JP2021089910A - Magnetic body core and reactor - Google Patents

Abstract

To provide a magnetic body core and a reactor, which have low loss by suppressing eddy current when a laminated magnetic material is applied, the laminated magnetic material being formed by laminating a thin plate-shaped soft magnetic material on a pot-type core.SOLUTION: A magnetic body core 14 of a reactor 10 includes: an inner core 22 arranged in the center of a coil 12; an outer core 26 arranged outside the coil 12; and connecting members 24A, 24B which are arranged on both ends of the inner core 22 and to which the outer core 26 is connected. The inner core 22 has a first laminate 28 including a plurality of thin plate-shaped magnetic materials and insulation materials alternately laminated therein, and the outer core 26 has a second laminate 34 including a plurality of thin plate-shaped magnetic materials and insulation materials alternately laminated therein. The connecting members 24A, 24B each comprise a magnetic body having a non-directional magnetic path.SELECTED DRAWING: Figure 1

Description

The present invention relates to a magnetic core and a reactor used in a reactor.

Patent Document 1 describes a pot-type core as a magnetic core, which is formed by compressing a powder such as soft magnetic metal powder or ferrite with a mold and covering most of the outer periphery of the coil with an outer core.

JP-A-2017-152539

In a conventional pot-type core as in Patent Document 1, since the inner core and the outer core are integrally molded, the thickness of the inner core around which the coil is wound and the outer core covering the outer peripheral side of the coil becomes thicker. Since eddy currents are likely to be generated, the loss tends to be large.

Therefore, it is conceivable to form the pot-type core with a laminated steel plate. However, when the inner core and the outer core of the pot type core are formed of the laminated steel plate, a magnetic path through which magnetic flux passes in a direction penetrating the laminated surface of the laminated steel plate is generated in a part thereof. Therefore, there is a problem that a portion where the eddy current increases is generated and the goodness of the laminated steel sheet cannot be fully utilized.

An object of the present invention is to provide a magnetic core and a reactor having low loss by suppressing an eddy current when applying a laminated magnetic material in which a thin plate-shaped soft magnetic material is laminated on a pot type core.

One aspect of the present invention is an inner core arranged at the center of the coil, an outer core arranged outside the coil, and a connecting member arranged at both ends of the inner core and connected to the outer core. The inner core has a first laminated body in which a plurality of thin plate-shaped magnetic materials and insulating layers are alternately laminated, and the outer core has a plurality of thin plate-shaped magnetic materials. It has a second laminated body in which a magnetic material and an insulating layer are alternately laminated, and the connecting member is in a magnetic material core in which the magnetic path is made of a non-directional magnetic material.

Another aspect of the present invention is the coil, the inner core arranged in the center of the coil, the outer core arranged outside the coil, and the outer core arranged at both ends of the inner core. The inner core has a first laminated body in which a plurality of thin plate-shaped magnetic materials and insulating layers are alternately laminated, and the outer core is a reactor. It has a second laminated body in which a plurality of thin plate-shaped magnetic materials and insulating layers are alternately laminated, and the connecting member is in a reactor in which the magnetic path is made of a non-directional magnetic material.

According to the magnetic core and the reactor from the above viewpoint, when applying the laminated steel plate to the pot type core, it is possible to prevent the generation of a portion through which the magnetic flux passes in the direction penetrating the laminated steel plate, and suppress the eddy current to reduce the loss. Can be reduced.

It is a perspective sectional view of the reactor which concerns on 1st Embodiment of this invention. It is a perspective view of the magnetic core of FIG. FIG. 3 is an exploded perspective view of a part of the magnetic core of FIG. FIG. 4A is a perspective view of the magnetic material core according to the second embodiment, and FIG. 4B is a perspective view showing a modified example of the outer magnetic material of FIG. 4A. It is an exploded perspective view of the magnetic core which concerns on 3rd Embodiment. It is an exploded perspective view of the magnetic core which concerns on 4th Embodiment.

Hereinafter, preferred embodiments of the present invention will be mentioned and described in detail with reference to the accompanying drawings.

(First Embodiment)
As shown in FIG. 1, the reactor 10 according to the present embodiment is composed of a coil 12 and a magnetic core 14 that forms a magnetic path around the coil 12. The reactor 10 is an element used as an inductor of a power supply circuit of, for example, a step-up / step-down converter, and is mounted on an electric vehicle, a hybrid vehicle, or the like.

The coil 12 includes a frame member 16 and a winding 18 housed in the frame member 16. The frame member 16 is a ring-shaped member having a hollow portion 16a penetrating in the axis A direction, and includes a winding accommodating portion 20 having a U-shaped cross section opened on the outer peripheral side. The winding 18 is configured by winding a wiring material such as a copper wire around the winding accommodating portion 20, and generates magnetic poles at one end and the other end in the axis A direction in the drawing.

As shown in FIG. 2, the magnetic core 14 has an inner core 22 arranged in a hollow portion 16a at the center (center portion) of the coil 12 and a connection arranged at one end and the other end of the inner core 22, respectively. It includes members 24A and 24B, and an outer core 26 that is arranged so as to cover the outside of the coil 12 and forms a magnetic path connecting one connecting member 24A and the other connecting member 24B.

The inner core 22 includes two rectangular parallelepiped block-shaped magnetic bodies 28 (first laminated body). These block-shaped magnetic bodies 28 are arranged with each other via a gap 30 having a predetermined width. The gap 30 is provided to prevent magnetic saturation, and is composed of, for example, a non-magnetic and insulating member such as a resin. The width of the gap 30 is appropriately set according to the value of the current flowing through the coil 12.

As shown in FIG. 3, the block-shaped magnetic material 28 is formed in a rectangular shape when viewed from the axis A direction, and a plurality of rectangular thin plates 32 made of a soft magnetic material and an insulating layer 65 are alternately laminated. It is made of a formed laminated magnetic material (for example, a laminated steel plate). In the block-shaped magnetic material 28, the thin plate 32 and the insulating layer 65 are alternately laminated in a direction in which the main surface thereof is parallel to the magnetic flux passing direction (direction of the axis A) in order to prevent the occurrence of loss due to eddy current. .. Examples of the soft magnetic material constituting the thin plate 32 include an electromagnetic steel plate (silicon steel plate), permalloy, and an amorphous soft magnetic alloy. Examples of the insulating material constituting the insulating layer 65 include an organic varnish coating and an enamel coating.

As shown in FIG. 1, a connecting member 24A is joined to one end (upper end in the drawing) of the inner core 22 in the axial direction A direction, and a connecting member 24B is joined to the other end (lower end in the drawing) of the inner core 22. There is. A gap 30 made of a non-magnetic insulating material is provided between the connecting member 24A and the block-shaped magnetic body 28 and between the connecting member 24B and the block-shaped magnetic body 28, if necessary. The connecting members 24A and 24B are square plate-shaped members having the same dimensions as the block-shaped magnetic body 28 when viewed in a plan view from the axis A direction, and together with the inner core 22, form a prismatic structure.

The connecting members 24A and 24B are made of a non-directional soft magnetic material having no directionality in the magnetic path. This soft magnetic material is obtained by solidifying a plurality of granular soft magnetic materials into a bulk shape via a non-magnetic insulator, and has a structure finely divided by a non-directional non-magnetic insulator. ing. The connecting members 24A and 24B have isotropic magnetic characteristics, and the granular soft magnetic material is finely divided by the insulator, so that the generation of eddy current can be prevented. Specifically, as the material of the connecting members 24A and 24B, a green compact obtained by compression-molding powders such as iron, iron-silicon alloy, sendust or ferrite, a sintered body obtained by sintering these powders, and the like are used. be able to.

As shown in FIG. 2, the outer core 26 is composed of a plurality of outer magnetic materials 34 (second laminated body). The outer magnetic body 34 is formed in a C shape having bent portions formed at right angles. One outer magnetic body 34 is provided on each of the four side surfaces of the connecting members 24A and 24B, and the outer magnetic body 34 projects in four directions at a distance of 90 ° in the circumferential direction when viewed from the axis A direction. The four outer magnetic bodies 34 of the outer core 26 cover the majority of the outer circumference of the coil 12.

In the present embodiment, each outer magnetic body 34 is divided into two in the axis A direction, and is composed of two L-shaped blocks 36. The L-shaped block 36 is formed by alternately laminating a thin plate 38 of a soft magnetic material formed into an L shape and an insulating layer 70 in the thickness direction. The thin plate 38 is made of the same material as the thin plate 32 constituting the block-shaped magnetic material 28.

Next, the outline of the manufacturing method of the magnetic core 14 will be described. As shown in FIG. 3, the connecting member 24A (or the connecting member 24B) is joined to one end of the block-shaped magnetic body 28, and the L-shaped block 36 is further joined to the four side sides of the connecting member 24A to join the magnetic body. Assemble the structure 40 that constitutes half of the core 14. Each member is joined with an adhesive. Further, if necessary, a gap 30 made of a resin member or the like may be provided between the block-shaped magnetic body 28 and the connecting member 24A.

Next, another set of the structures 40 shown in FIG. 3 is created, and the pair of structures 40 are assembled from above and below the coil 12 (see FIG. 1) to complete the reactor 10 shown in FIG.

Hereinafter, the operation of the magnetic core 14 and the reactor 10 using the magnetic core 14 will be described.

When a current flows through the coil 12 of the reactor 10 of FIG. 1, a magnetic field is generated, and magnetic poles are generated at one end and the other end of the inner core 22. The magnetic flux of the inner core 22 flows into the outer magnetic body 34 via the connecting members 24A and 24B provided at one end and the other end. At that time, as shown by arrows in FIG. 2, in the connecting members 24A and 24B, magnetic flux passes in four directions toward the arrangement direction of the outer magnetic body 34.

In such a case, if the structure is such that all parts are laminated with a thin plate-shaped magnetic material like a conventional pot-type core, magnetic flux passes through the thin plate in two of the four directions. Therefore, an eddy current is generated in the in-plane direction of the thin plate, and the loss becomes large.

On the other hand, in the reactor 10 of the present embodiment, the connecting members 24A and 24B provided at both ends of the inner core 22 are made of a magnetic material having no directionality in the magnetic path, so that any of the four directions can be obtained. Also, the generation of eddy current can be prevented and the loss can be reduced. Thereby, even when the laminated magnetic material is applied to the pot type core in which the majority of the outer circumference of the coil 12 is covered with the outer core 26, the loss can be reduced.

The reactor 10 of the present embodiment has the following effects.

The magnetic core 14 used for the reactor 10 is attached to the inner core 22 via the inner core 22 around which the coil 12 is wound, the connecting members 24A and 24B arranged at the ends of the inner core 22, and the connecting members 24A and 24B. An outer core 26 that is connected and covers at least a part of the outer side of the coil 12 is provided, and the inner core 22 and the outer core 26 are made of a laminated magnetic material in which a thin plate-shaped soft magnetic material and an insulating material are laminated, and are a connecting member. 24A and 24B are made of a soft magnetic material having no magnetic path directionality. As a result, the loss due to the eddy current in the connecting members 24A and 24B can be reduced.

In the above magnetic material core 14, the connecting members 24A and 24B may be made of a magnetic material obtained by molding a powder of a soft magnetic material. Thereby, the connecting members 24A and 24B having no directionality of the magnetic path can be easily manufactured.

In the magnetic core 14, the connecting members 24A and 24B may be provided so as to project in the axial direction with respect to the coil 12. Since the portion protruding in the axial direction with respect to the coil 12 corresponds to the connecting portion with the outer magnetic body 34, the generation of eddy current can be prevented by using the connecting members 24A and 24B in this portion.

In the magnetic core 14, the connecting members 24A and 24B may be formed to have the same size as the inner core 22 when viewed from the axial direction of the coil 12. With such a configuration, the range occupied by the laminated magnetic material can be increased in the magnetic path, and the merit of low loss of the laminated magnetic material can be utilized.

In the above magnetic body core 14, the outer core 26 is composed of a plurality of outer magnetic bodies 34 formed in a C shape when viewed from the side, and the outer magnetic body 34 is viewed from a plurality of directions when viewed from the axial direction of the coil 12. It may be connected to the connecting members 24A and 24B. With this configuration, the majority of the outer circumference of the coil 12 can be covered with the outer core 26, so that the inductance of the reactor 10 becomes high and miniaturization becomes possible.

By providing the above-mentioned magnetic material core 14, the reactor 10 of the present embodiment reduces the loss due to eddy current when applying a laminated magnetic material in which thin plate-shaped soft magnetic materials and insulating materials are alternately laminated on a pot-type core. Can be made to.

(Second Embodiment)
As shown in FIG. 4A, the magnetic core 14A of the present embodiment has the outer magnetic body 34 divided into two in that the outer core 26 is integrally formed of the C-shaped outer magnetic body 34A. It is different from the magnetic core 14 (see FIG. 2). In the magnetic core 14A, the configurations other than the outer core 26 are the same as those of the magnetic core 14 of FIG. 2, so the same reference numerals are given to the same configurations and detailed description thereof will be omitted.

The outer magnetic material 34A is made of a laminated magnetic material in which thin plates 42 of soft magnetic material formed in a C shape and insulating layers 75 are alternately laminated. Since the outer magnetic material 34A is made of a laminated magnetic material, the direction orthogonal to the passage direction of the magnetic flux is divided into thin plates, so that the generation of eddy current can be prevented. Further, the number of parts can be reduced as compared with the outer magnetic body 34 formed by combining the L-shaped blocks 36 of the first embodiment, and the structure is simplified.

The outer magnetic material 34A according to the present embodiment is not limited to the above example, and both ends of the thin plate 42 made of a soft magnetic material are bent in the thickness direction as in the outer magnetic material 34B shown in FIG. 4B. As a result, it may be formed in a C shape, and a plurality of the insulating layers 75 may be alternately laminated. Even in such a configuration, the generation of eddy current can be prevented by finely dividing the direction orthogonal to the passage direction of the magnetic flux into a thin plate shape.

(Third Embodiment)
As shown in FIG. 5, in the magnetic core 14B of the present embodiment, the shapes of the connecting members 44A and 44B provided at both ends of the inner core 22 and the shape of the outer core 46 are the magnetic core 14 of FIG. 1 Embodiment) is different. In the magnetic core 14B of the present embodiment, the same components as those of the magnetic core 14 of FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

The connecting member 44A is a plate-shaped member formed in a rectangular shape having a size larger than that of the inner core 22 (block-shaped magnetic body 28) when viewed from the axis A direction, and protrudes to the outside of the inner core 22. The outer peripheral portion of the connecting member 44A extends to the outside of the outer circumference of the coil 12 shown in FIG. The connecting member 44B provided at the other end of the inner core 22 is formed to have the same shape and dimensions as the connecting member 44A. The connecting members 44A and 44B of the present embodiment can be made of the same material as the connecting members 24A and 24B.

The outer core 46 includes four outer magnetic bodies 48, and these outer magnetic bodies 48 form a wall shape surrounding the peripheral edge of the magnetic body core 14B. The outer magnetic material 48 is formed by alternately laminating a plurality of thin plates 50 of a soft magnetic material formed in a rectangular shape and an insulating layer 80, and is configured as a rectangular plate-shaped member when viewed from the side. The outer magnetic body 48 is joined between one connecting member 44A and the other connecting member 44B to form a magnetic path between them. The outer magnetic body 48 may be joined to the outer surface 44a of the connecting members 44A and 44B. Further, the outer magnetic body 48 is not limited to the four separated plate-like structures, and may be integrally formed in a rectangular tubular shape.

In the magnetic core 14B of the present embodiment, the reactor 10 is provided by arranging the coil 12 (see FIG. 1) in the space formed between the four outer magnetic bodies 48 and the block-shaped magnetic body 28. Can be configured.

In the magnetic core 14B of the present embodiment configured as described above, the connecting members 44A and 44B are formed to have a size larger than that of the block-shaped magnetic body 28 of the inner core 22, and are outside the coil 12 (see FIG. 1). The outer core 46 is formed in a wall shape so as to cover the outer peripheral portion of the coil 12, and is connected to the peripheral portions of the connecting members 44A and 44B. In this case, the outer core 46 of the magnetic core 14B has a simple shape, which facilitates manufacturing.

(Fourth Embodiment)
As shown in FIG. 6, the magnetic core 14C of the present embodiment relates to a modified example in which the magnetic core 14B (third embodiment) of FIG. 5 is formed in a columnar shape. In the magnetic core 14C of the present embodiment, the same components as those of the magnetic core 14B of FIG. 5 are designated by the same reference numerals, and detailed description thereof will be omitted.

In the magnetic core 14C, the connecting member 52A is a disk-shaped member formed in a circle having a size larger than that of the inner core 22 (block-shaped magnetic body 28) when viewed from the axis A direction, and is outside the inner core 22. It protrudes into. The outer peripheral portion of the connecting member 52A extends to the outside of the outer circumference of the coil 12 shown in FIG. The connecting member 52B provided at the other end of the inner core 22 is formed in a disk shape having the same dimensions as the connecting member 52A. The connecting members 52A and 52B of the present embodiment can be made of the same magnetic material as the connecting members 24A and 24B described with reference to FIG.

The outer core 54 is formed in a cylindrical shape that can be joined to the peripheral edges of the connecting members 52A and 52B. The outer magnetic body 56 constituting the outer core 54 is formed by alternately laminating a plurality of thin plates 58 of a soft magnetic material formed in a cylindrical shape and an insulating layer 85 in the radial direction. The outer magnetic body 56 is joined between one connecting member 52A and the other connecting member 52B to form a magnetic path connecting the connecting members 52A and 52B. It should be noted that the connecting members 52A and 52B may be configured to be joined from the outside of the outer surface 52a. Further, a notch 60 for pulling out the wire rod of the coil 12 is provided in a part of the outer magnetic body 56 in the circumferential direction.

The magnetic core 14C of the present embodiment configured as described above has the same effect as the magnetic core 14B described with reference to FIG.

Although the present invention has been described above with reference to preferred embodiments, it goes without saying that the present invention is not limited to the above-described embodiments and various modifications can be made without departing from the spirit of the present invention. No.

10 ... Reactor 12 ... Coil 14, 14A, 14B, 14C ... Magnetic core 22 ... Inner core 24A, 24B, 44A, 44B, 52A, 52B ... Connecting members 26, 46, 54 ... Outer core 28 ... Block-shaped magnetic material 30 ... Gap 32, 38, 42, 50, 58 ... Thin plate 34, 34A, 34B, 48, 56 ... Outer magnetic material 65, 70, 75, 80, 85 ... Insulating layer

Claims (5)

With the inner core located in the center of the coil,
An outer core arranged outside the coil and
A connecting member arranged at both ends of the inner core and connecting the outer core,
It is a magnetic core equipped with
The inner core has a first laminated body in which a plurality of thin plate-shaped magnetic materials and insulating layers are alternately laminated.
The outer core has a second laminated body in which a plurality of thin plate-shaped magnetic materials and insulating layers are alternately laminated.
The connecting member is a magnetic core made of a magnetic material whose magnetic path is non-directional. The magnetic core according to claim 1, wherein the connecting member is made of a green compact or a sintered body obtained by molding a powder of a soft magnetic material. The magnetic core according to claim 2, wherein the outer core includes a plurality of the second laminated bodies, and the plurality of the second laminated bodies are the connecting members from a plurality of directions when viewed from the axial direction of the coil. A magnetic core that is connected to. The magnetic core according to claim 3, wherein the second laminated body is a C-shaped magnetic core. With the coil
An inner core located in the center of the coil and
An outer core arranged outside the coil and
A connecting member arranged at both ends of the inner core and to which the outer core is connected,
It is a reactor equipped with
The inner core has a first laminated body in which a plurality of thin plate-shaped magnetic materials and insulating layers are alternately laminated.
The outer core has a second laminated body in which a plurality of thin plate-shaped magnetic materials and insulating layers are alternately laminated.
The connecting member is a reactor in which the magnetic path is made of a non-directional magnetic material.

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