JP2020120136A - Reactor - Google Patents

Abstract

To provide a reactor excellent in heat dissipation.SOLUTION: In a reactor including a coil having a wound part, a magnetic core having an inner core part placed in the wound part, and an inner inclusion member for ensuring insulation between the wound part and the inner core part, the inner inclusion member includes a thin wall part which is made thin as the inner peripheral surface is recessed, and a thick part thicker than the thin wall part. The inner core part is provided, on the outer peripheral surface facing the inner inclusion member, a core side protrusion having a shape copying the inner peripheral surface shape of the thin wall part. The thickness of the thick part is 0.2-1.0 mm, the thickness of the thick wall part is 1.1-2.5 mm, the inner core part and the inner inclusion member adhere substantially, and there is a clearance at least partially between the inner inclusion member and the wound part.SELECTED DRAWING: Figure 3

Description

The present invention relates to a reactor.

For example, Patent Documents 1 and 2 disclose a reactor which is a magnetic component used in a converter of an electric vehicle such as a hybrid vehicle. The reactors of Patent Documents 1 and 2 include a coil having a pair of winding portions, a magnetic core partially disposed inside the winding portion, and a bobbin (insulating interposition) that ensures insulation between the coil and the magnetic core. Members).

JP 2012-253289 A JP, 2013-4531, A

With the development of electric vehicles in recent years, it is required to improve the performance of the reactor. For example, it is required to suppress the change in the magnetic characteristics of the reactor due to heat trapped in the reactor by increasing the heat dissipation of the reactor. Further, the reactor is required to be small and have excellent magnetic characteristics. In order to meet such demands, the structure of the reactor is being reexamined.

Therefore, one of the objects of the present disclosure is to provide a reactor having excellent heat dissipation. Another object of the present disclosure is to provide a compact reactor having excellent magnetic characteristics.

The reactor according to the present disclosure is
A coil having a winding portion,
A magnetic core having an inner core portion arranged inside the winding portion;
A reactor including an inner intervening member that secures insulation between the winding portion and the inner core portion,
The inner intervening member includes a thin-walled portion whose thickness is reduced by recessing the inner peripheral surface side thereof, and a thick-walled portion whose thickness is thicker than the thin-walled portion,
The inner core portion is provided with a core-side convex portion having a shape along the inner peripheral surface shape of the thin portion on the outer peripheral surface facing the inner interposing member,
The thickness of the thin portion is 0.2 mm or more and 1.0 mm or less, the thickness of the thick portion is 1.1 mm or more and 2.5 mm or less,
The inner core portion and the inner interposition member substantially come into close contact with each other,
There is a clearance in at least a part between the inner interposition member and the winding portion.

The reactor has excellent heat dissipation. Further, the reactor is small and has excellent magnetic characteristics.

1 is a schematic perspective view of a reactor including a coil having a pair of winding parts shown in Embodiment 1. FIG. FIG. 3 is an exploded perspective view of the reactor combination shown in the first embodiment. FIG. 3 is a sectional view taken along line III-III in FIG. 1 and a partially enlarged view thereof. FIG. 4 is a partially enlarged view showing a positional relationship between an inner interposition member having an interposition side recess different from that of FIG. 3, and an inner core portion and a winding portion arranged inside and outside thereof. FIG. 3 is a schematic perspective view of an inner core portion shown in the first embodiment. It is a schematic perspective view of the inner core part different from FIG.

[Description of Embodiments of the Present Invention]
First, embodiments of the present invention will be listed and described.

The inner interposed member is often formed by injection molding. The dimensions of the injection-molded product tend to vary as the thickness of the inner intervening member decreases. Therefore, conventionally, the thickness of the inner intervening member is set to a certain value or more (for example, 2.5 mm or more), or ribs are provided on the inner intervening member as described in Patent Documents 1 and 2 to measure the size of the inner interposing member. The accuracy is being improved. However, with such a configuration, the distance between the winding portion and the inner core portion becomes large. Therefore, there is a restriction on the heat dissipation from the inner core portion to the winding portion, and when the cross-sectional area of the winding portion is constant, the magnetic path cross-sectional area of the inner core portion arranged inside the winding portion is It cannot be increased beyond a certain level. In view of these points, the inventors of the present invention have completed a reactor according to the following embodiment.

<1> The reactor according to the embodiment,
A coil having a winding portion,
A magnetic core having an inner core portion arranged inside the winding portion;
A reactor including an inner intervening member that secures insulation between the winding portion and the inner core portion,
The inner intervening member includes a thin-walled portion whose thickness is reduced by recessing the inner peripheral surface side thereof, and a thick-walled portion whose thickness is thicker than the thin-walled portion,
The inner core portion is provided with a core-side convex portion having a shape along the inner peripheral surface shape of the thin portion on the outer peripheral surface facing the inner interposing member,
The thickness of the thin portion is 0.2 mm or more and 1.0 mm or less, the thickness of the thick portion is 1.1 mm or more and 2.5 mm or less,
The inner core portion and the inner interposition member substantially come into close contact with each other,
There is a clearance in at least a part between the inner interposition member and the winding portion.

When the inner intervening member is made by injection molding that injects resin into the mold, the resin injected into the mold with wide gaps is thick, and the resin injected into the mold with narrow gaps is thin. It becomes a part. The wide gap between the molds serves to quickly spread the resin throughout the gap between the molds. Therefore, even if a thin portion having a thickness smaller than that of a conventional one is provided, an inner intervening member having a thick portion having a predetermined thickness or more can be easily manufactured according to a design dimension. In order to make the inner interposition member substantially adhere to the outer periphery of the inner core unit, resin is molded on the inner core unit or the inner core unit is pressed into the inner interposition member. In any case, since the inner intervening member can be manufactured in accordance with the designed dimensions, the inner intervening member can be substantially in close contact with the outer periphery of the inner core portion. Here, even when resin is molded on the inner core portion or when the inner core portion is press-fitted into the inner interposition member, a separated portion may be formed at a part of the interface between the inner core portion and the inner interposition member. Therefore, even if there is a separation part in a part of the interface, if the total area of the separation part occupying the entire interface is small (for example, 40% or less, or 20% or less), the inner core portion and the inner interposition member It is considered that and are in close contact with each other.

If the inner intervening member has a small dimensional variation, the inner intervening member cannot be inserted into the winding part even if the inner interposing member is designed so that the clearance between the inner intervening member and the winding part is small. Can be suppressed.

By making the clearance small, the distance from the inner core portion to the winding portion can be made small, and the heat dissipation from the inner core portion to the winding portion can be improved. Moreover, since the inner core portion and the inner interposition member are substantially in close contact with each other, the thermal conductivity between them is good, and the heat dissipation from the inner core portion to the winding portion can be improved. In particular, in the reactor of the embodiment, since the core-side convex portion of the inner core portion is arranged in the recess of the thin-walled portion (hereinafter, also referred to as intervening-side concave portion), the core-side convex portion to the winding portion The heat dissipation distance is short, and as a result, the heat dissipation of the reactor can be improved.

Further, since the clearance can be reduced, the magnetic path cross-sectional area of the inner core portion in the winding portion can be increased without increasing the winding portion. In particular, in the reactor of the embodiment, the core side convex portion of the inner core portion is arranged in the interposing side concave portion of the inner interposing member, so that the magnetic path cross-sectional area of the inner core portion is large. Therefore, the magnetic path cross-sectional area of the inner core portion can be made larger than that of the reactor using the conventional inner intervening member having no intervening recess without changing the size of the winding portion.

Further, the configuration of the embodiment has an advantage that the magnetostrictive vibration of the inner core portion can be easily suppressed by the inner interposing member that is in close contact with the outer periphery of the inner core portion.

<2> As one mode of the reactor according to the embodiment,
An example is a form in which the inner intervening member is made of resin molded outside the inner core portion.

When the inner core part is placed in the mold and resin is molded on the outside of the inner core part to form the inner interposition member, in a place where there is a large gap between the outer peripheral surface of the inner core part and the inner peripheral surface of the mold. The injected resin becomes a thick portion, and the resin injected into a portion where the gap between the molds is narrow becomes a thin portion. By forming the inner intervening member by resin-molding the inner core portion, the inner core portion and the inner interposing member can be reliably brought into close contact with each other. Moreover, since the inner core portion and the inner interposition member can be handled integrally, the productivity of the reactor can be improved.

<3> As one mode of the reactor according to the embodiment,
An example is a form in which the difference between the thickness of the thin portion and the thickness of the thick portion is 0.2 mm or more.

By setting the difference between the thin-walled portion and the thick-walled portion to be 0.2 mm or more, it is possible to more sufficiently secure the resin filling property in the narrow portion of the mold corresponding to the thin-walled portion, and also the dimensional variation of the inner intervening member. Can be made smaller.

<4> As one mode of the reactor according to the embodiment,
The thin portion may have a thickness of 0.2 mm or more and 0.7 mm or less, and the thick portion may have a thickness of 1.1 mm or more and 2.0 mm or less.

By setting the thickness of the thin portion within the above range, the distance between the winding portion and the core-side convex portion of the inner core portion can be sufficiently shortened, and the heat dissipation of the reactor can be further improved. Further, by setting the thickness of the thick portion within the above range, it is possible to further reduce the dimensional variation of the inner interposition member.

<5> As one form of the reactor according to the embodiment,
The thick part and the thin part may be distributed in the circumferential direction of the inner interposition member and exist in plural.

In the mold for producing the inner intervening member having the above configuration, when the resin is injected, the resin easily spreads over the entire gap of the die, and it is easy to produce the inner intervening member having small dimensional variation. That is, the inner interposition member having the above configuration is an inner interposition member having a small variation in size, and can improve the heat dissipation and magnetic characteristics of the reactor. In particular, if the narrow gap portion and the wide gap portion are alternately arranged in the circumferential direction of the gap for injecting the resin in the mold, the resin is even more easily spread over the entire gap of the mold. With such a mold, it is possible to manufacture an inner interposition member in which thick-walled portions and thin-walled portions are alternately arranged in the circumferential direction of the inner intervening member with high dimensional accuracy.

<6> As one mode of the reactor according to the embodiment,
At least a part of the thick portion may reach the end surface of the inner interposing member in the axial direction of the winding portion.

When the inner intervening member is manufactured by injection molding, the resin is often injected from a position which is an end surface of the inner interposing member in the mold. In this case, since the end surface of the inner intervening member serves as the resin inlet, the formability of the inner intervening member is improved if the resin has a large gap corresponding to the thick portion. Here, when an inner interposition member having a thick portion reaching the end surface of the inner interposition member is produced, a portion having a wide gap corresponding to the thick portion is formed at the resin inlet. Therefore, the inner interposition member having the above-described configuration has excellent formability and can be accurately manufactured even if the thin portion has a small thickness.

<7> As one mode of the reactor according to the embodiment,
The outer peripheral surface of the inner interposition member may have a shape that follows the shape of the inner peripheral surface of the wound portion.

If the outer peripheral surface of the inner intervening member has a shape that conforms to the inner peripheral surface shape of the winding portion, there is almost no gap between the inner intervening member and the winding portion, and the outer peripheral surface of the inner interposing member and the winding portion It is easy to reduce the clearance with the inner surface. As a result, it is easy to improve the heat dissipation and magnetic properties of the reactor.

<8> As one mode of the reactor according to the embodiment,
An example is a mode in which the thickness of the inner interposition member gradually increases from the thin portion to the thick portion.

The formability of the inner intervening member can be improved by adopting a configuration in which the thickness of the inner intervening member gradually increases from the thin portion to the thick portion. Examples of the configuration in which the thickness gradually increases from the thin portion to the thick portion include, for example, a curved surface from the thin portion to the thick portion, or an inclined surface. The above-mentioned configuration improves the moldability of the inner intervening member because when the inner intervening member is injection-molded, the resin injected into the thick-walled portion of the mold easily flows into the thin-walled portion. Because it will be.

<9> As one mode of the reactor according to the embodiment,
The form which the said clearance formed between the said inner side interposition member and the said winding part is more than 0 mm and 0.3 mm or less can be mentioned.

When the clearance is more than 0 mm and 0.3 mm or less, the heat dissipation and magnetic characteristics of the reactor can be further improved.

[Details of Embodiment of Present Invention]
Hereinafter, embodiments of the reactor of the present invention will be described with reference to the drawings. The same reference numerals in the drawings indicate the same names. It should be noted that the present invention is not limited to the configurations shown in the embodiments, and is shown by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

<Embodiment 1>
<<Overall structure>>
The reactor 1 shown in FIG. 1 includes a combined body 10 in which a coil 2, a magnetic core 3, and an insulating interposition member 4 are combined. One of the characteristics of this reactor 1 is that the shape of a part of the insulating intervening member 4 (the inner intervening member 41 in FIGS. 2 and 3 described later) is different from the conventional one. First, each configuration of the reactor 1 will be briefly described with reference to FIGS. 1 and 2, and then, the shape of the inner interposition member 41, the inner interposition member 41, and the magnetic core 3 and the winding portions 2A and 2B arranged inside and outside thereof. The relationship with and will be described in detail with reference to FIGS.

<< coil >>
The coil 2 in the present embodiment includes a pair of winding parts 2A and 2B arranged in parallel, and a connecting part 2R connecting the winding parts 2A and 2B. Both ends 2a, 2b of the coil 2 are pulled out from the winding portions 2A, 2B and connected to a terminal member (not shown). Through this terminal member, an external device such as a power supply for supplying power to the coil 2 is connected. The winding parts 2A and 2B provided in the coil 2 of this example are formed in a substantially rectangular tube shape with the same number of turns and the same winding direction, and are arranged in parallel so that the respective axial directions are parallel to each other. The number of turns and the cross-sectional area of the windings may be different between the winding parts 2A and 2B. Further, the connecting portion 2R of this example is formed by joining the ends of the windings of the winding portions 2A and 2B to each other by welding, crimping, or the like. The coil 2 may be formed by spirally winding a single winding having no joint.

The coil 2 including the winding portions 2A and 2B is a covered wire having an insulating coating made of an insulating material on the outer periphery of a conductor such as a rectangular wire or a round wire made of a conductive material such as copper, aluminum, magnesium, or an alloy thereof. Can be configured by. In the present embodiment, the conductor is made of copper rectangular wire, and the coated rectangular wire whose insulating coating is made of enamel (typically polyamide imide) is edgewise wound to form the winding portions 2A and 2B. There is.

≪Magnetic core≫
As shown in FIG. 2, the magnetic core 3 of this example can be divided into inner core portions 31 and 31 and outer core portions 32 and 32. The inner core portion 31 is a portion arranged inside the winding portions 2A and 2B of the coil 2, and is inside the inner interposition member 41, which will be described later in this example, and is in a position not visible in FIG. The inner core portion 31 of the present example is configured by combining two divided ones. Here, the inner core portion 31 means a portion of the magnetic core 3 along the axial direction of the winding portions 2A and 2B of the coil 2. For example, the part projecting from the inside of the winding parts 2A and 2B to the outside of the end face is also a part of the inner core part 31. The overall schematic shape of the inner core portion 31 is a shape corresponding to the internal shape of the winding portion 2A (2B), and in the case of this example, it is a substantially rectangular parallelepiped shape.

An uneven shape is formed on the outer peripheral surface of the inner core portion 31 of this example. The uneven shape of the outer peripheral surface of the inner core portion 31 corresponds to the inner peripheral surface shape of the inner interposition member 41 described later. The detailed configuration of the concavo-convex shape will be described later with reference to FIGS.

The outer core portion 32 is a portion arranged outside the winding portions 2A and 2B, and has a shape that connects the end portions of the pair of inner core portions 31 and 31. Each outer core portion 32 of this example is formed in a rectangular parallelepiped shape. The lower surface of the outer core portion 32 is substantially flush with the lower surfaces of the winding portions 2A and 2B of the coil 2 (see FIG. 1). Of course, both lower surfaces do not have to be flush with each other.

Both core portions 31 and 32 can be formed of a molded body of a composite material containing soft magnetic powder and resin. The soft magnetic powder is an aggregate of magnetic particles composed of an iron group metal such as iron and its alloys (Fe-Si alloy, Fe-Si-Al alloy, Fe-Ni alloy, etc.). An insulating coating made of phosphate or the like may be formed on the surface of the magnetic particles. Examples of the resin include thermosetting resins such as epoxy resin, phenol resin, silicone resin and urethane resin, polyamide (PA) resin such as polyphenylene sulfide (PPS) resin, nylon 6 and nylon 66, polyimide resin, fluorine. A thermoplastic resin such as a resin can be used.

The content of the soft magnetic powder in the composite material may be 50% by volume or more and 80% by volume or less, based on 100% of the composite material. When the magnetic powder is 50% by volume or more, the ratio of the magnetic component is sufficiently high, so that the saturation magnetic flux density is easily increased. When the content of the magnetic powder is 80% by volume or less, the fluidity of the mixture of the magnetic powder and the resin is high, and the composite material having excellent moldability can be obtained. The lower limit of the content of the magnetic powder may be 60% by volume or more. Further, the upper limit of the content of the magnetic powder is 75% by volume or less, and further 70% by volume or less.

Unlike the present example, both core portions 31 and 32 may be formed of a powder compact formed by pressure-molding a raw material powder containing soft magnetic powder. As the soft magnetic powder, the same soft magnetic powder that can be used for the molded body of the composite material can be used. One of the inner core portion 31 and the outer core portion 32 may be a molded body of a composite material, and the other may be a powder compact.

<<Insulating material>>
The insulating intervening member 4 is a member that ensures insulation between the coil 2 and the magnetic core 3, and is interposed between the inner peripheral surfaces of the winding portions 2A and 2B and the outer peripheral surface of the inner core portion 31. The inner intervening members 41, 41 and the end intervening member 42 interposed between the end faces of the winding portions 2A, 2B and the outer core portion 32 are included. In this example, the insulating intervening member 4 is used in the form of a pair of mold core members 5A and 5B integrated with the inner core portion 31. The mold core members 5A and 5B of this example may have the same shape, and the mold core member 5A on the side where the ends 2a and 2b of the winding portions 2A and 2B are arranged and the connecting portion 2R are arranged. The shape may be different from that of the mold core member 5B on the side.

The mold core members 5</b>A and 5</b>B are a combination of a pair of inner core portions 31, a pair of inner intervening members 41 and 41 that cover the outer circumference of each inner core portion 31, and a frame-shaped end face interposing member 42. It is a π-shaped member. In the production of the mold core members 5A and 5B in which the inner core portion 31 is arranged in the mold and the resin is injected into the mold to form the inner interposition member 41 and the end surface interposition member 42, the inner circumference of the mold A positioning member that separates the inner core portion 31 from the surface and determines the position of the inner core portion 31 in the mold is used. Therefore, in the mold core members 5A and 5B, the positioning member is embedded in the inner interposition member 41, that is, the positioning member constitutes a part of the inner interposition member 41. In view of this point, the positioning member is preferably made of an insulating resin. More preferably, in order to make the coefficient of thermal expansion of the inner interposition member 41 uniform, the entire inner interposition member 41 including the positioning member is made of the same type of insulating resin.

On the surface of the end surface interposing member 42 on the coil 2 side, two turn accommodating portions 42s (especially see the mold core member 5B) for accommodating the axial ends of the winding portions 2A and 2B are formed. The turn accommodating portion 42s is a recess along the shape of the axial end faces of the winding portions 2A and 2B, and is formed to bring the entire end face into surface contact with the end face interposing member 42. Further, a partition portion 42d that is arranged between the winding portions 2A and 2B and that separates the winding portions 2A and 2B is provided on the surface of the end face interposing member 42 on the coil 2 side.

Here, in the mold core members 5A and 5B of this example, the inner intervening members 41 and 41 and the end face interposing member 42 are integrally molded, and the portion indicated by the two-dot chain line of the mold core member 5A is the inner interposing member. 41 and 41.

The insulating intervening member 4 having the above-described configuration is, for example, PPS resin, polytetrafluoroethylene (PTFE) resin, liquid crystal polymer (LCP), PA resin such as nylon 6 or nylon 66, polybutylene terephthalate (PBT) resin, acrylonitrile butadiene. It can be composed of a thermoplastic resin such as styrene (ABS) resin. Alternatively, the insulating intervening member 4 can be formed of a thermosetting resin such as unsaturated polyester resin, epoxy resin, urethane resin, or silicone resin. The resin may contain a ceramics filler to improve the heat dissipation of the insulating interposition member 4. As the ceramic filler, for example, non-magnetic powder such as alumina or silica can be used.

≪Other configurations≫
Although the reactor 1 of this example has a caseless structure, the combination 10 may be arranged inside the case.

<<Relationship between the inner interposing member and the inner core portion and the winding portion>>
FIG. 3 is a III-III cross-sectional view orthogonal to the axial direction of the winding portions 2A and 2B in FIG. In FIG. 3, illustration of the connecting portion 2R is omitted. Further, in FIG. 3, the shape and clearance of each member are exaggerated.

As shown in the enlarged view of the circle in FIG. 3, the inner interposition member 41 has a plurality of interposition side recesses 411 formed on the inner peripheral surface 410 thereof. The inner interposition member 41 includes a thin portion 41a having a smaller thickness due to the inner peripheral surface 410 being recessed by the interposition concave portion 411, and a thick portion 41b having a larger thickness than the thin portion 41a.

The shape of the inner peripheral surface of the interposition side recess 411 in a cross section orthogonal to the extending direction of the interposition side recess 411 (the same as the axial direction of the winding portions 2A and 2B in the paper depth direction of FIG. 3) is not particularly limited. For example, as shown in FIG. 3, the shape of the inner peripheral surface of the interposition side recess 411 can be a semi-circular shape, or can be a substantially rectangular shape as shown in FIG. In addition, the inner peripheral surface shape of the interposition side concave portion 411 may be a V groove shape or a dovetail groove shape.

The thickness t1 of the thin portion 41a is 0.2 mm or more and 1.0 mm or less, and the thickness t2 of the thick portion 41b is 1.1 mm or more and 2.5 mm or less. Here, the thickness t1 of the thin portion 41a is the thickness of the portion corresponding to the deepest position of the interposition side recess 411, that is, the minimum thickness of the thin portion 41a, as shown in FIGS. .. The thickness t1 of the thin portion 41a is obviously thinner than the thickness (for example, 2.5 mm) of the conventional inner intervening member having a uniform thickness. In addition, the thickness t2 of the thick portion 41b is the maximum thickness in the portion where the interposition side recess 411 does not exist.

When the inner interposition member 41 having the above-described configuration is formed on the outer periphery of the inner core portion 31 by injection molding, the gap between the injection molding die and the inner core portion 31 (hereinafter, the die gap) is injected into a wide area. The thick resin portion 41b serves as the thick portion 41b, and the resin injected into the portion having a narrow gap between the molds serves as the thin portion 41a. The wide gap between the molds serves to quickly spread the resin throughout the gap between the molds. Therefore, even if the inner intervening member 41 including the thin-walled portion 41a having a smaller thickness than the conventional one is provided with the thick-walled portion 41b having a predetermined thickness or more, the inner intervening member 41 can be easily manufactured according to the design dimension, and the entire inner periphery of the inner core portion 31 The inner interposition member 41 can be brought into a substantially close contact state. If the dimensional variation of the inner intervening member 41 is small, the inner intervening member 41 can be designed so that the outer clearance c2 between the inner intervening member 41 and the winding portions 2A and 2B becomes small. Even if the outer clearance c2 is reduced, the dimensional accuracy of the inner interposition member 41 is high, and therefore the problem that the inner interposition member 41 cannot be inserted into the winding portions 2A and 2B hardly occurs.

Considering the formability of the inner interposition member 41, it is preferable that the plurality of interposition side recesses 411 are dispersed and exist in the circumferential direction of the inner peripheral surface 410 of the inner interposition member 41. In other words, this configuration is a configuration in which there are a plurality of thick-walled portions 41b and thin-walled portions 41a dispersed in the circumferential direction of the inner interposition member 41. In the mold for manufacturing the inner interposition member 41, a portion having a narrow gap and a portion having a wide gap are alternately arranged in the circumferential direction of the gap for injecting the resin in the mold. With such a mold, when the resin is injected, the resin easily spreads over the entire gap of the mold, and it is easy to manufacture the inner interposition member 41 having small dimensional variation. In particular, if the thin portion 41a and the thick portion 41b are arranged along the axial direction of the inner interposition member 41 as in this example, it is easier to fill the resin into the mold during molding.

Further, in consideration of the formability of the inner interposition member 41, it is preferable that at least a part of the thick portion 41b reaches the end surface of the inner interposition member 41 in the axial direction of the winding portions 2A and 2B. It is preferable that the entire thick portion 41b reaches the end surface of the inner interposition member 41 shown in FIG. When the inner interposition member 41 is manufactured by injection molding, resin is often injected from a position which is an end surface of the inner interposition member 41 in the mold. In this case, if the gap between the molds at the resin inlet is large, the moldability of the inner interposition member 41 is improved. That is, the inner interposition member 41 including the thick portion 41b reaching the end surface of the inner interposition member 41 has excellent formability and can be accurately manufactured even if the thin portion 41a has a small thickness.

On the other hand, the inner core portion 31 arranged inside the inner interposition member 41 includes a core-side convex portion 311 formed on its outer peripheral surface (core outer peripheral surface 319) (see also FIG. 5). In this example, since the inner core member 31 is molded with the inner interposition member 41, the interposition side recess 411 formed on the inner peripheral surface 410 of the inner interposition member 41 is formed in a shape corresponding to the core side projection 311. As described above, the thin portion 41a of the inner interposition member 41 in which the interposition side recess 411 is formed is thinner than the conventional inner interposition member having a uniform thickness. Therefore, the magnetic path cross-sectional area of the inner core portion 31 including the core-side convex portion 311 arranged in the intervening-side concave portion 411 is certainly larger than that of the conventional inner core portion by the core-side convex portion 311.

It is preferable that the outer peripheral surface 419 of the inner interposition member 41 has a shape along the inner peripheral surface shape of the winding portions 2A and 2B. By doing so, it is easy to reduce the outer clearance c2 between the outer peripheral surface 419 of the inner interposing member 41 and the coil inner peripheral surfaces 210 of the winding portions 2A and 2B. Specifically, it is easy to set the outer clearance c2 to more than 0 mm and 0.3 mm or less. By making the outer clearance c2 small, the distance from the inner core portion 31 to the winding portions 2A, 2B can be made small, the heat dissipation from the inner core portion 31 to the winding portions 2A, 2B can be improved, and the inner side can be improved. The magnetic path cross-sectional area of the core portion 31 can be increased. Ease of inserting the inner interposition member 41 into the winding portions 2A and 2B, an effect of improving heat dissipation from the inner core portion 31 to the winding portions 2A and 2B, and a magnetic path cross-sectional area of the inner core portion 31. The outer clearance c2 is preferably 0.2 mm or less, and more preferably 0.1 mm or less in consideration of the effect of increasing the above.

[More preferable configuration]
In consideration of improving the moldability of the inner interposition member 41, the portion of the mold having a wide gap corresponding to the thick portion 41b has a thickness t1 of the thin portion 41a and a thickness t2 of the thick portion 41b. It is preferable that the difference (thickness t2−thickness t1) is 0.2 mm or more. If the thin portion 41a and the thick portion 41b are specified by specific numerical values, the thickness t1 of the thin portion 41a is 0.2 mm or more and 0.7 mm or less, and the thickness t2 of the thick portion 41b is 1.1 mm or more.2. The thickness t1 of the thin portion 41a is preferably 0.2 mm or more and 0.5 mm or less, and the thickness t2 of the thick portion 41b is preferably 1.1 mm or more and 2.0 mm or less.

The formability of the inner interposition member 41 can be improved by adopting a form in which the thickness of the inner interposition member 41 gradually increases from the thin portion 41a to the thick portion 41b. This is because when the inner interposition member 41 is injection-molded, the resin injected into the portion that becomes the thick portion 41b of the mold easily flows into the portion that becomes the thin portion 41a. As a specific example of the above-described embodiment, as shown in FIGS. 3 and 4, for example, the width direction edge portion of the thin portion 41a (the edge portion in the direction in which the thick portion 41b is present) is recessed to the outside of the inner interposition member 41. The rounded shape is as follows. Further, it is also preferable that the widthwise edge of the thick portion 41b (the edge in the direction in which the thin portion 41a is present) has a rounded shape that is convex toward the outside of the inner interposition member 41. The widthwise edge can be arcuate, and in that case, the radius of curvature of the arc can be 0.05 mm or more and 20 mm or less, and further 0.1 mm or more and 10 mm or less. When the radius of curvature of the arc is large, the widthwise edge of the thin portion 41a and the widthwise edge of the thick portion 41b are connected to each other as shown in FIG. It has a wavy shape. When the radius of curvature of the arc is small, as shown in FIG. 4, the inner peripheral surface 410 of the inner interposition member 41 has a shape in which intervening recesses 411 in the form of rectangular grooves with rounded corners are arranged. In addition, the intervening recesses 411 having V-shaped grooves with rounded corners may be arranged side by side.

In the configuration in which the inner interposition member 41 is molded on the outer periphery of the inner core portion 31, the inner core portion 31 is configured to include a plurality of core-side convex portions 311 formed on the core outer peripheral surface 319, as shown in FIG. It is preferable. The core-side convex portion 311 of FIG. 5 is formed in a protrusion along the axial direction of the inner core portion 31, and each core-side convex portion 311 is spaced at a predetermined interval in the circumferential direction of the core outer peripheral surface 319. It is arranged. With such an inner core portion 31, when the resin is molded from the end surface side of the inner core portion 31, the resin easily spreads over the entire outer peripheral surface 319 of the core. This is because the groove portion formed between the core-side convex portions 311 facilitates the movement of the resin in the axial direction of the inner core portion 31, and the resin also spreads from the position of the groove portion to the outer periphery of the core-side convex portion 311. When this inner core portion 31 is used, the interposition side concave portion 411 of the inner interposition member 41 extends from the end surface on one end side to the other end side in the axial direction of the inner interposition member 41 (same as the axial direction of the winding portions 2A and 2B). The shape extends to the end face of.

It is also possible to use an inner interposition member having an inner peripheral surface corresponding to the inner core portion 31 as shown in FIG. In the inner core portion 31 of FIG. 6, the core-side convex portion 311 on one end side in the axial direction of the inner core portion 31 and the core-side convex portion 311 on the other end side are displaced in the circumferential direction of the inner core portion 31. Equipped with. When the resin is injected from both end surfaces of the inner core portion 31, the resin is easily spread over the entire core outer peripheral surface 319 of the inner core portion 31 for the same reason as in the configuration of FIG. In addition, the core-side convex portion 311 is further extended in the axial direction of the inner core portion 31, and the groove between the core-side convex portions 311 adjacent to the circumferential direction on one end side and the core side adjacent to the circumferential direction on the other end side. The grooves between the convex portions 311 may be engaged with each other.

≪Reactor manufacturing method≫
The reactor 1 of the first embodiment can be manufactured by separately manufacturing the coil 2, the mold core members 5A and 5B, and the outer core portions 32 and 32 and combining them. Specifically, the inside intervening members 41, 41 of the mold core members 5A, 5B are inserted into the winding portions 2A, 2B of the coil 2 and the outside of the end face interposing member 42 of the mold core members 5A, 5B is inserted. The outer core portions 32, 32 are arranged. The outer core portion 32 can be joined to the end face interposing member 42 with an adhesive or the like.

<Modification 1-1>
The divided state of the magnetic core 3 and the insulating interposition member 4 is not limited to the example of the first embodiment. For example, a pair of approximately π-shaped mold core members obtained by molding a pair of inner core portions 31 and one outer core portion 32 having a length of about half with the material of the insulating interposition member 4 may be used. .. In addition, a pair of generally L-shaped mold core members obtained by molding one inner core portion 31 and one outer core portion 32 over the entire length of the winding portion 2A (2B) with the material of the insulating interposition member 4 are used. It doesn't matter. In addition, two members obtained by molding the inner core portion 31 over the entire length of the winding portion 2A (2B) with the inner interposition member 41 are prepared, and the two outer core portions 32 are combined therewith to form the magnetic core 3 and the insulating interposition member 4. And can also be configured.

<Modification 1-2>
Unlike the mold core member of the first embodiment, it is also possible to use a press-fit core member in which the inner intervening member 41 is formed by injection molding and then the inner core portion 31 is press-fit into the inner interposing member 41. If the inner core portion 31 is press-fitted into the inner interposition member 41, the clearance between the inner core portion 31 and the inner interposition member 41 can be set to approximately 0 mm, that is, the inner core portion 31 and the inner interposition member 41. And can be in a state of being substantially in close contact with each other. In this way, the inner core portion 31 can be press-fitted into the inner interposition member 41 afterward because the inner interposition member 41 is made up of the thin portion 41a and the thick portion 41b, so that the inner interposition member 41 can be dimensioned with high dimensional accuracy. This is because it can be manufactured.

<Embodiment 2>
In the first embodiment, the coil 2 includes the pair of winding portions 2A and 2B. On the other hand, also in a reactor including a coil having one winding portion, the same configuration as that of the first embodiment can be adopted.

When a coil having one winding portion is used, the magnetic core may be configured by combining two mold core members having a substantially E-shape when viewed from above. In this case, the E-shaped middle protruding portion of the mold core member is inserted into the winding portion to form the inner core portion. Further, the outer core portion is formed in a portion other than the E-shaped middle protruding portion of the mold core member. Needless to say, the divided state of the magnetic core and the insulating interposition member is not limited to the E shape.

<Use>
The reactor of the embodiment can be used for a power conversion device such as a bidirectional DC-DC converter mounted on an electric vehicle such as a hybrid vehicle, an electric vehicle, and a fuel cell vehicle.

DESCRIPTION OF SYMBOLS 1 reactor 10 combination 2 coil 2A, 2B winding part 2R connecting part 2a, 2b end part 210 coil inner peripheral surface 3 magnetic core 31 inner core part 32 outer core part 311 core side convex part 319 core outer peripheral surface 4 insulating intervening member 41 inner interposed member 410 inner peripheral surface 411 intervening concave portion 419 outer peripheral surface 41a thin portion 41b thick portion 42 end face intervening member 42d partition portion 42s turn accommodating portion 5A, 5B mold core member c2 outer clearance

Claims (9)

A coil having a winding portion,
A magnetic core having an inner core portion arranged inside the winding portion;
A reactor including an inner intervening member that secures insulation between the winding portion and the inner core portion,
The inner intervening member includes a thin-walled portion whose thickness is reduced by recessing the inner peripheral surface side thereof, and a thick-walled portion whose thickness is thicker than the thin-walled portion,
The inner core portion is provided with a core-side convex portion having a shape along the inner peripheral surface shape of the thin portion on the outer peripheral surface facing the inner interposing member,
The thickness of the thin portion is 0.2 mm or more and 1.0 mm or less, the thickness of the thick portion is 1.1 mm or more and 2.5 mm or less,
The inner core portion and the inner interposition member substantially come into close contact with each other,
A reactor having a clearance at least at a part between the inner interposition member and the winding portion. The reactor according to claim 1, wherein the inner intervening member is made of a resin molded outside the inner core portion. The reactor according to claim 1 or 2, wherein a difference between the thickness of the thin portion and the thickness of the thick portion is 0.2 mm or more. The reactor according to any one of claims 1 to 3, wherein the thin portion has a thickness of 0.2 mm or more and 0.7 mm or less, and the thick portion has a thickness of 1.1 mm or more and 2.0 mm or less. .. The reactor according to any one of claims 1 to 4, wherein a plurality of the thick-walled portions and the thin-walled portions are dispersed in the circumferential direction of the inner intervening member. The reactor according to any one of claims 1 to 5, wherein at least a part of the thick portion reaches an end surface of the inner intervening member in the axial direction of the winding portion. The reactor according to any one of claims 1 to 6, wherein an outer peripheral surface of the inner intervening member has a shape along the inner peripheral surface of the winding portion. The reactor according to any one of claims 1 to 7, wherein the thickness of the inner interposition member gradually increases from the thin portion to the thick portion. The reactor according to any one of claims 1 to 8, wherein the clearance formed between the inner interposition member and the winding portion is more than 0 mm and 0.3 mm or less.

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