JP2022063373A - Magnetic core unit, and noise filter using the same - Google Patents

Abstract

To provide a magnetic unit which can suppress reduction in magnetic characteristics due to a stress caused by shrinkage in curing of an adhesive used in fixation of a magnetic core while surely obtaining a fixation force of the magnetic core in a case, and a noise filter using the same.SOLUTION: A magnetic core unit has: a resin case that is formed by combining a plurality of case members 10 and 20 and has a plurality of annular space parts arranged in the same axial line direction; and annular magnetic cores 5 stored in each of the annular space parts of the resin case, in which each of the case members has a plurality of projections 71 projecting in the axial line direction in the annular space parts. The annular magnetic cores are wound bodies around which an Fe group amorphous alloy strip or an Fe group nanocrystal alloy strip is around, and that has an end face facing an inner periphery and an outer periphery, the annular magnetic cores and the resin case are bonded and fixed to each other so that a surface where the projections of the case member are formed and the end faces of the annular magnetic cores face each other, and a through hole is provided on the inner peripheral side of the annular magnetic cores.SELECTED DRAWING: Figure 2

Description

The present invention relates to a magnetic core unit having a plurality of annular magnetic cores covered with a resin case, and a noise filter such as a choke coil using the magnetic core unit.

Bus bars (bar-shaped thick plate copper plates) are used for paths where relatively large currents exceeding 100 A flow, such as between the in-vehicle charging circuit of hybrid and electric vehicles and an external power supply, or between an AC motor and a power supply circuit. Is used. Since the current flowing through the bus bar becomes a source of noise, in consideration of the influence on peripheral electronic devices, a magnetic core is arranged in the current path, and a noise filter is configured through the bus bar. In such a noise filter, a magnetic core unit in which the circumference of the magnetic core is covered with a resin member is used so as to insulate the bus bar from the magnetic core or other members.

Although the form of the magnetic core unit varies, Patent Document 1 discloses a noise filter having a core case structure in which annular magnetic cores are coaxially overlapped. As shown in FIG. 17, a resin case including an upper core case 510, a lower core case 530, an intermediate core case 520, and a connecting member 700, and a plurality of magnetic cores 610 housed in an annular storage portion formed in the resin case, It is composed of 620. A slit groove is provided on the inner peripheral side of the upper core case 510 and the lower core case 530, and the connecting member 700 is fitted therein and connected together with the intermediate core case 520, and the magnetic cores 610 and 620 are connected to the annular storage portion. It has a core case structure that houses. The depth of the annular storage portion corresponds to the thickness of the magnetic cores 610 and 620, and the upper core case 510, the lower core case 530 and the intermediate core case 520 sandwich the magnetic cores 610 and 620 and fix the whole. ing.

JP-A-2017-152549

In the path where a relatively large current flows, a metal-based magnetic material having a higher saturation magnetic flux density than ferrite is selected as the magnetic material of the magnetic core used for the noise filter. For example, Fe-based amorphous alloys and Fe-based nanocrystalline alloys are often used. A noise filter using an annular magnetic core in which a thin band of an Fe-based amorphous alloy or Fe-based nanocrystalline alloy (hereinafter, may be referred to as an alloy thin band) is wound in a ring shape is used in a wide frequency range of several kHz to several MHz. It is easy to obtain high impedance, and it is suitable for preventing malfunction of in-vehicle electronic devices due to noise in automobiles in which a vehicle control system that performs data communication between a plurality of electronic control devices by an in-vehicle LAN (Local Area Network) is adopted. Is.

On the other hand, magnetic materials of Fe-based amorphous alloys and Fe-based nanocrystalline alloys are characterized by large magnetostriction, sensitivity to impact and stress, and their thin bands being brittle. Therefore, in the method of pressing and holding the magnetic core of the annular storage portion with the core case as in the conventional noise filter, deterioration of magnetic characteristics such as an increase in coercive force and a decrease in magnetic permeability may occur. Further, if the pressing force is insufficient, the magnetic core moves in the annular storage portion, and there is a risk that the magnetic core itself will be damaged due to a collision with the core case.

Therefore, the core case and the magnetic core are adhesively fixed by making the annular storage portion substantially the same as or thicker than the thickness of the magnetic core. However, even when the magnetic core is fixed by adhesion, there still remains a problem that stress is applied to the magnetic core due to shrinkage due to the curing of the adhesive, and the magnetic characteristics are deteriorated to some extent. Details will be described later, but the problem may become remarkable especially in a structure using a plurality of magnetic cores such as the conventional noise filter shown in Patent Document 1.

Therefore, the present invention is a magnetic core unit capable of suppressing deterioration of magnetic characteristics due to stress caused by shrinkage during curing of the adhesive while obtaining a fixing force of the magnetic core in the case by an adhesive, and noise using the unit. The purpose is to provide a filter.

The first invention comprises a resin case configured by combining a plurality of case members and having a plurality of annular spaces arranged in the same axial direction, and an annular magnetic core accommodated in each of the annular spaces of the resin case. Each of the case members is provided with a plurality of protrusions protruding in the axial direction in the annular space portion, and the annular magnetic core is wound with a Fe-based amorphous alloy ribbon or an Fe-based nanocrystal alloy strip. It is a wound body having an inner circumference and an end surface facing the outer circumference, which is rotated, and the annular magnetic core and the resin so that the surface on which the protrusion of the case member is formed and the end surface of the annular magnetic core face each other. It is a magnetic core unit in which a case is adhesively fixed and at least two of the annular magnetic cores are arranged side by side.

It is preferable that the magnetic core unit of the present invention has a through hole on the inner peripheral side of the annular magnetic core, and the through hole is partitioned in the axial direction by a partition portion formed by a plurality of case members.

In the magnetic core unit of the present invention, the resin case includes a first case member and a second case member, and each of the first case member and the second case member has a groove-shaped cross section cut in the axial direction. The first case member has an opening, the first case member has one groove-shaped opening that opens in the axial direction, and the second case member opens in the axial direction and opens in opposite directions to each other. It has two groove-shaped openings, and the second case member is combined with the two first case members, and the groove-shaped opening of the first case member and the groove-shaped opening of the second case member are combined. It is preferable to combine the portions to form two annular accommodating portions.

In the magnetic core unit of the present invention, it is preferable that both ends of the resin case in the axial direction are honeycomb structures.

The second invention is a noise filter composed of the magnetic core unit of the first invention and a plurality of bus bars, in which the bus bar is passed through the through hole of the magnetic core unit.

According to the present invention, a magnetic core unit capable of suppressing deterioration of magnetic properties due to stress caused by shrinkage during curing of the adhesive while obtaining a fixing force of the magnetic core in the case by an adhesive and a magnetic core unit thereof are used. A noise filter can be provided.

It is a perspective view of the magnetic core unit which concerns on one Embodiment of this invention. It is an exploded perspective view of the magnetic core unit shown in FIG. It is a perspective view of the noise filter using the magnetic core unit shown in FIG. 1. It is a front view of the 1st case member used for the magnetic core unit which concerns on one Embodiment of this invention. FIG. 4 is a partial cross-sectional view taken along the line b—b'of the lower surface of the first case member shown in FIG. It is a rear view of the 1st case member shown in FIG. It is a partial cross-sectional view of the b-b'line of the right side surface of the 1st case member shown in FIG. FIG. 7 is an enlarged view of part A of the first case member shown in FIG. 7. It is a front view of the 2nd case member used for the magnetic core unit which concerns on one Embodiment of this invention. FIG. 9 is a partial cross-sectional view taken along the line c-c'of the lower surface of the second case member shown in FIG. FIG. 9 is a partial cross-sectional view taken along the line c-c'of the right side surface of the second case member shown in FIG. FIG. 11 is an enlarged view of a portion B of the second case member shown in FIG. It is a perspective view of the annular magnetic core used for the magnetic core unit which concerns on one Embodiment of this invention. It is a front view of the magnetic core unit which concerns on one Embodiment of this invention. FIG. 14 is a partial cross-sectional view taken along the line aa'of the lower surface of the magnetic core unit shown in FIG. FIG. 14 is a partial cross-sectional view taken along the line aa'of the right side surface of the magnetic core unit shown in FIG. It is an exploded perspective view of the conventional noise filter.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to this. In the present specification, as a relative positional relationship in the description of the structure, one direction may be described as the upper side and the opposite direction may be described as the lower side with reference to the drawings, but this is a common positional relationship between the drawings. It does not indicate the direction. In addition, in some or all of the figures, structural parts that are not necessary for explanation are omitted, and some parts are enlarged and shown for ease of explanation. Unless otherwise specified, the shapes and the like shown in the explanations are not limited to those explanations, drawings and the like. Further, in the description, members of the same or the same quality are shown with the same name and reference numeral, and detailed description may be omitted even if the figures are shown.

FIG. 1 is a perspective view showing an embodiment of a magnetic core unit, and FIG. 2 is an exploded perspective view thereof. As shown in the figure, the magnetic core unit 1 of the present embodiment has an oval pillar shape having a plane facing the z-axis direction and a curved surface facing the x-axis direction on the side surface. With such a shape, the plane of the magnetic core unit 1 is arranged so as to face the xy plane, so that a noise filter having a low profile in the z-axis direction can be obtained. Two first case members 10 are arranged in the y-axis direction of the magnetic core unit 1, and a second case member 20 is arranged between the first case members 10. Each of the first case member 10 and the second case member 20 is made of a resin material and is formed by a known method such as an injection molding method. In the illustrated example, the first case members 10 located on both ends of the magnetic core unit 1 have the same structure, but may be different.

Circular magnetic cores 5 are arranged on both sides of the second case member 20 in the y-axis direction. Although the details will be described later, the annular magnetic core 5 is housed in an annular space formed by combining the first case member 10 and the second case member 20, and is adhered to the first case member 10 and the second case member 20, respectively. It is adhesively fixed by the agent. The first case member 10 and the second case member 20 have a structure including a protrusion protruding inward in the annular space portion.

The alloy strips constituting the annular magnetic core 5 have larger waviness as they are made wider, and the space factor of the magnetic core using such alloy strips tends to decrease. It is known that the decrease in space factor affects the impedance characteristics of the noise filter. Therefore, in the magnetic core unit of the present embodiment, the magnetic path cross-sectional area is secured and the magnetic core is secured by using a plurality of annular magnetic cores 5 using the alloy thin strips having small waviness obtained by cutting the wide alloy strips. It prevents a decrease in the space factor of the noise filter and prevents deterioration of the characteristics of the noise filter, such as not being able to obtain a high impedance at a predetermined frequency.

In the magnetic core unit 1 configured by combining each member, the annular space portion is closed by the first case member 10 and the second case member 20, and the annular magnetic core 5 housed in the annular space portion does not appear on the surface in appearance. .. Both ends of the magnetic core unit 1 in the y-axis direction are honeycomb structure portions 110 formed as an aggregate of a row of holes formed by a plurality of bottomed holes 111 and 112 formed in the first case member 10. Here, the hole shape in the honeycomb structure is not limited to the hexagonal shape. Further, the magnetic core unit 1 is formed with two through holes 131 and 132 on the inner peripheral side of the annular magnetic core 5 through which a bus bar partitioned by a partition portion 141 is passed.

FIG. 3 is an external perspective view of the noise filter according to the embodiment of the present invention. The noise filter includes a magnetic core unit 1 and bus bars 101 and 102. The bus bars 101 and 102 are passed through the through holes 131 and 132 partitioned by the partition portion 141 of the magnetic core unit 1 so that the surface directions are the same. The through holes 131 and 132 of the magnetic core unit 1 allow the bus bars 101 and 102 to be easily positioned and arranged. Further, since the spatial distance between the bus bars 101 and 102 is determined by the partition portion 141, electrical insulation can be easily secured. Further, since the annular magnetic core 5 is arranged in the annular space portion closed by the first case member 10 and the second case member 20, it is easy to secure the electrical insulation between the bus bars 101 and 102 and the annular magnetic core 5.

In the illustrated noise filter, both ends of the bus bars 101 and 102 are arranged at equal intervals and extend linearly. The form of the bus bars 101 and 102 is not limited to that, and can be transformed into various forms as long as they can pass through the through holes 131 and 132 of the magnetic core unit 1. For example, the ends of the bus bars 101 and 102 may be bent, for example, they may be formed in an L shape so that the distance between the bus bars 101 and 102 is widened on at least one end side of the magnetic core unit 1.

The space in which the noise filter is placed is often limited, and there is always a demand for the noise filter to be compact. When trying to make the noise filter compact, the magnetic core unit 1 and the bus bars 101 and 102 are naturally close to each other. When the bus bars 101 and 102 are energized and a large current flows, the bus bars generate heat due to copper loss due to resistance and become hot, so that the magnetic core unit 1 adjacent to the bus bars 101 and 102 also tends to be hot.
If the magnetic core unit 1 becomes extremely hot, the first case member 10 and the second case member 20 may be thermally damaged. Further, there is a difference in the coefficient of linear expansion between the case members 10 and 20, the annular magnetic core 5 and the adhesive for fixing them, and the stress applied to the annular magnetic core 5 changes due to the dimensional change due to the difference in the linear expansion coefficient with the temperature change. The magnetic characteristics may deteriorate. Further, the adhesive fixing of the annular magnetic core 5 may be released, and the annular magnetic core 5 may fall off in the annular space portion. To solve such a problem, the magnetic core unit 1 of the present embodiment has a honeycomb structure at the end to increase the surface area and improve heat dissipation. As a result, the temperature rise can be suppressed, and damage to the case member and deterioration of the magnetic characteristics can be prevented.

As shown in FIGS. 1 and 2, the magnetic core unit of the present embodiment is composed of two types of case members, a first case member and a second case member, and an annular magnetic core. Each structure and material will be explained in detail.

(Structure of first case member)
4 is a front view of the first case member, FIG. 5 is a partial cross-sectional view of the lower surface of the first case member along the b-b'line, FIG. 6 is a rear view thereof, and FIG. 7 is a b-b on the right side surface thereof. 'It is a partial cross-sectional view taken along the line, and FIG. 8 is a partially enlarged view of a protrusion provided on the first case member.
The first case member 10 is formed with two through holes 55 and 56 arranged side by side through a partition portion 51 provided in the center thereof. The shapes of the through holes 55 and 56 are not particularly limited as long as they do not obstruct the passage of the bus bar, but since the cross sections of the bus bars 101 and 102 are rectangular, in the illustrated example, one of the arcs is cut off. It is an oval.

When the first case member 10 is viewed from the upper surface side, the annular bottom plate portion 53 appears around the through holes 55 and 56. As shown in FIGS. 4 and 5, the inner and outer edges have an inner tubular wall and an outer tubular wall that extend concentrically upward, and the upper end side is open. There is. The inner cylindrical wall constitutes a part of the inner side wall portion 81 of the first case member 10, and the outer cylindrical wall constitutes a part of the outer wall portion 91. A bottomed annular space 63 (opening) is formed by the inner side wall portion 81 (inner tubular wall), the outer wall portion 91 (outer tubular wall), and the annular bottom plate portion 53. As shown in FIGS. 5 and 7, the bottomed annular space 63 has a groove-shaped cross section that appears in a cross section cut in the penetrating direction of the through holes 55 and 56. The depth is set according to the thickness (height) of the annular magnetic core 5, and at least a part of the annular magnetic core 5 in the height direction can be accommodated. In the illustrated example, the upper end of the partition portion 51 has the same height as the inner side wall portion 81 and the outer wall portion 91 and is formed flat, but may have different heights.

Further, the annular bottom plate portion 53 of the bottomed annular space 63 is provided with a plurality of protrusions 71 protruding toward the opening side. With the protrusion 71, the end surface 8 of the annular magnetic core accommodated in the bottomed annular space 63 can be opposed to each other at least by the height of the protrusion 71 without directly contacting one surface of the annular bottom plate portion 53. .. The shape of the protrusion 71 is not particularly limited, such as a circle or a polygon. In the examples shown in FIGS. 4 and 8, the protrusion 71 has a disk shape with a flat upper end side, but if the area in contact with the end surface 8 of the annular magnetic core 5 is to be reduced, a hemispherical shape or a truncated cone shape is used. It may be formed in a tapered shape. Further, the shape that can be seen from the upper surface side may be a ring shape or a form divided into a plurality of parts. In the illustrated example, the protrusions 71 are axisymmetrically provided at four positions, but the annular magnetic cores may be formed at at least two or more positions at predetermined intervals so that the annular magnetic cores can be stably arranged.

A honeycomb structure portion 110 is formed on the lower surface side of the first case member 10. The honeycomb structure 110 is the lower part of the bottomed annular space 63, and includes a plurality of bottomed holes 111, 112 provided in multiple layers around the through holes 55, 56. The shapes of the bottomed holes 111 and 112 are not particularly limited. The bottomed holes 111 adjacent to the through holes 55 and 56 and the bottomed holes 112 surrounding them are provided between the radial wall portions connected to the inner side wall portion 81 and the outer wall portion 91 and the bottomed holes 111 and 112. It is partitioned by a wall, which increases the surface area and ensures strength.

(Structure of second case member)
9 is a front view of the second case member, FIG. 10 is a partial cross-sectional view taken along the c-c'line of the lower surface thereof, and FIG. 11 is a partial cross-sectional view taken along the c-c' line on the right side thereof. FIG. 12 is a partially enlarged view of a protrusion provided on the second case member. Since the back surface of the second case member appears in the same manner as the front view, it is omitted.
The second case member 20 is formed with two through holes 57 and 58 arranged side by side through a partition portion 52 provided in the center thereof. The form of the through holes 57 and 58 is the same as that of the through holes 55 and 56 of the first case member 10, and the shape and the like are not limited as long as they do not obstruct the passage of the bus bar.

When the second case member 20 is viewed from the upper surface side, the annular bottom plate portion 54 appears around the through holes 57 and 58. As shown in FIG. 10, the inner edge portion and the outer edge portion have an inner tubular wall and an outer tubular wall extending concentrically upward, and the upper end side is open. The inner cylindrical wall constitutes a part of the inner side wall portion 82 of the second case member 20, and the outer cylindrical wall constitutes a part of the outer wall portion 92. A bottomed annular space 64 (opening) is formed by the inner side wall portion 82 (inner tubular wall), the outer wall portion 92 (outer tubular wall), and the annular bottom plate portion 53. As shown in FIGS. 10 and 11, the bottomed annular space 64 has a groove-shaped cross section in the cross section in the penetrating direction of the through holes 57 and 58. The depth is set according to the thickness (height) of the annular magnetic core 5, and at least a part of the annular magnetic core 5 in the height direction can be accommodated. In the illustrated example, the depth is almost the same as the height of the annular magnetic core.

A step 32 is provided on the upper end side of the inner side wall portion 82 and the outer wall portion 92 over the entire circumference, and is shaped to receive the upper end side of the inner side wall portion 82 and the outer wall portion 92 of the first case member 10. In the illustrated example, the upper end of the partition portion 52 is located lower than the inner side wall portion 82 and the outer wall portion 92, is formed flat, and has the same height as the lower end of the step 32. It should be noted that the position may be different from the lower end of the step 32 according to the structure of the first case member 10.

As shown in FIGS. 11 and 12, the annular bottom plate portion 54 of the bottomed annular space 64 is provided with a plurality of protrusions 72 protruding toward the opening side. With the protrusion 72, the end face 8 of the annular magnetic core accommodated in the bottomed annular space 64 can be opposed to each other at least by the height of the protrusion 72 without directly contacting the annular bottom plate portion 54. The shape of the protrusion 72 is the same as that of the protrusion 71 of the first case member 10. The number of formations, positions, dimensions, and the like may be the same as or different from those of the protrusion 71.

Although not shown, on the back surface of the second case member 20, an annular bottom plate portion 54 appears around the through holes 57 and 58, as when viewed from the front side. The structure seen from the back side is the same as the front side, so the description is omitted. The second case member 20 has two groove-shaped bottomed annular spaces 64 that open in opposite directions in the penetrating directions of the through holes 57 and 58, and the bottomed annular space 64 is the same via the partition wall 59. It has a structure formed in parallel in the direction. In the second case member 20 formed by injection molding, a draft of about 0.5 to 2 ° is provided on the inner side wall on the bottomed annular space 64 side. As a result, the bottomed annular space 64 becomes wider on the opening side and narrower on the annular bottom plate portion 54 side, and the difference increases as the depth increases, and the outer shape of the second case member 20 tends to increase. In the magnetic core unit of the present embodiment, the depth of each of the bottomed annular spaces 64 of the second case member 20 is made shallow. As a result, the influence of the draft on the external dimensions can be reduced, and the volume ratio effective for accommodating the annular magnetic core 5 in the bottomed annular space 64 can be increased.

The first case member 10 and the second case member 20 are preferably formed of a resin having excellent insulating properties, heat resistance, and moldability, and specifically, polyphenylene sulfide, liquid crystal polymer, polyethylene terephthalate, and polybutylene terephthalate. , Nylon 66 and the like are preferable.

(Circular magnetic core)
FIG. 13 is a perspective view showing the appearance of the annular magnetic core. A wound body having an inner peripheral surface 6 and an end surface 8 facing the outer peripheral surface 7 wound with a Fe-based amorphous alloy thin band or an Fe-based nanocrystalline alloy thin band, and the end face 8 of the annular magnetic core 5 has a thin band. It is a laminated surface that appears by stacking. As the Fe-based amorphous alloy strip, it is preferable to have a saturation magnetic flux density Bs of 1.4 T or more. For example, a Fe-based amorphous alloy strip such as Fe—Si—B system represented by Metglass® 2605SA1 material can be used. Further, a composition such as Fe—Si—B—C system or Fe—Si—B—C—Cr system containing other elements can be adopted. A part of Fe may be replaced with Co, Ni or the like. As an example of the alloy composition of the Fe-based amorphous alloy ribbon used in the embodiment of the present invention, Fe _a Si _b B _{c Cd Me} (where M is selected from the group consisting of Cr, Mo, Mn, Zr and Hf). At least one element, 50 ≦ a ≦ 90, 2 ≦ b ≦ 15, 5 ≦ c ≦ 30, 0 ≦ d ≦ 3, 0 ≦ e ≦ 10, a + b + c + d + e = 100). What is preferred. The alloy composition is not particularly limited to this, and can be selected according to the required characteristics.

The Fe-based nanocrystal alloy strip has a saturation magnetic flux density Bs of 1.2 T or more, and is preferable. Specifically, for example, Fe-based nanocrystals such as Fe-Si-B-Cu-Nb-based, Fe-Cu-Si-B-based, Fe-Cu-B-based, and Fe-Ni-Cu-Si-B-based. Amorphous alloy strips for alloys can be used. Alloys in which some of these elements are substituted, and alloys to which other elements are added may be used. As an example of the alloy composition used in the embodiment of the present invention, Fe _100-xy A _x X _y (where A is Cu and / or Au, X is B, Si, S, C, P, Al, Ge). , B, Sn, Nb, Mo and at least one element selected from the group consisting of Cr), and is preferably represented by 0 <x ≦ 5, 10 ≦ y ≦ 24 in atomic%. Further, a part of Fe may be replaced with Ni or Co, and the replacement amount is preferably 5 or less in atomic%. The nanocrystal is a microcrystal structure having a particle size of 100 nm or less.

(Magnetic core unit)
FIG. 14 is a front view showing a state in which the first case member and the second case member are combined, FIG. 15 is a partial cross-sectional view taken along the aa'line of the lower surface thereof, and FIG. It is a partial cross-sectional view of a'line. Since the configuration shown in FIG. 14 is the same as the back surface of the first case member 10 shown in FIG. 6, the description thereof will be omitted. Further, the annular magnetic core is also omitted from each figure, and the positional relationship of each member will be described with reference to FIGS. 1 and 2.

As shown in FIG. 15, the second case member 20 is combined so as to be located in the center and the first case member 10 is located above and below the second case member 20. Since the inner cylindrical wall and the outer cylindrical wall of the first case member 10 are fitted into the step 32 of the second case member 20, the inner peripheral edge 151 and the outer peripheral 152 of the magnetic core unit 1 can be formed substantially without a step. I can.

When the first case member 10 and the second case member 20 are combined, the through holes 55 and 57 and the through holes 56 and 58 communicate with each other to form the through holes 131 and 132 of the magnetic core unit 1. Further, the partition portion 51 of the first case member 10 and the partition portion 52 of the second case member 20 are connected to form the partition portion 141 of the magnetic core unit 1. Further, a plurality of annular space portions 161 arranged in the same axial direction are formed by the bottomed annular space 63 and the bottomed annular space 64 of each case member, and the annular magnetic core 5 is arranged in each of them as shown in FIG. ..

Projecting portions 71 and 72 project from the annular space portion 161 so as to face the end portion 8 of the annular magnetic core 5. In the state where the first case member 10 and the second case member 20 are combined, the interval w determined by the upper ends of the protrusions 71 and 72 is wider than the height h of the annular magnetic core 5 (w> h), and the annular magnetic core 5 is pressed. I try not to attach it. Further, at the time of assembly, the protrusions 71 and 72 limit the movement of the annular magnetic core 5 in the annular space portion 161. However, the distance w between the protrusions 71 and 72 is +0. If the upper limit is 5 mm (0 <wh ≦ 0.5), the amount of movement of the annular magnetic core 5 can be further limited, which is preferable.

(How to make a magnetic core unit)
Next, an example of a method for manufacturing the magnetic core unit 1 will be described. First, the second case member 20 is vertically placed so that the bottomed annular space 64 appears vertically. Next, after applying a predetermined amount of adhesive on the surface of the annular bottom plate portion 54, the annular magnetic core 5 is housed in the bottomed annular space 64. Further, the first case member 10 to which a predetermined amount of adhesive is applied to the annular bottom plate portion 53 is combined so as to cover the annular magnetic core 5 from above (first step). Subsequently, the top and bottom of the magnetic core unit being assembled is reversed, a predetermined amount of adhesive is applied to the other annular bottom plate portion 54 of the second case member 20, and then another annular magnetic core 5 is provided in the bottomed annular space 64. Store in. Then, another first case member 10 to which a predetermined amount of adhesive is applied to the annular bottom plate portion 53 is combined so as to cover the annular magnetic core 5 from above (second step). Next, the adhesive is cured to bond and fix the case members 10 and 20 and the annular magnetic core 5 (third step) to complete the magnetic core unit 1. The adhesive is not particularly limited as long as each member can be bonded, but a thermosetting adhesive can be used, and among them, a silicon adhesive or an epoxy-based adhesive having a viscosity that does not easily lean on a vertical surface is preferable.

Since the adhesive is uncured in the middle of assembly, the annular magnetic core 5 can be easily moved and sinks in the annular space 161 due to its own weight in the vertical installation state. For example, in the state where the second step is completed, the annular magnetic core 5 in the upper annular space portion 161 is offset toward the annular bottom plate portion 54 side of the second case member 20, and the annular magnetic core in the lower annular space portion 161 is offset. 5 may be offset toward the annular bottom plate portion 53 side of the first case member 10. When the protrusions 71 and 72 protruding from the annular space portion 161 are not provided, one of the end faces 8 of the annular magnetic core 5 abuts on one surface of the annular bottom plate portion 53 and the annular bottom plate portion 54, and the intervening adhesive is the annular magnetic core 5. It tends to be thinly wet and spread on the end face 8. On the other end surface 8 side, the space between the annular bottom plate portion 53 and the annular bottom plate portion 54 is widened, and the adhesive area tends to be insufficient. In such a state, after the adhesive is cured, the annular magnetic core 5 is easily affected by the stress caused by the shrinkage of the adhesive during curing, the magnetic properties are deteriorated, the adhesion is insufficient, and the fixing force is reliable. It may not be obtained.

On the other hand, by providing the protrusions 71 and 72 protruding into the annular space portion 161 even if the annular magnetic core 5 in the annular space portion 161 is offset at the time of assembly, the end surface 8 of the annular magnetic core 5 and the annular bottom plate portion 53 or the annular bottom plate are provided. A space is secured between the annular bottom plate portion 54 and the end surface 8 of the annular magnetic core 5 does not come into contact with the annular bottom plate portion 53 or the annular bottom plate portion 54. Since the applied adhesive is accumulated in the space, even if the annular magnetic core 5 moves between the protrusions 71 and 72, it is possible to prevent the adhesive from being unnecessarily wet and spread on the end surface 8 of the annular magnetic core 5. Further, by limiting the amount of movement of the annular magnetic core 5 between the protrusions 71 and 72, it is possible to prevent the adhesive area of the end surface 8 of the annular magnetic core 5 from being insufficient. As a result, it is possible to surely obtain a fixing force between the annular magnetic core 5 and each of the case members 10 and 20, while suppressing a decrease in magnetic properties due to stress caused by shrinkage during curing of the adhesive.

Further, by limiting the amount of movement of the annular magnetic core 5 and reducing the kinetic energy given to the annular magnetic core 5 even if the annular magnetic core 5 is loosened after bonding, the annular magnetic core 5 is inside the annular space portion 161. It is possible to prevent the case from colliding with the inner wall of the case and being damaged.

1 Magnetic core unit 5 Circular magnetic core 10 1st case member 20 2nd case member 71, 72 Protrusions 161 Circular space 101, 102 Bus bar

Claims (5)

It has a resin case configured by combining a plurality of case members and having a plurality of annular spaces arranged in the same axial direction, and an annular magnetic core accommodated in each of the annular spaces of the resin case.
Each of the case members is provided with a plurality of protrusions protruding in the axial direction in the annular space portion.
The annular magnetic core is a wound body having an inner circumference and an end face facing the outer circumference, which is wound with a Fe-based amorphous alloy ribbon or a Fe-based nanocrystalline alloy strip.
The annular magnetic core and the resin case are adhesively fixed so that the surface on which the protrusion of the case member is formed and the end surface of the annular magnetic core face each other.
A magnetic core unit in which at least two of the annular magnetic cores are arranged side by side. The magnetic core unit according to claim 1.
It has a through hole on the inner peripheral side of the annular magnetic core and has a through hole.
A magnetic core unit in which the through hole is partitioned in the axial direction by a partition portion formed by a plurality of case members. The magnetic core unit according to claim 1 or 2.
The resin case includes a first case member and a second case member.
Each of the first case member and the second case member has an opening having a groove-shaped cross section cut in the axial direction.
The first case member has one groove-shaped opening that opens in the axial direction.
The second case member has two groove-shaped openings that open in the axial direction and open in opposite directions.
The second case member is combined with the two first case members, and the groove-shaped opening of the first case member and the groove-shaped opening of the second case member are combined to form two annular housing portions. The configured magnetic core unit. The magnetic core unit according to any one of claims 1 to 3.
A magnetic core unit having a honeycomb structure on both ends of the resin case in the axial direction. A noise filter composed of the magnetic core unit according to any one of claims 1 to 4 and a plurality of bus bars.

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