portion 11B, and a gap is formed. In this case, depending on the size and crushing condition of the burr 50, the distance between the main surface 2Ca of the magnetic body 2C and the side surface 3Bb of the conductor portion 11B changes. The closer the magnetic body 2C and the conductor portion 11B are, the larger the inductance becomes, and the farther they are, the smaller the inductance becomes. Thus, the inductors 200 and 300 according to the comparative example have a problem that the magnetic characteristics become unstable due to displacement occurring between the magnetic body 2C and the conductor portion 11B.

[0047] In contrast, in the inductor 1 according to the present embodiment, the terminal portion 14B and the conductor portion 11B have first recessed portions 21 and 22 that are recessed from the inside to the outside at positions adjacent to the connection conductor 15. Further, the dimensions of the first recessed portions 21 and 22 in the Y-axis direction (the third direction) are equal to or greater than the dimension of the conductor (here, the conductor portion 11B) having the shorter dimension in the Y-axis direction among the conductor portion 11B and the terminal portion 14B in the Y-axis direction. Therefore, even when burrs 50 are generated in the resin member 6C, the burrs 50 can be accommodated in at least one of the first recessed portions 21 and 22. In this case, the main surface 2Ca of the magnetic body 2C can be stably brought into contact with the side surface 3Bb of the conductor portion 11B. For this reason, displacement of the magnetic body 2C with respect to the conductor portion 11B can be suppressed. As described above, stable magnetic characteristics can be obtained. When no burrs 50 are generated in the resin member 6C, a part of the resin member 6C does not have to be accommodated in the first recessed portions 21 and 22.

[0048] At least a part of the resin member 6C (burrs 50) may be accommodated in any one of the first recessed portions 21 and 22. In this case, as described above, the main surface 2Ca of the magnetic body 2C can be stably brought into contact with the side surface 3Bb of the conductor portion 11B. For this reason, displacement of the magnetic body 2C with respect to the conductor portion 11B can be suppressed.

[0049] The terminal portion 14B (the first conductor) and the conductor portion 11B (the second conductor) may each have first recessed portions 21 and 22 that are recessed from the inside to the outside at positions adjacent to the connection conductor 15. By having both of the first recesses 21 and 22, it becomes possible to accommodate the burrs 50 in either the first recessed portion 21 or the first recessed portion 22 regardless of the deformation mode of the burrs 50. In this way, it becomes easier to accommodate the burrs 50.

[0050] The connection conductor 15 has a second recessed portion 23 that is recessed from the inside to the outside, and the second recessed portion 23 of the connection conductor 15 may communicate with the first recessed portions 21 and 22 of at least one of the conductors. In this case, since the recess 20 capable of accommodating the burr 50 becomes wider, the burr 50 can be accommodated in the recess 20 while suppressing excessive deformation of the burr 50. Therefore, the displacement between the magnetic body 2C and the conductor portion 11B can be further suppressed, and more stable magnetic characteristics can be obtained.

[0051] The length dimension of the first recessed portion 22 of the conductor portion 11B in the Z-axis direction may be larger than the thickness of the resin member 6C. In this case, the first recessed portion 22 can improve the certainty of accommodating the burr 50.

[0052] The depth of the first recessed portion 21 of the terminal portion 14B may be smaller than half of the thickness dimension of the terminal portion 14B. Also, the depth of the first recessed portion 22 of the conductor portion 11B may be smaller than half of the thickness dimension of the conductor portion 11B. In this case, by suppressing a decrease in the conductor volume of the coil conductor 3B, an increase in electrical resistance can be suppressed.

[0053] The inner radius of curvature of the connection conductor 15 may be smaller than the thickness of the resin member 6C. In this case, it is possible to suppress interference between the inner peripheral corner R of the connection conductor 15 and the burr 50. Therefore, since the magnetic body 2C can be disposed close to the conductor portion 11B, stable and high magnetic characteristics can be obtained.

[0054] The outside of the connection conductor 15 has a curved shape 15a, and the length dimension of the first recessed portion 22 of the conductor portion 11B in the Z-axis direction may be smaller than the radius of curvature of the curved shape 15a of the connection conductor 15. In this case, by suppressing a decrease in the conductor volume of the coil conductor 3B, an increase in electrical resistance can be suppressed.

[0055] The outside of the connection conductor 15 has a curved shape 15a, and the length dimension of the first recessed portion 21 of the terminal portion 14B in the X-axis direction may be smaller than the radius of curvature of the curved shape 15a of the connection conductor 15. In this case, by suppressing a decrease in the conductor volume of the coil conductor 3B, an increase in electrical resistance can be suppressed.

[0056] The coil conductor 3B includes a conductor portion 12B (third conductor) extending in the Z-axis direction, a connecting portion 13B (fourth conductor) connecting the other end 11b of the conductor portion 11B and one end of the conductor portion 12B, and a terminal portion 16B (fifth conductor) connected to the other end of the conductor portion 12B and extending in the X-axis direction. The magnetic body 2C may be placed on the terminal portions 14B and 16B via a resin member 6. In this way, by supporting the magnetic body 2C on both sides in the Y-axis direction with the terminal portions 14B and 16B, the positional relationship between the magnetic body 2C and the coil conductor 3B can be fixed, and stable magnetic characteristics can be obtained.

[0057] The DC-DC converter 100 according to this embodiment includes the above-described inductor.

[0058] According to this DC-DC converter 100, since the variation in the inductance of the inductor 1 is small, a DC-DC converter 100 with a small variation in the output waveform can be obtained. Also, since the adhesion between the resin and the magnetic body is high, a DC-DC converter 100 with high long-term reliability can be obtained.

[0059] The present disclosure is not limited to the above-described embodiments.

[0060] For example, the inductor 1 shown in FIG. 8 may be employed. In the inductor 1 shown in FIG. 8, the conductor portion 11B and the magnetic body 2C may be in close contact via an adhesive layer 60. In this case, the adhesive layer 60 is interposed between the main surface 2Ca of the magnetic body 2C and the side surface 3Bb of the conductor portion 11B. Therefore, by adjusting the thickness of the adhesive layer 60, displacement between the magnetic body 2C and the conductor portion 11B can be suppressed. For example, as shown in FIG. 9(b), even when the adhesive layer 60 is provided and the recessed portion 20 is not formed, the curved shape 55 of the corner and the burr 50 may interfere with each other. On the other hand, according to the structure shown in FIG. 8, the burr 50 can be accommodated in the recessed portion 20.

[0061] Here, as shown in FIG. 9(a), within the recessed portion 20, the connection conductor 15 may have a curved shape 15b on the inner side. At this time, the radius of curvature of the inner curved shape 15b of the connection conductor 15 may be smaller than the thickness of the adhesive layer 60. In this case, it is possible to suppress the interference between the burrs 50 accommodated in the recess 20 and the curved shape 15b of the connection conductor 15. Therefore, since the magnetic body 2C can be arranged close to the conductor portion 11B, stable and high magnetic characteristics can be obtained.

[0062] The shape of the coil conductor is not limited to that employed in the above-described embodiment, and may be appropriately changed without departing from the spirit of the present disclosure.

[0063] For example, a coil conductor 3B as shown in FIG. 10 may be employed. The coil conductor 3B shown in FIG. 10 has the positive-side portion of the conductor portion 11B (and the conductor portion 12B) in the Z-axis direction and the portion of the connecting portion 13B as the bent portion 30. The bent portion 30 has a shape extending toward the negative side in the X-axis direction. Thus, the shape of the coil conductor may be appropriately changed.

[0064] Also, as the shape of the coil conductor is changed, the location where the recessed portion 20 is formed may be appropriately changed. For example, a coil conductor 130 as shown in FIG. 11 may be employed. The coil conductor 130 has a pair of conductor portions 111 and 112 that rise from the substrate 101 in the positive Z-axis direction and a connecting portion 113 that extends in the Y-axis direction so as to connect the upper ends of the conductor portions 111 and 112. The magnetic body 120 is arranged so as to be inserted into the inner peripheral portion of the coil conductor 130 in the X-axis direction. The magnetic body 120 contacts the connecting portion 113 and contacts the conductor portion 111 via the resin member 6. In this case, a recessed portion 20 may be formed at the bent portion between the conductor portion 111 and the connecting portion 113. In this case, the conductor portion 111 corresponds to the "first conductor" in the claims, and the connecting portion 113 corresponds to the "second conductor" in the claims.

[0065] Alternatively, a configuration as shown in Fig. 12(a) may be adopted. In Fig. 12(a), for the coil conductor 130 shown in Fig. 11, the magnetic body 120 is in contact with the connecting portion 113 via the resin member 6. A recess 20 may be formed at the bent portion between the conductor portion 111 and the connecting portion 113. Also, a recess 20 may be formed at the bent portion between the conductor portion 112 and the connecting portion 113. In this case, the connecting portion 113 corresponds to the "first conductor" in the claims, and the conductor portions 111 and 112 correspond to the "second conductor" in the claims.

[0066] Alternatively, a structure as shown in Fig. 12(b) may be adopted. This coil conductor 203 has a structure obtained by removing the terminal portions 14B and 16B from the coil conductor 3B shown in Fig. 10. Also, the magnetic body 2C is in contact with the bent portion 30 via the resin member 6. In this case, a recess 20 is formed between the bent portion 30 and the conductor portion 11B. In this case, the bent portion 30 corresponds to the "first conductor" in the claims, and the conductor portion 11B corresponds to the "second conductor" in the claims.

[0067] In the above-described embodiment, the inductor had a plurality of coil conductors, but the number of coil conductors is not particularly limited, and an inductor having one coil conductor may be provided. For example, the inductor 1 shown in FIG. 13 includes one coil conductor 3A and magnetic bodies 2A and 2B. Such a single coil conductor 3A may be employed in the DC-DC converter 100 shown in FIG. 14. As shown in FIG. 14, the DC-DC converter 100 includes a pair of input terminals to which a DC input voltage is input, a pair of output terminals, a switching element 105 and a choke coil 106 connected in series to the high-potential side of the pair of input terminals, a diode 103 connected between the connection point of the switching element 105 and the choke coil 106 and the low-potential side of the pair of input terminals, and a capacitor 104 connected between the pair of output terminals. The DC-DC converter 100 operates as a step-down converter that steps down the input DC voltage by switching the on and off states of the switching element 105 based on a control signal from a control circuit (not shown). Note that the DC-DC converter 100 may include a plurality of conversion units including the switching element 105, the choke coil 106, and the diode 103, and may be a multi-phase converter in which these conversion units are connected in parallel, and the inductor 1 described above may be employed as the choke coil 106 of each conversion unit.

[0068] [Embodiment 1] A coil conductor including a first conductor extending in a first direction, a second conductor extending in a second direction intersecting the first direction, and a connecting conductor connecting one end portion of the first conductor and the second conductor; A magnetic body having a corner portion and arranged such that the corner portion faces the connecting conductor of the coil conductor; A resin member disposed between the magnetic body and the first conductor of the coil conductor; At least one of the first conductor and the second conductor has a first recessed portion that is recessed from the inside to the outside at a position adjacent to the connecting conductor; The dimension of the first recessed portion in a third direction intersecting the first and second directions is equal to or greater than the dimension of the conductor with the shorter dimension in the third direction among the one conductor and the other conductor in the third direction. Inductor. [Embodiment 2] At least a part of the resin member is housed in the first recessed portion. The inductor according to Embodiment 1. [Embodiment 3] The first conductor and the second conductor each have the first recessed portion that is recessed from the inside to the outside at a position adjacent to the connection conductor. The inductor according to Embodiment 1 or 2. [Embodiment 4] The connection conductor has a second recessed portion that is recessed from the inside to the outside. The second recessed portion of the connection conductor communicates with the first recessed portion of at least one of the conductors. The inductor according to any one of Embodiments 1 to 3. [Embodiment 5] The length dimension in the second direction of the first recessed portion of the second conductor is greater than the thickness of the resin member. The inductor according to any one of Embodiments 1 to 4. [Embodiment 6] The depth of the first recessed portion of at least one of the conductors is less than half of the thickness dimension of the conductor. The inductor according to any one of Embodiments 1 to 5. [Embodiment 7] The second conductor and the magnetic body are in close contact via an adhesive layer. The inner radius of curvature of the connection conductor is less than the thickness of the adhesive layer. The inductor according to any one of Embodiments 1 to 6. [Embodiment 8] The inner radius of curvature of the connection conductor is less than the thickness of the resin member. The inductor according to any one of Embodiments 1 to 7. [Embodiment 9] The outside of the connection conductor has a curved shape. The length dimension in the second direction of the first recessed portion of the second conductor is less than the radius of curvature of the curved shape of the connection conductor. The inductor according to any one of Embodiments 1 to 8. [Form 10] The outer side of the connection conductor has a curved shape, The length dimension in the first direction of the first recess of the first conductor is smaller than the radius of curvature of the curved shape of the connection conductor. The inductor according to any one of Forms 1 to 9. [Form 11] The coil conductor includes a third conductor extending in the second direction, a fourth conductor connecting the other end of the second conductor and one end of the third conductor, and a fifth conductor connected to the other end of the third conductor and extending in the first direction. The inductor according to any one of Forms 1 to 10, wherein the magnetic body is placed on the first conductor and the fifth conductor via the resin member. The magnetic body is placed on the first conductor and the fifth conductor via the resin member. The inductor according to any one of Forms 1 to 10. [Form 12] A DC-DC converter including the inductor according to any one of Forms 1 to 11.

Explanation of Signs

[0069] 1... Inductor, 2A, 2B, 2C... Magnetic bodies (magnetic substances), 3A, 3B... Coil conductors, 6A, 6B, 6C... Resin members, 11A, 11B... Conductor parts (second conductor, third conductor), 12A, 12B... Conductor parts (second conductor, third conductor), 13A, 13B... Connection parts (fourth conductor), 14A, 14B... Terminal parts (first conductor, fifth conductor), 15... Connection conductor, 16A, 16B... Terminal parts (first conductor, fifth conductor), 21, 22... First recesses, 23... Second recess, 30... Bending part (first conductor), 50... Burr (at least a part of the resin material), 60... Adhesive layer, 100, 500... DC-DC converters, 111... Conductor parts (first conductor, second conductor), 112... Conductor part (second conductor), 113... Connection part (first conductor, second conductor).

Claims

1. A coil conductor including a first conductor extending in a first direction, a second conductor extending in a second direction intersecting the first direction, and a connection conductor connecting one ends of the first conductor and the second conductor; A magnetic body having a corner portion and arranged such that the corner portion faces the connection conductor of the coil conductor; A resin member disposed between the magnetic body and the first conductor of the coil conductor; At least one of the first conductor and the second conductor has a first recessed portion that is recessed from the inside to the outside at a position adjacent to the connection conductor; An inductor, wherein a dimension of the first recessed portion in a third direction intersecting the first and second directions is equal to or greater than a dimension of the conductor having a shorter dimension in the third direction among the one conductor and the other conductor in the third direction.

2. The inductor according to claim 1, wherein at least a part of the resin member is accommodated in the first recessed portion.

3. The inductor according to claim 1, wherein the first conductor and the second conductor each have the first recessed portion that is recessed from the inside to the outside at a position adjacent to the connection conductor.

4. The connection conductor has a second recessed portion that is recessed from the inside to the outside; The inductor according to claim 1, wherein the second recessed portion of the connection conductor communicates with the first recessed portion of the at least one conductor.

5. The inductor according to claim 1, wherein a length dimension of the first recessed portion of the second conductor in the second direction is greater than a thickness of the resin member.

6. The inductor according to claim 1, wherein a depth of the first recessed portion of the at least one conductor is less than half of a thickness dimension of the conductor.

7. The second conductor and the magnetic body are in close contact via an adhesive layer; The inductor according to claim 1, wherein an inner radius of curvature of the connection conductor is smaller than a thickness of the adhesive layer.

8. The inductor according to claim 1, wherein an inner radius of curvature of the connection conductor is smaller than a thickness of the resin member.

9. The outside of the connection conductor has a curved shape; The inductor according to claim 1, wherein a length dimension of the first recessed portion of the second conductor in the second direction is smaller than a radius of curvature of the curved shape of the connection conductor.

10. The outside of the connection conductor has a curved shape; The length dimension of the first recessed portion of the first conductor in the first direction is smaller than the radius of curvature of the curved shape of the connecting conductor. The inductor according to claim 1.

11. The coil conductor includes a third conductor extending in the second direction, a fourth conductor connecting the other end of the second conductor and one end of the third conductor, and a fifth conductor connected to the other end of the third conductor and extending in the first direction. The inductor according to claim 1, wherein the magnetic body is placed on the first conductor and the fifth conductor via the resin member.

12. A DC-DC converter comprising the inductor according to any one of claims 1 to 11.

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