JP2015088668A - Power transmission inductor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission inductor capable of preventing increase of core loss.SOLUTION: The power transmission inductor includes: a magnetic material core 11 having plural magnetic body pieces 14 which are disposed in plane-like configuration and which are coupled with each other with a material containing a magnetic material; and a winding 13 provided to the magnetic material core. The winding is wound in a first direction on the magnetic material core. The magnetic body pieces which are aligned along a direction perpendicular to the first direction are coupled with the material containing the magnetic material. The magnetic body pieces which are aligned along the first direction are coupled with each other without the material containing the magnetic material.

Description

  Embodiments described herein relate generally to an inductor for power transmission.

  There is a system that uses a power transmission inductor in which a winding is wound around a magnetic core and wirelessly transmits power between the power transmission inductors by magnetic coupling. In order to extend the distance of power transmission between the inductors, it is necessary to use a large inductor. For example, when a ferrite core is used as the magnetic core, it is difficult to manufacture a large core due to a molding process and a firing process. Therefore, a plurality of small magnetic pieces are prepared, and a plurality of magnetic pieces are combined to obtain one large core. This is used as a magnetic core.

  However, due to the surface accuracy and dimensional accuracy of the magnetic material pieces, when a plurality of magnetic material pieces are arranged, gaps are unevenly generated between the magnetic material pieces. In addition, when the inductor is manufactured, when resin casting or injection molding is performed, there is a case where the resin is mixed between the magnetic pieces and a gap is formed. Alternatively, there may be a gap between the magnetic pieces due to vibration during use of the inductor or expansion and contraction due to thermal cycling. When the gap between the magnetic pieces is large, the magnetic resistance increases, and this causes the magnetic flux in the inductor to concentrate in a place where there is no gap or is small. For this reason, there is a problem that the core loss increases.

JP 2012-15311 A

  An object of the embodiment of the present invention is to provide an inductor for power transmission that can prevent an increase in core loss even when a magnetic core including a plurality of magnetic pieces is used.

  An inductor for power transmission as an embodiment of the present invention is provided on a magnetic core including a plurality of magnetic pieces arranged in a plane and coupled to each other by a material containing a magnetic material, and the magnetic core A wound winding.

The figure which shows the example of the inductor for electric power transmission which concerns on 1st Embodiment. The figure which shows the relationship between a filling factor and an equivalent relative magnetic permeability. The figure which shows the inductor structure which performed simulation. The figure which shows magnetic flux density distribution of the inductor structure shown in FIG. The figure which shows magnetic flux density distribution of the inductor used as a comparison object. The figure which shows a simulation result. The figure which shows the modification of the inductor of FIG. The figure which shows the example of the inductor for electric power transmission which concerns on 2nd Embodiment. The figure which shows the example of the inductor for electric power transmission which concerns on 3rd Embodiment. The figure which shows the example of the inductor for electric power transmission which concerns on 4th Embodiment. The figure which shows the example of the inductor for electric power transmission which concerns on 5th Embodiment. The figure which shows the example of the inductor for electric power transmission which concerns on 6th Embodiment. The figure which shows the example of the inductor for electric power transmission which concerns on 7th Embodiment. The figure which shows the example of the inductor for electric power transmission which concerns on 8th Embodiment. The figure which shows the example of the inductor for electric power transmission which concerns on 9th Embodiment. The figure which shows the other example of the inductor for electric power transmission which concerns on 9th Embodiment.

  The present embodiment will be described below with reference to the drawings.

(First embodiment)
FIG. 1 shows an inductor for wireless power transmission according to the first embodiment. 1A is a top view, and FIG. 1B is a cross-sectional view taken along the line H1-H1.

  The inductor shown in FIG. 1 includes a magnetic core 11, a bobbin 12, and a winding 13.

  The magnetic core 11 is formed by arranging a plurality of magnetic body pieces 14 in a planar shape and coupling them together. Each magnetic piece 14 has a generally flat plate shape, and the magnetic core 11 has a large plate shape as a whole.

  Each magnetic piece 14 is made of ferrite, a dust core, an electromagnetic steel plate or the like. The reason why the magnetic core 11 is formed from the plurality of magnetic pieces 14 is as follows.

  Inductors for wireless power transmission have an inductor size determined by the power to be transmitted and the distance to be transmitted. For example, when electric power is transmitted to a position separated by about 10 cm, a large inductor having a side of several tens of cm is used. When the magnetic core 11 is formed of a ferrite core, a dust core, or the like, it is difficult to manufacture a large core due to the molding process and firing process. Therefore, as in the present embodiment, a plurality of small magnetic pieces 14 are combined and used as a large inductor and a core.

  The magnetic core 11 is provided in a cylindrical or box-shaped bobbin 12. In the illustrated example, the magnetic core 11 is inserted through a cylindrical bobbin 12. The bobbin 12 is made of an insulator. The winding 13 is wound around the bobbin 12 in the vertical direction (X-axis direction) along the paper surface. That is, the winding wire 13 is wound around the magnetic core 11 via the bobbin 12. Winding 13 is, for example, a copper wire or an aluminum wire. The winding 13 may be a litz wire.

  In the example of FIG. 1, the winding wire 13 is wound around the bobbin 12, but the winding wire 13 may be wound directly around the magnetic core 11 without using the bobbin 12.

  Here, between the plurality of magnetic body pieces 14 forming the magnetic body core 11, the adjacent magnetic body pieces 14 are coupled to each other via a fluid material filled with the magnetic body material. As the magnetic material to be filled, for example, a powdery or granular material can be used. As the fluid material, for example, an adhesive made of a resin material such as epoxy resin or silicon can be used. Here, each magnetic piece 14 is coupled by an adhesive 15 filled with ferrite powder as magnetic powder. In addition, the structure which couple | bonds each magnetic body piece 14 using the material which consists only of ferrite powder so that it may mention later is also possible.

  As an example, the bonding between the magnetic pieces 14 is performed by applying the adhesive 15 to the side surface of each magnetic piece 14 and pressing the magnetic pieces 14 together for a predetermined time or more. Thereby, it is possible to form the magnetic core 11 that prevents the generation of a region having a low relative permeability due to an air gap or the like between the magnetic pieces 14. By performing wireless power transmission using the inductor using the magnetic core 11, local concentration of magnetic flux is prevented, so that an increase in magnetic resistance is suppressed and core loss can be reduced.

  Here, the equivalent relative magnetic permeability of the adhesive when the adhesive is filled with magnetic powder is calculated as follows.

That is, when a non-magnetic adhesive having a relative permeability of 1 is filled with a powdered magnetic substance powder having a relative permeability μr at a filling rate α%, the equivalent relative permeability of the adhesive is obtained.
Is the geometric mean of the volume ratio, which is the ratio of magnetic powder to the total volume of magnetic powder and adhesive,
It becomes.

  When the magnetic powder is not filled (when 0%), the equivalent relative permeability is 1, and when the filling rate is 100% (without using an adhesive, all are magnetic powder), the equivalent relative permeability is μr.

  FIG. 2 shows the relationship between the filling rate (volume ratio) and the equivalent relative permeability when a magnetic powder having a relative permeability of 1500 is filled in an adhesive. The vertical axis is the logarithmic axis. The greater the filling factor, the greater the equivalent relative permeability.

  A simulation performed by the present inventors will be described with reference to FIGS. 3, 4, 5, and 6.

  FIG. 3 shows a simulated inductor configuration. In this configuration, the winding 22 is wound around the magnetic core 21. The winding 22 is schematically represented by a horizontally long rectangle. The magnetic core 11 has a square planar shape with a side of 150 mm and a thickness of 5 mm. A gap 23 having a length L1 and a width L2 is formed in the magnetic core 11, and the length L1 is 50 mm and the width L2 is 1 mm. The magnetic core 11 is virtually assumed to be a single magnetic plate, and there is no gap other than the gap 23.

  FIG. 4 shows the magnetic flux density distribution of the inductor configuration shown in FIG. Since the magnetic resistance increases in the gap 23, the magnetic flux in the inductor is concentrated in a region having a small gap. As a result, the core loss increases.

  FIG. 5 shows the magnetic flux density distribution of the inductor configuration when there is no gap in the magnetic core as a comparison object. The magnetic flux is distributed almost uniformly in the portion where the winding is wound and the other portion.

  FIG. 6 shows a simulation in which the core loss is measured by filling the gap 23 of the magnetic core 21 shown in FIG. 3 with the adhesive filled with the magnetic powder while changing the filling rate of the magnetic powder. Results are shown. The simulation was performed using an electromagnetic field simulator. FIG. 6 shows the relationship between the filling rate (%) of the magnetic powder and the core loss (W). The filling rate is a ratio (volume ratio) of the volume of the magnetic powder to the total volume of the magnetic powder and the adhesive.

  The filling rate of 0% corresponds to the case where the adhesive is not filled with the magnetic powder, and the filling rate of 100% corresponds to the case where all the gaps are filled with only the magnetic powder without using the adhesive. .

  It can be seen that as the filling rate of the magnetic powder is increased, the concentration of magnetic flux becomes weaker and the core loss decreases. In particular, the core loss starts to decrease significantly when the filling rate of the magnetic powder is 20% or more. When the filling rate of the magnetic powder reaches 60%, the effect of lowering the core loss is almost saturated, and beyond this, even if the filling rate of the magnetic powder is increased, the core loss is hardly reduced. Accordingly, the filling rate of the magnetic powder is preferably 20% or more and 60% or less. In addition, since the adhesive strength is weakened when the filling rate of the magnetic powder is high, the filling rate of the magnetic powder is preferably 20% or more and 40% or less from the viewpoint of achieving both a reduction in core loss and adhesion ability.

  In the example shown in FIG. 1, the adjacent magnetic material pieces 14 are all bonded with an adhesive 15 filled with magnetic powder. This is an example, and a configuration in which some of the magnetic body pieces 14 are not coupled by the adhesive 15 is also possible. For example, the magnetic pieces 14 adjacent in the Y-axis direction shown in FIG. 1 may be coupled by the adhesive 15, and the magnetic pieces 14 adjacent in the X-axis direction may not be coupled by the adhesive 15. It is. The configuration in this case is shown in a top view in FIG.

  As shown in FIG. 7, when the winding wire 13 is wound in the X-axis direction, the magnetic flux generated during power transmission is generated in the Y-axis direction orthogonal to the X-axis. Therefore, the influence of the gap between the magnetic pieces 14 is dominant due to the gap that blocks the magnetic flux, that is, the gap extending in the X-axis direction. Therefore, the magnetic substance groups arranged in a line in the Y-axis direction are bonded to each other with the adhesive 15 filled with the magnetic substance powder. That is, a plurality of magnetic material piece rows (seven in the illustrated example) are generated by joining the magnetic material pieces together with the adhesive 15 in the Y-axis direction. And the magnetic body core 19 is formed by arrange | positioning these magnetic body piece rows so that it may mutually contact in an X-axis direction. According to this configuration, there is no portion where the magnetic resistance increases locally in the direction of the magnetic flux. Even if there is a gap between the magnetic pieces 14 adjacent in the X-axis direction, the gap has little influence on the magnetic flux. Therefore, the core loss can be greatly reduced also by the configuration of FIG. In the configuration of FIG. 7, the magnetic pieces 14 adjacent in the X-axis direction are not bonded with an adhesive, so that the overall weight can be reduced and the manufacturing cost can be reduced.

  In this embodiment, the adhesive 15 filled with magnetic powder is used. However, a magnetic piece is obtained by using a fluid material such as a resin-based material that has no or weak adhesive force and is filled with the magnetic powder. 14 may be combined. In this case, in order to maintain the coupling between the magnetic pieces 14, each sheet or glass cloth is adhered to both sides or one side of the magnetic core with an adhesive, as will be described in the following embodiments. The magnetic piece 14 may be fixed. Alternatively, the magnetic core may be fixed to the inner wall of the bobbin 12 with an adhesive.

  In the present embodiment, the adhesive 15 filled with the magnetic powder is used. However, the magnetic pieces 14 may be bonded to each other using a material containing only the magnetic powder. For example, the magnetic powder is embedded in the gaps between the sides of the magnetic bodies that are vacant when the plurality of magnetic pieces 14 are combined into one. In order to maintain the coupling between the magnetic pieces 14, as will be described in the embodiments described later, a sheet or a glass cloth is attached to both surfaces or one surface of the magnetic core with an adhesive, whereby each magnetic piece 14. To fix. Alternatively, the magnetic core is fixed to the inner wall of the bobbin 12 with an adhesive.

  As described above, according to the present embodiment, it is possible to prevent an increase in core loss even when a magnetic core including a plurality of magnetic pieces is used.

(Second Embodiment)
FIG. 8 shows a configuration example in which the inductor shown in FIG. 1 is arranged in the housing 17 and the conductor plate 18 is arranged on the upper surface side of the inductor. 8A is a top view, and FIG. 8B is a cross-sectional view taken along the line H2-H2. However, in FIG. 8A, the display of the conductor plate 18 is omitted, and the magnetic core in the bobbin is transparently displayed.

  The housing 17 has a box shape composed of a lower surface portion and four side surface portions, and is made of a dielectric. The inductor shown in FIG. 1 is disposed in the housing 17, and the conductor 18 is disposed on the upper surface side of the housing 17. By disposing the inductor in the housing 17, it is possible to protect the inductor from external impacts and the like.

  The conductor plate 18 has an electrical shielding function with respect to the inductor in the housing 17. Moreover, it has the effect of releasing the heat generated in the inductor.

  The inductor to which power is transmitted is disposed so as to face the lower surface of the housing 17 in FIG. The conductor plate 18 also has a function of blocking magnetic field lines generated by the inductor during power transmission from leaking to the opposite side of the counterpart inductor and enhancing magnetic coupling with the counterpart inductor.

(Third embodiment)
FIG. 9 shows a cross-sectional view of an inductor for power transmission according to the third embodiment. In the present embodiment, the magnetic core is formed from a plurality of magnetic core layers in order to increase the overall adhesive strength of the magnetic core. Since other than this is basically the same as in the first embodiment, the following description will focus on differences from the first embodiment.

  As shown in FIG. 9, the magnetic core 36 is formed of two magnetic core layers 14A and 14B stacked in the Z-axis direction. The lower magnetic core layer 14A and the upper magnetic core layer 14B have the same configuration as the magnetic core 11 of FIG. 1 or FIG. In the lower magnetic core layer 14A, the size of the magnetic piece at both ends is made smaller than that of the other magnetic pieces. In each layer, at least the magnetic pieces adjacent in the Y-axis direction are bonded to each other with the first adhesive 21 filled with magnetic powder or the like. The first adhesive 21 may be the same as the adhesive 15 of the first embodiment, for example.

  The magnetic pieces in the Z-axis direction (stacking direction) are bonded together by the second adhesive 22. The second adhesive 22 may be an adhesive filled with a magnetic material such as magnetic powder, or an adhesive not filled with a magnetic material. When the same adhesive as the first adhesive 21 is used, there is an advantage that fewer types of adhesives are prepared. Adhesion in the Y-axis direction can be indirectly reinforced by bonding the magnetic pieces in the stacking direction.

  In FIG. 9, the boundary positions 28 and 29 between the magnetic pieces bonded in the Y-axis direction are different in each layer. Thereby, for example, even when the magnetic pieces at the boundary position 28 are separated from each other and a gap such as air is generated here, no gap is present in the magnetic core layer 14A immediately below. Therefore, a local increase in magnetic resistance can be suppressed and core loss can be reduced.

(Fourth embodiment)
FIG. 10 shows a cross-sectional view of the power transmission inductor according to the fourth embodiment. In this embodiment, the surface of the magnetic core inserted through the bobbin is bonded to the inner wall of the bobbin with an adhesive. Since other than this is basically the same as in the first embodiment, the following description will focus on differences from the first embodiment.

  As shown in FIG. 10, the magnetic pieces 14 are bonded with a first adhesive 25 along the Y-axis direction. As in the first embodiment, the first adhesive 25 is an adhesive filled with magnetic powder or the like. The magnetic core 11 (each magnetic piece 14) and the inner wall of the bobbin are bonded by a second adhesive 26. The second adhesive 26 may be an adhesive filled with magnetic powder or an adhesive not filled with magnetic powder. Further, the second adhesive 26 may be an adhesive filled with a conductive filler. Thereby, when a gap such as air is generated between the inner wall of the bobbin and the surface of the magnetic piece, partial discharge that may occur due to potential concentration can be prevented. Note that an adhesive filled with both a magnetic material and a conductive material may be used as the second adhesive.

(Fifth embodiment)
FIG. 11 is a cross-sectional view of the power transmission inductor according to the fifth embodiment. The periphery of the bobbin and the winding is covered with a resin 31, and the conductor plate 18 is disposed on the upper surface of the resin 31. Since other than this is basically the same as in the first embodiment, the following description will focus on differences from the first embodiment.

  As shown in FIG. 11, a resin 31 is cast or injection molded around the bobbin 12 and the winding 13. As the resin 31, for example, a thermosetting resin such as an epoxy resin or an unsaturated polyester, or a thermoplastic resin such as PPS (polyphenylene sulfide) may be used. The resin 31 can reinforce the adhesion between the magnetic pieces 14. In addition, the resin 31 can radiate heat generated in the inductor during power transmission to the outside. In order to improve heat dissipation, the resin 31 may be formed using a resin material filled with a filler for increasing thermal conductivity such as silica or boron nitride. In FIG. 11, the bobbin 12 and the winding 13 are entirely covered with resin, but only a part may be covered. When the resin 31 is cast or injection-molded, the plurality of magnetic pieces 14 are bonded to each other with an adhesive, so that the resin material can be prevented from entering between the magnetic pieces 14.

  A conductor plate 18 is disposed on the upper surface of the resin. As described in the second embodiment, the conductor plate 18 can provide the effect of increasing the electrical shield, heat dissipation, and transmission efficiency.

(Sixth embodiment)
FIG. 12 is a cross-sectional view of the power transmission inductor according to the sixth embodiment. A cushioning material is disposed between the magnetic core and the bobbin. Except this, it is basically the same as the fifth embodiment. Hereinafter, the difference of the fifth embodiment will be mainly described.

  As shown in FIG. 12, a cushioning material 32 is disposed between the magnetic core 38 and the box-shaped or cylindrical bobbin 12.

  The buffer material 32 is, for example, a synthetic rubber such as nitrile rubber, chloroprene rubber, acrylic rubber, silicone rubber or fluorine rubber, or natural rubber.

  Alternatively, the buffer material 32 may be, for example, a polyimide film, a silicon-based sheet, an acrylic-based sheet, or a glass cloth. In this case, the sheet or glass cloth may be fixed to the surface of the magnetic core 38 with an adhesive. This adhesive may be a resin material such as unsaturated polyester. Further, the adhesive may be filled with a conductive material. Thereby, when a gap such as air is generated between the inner wall of the bobbin 12 and the surface of the magnetic piece 14, it is possible to prevent partial discharge that may occur due to potential concentration.

  By providing the buffer material 32 between the bobbin 12 and the magnetic core 11, stress such as thermal stress applied to the magnetic core 11 due to, for example, a difference in linear expansion coefficient from the casting resin can be relieved. That is, when the shape of the magnetic core 11 is distorted by the stress generated in the resin 31, the magnetic properties of the magnetic piece 14 are deteriorated. Degradation of characteristics can be reduced.

(Seventh embodiment)
FIG. 13 shows a side view of the power transmission inductor according to the seventh embodiment. In the inductor of this embodiment, an additional magnetic body 34 is laminated in the Z-axis direction on the magnetic body pieces at both ends in the Y-axis direction (magnetic flux direction). The additional magnetic body 34 is bonded to the magnetic piece 14 with an adhesive 37. The additional magnetic body 34 is disposed on the side opposite to the conductor plate 18, that is, on the side where the counterpart inductor is disposed during power transmission (the lower side along the paper surface). Similarly to the inductor shown in FIG. 13, the counterpart inductor may adopt a structure in which magnetic pieces are laminated on both ends. The adhesive 37 may be filled with a magnetic material such as magnetic powder. Thereby, core loss can be reduced. However, it is also possible to use an adhesive that does not contain a magnetic material. In this example, the additional magnetic body 34 is provided only at both ends of the magnetic core. However, an additional magnetic body may be further disposed inside the magnetic piece 14 at both ends as long as it can be disposed. .

  By arranging the additional magnetic body 34 in this manner, the distance between the opposing inductors can be reduced and the coupling coefficient between the transmitting and receiving inductors can be increased.

(Eighth embodiment)
FIG. 14 shows an inductor for power transmission according to the eighth embodiment. 14A is a top view, and FIG. 14B is a cross-sectional view taken along H3-H3. In FIG. 14A, the conductor plate 18 is not shown, and the magnetic core 39 is transparently displayed. In the present embodiment, a part of the magnetic body piece is removed from the magnetic core to form a notch 42, and a circuit element 41 such as a capacitor or a rectifier is disposed in the notch 42.

  In the illustrated example, a capacitor is disposed as the circuit element 41. The capacitor can be used for adjusting the resonance frequency of the inductor, for example. The circuit element is connected to the winding wire 13 by a wiring (not shown).

  In this example, the circuit element 41 is disposed in the notch 42, but may be disposed on the position P1 facing the notch 42, for example, on the outer surface of the bobbin. Since the magnetic force is weak at the notch portion 42 or the position of the notch portion 42 in the Z-axis direction, the influence on the circuit element can be reduced by arranging the circuit element in the notch portion 42. Further, by providing the circuit element 41 at a position facing the notch 42 or the notch 42, the circuit element can be provided in the inductor, and the apparatus can be downsized.

(Ninth embodiment)
In the first to eighth embodiments, an inductor in which a solenoid-type winding is wound around a magnetic core is shown. However, in this embodiment, other types of inductors are shown. Specifically, an example of an inductor in which a spiral type winding or a DD type (eighth-shaped) winding is arranged on a magnetic core is shown.

  FIG. 15 shows an example of an inductor for power transmission according to the ninth embodiment. FIG. 15A is a top view, and FIG. 15B is a cross-sectional view taken along H4-H4. In FIG. 15A, the display of the conductor plate 18 is omitted, and the magnetic core 11 is transparently displayed. A spiral winding 61 is disposed on the magnetic core 11 via the bobbin 12. Here, the spiral winding 61 is disposed outside the bobbin, but a configuration in which it is disposed inside the bobbin is also possible.

  FIG. 16 shows another example of the power transmission inductor according to the ninth embodiment. 16A is a top view, and FIG. 16B is a cross-sectional view taken along H5-H5. In FIG. 16A, the display of the conductor plate 18 is omitted, and the magnetic core 11 is transparently displayed. A DD type (eighth-shaped) winding 62 is disposed on the magnetic core 11 via the bobbin 12. Here, the eight-shaped winding 62 is disposed outside the bobbin 12, but a configuration in which it is disposed inside the bobbin is also possible.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

11, 19, 21, 36, 38, 39: magnetic core 12: bobbin 13: winding 14: magnetic pieces 15, 21, 22, 25, 26: adhesive 17: casing 18: conductor plates 28, 29 : Boundary position 31: resin 32: buffer material 34: magnetic body piece 41: circuit element 42: notch

Claims (14)

A magnetic core comprising a plurality of magnetic pieces arranged in a plane and coupled together by a material comprising a magnetic material;
Windings provided for the magnetic core;
Inductor for power transmission with The inductor for power transmission according to claim 1, wherein the material including the magnetic material is a fluid material filled with the magnetic material. The inductor for power transmission according to claim 3, wherein the fluid material is an adhesive. The inductor for power transmission according to any one of claims 1 to 3, wherein the magnetic material is ferrite powder. The winding is wound around the magnetic core in a first direction,
The magnetic pieces along the direction orthogonal to the first direction are joined by a material containing the magnetic material,
5. The inductor for power transmission according to claim 1, wherein the magnetic pieces along the first direction are coupled without a material including the magnetic material. The magnetic body core includes a plurality of magnetic body core layers, and in each magnetic body core layer, a plurality of magnetic body pieces are coupled by a material including the magnetic body material, and a boundary position between adjacent magnetic body pieces is The power transmission inductor according to any one of claims 1 to 5, wherein the power transmission inductor is different between magnetic core layers. The inductor for power transmission according to claim 6, wherein the magnetic pieces are fixed with an adhesive between the adjacent magnetic core layers. The inductor for power transmission according to any one of claims 1 to 7, further comprising a sheet or a glass cloth adhered to both surfaces or one surface of the plurality of magnetic material pieces with an adhesive. With a cylindrical bobbin,
The magnetic core is disposed in the bobbin hole,
The winding is wound around the bobbin,
The inductor for power transmission according to any one of claims 1 to 8, wherein the magnetic core is fixed to an inner wall of the bobbin with an adhesive. The inductor for power transmission according to claim 9, wherein the adhesive that fixes the magnetic core to the inner wall of the bobbin includes a conductive material. A box-shaped or cylindrical bobbin, a resin, and a cushioning material,
The magnetic core is inserted into the bobbin hole,
The winding is wound around the bobbin,
The resin is formed to cover the bobbin and the winding,
The inductor for power transmission according to any one of claims 1 to 8, wherein the buffer material is disposed between the magnetic core and an inner wall of the bobbin. The inductor for power transmission according to claim 11, wherein the buffer material includes a conductive material. The winding is wound around the magnetic core in a first direction;
The additional magnetic body pieces are laminated on the magnetic body pieces at both ends in the direction orthogonal to the first direction of the magnetic core, and the additional magnetic body pieces are made of a magnetic material containing a magnetic material. The inductor for power transmission according to any one of claims 1 to 12, wherein the inductor is coupled to a piece. The inductor for power transmission according to any one of claims 1 to 13, wherein a volume ratio of the magnetic material to a material including the magnetic material is 20% or more and 60% or less.