JP3163318B2 - Core for inductive element and inductive element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an inductive element core made of a magnetic material and used as a magnetic flux path, and an inductive element such as a coil or a transformer using the same.

[0002]

2. Description of the Related Art For example, toroidal core type, EI core type and substrate type choke coils are known as choke coils. The toroidal core type choke coil has an inductance value according to the number of conductors wound around the winding frame of the toroidal core. EI
The core type choke coil is formed by winding a conductor around an inner or outer frame of an E-shaped core and then overlapping the I-shaped core in a letter shape, and has an inductance value corresponding to the number of windings. are doing. On the other hand, a board type choke coil has an EI type core and a printed board. A hole is formed in the printed board, and the center frame of the E-shaped core penetrates through the hole to be disposed between the outer frames of the E-shaped core. Also, on the printed circuit board,
A spiral print pattern centering on the hole is formed, and the board type choke coil has an inductance value corresponding to the number of spirals of the print pattern.

[0003]

However, this conventional choke coil has the following problems. That is, first, in the conventional type choke coil, a required inductance value cannot be obtained unless the conductor is wound around the winding frame many times. For this reason, it is difficult to reduce the thickness of the inductive element due to the thickness of the wound conductor. In particular, when manufacturing a high power type inductive element, there is a problem in that it is very difficult to reduce the thickness because the diameter of the conductor must be increased. Also, it is difficult to reduce the thickness of the core itself. In other words, the conductor must be wound many times around the core in the toroidal core type, and around the center frame in the EI core type or the substrate type. Therefore, in order to secure a saturation magnetic flux density according to the number of turns and the current flowing through the conductor, the core must have a very large cross-sectional area. In particular, in the case of a substrate type, it is necessary to form the print pattern in a spiral shape, so that if a thick print pattern is formed, the substrate area becomes very large. In this case, it is conceivable to obtain a predetermined inductance value by stacking a plurality of printed boards, but in such a case, it is difficult to reduce the thickness of the EI core due to the thickness of the printed board itself, and a plurality of printed boards are required. The necessity of connecting the print patterns on the substrate in series increases the cost.

Second, the above three types have a problem that it is difficult to manufacture a choke coil for a large current. That is, the saturation magnetic flux density of the core is proportional to the product of the current and the number of turns. Therefore, the larger the number of turns and the current flowing, the higher the saturation magnetic flux density of the core. On the other hand, in the above three types, since the conductor is wound around the middle frame of the toroidal core or the EI core a plurality of times, if the cross-sectional area of the core per conductor is increased accordingly, the EI core becomes very large. It becomes large. For this reason, considering the miniaturization of the EI core, a core having a very high saturation magnetic flux density must be used,
Actually, in order to newly manufacture a core having a higher saturation magnetic flux density, it is necessary to wait for a new material to appear.

Further, in the case of the substrate type, since the conductor is spiral, the distance between the outer conductor and the EI core is increased, resulting in a large amount of leakage magnetic flux.

The present invention has been made in view of such a problem, and provides an inductive element core capable of manufacturing a thin and large-current inductive element, and an inductive element using the same. The main purpose is to

[0007]

According to a first aspect of the present invention, there is provided an inductive element core comprising: a base magnetic body on which at least four or more columnar magnetic bodies are erected; A core for an inductive element comprising a magnetic plate capable of being magnetically coupled to each of the columnar magnetic bodies disposed opposite to the base magnetic body, wherein the base magnetic body, two columnar magnetic bodies adjacent to each other, And at least three endless cores that close the magnetic path by a magnetic plate in the shortest way, and that an inductive element can be formed by inserting at least one conductor through a plurality of endless cores. In addition, the endless core means that the magnetic path is closed by the magnetic substance itself,
This is a concept that includes both cases where magnetic bodies are magnetically coupled to each other via a gap.

In this inductive element core, at least three endless cores whose magnetic paths are shortest and closed are formed by a base magnetic body, two adjacent columnar magnetic bodies, and a magnetic plate. In this case, when one conductor is inserted through the endless core, the conductor becomes an inductive element having a predetermined inductance based on the magnetic permeability and the cross-sectional area of the endless core. Therefore, when a conductor is inserted through a plurality of endless cores, an inductive element in which a plurality of the inductive elements are connected in series is equivalently formed. Therefore, when a large inductance value is required, a conductor may be inserted through many endless cores, and when a large current inductive element is required, a thick conductor may be used. . In this case, the conductor insertion hole of the endless core only needs to allow one conductor to pass therethrough, and the endless core only needs to have a cross-sectional area corresponding to the current flowing through one conductor. . Therefore, since the base magnetic body can be formed in a planar manner, the thickness of the inductive element core and the inductive element using the same can be reduced.

According to a second aspect of the present invention, in the core for an inductive element according to the first aspect, the base magnetic body is formed to be long, and the columnar magnetic bodies are erected in one row. It is characterized by the following.

In this inductive element core, since the columnar magnetic bodies are erected in one row, a thin and narrow inductive element core and an inductive element using the same can be manufactured. .

The core for an inductive element according to a third aspect is the core for an inductive element according to the first aspect, wherein the columnar magnetic body comprises:
It is characterized in that it is erected in a plurality of rows vertically and horizontally on a base magnetic body.

In this inductive element core, a large number of endless cores are formed since the columnar magnetic bodies are erected in a plurality of rows each in the vertical and horizontal directions. For this reason, an inductive element having a large inductance value can be easily manufactured, and any one of many insertion methods that can be easily inserted can be adopted.

According to a fourth aspect of the present invention, in the core for an inductive element according to any one of the first to third aspects, the columnar magnetic body has one of a polygonal or circular cross section. It is characterized by being formed.

In this inductive element core, since the cross section of the columnar magnetic body is formed in a polygonal shape or a circular shape such as a circle or an ellipse, the core is not easily damaged when the conductor is inserted. Thus, the reliability of the inductive element manufactured using the inductive element core is improved.

A core for an inductive element according to a fifth aspect of the present invention is the core for an inductive element according to any one of the first to fourth aspects, wherein a hole is formed in a portion of the base magnetic material other than the standing portion of the columnar magnetic material. Is provided.

With this inductive element core, when manufacturing an inductive element for a large current, heat is generated between the base magnetic material and the magnetic plate, based on the current flowing through the conductor. The heat is radiated to the outside from the hole provided in the base magnetic body. For this reason, it becomes a core suitable as a core of the inductive element for large current. In addition, by inserting a conductor into the hole, the endless core can be formed three-dimensionally.

According to a sixth aspect of the present invention, in the core for an inductive element according to any one of the first to fifth aspects, a hole is formed in a portion of the magnetic plate other than a portion facing the columnar magnetic body. A part is provided.

In the inductive element core, since the magnetic plate has the hole, heat can be easily released, and as a result, the heat radiation effect can be further improved.

According to a seventh aspect of the present invention, in the core for an inductive element according to any one of the first to sixth aspects, a gap is formed between the magnetic plate and at least one columnar magnetic body. It is characterized by being possible.

In this inductive element core, an endless core formed by a base magnetic body, a columnar magnetic body, and a magnetic plate is magnetically coupled via a gap. Therefore, when a conductor is inserted, a so-called unsaturated inductive element is easily formed. Therefore, it can be used for a so-called magnetic amplifier and the like.

The core for an inductive element according to claim 8 is the core for an inductive element according to any one of claims 1 to 7, wherein the base magnetic body is a wall-shaped magnetic body surrounding the columnar magnetic body. It is characterized by having.

In this inductive element core, since the columnar magnetic body is shielded by the base magnetic body and the magnetic body plate, an inductive element free from leakage magnetic flux can be formed by using this.

According to a ninth aspect of the present invention, there is provided an inductive element comprising the inductive element core according to any one of the first to eighth aspects and at least one conductor penetrating the plurality of endless cores. It is characterized by the following.

According to this inductive element, as described in the inductive element core according to the first aspect, an inductive element having a large inductance value and an inductive element for a large current can be provided.

The inductive element according to the tenth aspect is the ninth aspect.
The inductive element according to any one of the preceding claims, further comprising a plurality of conductors, wherein the inductive element is a transformer.

In this inductive element, a transformer can be easily manufactured by inserting a plurality of conductors through the endless core. Also, by appropriately changing the number of conductors to be inserted, a transformer having an arbitrary turns ratio can be easily manufactured.

The inductive element according to the eleventh aspect is the ninth aspect.
In the inductive element according to Item 10, the conductor is formed in a sheet shape.

In the core for an inductive element, a printed circuit board in which a conductor is printed and patterned is arranged in a gap between each columnar magnetic body before the magnetic body plate and the base magnetic body are bonded to each other, so that the inductive element core can be easily formed. A device can be manufactured.
In this case, if a plurality of endless cores are formed in the inductive element core, it is not necessary to insert many conductors into one endless core, so that the conductors can be inserted at the shortest distance. Therefore, compared with the conventional board type choke coil, the leakage magnetic flux can be extremely reduced.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the accompanying drawings, in which an inductive element core according to the present invention and an inductive element using the same are applied.

FIG. 1 shows a printed circuit board mounted type choke coil (inductive element) 1. Choke coil 1
As shown in the figure, a base magnetic body 2 and a magnetic body plate 3 each formed of a magnetic body are provided, and the base magnetic body 2 and the magnetic body plate 3 are adhered to each other with a printed circuit board 4 interposed therebetween. You. In this case, the material of the magnetic material is M
nZn ferrite, NiZn ferrite, NiZn
Ferrite materials such as Cu-based ferrite and NiFe-based ferrite, and oxide-based or metal-based materials such as Permalloy and Sendust are used, but are not limited thereto, and all materials that are magnetized when placed in a magnetic field are used. be able to.

The base magnetic body 2 is composed of nine rectangular parallelepiped core feet (columnar magnetic bodies) 12a, 12b, and 12c (three columns vertically and horizontally) standing on the base 11 (hereinafter simply referred to as "columns"). Core feet 12 "). Each of the core feet 12, 12,... Is formed at the same height, and when the magnetic body plate 3 is adhered to the base magnetic body 2, two core feet 12, 12, adjacent to each other, and the base 1
An endless unit core having the shortest magnetic path length is formed by the magnetic plate 1 and the magnetic plate 3. The hole of this unit core, that is,
In the groove 14 formed by the core feet 12, 12,.
A conductor 13 is provided. Although the unit core will be described in detail later, by inserting the conductor 13 through the hole of the unit core, a coil having a predetermined inductance value determined by the cross-sectional area of the unit core and the magnetic permeability of the magnetic material is obtained. It is formed.

The core leg 12 has a predetermined cross-sectional area. Specifically, assuming that the cross-sectional area of the core feet 12a arranged at the four corners of the base 11 is a value of 1, the cross-sectional area of the core feet 12b arranged around the base 11 other than the four corners is a value of 1.5. , The cross-sectional area of the other core feet 12c is 2. The cross-sectional shape of the core foot 12 is arbitrary, and can be formed in various shapes such as a square, a rectangle, an ellipse, and a circle. In the present embodiment, the conductor 13 is formed in a rectangular shape because it is easy to mold. However, in consideration of the fact that the conductor 13 is damaged when the conductor 13 is inserted, the cross section is configured as circular as possible, such as a circle or an ellipse. Is preferred.

The magnetic plate 3 is formed in a plate shape, and makes surface contact with the upper surfaces of the core feet 12, 12,. As a result, the magnetic plate 3 is magnetically coupled to the core feet 12 and 12 to form the unit core described above. However, the present invention is not limited to this. By providing fitting holes in the magnetic body plate 3 to be fitted in the core feet 12, 12,. Is also good.

The printed circuit board 4 is formed of, but not limited to, a glass epoxy material.
A plurality of holes 21, 21,... Are formed at positions opposing each other so that 12. The printed circuit board 4 has an end 13
The through holes 22a and 22b are formed to allow the soldering of the printed circuit board 4a and 13b upward from the lower side of the printed circuit board 4 in the same figure, and are not shown in both the through holes 22a and 22b. Print patterns 23a and 23b to which the other end is connected to the electric circuit are connected respectively.

Next, the principle of operation of the choke coil 1 will be described with reference to FIGS. Choke coil 1
Is, in principle, equivalent to a combination of 12 unit cores 31, 31,... As shown in FIG. The unit core 31 is a magnetic plate 32 shown in FIGS.
And a base magnetic body 33 shown in FIGS. As described above, the unit core 31 forms a closed magnetic path, and has the same area in all cross sections orthogonal to the magnetic path. The reason why the cross-sectional areas are made equal at this time is to reduce waste of the magnetic material by making the magnetic flux densities equal in all the cross sections. When the number of conductors 13 inserted into the unit core 31 is not the same, it is desirable that the cross-sectional area be proportional to the number of the conductors 13 inserted.

In the unit core 31, each core leg 34 in each unit core 31 is represented by a point 36, 36,..., And in each unit core 31, each hole 35 formed by the base magnetic body 33 and the magnetic body plate 32 is formed. To sides 37, 37
Is modeled as shown in FIG. In this case, inserting the conductor 13 through the hole 35 of the unit core 31 is equivalent to crossing the side 37 of the conductor 13. Then, by traversing once, one unit coil is formed. Therefore, the choke coil 1 in FIG. 1 crosses the side 37 12 times, which is equivalent to a series connection of 12 unit coils 38, 38,... As shown in FIG. Thus, the conductor 13
.. By appropriately changing the number of times the conductor 13 crosses the sides 37, 37.
By changing the number of insertions, the choke coil 1 having various inductance values can be formed.
Also, by appropriately changing the order in which the conductors 13 cross the sides 37, 37, that is, by changing the order in which the conductors 13 pass through the holes 35 in the unit core 31,
A method that allows the conductor 13 to be easily inserted can be adopted. Further, a plurality of conductors 13 can be inserted into the unit core 31 and the plurality of conductors 13 can be connected in parallel. In this case, a choke coil for a large current can be formed.

If only the unit core 31 is used, an opening 39 is inevitably formed as shown in FIG. Therefore, an opening may be formed in the base 11 in FIG. In such a case, when the choke coil 1 is used as a choke coil for a large current, even if a large current flows through the conductor 13 to generate heat, the heat can be radiated to the outside through the opening 39. The conductor 13 is provided in the opening 39.
Is inserted, the conductor 13 is inserted into the closed magnetic circuit composed of the four unit cores 31, 31,..., And in such a case, a unit coil is equivalently formed.

Further, as shown in FIG. 6, a choke coil 43 in which a plurality of core legs 41 are arranged in a row on a long base magnetic body 42 can be formed. In the figure, the illustration of the magnetic plate is omitted. In this case, if the cross-sectional area of the outer core feet 41, 41 is set to a value of 1, the cross-sectional area of the inner core feet 41, 41,. It can be uniform. This is the inner core feet 41, 41
Is because two core feet can be considered to be combined. When the choke coil 43 is further simplified and modeled, as shown in FIG.
This is equivalent to connecting a number of unit coils equal to the number of times crossing 7 in series.

Further, as shown in FIG.
By using 3, 44, 45, 46, and 47, a transformer can be configured. In this case, the conductor 43
Is inserted twice through each of the four holes 48, and each of the conductors 44 to 47 is inserted once through the hole 48, so that the primary coil 51 has eight turns as shown in FIG. Each of the four secondary-side coils 52, 52,... Constitutes a one-turn transformer 53.

Similarly, as shown in FIG. 10, a transformer 65 can be formed by adding other conductors 61, 62, 63 and 64 to the choke coil 1 shown in FIG. 1. FIG. 11 is shown. In this transformer 65, four openings (holes) 67, 67,.
Are formed, and each of the openings 67, 67... Functions as a heat radiating port for releasing heat trapped in the base magnetic body 66. The equivalent circuit is shown in FIG.
Is a 24-turn primary winding 71 corresponding to the conductor 13,
And three turns of secondary windings 72 to 75 corresponding to the conductors 61 to 64, respectively. In this case, the secondary winding can have an arbitrary number of turns according to the number of times the unit core is inserted, and the secondary winding can also have an arbitrary number of turns by using the necessary number of conductors. Can be a number.

As described above, according to the choke coil 1 of the present embodiment, the core foot 12 may be configured to have a height at which the conductor 13 can be inserted, so that the choke coil 1 can be made thinner. it can. In addition, by increasing the number of core feet 12 to increase the number of unit cores 31 and by increasing the number of unit cores 31 inserted by the conductors 13,
A choke coil and a transformer having a large inductance value can be easily formed. Further, in such a case, since the diameter of the conductor to be used can be arbitrarily set, a choke coil and a transformer for a large current can be easily configured.

In the above-described choke coil 1 and the like, a gap may be provided between the core leg 12 and the magnetic plate 3. In such a case, a so-called unsaturated choke coil can be formed, and can be used for a so-called magnetic amplifier and the like. Further, by providing the gap, the inductance value of the conductor 13 (unit coil) inserted into the unit core 31 can be finely adjusted.

Further, the number of the core feet 12 can be arbitrarily determined, and the arrangement thereof can be appropriately changed. Further, the conductor 13 does not need to be inserted through all of the unit cores 31 formed on the base magnetic body 2, and may be inserted as many as a desired inductance value is obtained.
Needless to say, the conductor 13 may be inserted into one unit core 31 a plurality of times.

Next, another embodiment of the inductive element will be described with reference to FIGS.

A transformer 81 shown in FIGS. 13 and 15 includes a base magnetic body 82, a magnetic body plate 83, and printed circuit boards 84 and 85.
And an insulating sheet 86. The base magnetic body 82 has four core feet (columnar magnetic bodies) 87, 8
7 and the walls (wall-shaped magnetic body) 88,
Are set up so as to surround the core feet 87, 87. Four notches 89, 89,... Are formed near the four corners of the base magnetic body 82. Each of the notches 89, 89,.
Are attached, connection terminals 93, 9 described later are provided.
3, 94, 94 function as outlets. on the other hand,
On the printed circuit boards 84 and 85, a printed pattern 91 for the primary coil and a printed pattern 92 for the secondary coil are formed, respectively. The print pattern 91 is coated with a resist to be insulated from other components, and has connection terminals 93, 93 formed at its ends. The printed pattern 92 is also coated with a resist so as to be insulated from other parts, and has a connection terminal 9 at its end.
4, 94 are formed. The connection terminals 93, 93 and 94, 94 are connected to the printed circuit boards 84 and 8, respectively.
5 is formed in a printed pattern on both front and back surfaces, and the printed patterns on both surfaces are electrically connected by through holes 93a, 93a and 94a, 94a. The resist is removed from the connection terminals 93, 93, 94, and 94 so that soldering can be easily performed with other components or a printed pattern on another printed circuit board. Thereby, for example, when the transformer 81 is arranged on another printed board, the connection between the printed patterns and the terminals formed on the printed board and the connection terminals 93, 93, 94, 94 can be made easily and reliably. Can be done. Note that the insulating sheet 86 completes the insulation between the printed board 84 and the printed board 85.
The transformer 81 includes the printed circuit board 8 in the base magnetic body 82.
4. By arranging the insulating sheet 86 and the printed circuit board 85 in that order and attaching the magnetic plate 83, as shown in FIG.
All of the components are built in 3.

Next, an outline of the operation principle of the transformer 81 will be described. The print patterns 91 and 92 are shown in FIG.
As shown in (a) and (b), the core feet 87, 8
.. and a plurality of unit cores formed by the wall portions 88, 88 .. respectively form a plurality of unit coils, and a magnetic coupling between the two printed patterns 91, 92 forms a transformer. Form a primary winding and a secondary winding. In the transformer 81, when the print pattern 91 is inserted through the notches 89, 89,..., One-turn unit coils are respectively formed. On the other hand, the notch 8
Even when the print pattern 92 passes through the unit 9, no unit coil is formed at that portion. This is because the print pattern 92 reciprocates in the unit core, and the magnetic fluxes cancel each other. Further, at the portion indicated by the arrow 96, the printed pattern 91 is inserted between the core legs 87, 87 facing each other obliquely, but the printed pattern 91 reciprocates in the unit core, and the unit coil Is not formed. As shown in FIG. 14, the transformer 81 is equivalently constituted by a 10-turn primary coil 97 and a 4-turn secondary coil 98.

As described above, according to the transformer 81, the walls 88, 88,... Surround the core feet 87, 87,... And the printed patterns 91, 92, so that magnetism does not leak outside. A complete magnetic shielding effect can be obtained. By disposing the printed circuit boards 84 and 85 in the base magnetic body 82, inductive elements such as coils and transformers can be easily manufactured. In this case, a choke coil and a transformer suitable for mass production can be provided. However, the present invention is not limited to this, and an inductive element can be easily formed by disposing a sheet-like conductor formed by punching a copper foil or the like into a predetermined shape in the base magnetic body 82. In addition, when configured as a transformer, a resist is applied to the print patterns 91 and 92 formed on the two printed boards 84 and 85, respectively, or an insulating sheet 86 is provided, so that the primary and primary layers are provided. The secondary circuits can be easily insulated.

In the transformer 81, the secondary coil can be omitted and the coil can be simply formed as a coil. By forming a printed pattern on each of the front and back surfaces of one printed circuit board, the primary coil and the secondary coil can be formed. You may comprise so that a next coil may be formed. Further, the printed boards 84 and 85 may be formed of a flexible printed board, or may be formed of a general paper or glass epoxy board.

[0049]

As described above, the inductive element core and the inductive element according to the present invention have the following effects. Since the cross-sectional area of the core per conductor can be made very small, the inductive element core can be made thin. At the same time, the thickness of the inductive element can be easily reduced. Since many endless cores can be arranged in a plane, by inserting conductors into multiple endless cores, it is possible to easily form an inductive element with a large inductance value, and by inserting a thick conductor. Inductive elements for large power can be easily formed. It is possible to manufacture inductive element cores of various shapes and to manufacture inductive elements of various windings. Further, a large number of independent coils can be formed on one inductive element core, and a transformer having many secondary coils can be formed. When used as a core for high power, the area of the base surface and the surface of the magnetic plate can be increased, so that an inductive element core having an excellent heat dissipation effect can be provided. By stacking a plurality of inductive elements formed using this inductive element core, it becomes possible to form an inductive element having an extremely large inductance value. The conductor can be easily arranged on the columnar magnetic tube without requiring a special winding machine or the like. Compared to a conventional inductive element in which a large number of conductors are wound on the same plane, the conductor length can be substantially shortened, and as a result, an inductive element with less copper loss can be provided. .

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a choke coil according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining the operation principle of the choke coil according to the embodiment of the present invention.

3A is a plan view of a magnetic plate, FIG. 3B is a side view of the magnetic plate, FIG. 3C is a plan view of a base magnetic unit, and FIG. It is a side view of a body part.

FIG. 4 is a diagram modeling the choke coil shown in FIG. 1;

FIG. 5 is an equivalent circuit diagram of the choke coil shown in FIG.

FIG. 6 is a plan view of a choke coil in which core legs are arranged in one row, with a magnetic plate removed.

FIG. 7 is a diagram modeling the choke coil in FIG. 6;

FIG. 8 is an external perspective view of a transformer according to the present embodiment.

FIG. 9 is an equivalent circuit diagram of the transformer shown in FIG.

FIG. 10 is a plan view of the transformer according to the present embodiment with a magnetic plate removed.

11 is an external perspective view of the transformer in FIG.

FIG. 12 is an equivalent circuit diagram of the transformer in FIG.

FIG. 13 is an exploded perspective view of a transformer according to another embodiment.

FIG. 14 is a circuit diagram of the transformer in FIG.

15 is an external perspective view of the transformer in FIG.

16A is a diagram showing a primary winding of the transformer in FIG. 13, and FIG. 16B is a diagram showing a secondary winding of the transformer in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Choke coil 2 Base magnetic body 3 Magnetic body board 4 Printed board 12 Core leg 13 Conductor 39 Opening 43 Choke coil 65 Trans 66 Base magnetic body 67 Opening 81 Trans 82 Base magnetic body 83 Magnetic board 84 Printed board 85 Printed board 91 Print pattern 92 Print pattern

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01F 3/10 H01F 17/04 H01F 27/24

Claims (11)

(57) [Claims] 1. A base magnetic body on which at least four or more columnar magnetic bodies are erected, and magnetically coupled to each of the columnar magnetic bodies arranged opposite to the base magnetic body with the columnar magnetic bodies interposed therebetween. At least the endless core that closes a magnetic path with the base magnetic body, the two columnar magnetic bodies adjacent to each other, and the magnetic body plate. A core for an inductive element, comprising three cores, wherein at least one conductor is inserted through the plurality of endless cores to form an inductive element. 2. The inductive element core according to claim 1, wherein the base magnetic body is formed in a long shape, and the columnar magnetic bodies are erected in one row. 3. The core for an inductive element according to claim 1, wherein the columnar magnetic bodies are provided on the base magnetic body in a plurality of rows each in a vertical and horizontal direction. 4. The core for an inductive element according to claim 1, wherein the columnar magnetic body has a cross section formed in one of a polygon and a circle. 5. The core for an inductive element according to claim 1, wherein a hole is provided in a part of the base magnetic body other than a standing part of the columnar magnetic body. . 6. The inductive element according to claim 1, wherein a hole is provided in a portion of the magnetic plate other than a portion facing the columnar magnetic body. core. 7. The inductive element core according to claim 1, wherein a gap can be formed between the magnetic plate and at least one of the columnar magnetic members. 8. The inductive element core according to claim 1, wherein the base magnetic body includes a wall-shaped magnetic body surrounding the columnar magnetic body. 9. An inductive element comprising: the inductive element core according to claim 1; and at least one conductor penetrating the plurality of endless cores. . 10. The inductive element according to claim 9, comprising a plurality of said conductors, wherein said inductive element is a transformer. 11. The inductive element according to claim 9, wherein the conductor is formed in a sheet shape.