JP2014239120A - Reactor, core piece for reactor, converter, and power conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reactor capable of reducing occurrence of a leakage magnetic flux.SOLUTION: A reactor 1a comprising a core 3 and coil 2, where a core piece 3a configuring at least part of the core 3 is made from composite material including magnetic substance powder and resin. The core piece 3a comprises: a coil arrangement unit 31 inserted into the inside of the coil 2; an exposure unit 32 which is integrally molded with the coil arrangement unit 31, and is arranged on the outside of the coil 2 so as to cover at least part of an edge face of the coil 2; and a chamfering unit 33 formed at a corner unit composed of the coil arrangement unit 31 and the exposure unit 32's part opposite to at least part of the coil edge face.

Description

  The present invention relates to a reactor, a core piece for the reactor, a converter including the reactor, and a power conversion device including the converter.

  A reactor is one of the parts of a circuit that performs a voltage step-up operation or a voltage step-down operation. The reactor is used for a converter mounted on a vehicle such as a hybrid vehicle or an electric vehicle. An example of such a reactor is shown in Patent Document 1.

  The reactor described in Patent Document 1 is configured by combining an annular core and a coil. The core includes a coil placement portion that is covered with a coil and an exposed portion that is not covered with the coil. This coil arrangement | positioning part and exposed part are produced separately, and an annular core is formed by mutually joining. A coil arrangement | positioning part can be comprised with a shaping | molding hardening body. The molded hardened body is made by mixing soft magnetic powder (mixed powder with non-magnetic powder added if necessary) and fluid binder resin, and applying this mixed fluid to the mold (die). It is obtained by curing the binder resin after pouring into the mold. The molded and hardened body can easily give desired magnetic characteristics to the reactor by adjusting the mixing ratio of the magnetic powder and the resin. Furthermore, since the molded cured body can be easily manufactured by cast molding, injection molding, or the like, it is excellent in productivity.

JP 2009-033055 A Japanese Patent Laid-Open No. 2008-112935 Japanese Patent No. 4650755 JP 2004-327569 A JP 2010-045112 A

  In recent years, it has been required to reduce the loss of the reactor. In order to satisfy this requirement, the core included in the reactor described in Patent Document 1 separately produces the exposed portion and the coil placement portion, and makes the relative permeability of the exposed portion higher than that of the coil placement portion. Yes. By doing in this way, compared with the cyclic | annular core comprised with the uniform magnetic material as a whole, it can reduce that a leakage magnetic flux arises in the inner space of the core and the circumference | surroundings.

  However, like the reactor described in Patent Document 1, when the coil placement portion and the exposed portion are separately produced and joined, the joining location often becomes a right angle. Leakage magnetic flux is likely to be generated from the corner (inner corner) of the joint. Leakage magnetic flux not only causes copper loss due to intrusion into the coil, but also may affect the peripheral devices of the reactor. Therefore, it is desirable that the leakage magnetic flux is as small as possible. Further, since the coil placement portion and the exposed portion are separately manufactured and joined, the productivity of the reactor is inferior.

  The present invention has been made in view of the above circumstances, and one of its purposes is to provide a reactor that can reduce leakage magnetic flux and is excellent in productivity. Another object of the present invention is to provide a core piece for a reactor. Furthermore, the other object of this invention is to provide a converter provided with this reactor, and to provide a power converter device provided with this converter.

  This invention is a reactor provided with a core and a coil, Comprising: The core piece which comprises at least one part of a core is a composite material containing magnetic body powder and resin. The core piece includes a coil placement portion, an exposed portion, and a chamfered portion. The coil placement portion is inserted inside the coil. The exposed portion is formed integrally with the coil placement portion, and is disposed outside the coil so as to cover at least a part of the coil end surface. The chamfered portion is formed at the corner. The corner portion is constituted by a coil placement portion and a portion facing at least a part of the coil end surface of the exposed portion.

  According to the said invention, the reactor which can reduce the leakage magnetic flux which generate | occur | produces in a reactor can be provided.

3 is a schematic perspective view of a core piece according to Embodiment 1. FIG. It is the end view which looked at the core piece which concerns on Embodiment 1 from the coil axial direction. 3 is a schematic perspective view of a core piece according to Embodiment 1. FIG. The upper stage shows a state where burrs are provided, and the lower stage shows a state where burrs are broken. 1 is an exploded perspective view of a reactor according to a first embodiment. 6 is a schematic perspective view of a core piece according to Embodiment 2. FIG. It is the schematic showing the inclined surface with which the core piece which concerns on Embodiment 2 is provided. The upper part shows a schematic top view, and the lower part shows a schematic side view. It is a disassembled perspective view of the reactor which concerns on Embodiment 2. FIG. It is a disassembled perspective view of the reactor which concerns on Embodiment 3. FIG. It is a top view of the reactor which concerns on Embodiment 3. FIG. It is a disassembled perspective view of the reactor which concerns on the modification 1. FIG. 1 is a schematic configuration diagram schematically showing a power supply system of a hybrid vehicle. It is a schematic circuit which shows an example of the power converter device of this invention provided with the converter of this invention.

[Description of Embodiment of Present Invention]
First, the contents of the embodiments of the present invention will be listed and described.
(1) The reactor which concerns on embodiment is a reactor provided with a core and a coil, Comprising: The core piece which comprises at least one part of a core is a composite material containing magnetic body powder and resin. The core piece includes a coil placement portion, an exposed portion, and a chamfered portion. The coil placement portion is inserted inside the coil. The exposed portion is formed integrally with the coil placement portion, and is disposed outside the coil so as to cover at least a part of the coil end surface. The chamfered portion is formed at the corner. The corner portion is constituted by a coil placement portion and a portion facing at least a part of the coil end surface of the exposed portion.

  According to this embodiment, the leakage magnetic flux generated from the core can be reduced. In particular, by forming a chamfered portion at a predetermined location on the core piece, it is possible to reduce the occurrence of leakage magnetic flux at the corner where the magnetic flux is bent sharply. Thereby, the reactor which concerns on embodiment can reduce a loss. Moreover, the fall of the efficiency of a reactor can be reduced by preventing the penetration | invasion of the leakage magnetic flux to the coil. Furthermore, problems such as leakage flux affecting peripheral devices can be prevented. Moreover, it is excellent in productivity because the coil arrangement | positioning part with which a core piece is provided and the exposed part are shape | molded integrally.

(2) The reactor which concerns on embodiment of said (1) WHEREIN: The form with which an exposed part is provided with a base and an outer side leg part is mentioned. The base includes a portion facing at least a part of the coil end surface. The outer leg covers a part of the outer periphery of the coil. And the chamfering part formed in the corner comprised by the part and outer leg part which oppose at least one part of the coil end surface of a base is provided.

  According to the present embodiment, the corner portion constituted by the portion facing the at least part of the coil end surface of the base portion and the outer leg portion is provided with the chamfered portion, so that generation of leakage magnetic flux from the corner portion can be reduced. The reduction in reactor loss can be reduced.

(3) In the reactor according to the embodiment of (1) or (2), the shape of the chamfered portion is an arc shape, and the radius R of the arc is preferably 0.5 mm or more. This is because leakage flux generated from the corner can be reduced by setting the shape and radius R of the chamfered portion as described above. Here, when the chamfered portion is cut by a surface orthogonal to any one of a plurality of surfaces constituting the corner, the arc shape is the direction of the bulge of the arc in the cross section. The shape that is.

(4) In the reactor according to the embodiments of (1) to (3), the coil may include a pair of coil elements. In this embodiment, the coil elements are arranged in parallel with each other in the axial direction, and the coil placement portion is inserted inside each of the pair of coil elements.

  The reactor of the present embodiment can reduce leakage magnetic flux generated from the corners of the core, and can reduce loss.

(5) In the reactor according to any one of the embodiments (1) to (4), when the reactor is installed so that the axial direction of the coil is parallel to the installation target, the exposed portion is the reactor The form containing the protrusion part which protruded in the at least one direction of the installation object side and the other side is mentioned. In this embodiment, chamfered portions are formed at the corners formed by the protruding portion and the coil placement portion.

  The reactor according to the present embodiment has an exposed portion provided with a projecting portion, so that heat generated in the core can be efficiently transmitted to an installation target such as a cooling base through the projecting portion, and a reactor excellent in heat dissipation. can do. Moreover, since the chamfered portion is formed at the corner formed by the protruding portion and the coil placement portion, the leakage magnetic flux generated from the corner can be reduced, and the reactor loss can be further reduced.

(6) In the reactor according to the embodiment of (5), it is preferable that the projecting portion includes an injection trace of the composite material.

  In the process of producing the core piece, the composite material may not be smoothly distributed in the mold depending on the place where the injection port for the composite material is provided. However, by providing the injection mark of the composite material in the protruding portion, in other words, in the mold when forming the core piece, by providing the injection port of the composite material in the region where the protruding portion of the core piece is formed, It becomes easy to fill the composite material smoothly into the mold without unevenness. Therefore, this embodiment can reduce molding defects such as chipping or deformation of the core piece, and is excellent in yield (productivity).

(7) In the reactor according to any one of the embodiments (1) to (6), it is preferable that the coil placement portion includes an inclined surface that is inclined from the end surface side to the inner side of the coil.

  In the process of producing the core piece, when the core piece is removed from the mold, the core piece may be damaged due to friction with the inner peripheral surface of the mold. By providing the coil placement part with an inclined surface that is inclined from the coil end face side to the inner side, in other words, by providing a so-called draft angle in the mold for producing the core piece, the core piece and the metal mold Friction with the inner peripheral surface of the mold can be reduced, and the core piece can be removed easily. Thereby, the yield (productivity) of a core piece and the yield of a reactor can be improved further.

(8) In the reactor according to any one of the embodiments (1) to (7), it is preferable that at least one of the peripheral edges of the coil placement portion, the exposed portion, and the chamfered portion is dropped.

  In the process of manufacturing the reactor, the core piece may come into contact with other members and receive a physical impact, so that the peripheral edge constituted by the ridge line portion may be lost. By cutting off at least one of the peripheral edges so that the peripheral edge of the core piece is not sharpened, it is possible to prevent the peripheral edge of the core piece from being damaged. Therefore, when the reactor is manufactured, the possibility that the core piece is defective and becomes a defective product can be greatly reduced, and the yield can be improved.

(9) A core piece for a reactor according to an embodiment of the present invention includes a coil placement portion, a coil placement portion, an exposure portion, and a chamfered portion. The coil placement portion is inserted inside the coil. The exposed portion is formed integrally with the coil placement portion, and is disposed outside the coil so as to cover at least a part of the coil end surface. The chamfered portion is formed at a corner formed by the coil placement portion and a portion facing at least a part of the coil end surface of the exposed portion. And this core piece is comprised from the composite material containing magnetic body powder and resin.

  According to this embodiment, it consists of a composite material, and it is excellent in productivity because a coil arrangement | positioning part and an exposed part are shape | molded integrally. Moreover, the leakage magnetic flux which generate | occur | produces in a reactor can be reduced by forming a chamfer part in the predetermined location of a core piece. In particular, it is possible to reduce the occurrence of leakage magnetic flux at the corner where the magnetic flux is bent sharply. Thereby, the reactor which combined the core and coil which combined the core piece for reactors which concerns on this embodiment can reduce loss.

(10) The converter which concerns on embodiment of this invention is a converter provided with the reactor in any one of said (1) to (8).

(11) The power converter device which concerns on embodiment of this invention is a power converter device provided with the converter as described in said (10).

  The converter according to the embodiment of the present invention and the power conversion device according to the embodiment of the present invention can be suitably used for in-vehicle components and the like by including the reactor of the present invention with reduced loss and excellent productivity.

[Details of the embodiment of the present invention]
Embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to these embodiment, It is shown by the claim and it is intended that all the changes within the meaning and range equivalent to a claim are included.

<Embodiment 1>
In the first embodiment, the reactor and the core piece for the reactor of the present embodiment will be described with reference to FIGS. 1 to 4. The reactor is attached to an installation target such as a cooling base (not shown). In FIG. 4, the lower side of the figure is the installation target side and the upper side is the opposite side.

[Reactor]
As shown in FIG. 4, the reactor 1a of this embodiment is provided with the coil 2 and the core 3 which combined several core pieces 3a and 3a. Each core piece 3a, 3a is comprised with the composite material containing magnetic body powder and resin. As will be described later, each of the core pieces includes a coil placement portion and an exposed portion that are integrally formed with each other, and has a chamfered portion at a corner portion formed by both.

[coil]
The coil 2 is configured by winding a winding spirally. The coil according to the present embodiment includes a pair of coil elements 2A and 2B and a coil element coupling portion 2r that couples both coil elements 2A and 2B. The coil elements 2A and 2B are formed in a hollow cylindrical shape with the same number of turns and the same winding direction, and are arranged side by side so that the axial directions are parallel to each other. The coil element connecting portion 2r is a U-shaped portion that connects the coil elements 2A and 2B on the other end side of the coil 2 (right side in FIG. 3). The coil 2 may be formed by spirally winding a single winding without a joint. Alternatively, the coil elements 2A and 2B may be formed by separate windings, and the coil elements 2A and 2B may be formed. You may form by joining the edge parts of a coil | winding by soldering or press-contacting. Both ends 2a and 2b of the winding are extended upward from the turn forming portion and connected to a terminal member (not shown). An external device (not shown) such as a power source for supplying power is connected to the coil 2 through this terminal member.

  As the coil 2, a coated wire having an insulating coating made of an insulating material on the outer periphery of a conductor such as a flat wire or a round wire made of a conductive material such as copper, aluminum, or an alloy thereof can be suitably used. In the present embodiment, the conductor is made of a copper rectangular wire, and the insulation coating is made of a coated rectangular wire made of enamel (typically polyamideimide), and each of the coil elements 2A and 2B uses the covered rectangular wire as edgewise. It is a wound edgewise coil. Here, the end face shape of each of the coil elements 2A and 2B is a shape in which each of the outer corner and the inner corner of the rectangular frame is rounded. The end face shape can be changed as appropriate, such as a circular shape or a rectangular shape without rounded corners.

[Core piece]
As shown in the lower part of FIG. 1 and FIG. 3, the core piece 3a of this embodiment has a substantially U-shape when viewed from above. The core piece 3 a includes coil placement portions 31, 31, an exposed portion 32, and a chamfered portion 33. In the reactor 1a, the coil arrangement portions 31 and 31 of the two core pieces 3a and 3a are inserted into the coil elements 2A and 2B from both ends of the coil elements 2A and 2B, respectively. At this time, the end surfaces (core facing surfaces) of the opposing coil placement portions 31 are joined to each other to form the annular core 3a, and a closed magnetic path can be formed in the reactor 1a. Hereinafter, each part mentioned above is demonstrated.

(Coil placement part)
As shown in FIG. 1, the coil arrangement | positioning parts 31 and 31 are some core pieces 3a, Comprising: It is a part penetrated inside a coil. Here, it is set as the substantially rectangular parallelepiped coil arrangement | positioning parts 31 and 31, The end surface shape is a substantially rectangular shape corresponding to the shape of the hollow part in the end surface of coil element 2A, 2B. The coil placement portions 31 and 31 each have a length that is approximately half of the axial length of the coil elements 2A and 2B. Moreover, the corner | angular drop part is formed in the periphery of the surface (core surrounding surface) which opposes the coil internal peripheral surface of the coil arrangement | positioning parts 31 and 31. FIG. This corner dropping part will be described later.

(Exposed part)
The exposed part 32 is a part of the core piece 3 a and is a part disposed outside the coil 2. The exposed portion 32 is formed integrally with the coil placement portions 31 and 31. The exposed portion in the present embodiment has a trapezoidal columnar shape. The exposed portion 32 includes a base portion 32a and a protruding portion 32b. In the following description, the surface of the exposed portion that faces the end face of each coil element may be referred to as the coil facing surface of the exposed portion, the coil facing surface of the base portion, and the coil facing surface of the protruding portion.

〔base〕
The base is a part of the exposed part that satisfies the following requirements. In a state where the coil and the core are combined, a portion of the core piece that is substantially along the axial direction of the coil is a leg portion. When this core piece is viewed from the axial direction of the coil, a portion of the exposed portion located within the envelope contour S of all the leg portions is used as a base portion. In other words, the base portion is a portion having a surface (base coil facing surface) covering at least a part of the coil end surface, and the leg portion is a portion protruding from the coil facing surface of the base portion in a direction intersecting the base portion. It is. For example, in the case of the core piece 3a of Embodiment 1, as shown in FIG. 1, each coil arrangement | positioning part 31 and 31 is a leg part. Further, as shown in FIG. 2, when the core piece 3 a is viewed from the axial direction of the coil 2, the trapezoid located within the envelope contour S (see solid line) of both the coil placement portions 31 and 31 in the exposed portion 32. The columnar portion becomes the base 32a. In other words, a portion of the exposed portion 32 that is above the extended surface of the lower surfaces of the coil placement portions 31 and 31 is the base portion 32a. Two corner portions are formed between the coil facing surface of the base portion 32a and the outer peripheral surfaces of the coil placement portions 31, 31, and chamfered portions 33a described later are formed at the respective corner portions.

  The shape of the base is not particularly limited as long as the shape can connect the legs. As shown in FIG. 1, in the present embodiment, the base portion 32a has a substantially trapezoidal shape such that the coil 2 side has a long side when viewed from above. In addition, the shape when viewed from above may be a rectangular shape or a substantially semicircular shape in which the end face side of the coil is a chord. A part of the periphery of the base portion 32a is dropped. This corner drop will also be described later.

(Protrusion)
A protrusion part is a part which protrudes in the direction which cross | intersects the axial direction of a coil from a base part among exposed parts. For example, in the case of the core piece 3a of the first embodiment, as shown in FIGS. 1 and 2, the trapezoidal columnar portion of the exposed portion 32 that protrudes downward from the base portion 32a is the protruding portion 32b. The coil facing surface of the protruding portion 32b is flush with the coil facing surface of the base portion 32a. Further, the lower surface of the protruding portion 32 b is lower than the lower surface of the coil placement portion 31. As a result, two corners are formed by the lower surfaces of the coil placement portions 31 and 31 and the coil facing surface of the protruding portion 32a, and a chamfered portion 33b described later is formed at each corner. In the present embodiment, when the core piece 3a is assembled to the coil 2, the lower surface of the exposed portion 32 of the core piece 3a (that is, the lower surface of the protruding portion 32b) is flush with the lower surface of the coil 2.

(Chamfered part)
The chamfered portion is formed at a corner portion composed of a leg portion and a base portion or a protruding portion, and is a portion for reducing stray direction change of the core piece at this corner portion and reducing leakage magnetic flux from the corner portion. It is. In the first embodiment, the chamfered portion 33 is formed at a corner formed by the coil placement portions 31 and 31 and a portion facing at least a part of the coil end surface of the exposed portion 32. More specifically, the chamfered portion 33 includes a chamfered portion 33a, a chamfered portion 33b, and a chamfered portion 33r. The chamfered portion 33a is formed at a corner portion constituted by an inner side surface of the coil placement portions 31 and 31 where the two coil placement portions face each other and a coil facing surface of the base portion 32a. The chamfered portion 33b is formed at a corner portion constituted by the lower surfaces of the coil placement portions 31, 31 and the coil facing surface of the protruding portion 32b. The chamfered portion 33r is formed at both ends of the chamfered portion 33a and the chamfered portion 33b. The chamfered portion 33r will be described together with a corner dropping item described later.

  In this embodiment, the shape of the chamfered portion 33 is an arc shape, particularly a perfect circular arc shape, but other shapes, for example, an inclined surface (C surface) is formed at a corner, or an elliptical arc shape is used. Therefore, the chamfered portion 33 may be used. In the case of a perfect circular arc shape, the radius R of the circular arc may be designed as appropriate, but is preferably 0.5 mm or more. If it is less than 0.5 mm, the rapid bending of the magnetic flux cannot be relaxed, and the leakage magnetic flux may not be reduced. The radius R is preferably 2.0 mm or less. If the radius R is too large, when the reactor 1 is combined with the coil 2, the end surface of the exposed portion 32 on the coil 2 side and the end surface of the coil 2 cannot be in close contact with each other, and the core piece 3a and the coil 2 are reliably combined. This may be difficult. For the same reason, when the C surface is formed as the chamfered portion 33, the C surface of 0.5 mm or more and 2.0 mm or less (C5 or more and C20 or less) may be formed. Even in the case of an elliptical arc shape, the major and minor radii may be set so as to alleviate the sudden bending of the magnetic flux.

  The chamfering method is not limited as long as the chamfered portion is formed on the core piece as a result. For example, a mold used for manufacturing the core piece 3a described later is designed so that a chamfered portion having a desired shape and size can be formed. After the core piece is molded, the composite material before curing is formed on the chamfered portion. The chamfered portion is filled by a method such as filling the corner not filled and forming the corner with an appropriate jig corresponding to the shape of the predetermined chamfered portion such as a C surface or an arc. be able to.

(Corner drop)
As shown in the lower part of FIG. 1 and FIG. 3, among the peripheral edges of the core circumferential surface of the coil placement portions 31, 31, eight sides facing the corners inside the coil elements 2 </ b> A, 2 </ b> B (hereinafter referred to as corner R portions) The corner is dropped along the shape of the corner R portion. By chamfering the area in the vicinity of the exposed portion 32 in the six sides that form the corners with the exposed portion 32 among the eight corner-cut sides, six chamfered portions 33r are formed. Here, the chamfered shapes of the six chamfered portions 33r are the same as those of the chamfered portions 33a and 33b described above.

  As shown in FIGS. 1, 2, and 4, the periphery of the exposed portion 32 is cut off except for a part thereof. More specifically, corners other than the peripheral edge of the lower surface of the protruding portion 32b are dropped. The shape of the corner drop may be a C-surface shape or an R-surface shape, but in this embodiment, a defect is less likely to occur, and an R-surface shape that is a shape along the inner peripheral surface of the coil is used. The R surface shape preferably has a radius R of 0.5 mm to 5.0 mm, and more preferably 2.0 mm to 3.0 mm. In the case of a C-plane shape, it is preferably 0.5 mm or more and 5.0 mm or less (C5 or more and C50 or less), more preferably 2.0 mm or more and 3.0 mm or less (C20 or more and C30 or less). If the R surface shape and the C surface shape are in this range, it is possible to effectively prevent the peripheral edge of the core piece 3a from being lost, and to sufficiently secure the magnetic path area of the core 3.

  The above corner dropping may be performed at a place other than the above-described places. For example, the edge of the upper surface of the base portion 32a on the coil end surface side, the periphery of the lower surface of the projecting portion 32b, the periphery of the core facing surface of the coil placement portions 31 and 31 and the like that are not dropped in this embodiment are dropped. May be. That is, any corner of the peripheral edge of the core piece 3a may be dropped. Moreover, in order to fix the coil 2 and the core piece 3a for reactors closer to each other, the inner peripheral edges of the coil elements 2A and 2B may be cut according to the shape of the chamfered portion.

  The method of corner dropping is not limited as long as the corner dropping is formed on the core piece as a result. For example, it is possible to cut the corners by forming the core piece and then cutting off the corners, or by designing the mold so that the corner pieces are formed when the core piece is formed.

[Composite material]
The composite material constituting the core piece 3a in the present embodiment is a magnetic body having a structure in which particles constituting the magnetic powder are dispersed in a resin.

  As the magnetic powder contained in the composite material, iron, an iron-based alloy, an alloy containing a rare earth metal, or the like can be used. Further, as the magnetic powder, a coating powder having an insulating coating on the surface of the magnetic particles can be used. In particular, the eddy current loss in the reactor can be effectively reduced by using the coating powder. Examples of the insulating coating include a phosphoric acid compound, a silicon compound, a zirconium compound, an aluminum compound, and a boron compound.

  The average particle size of the magnetic powder is preferably 1 μm or more and 1000 μm or less, particularly preferably 10 μm or more and 500 μm or less. The magnetic powder may be a mixture of a plurality of powders having different average particle diameters, a mixture of a plurality of powders having different materials, or a mixture of a plurality of powders having different average particle diameters and materials. It may be what was done. If the magnetic powder has an average particle size satisfying the above range, it is excellent in fluidity when used in a composite material, and the core piece can be produced with high productivity using injection molding or the like.

  On the other hand, as the resin in the composite material, for example, a thermosetting resin such as an epoxy resin, a phenol resin, a silicone resin, or a urethane resin can be used. In addition, a thermoplastic resin such as a polyphenylene sulfide (PPS) resin, a polyimide resin, a polyamide resin, or a fluororesin, a room temperature curable resin, or a low temperature curable resin may be used. Further, BMC (Bulk molding compound) in which calcium carbonate or glass fiber is mixed with unsaturated polyester, millable silicone rubber, millable urethane rubber, or the like can also be used.

  In addition, the composite material may contain a ceramic filler. Examples of the ceramic filler include at least one selected from silicon nitride, alumina, aluminum nitride, boron nitride, mullite, and silicon carbide. This ceramic filler contributes to the improvement of the heat dissipation of the core piece and the suppression (uniform dispersion) of the uneven distribution of the magnetic powder in the composite material.

  The content of the magnetic powder in the composite material is preferably 20% by volume or more and 75% by volume or less when the composite material is 100% by volume. When the magnetic powder is 20% by volume or more, it is easy to ensure magnetic characteristics such as relative magnetic permeability and saturation magnetic flux density. When the magnetic powder is 75% by volume or less, mixing with the resin is easy to perform, and the core piece is excellent in manufacturability.

  The relative permeability of the core piece having the content of the magnetic powder in the above range is desirably 5 to 50 and the saturation magnetic flux density is desirably 0.6 T to 1.5 T. Further, the thermal conductivity of the core piece is desirably 0.25 W / m · K or more. The magnetic properties of the core piece can be adjusted by changing the content of the magnetic powder. Of course, the magnetic properties of the core piece can also be adjusted by changing the material of the magnetic powder.

  In addition, when making a core piece contain a ceramic filler, the said effect is fully acquired as the content is 0.2 mass% or more and 20 mass% or less, when a core piece shall be 100 mass%.

  The relative magnetic permeability of the core piece is determined as follows. A ring-shaped test piece having an outer diameter of 34 mm, an inner diameter of 20 mm, and a thickness of 5 mm is made of the same constituent material as the composite material used for the core piece. The test piece is subjected to winding of 300 turns on the primary side and 20 turns on the secondary side, and the BH initial magnetization curve of the test piece is measured in the range of H = 0 to 100 Oersted (Oe). For the measurement, for example, a BH curve tracer “BHS-40S10K” manufactured by Riken Denshi Co., Ltd. can be used. The maximum value of the gradient (B / H) of the obtained BH initial magnetization curve is obtained and used as the relative permeability of the core piece. Normally, the gradient (B / H) of the BH initial magnetization curve becomes maximum at around H = 0 or H = 0. The magnetization curve here is a so-called DC magnetization curve. Further, the relative permeability here is a so-called DC permeability, which is different from the AC relative permeability measured in an AC magnetic field. On the other hand, the saturation magnetic flux density of the core piece is defined as the magnetic flux density when a magnetic field of 10,000 (Oe) is applied to the test piece with an electromagnet and sufficiently magnetically saturated.

  The core piece comprised from the composite material demonstrated above can be produced with the manufacturing method of a core piece provided with the preparation process shown below and a formation process.

  In the preparation step, a magnetic material powder and a resin are prepared and mixed to produce a composite material. When a ceramic filler is contained in the core piece, the ceramic filler is preferably mixed with the composite material. In addition, it may be considered that the blending ratio of the magnetic powder and the resin in the composite material (the blending ratio including the ceramic filler when the ceramic filler is included) is the same as the blending ratio in the core piece.

  Next, a mold (not shown) is prepared, the composite material produced in the preparation process is filled in the cavity of the mold, the resin is cured, and the core piece is completed. As a method for producing a core piece using a mold, injection molding, transfer molding, MIM (Metal Injection Molding), cast molding, press molding using magnetic powder and powdered solid resin, or the like should be used. Can do. In the case of injection molding, the core piece can be obtained by curing the resin after filling the mold with a mixed material of magnetic powder and resin under a predetermined pressure. Also in the case of transfer molding or MIM, molding is performed by filling the above-mentioned mixed material into a mold. In the case of cast molding, a core piece composed of a composite material can be obtained by injecting the composite material into a mold without applying pressure and molding and curing the composite material.

(Injection trace)
As another configuration of the core piece, when the core piece is manufactured by injection molding, an injection trace of the composite material is provided. The upper part of FIG. 3 shows the core piece 3a ′ taken out from the mold. The core piece 3a ′ includes a burr B formed by a sprue, a runner, a gate, and the like for introducing a composite material into the cavity of the mold. By breaking this burr B, the core piece 3a is formed in which the injection mark 32m of the composite material is formed in the protrusion 32b. This injection trace is usually subjected to a polishing treatment, but even in this case, it remains as a polishing trace. In the present embodiment, the injection port for the composite material in the mold is provided on the lower surface of the region where the protrusion 32b is formed.

  As shown in FIG. 3, the burr B is composed of a triangular plate portion and a rod portion. A groove is formed at a location corresponding to the bottom side of the triangular plate portion. That is, in the triangular plate-like portion of the burr B, the thickness of the region in the vicinity of the protruding portion 32b is locally thin.

The reactor 1a and the core piece 3a for the reactor of the present embodiment described above have the following operational effects.
(1) By chamfering the corner to form the chamfered portion 33, leakage magnetic flux generated from the corner can be reduced. Since the magnetic flux bends sharply at the corner, leakage magnetic flux is likely to occur. Therefore, the leakage magnetic flux can be reduced by setting the corners to be chamfered portions 33 in order to alleviate this sudden bending.

(2) Since the lower surface of the protrusion 32b is flush with the lower surface of the coil 2, heat generated during the operation of the reactor 1, particularly heat generated in the core 3, can be efficiently transferred to the cooling base via the protrusion. It can be transmitted and it can be set as the reactor excellent in heat dissipation.

(3) By cutting off the edges of the coil placement portions 31, 31, the loss of the coil placement portions 31, 31 and the damage to the insulating coating of the coil 2 can be suppressed. When the core piece 3a is assembled to the coil 2, the peripheral edges of the coil placement portions 31 and 31 may come into contact with the inner peripheral surfaces of the coil elements 2A and 2B and be lost. Moreover, the peripheral edges of the coil placement portions 31 and 31 are positions that are difficult to see when covered with the coil 2 when the core piece 3a is assembled. Therefore, the coil placement portions 31 and 31 are not only likely to cause the above-described defect during assembly, but also have a problem that the generated defect cannot be easily confirmed from the outside. Conversely, the peripheral edges of the coil placement portions 31, 31 may damage the insulation coating on the inner peripheral side of the coil elements 2A, 2B. Therefore, if the edge of the core piece 3a facing the corner R portion of the coil is cut off as in this embodiment, the possibility of the above-mentioned defect / damage can be greatly reduced, and the incidence of defective products is reduced. can do. As a result, the incidence of defective products of the reactor 1 can be reduced, and the productivity of the reactor 1 can be improved. Further, by setting the shape of the corner drop along the corner R portion of the coil elements 2A and 2B, the peripheral edge of the core circumferential surface can be brought close to the corner R portion of the coil 2, and the coil 2 and the core piece Fixing with 3a can be performed reliably.

(4) By removing the corners of the exposed portion 32, it is possible to make it difficult for defects to occur in these margins. Similarly to the above (3), in the process of manufacturing the reactor 1, the periphery of the exposed portion 32 may come into contact with other members and the periphery may be lost. Therefore, according to the present embodiment, it is difficult for defects to occur in these peripheral edges.

(5) By injecting the composite material, the core piece 3a having a complicated shape in which the exposed portion 32 and the coil placement portions 31, 31 are integrated can be easily produced. Further, by providing the composite material injection port in the region where the protrusion 32b of the mold is formed, it becomes easy to smoothly fill the composite material into the cavity without being biased. This is because the composite material may not smoothly enter the cavity depending on the location where the injection port is provided. Further, as in the present embodiment, it is preferable to provide an injection port on the lower surface of the region where the protruding portion 32b is formed because the composite material can be filled more smoothly.

(6) The vicinity of the boundary between the burr B and the triangular plate-like portion (in this embodiment, the bottom side of the triangular plate-like portion) is provided with a groove, so that the burr B can be easily broken off from the core piece 3a ′, thereby improving the productivity of the core piece 3a. Excellent.

<Embodiment 2>
In the second embodiment, a reactor 1b including a core piece 3b having a configuration different from that of the first embodiment will be described with reference to FIGS.

[Reactor]
As shown in FIG. 7, the reactor 1b of the present embodiment basically includes the same configuration as the reactor 1a described in the first embodiment, but the core piece 3b includes a protruding portion 32c on the upper side, And the coil arrangement | positioning part 31 differs from the piece 3a of Embodiment 1 in the point provided with the inclined surface which inclines toward the end surface of the other side from the end surface by the side of the exposed part 32 of the coil arrangement | positioning part 31. Since the other points are the same as those of the reactor 1a and the core piece 3a of the first embodiment, the description thereof will be omitted, and in the following, the protrusion 32c and the inclined surface will be described.

  As shown in FIG. 5, in the core piece 3b of the present embodiment, the exposed portion 32 includes a base portion 32a, a protruding portion 32b, and a protruding portion 32c. 5 and 6 is a boundary between the base portion 32a and the leg portions (the coil placement portion 31 and the pair of outer leg portions 32d and 32d). The protruding portion 32 c is a trapezoidal columnar portion that protrudes upward from the base portion 32 a in the exposed portion 32. The upper surface of the base portion 32a is flush with the upper surfaces of the coil placement portions 31, 31, but the upper surface of the protruding portion 32c is higher than the upper surface of the base portion 32a. In the present embodiment, when the core piece 3 b is assembled to the coil 2, the upper surface of the protruding portion 32 c is flush with the upper surface of the coil 2. In addition, it is good also as a chamfering part by chamfering the corner comprised by the upper surface of the base 32a, and the coil opposing surface of the protrusion part 32c. The coil facing surface of the protruding portion 32c is configured by a plane that is substantially orthogonal to the axial direction of the coil 2. However, the coil facing surface may be an inclined surface corresponding to the end surface of the coil element connecting portion 2r.

  As shown in FIG. 6, the core piece 3 b of the present embodiment is an inclined surface in which the core circumferential surface of the coil placement portions 31, 31 that are legs is inclined from the end surface side of the coil 2 to the inner side of the coil 2. .

  The inclined surface may be provided on all the surfaces parallel to the coil axis direction when the split surface is provided so that the movable extraction direction is the longitudinal direction of the leg as in this embodiment. It may be provided only on a part of the surface. Moreover, what is necessary is just to make it a substantially conical shape when a leg part is cylindrical. As shown in FIG. 6, the angle θ with respect to the coil axis direction of the inclined surface (substantially the same as the axial direction of the coil placement portion) is 0. The angle is preferably 3 ° or more and 1.0 ° or less. By setting the angle to 0.3 ° or more, it is easy to remove the legs. Further, by setting the angle to 1.0 ° or less, it is possible to have inferior magnetic characteristics as compared with legs having no inclination angle such as a rectangular parallelepiped or a columnar shape.

The reactor 1b and the core piece 3b of the present embodiment described above have the following functions and effects in addition to the functions and effects of the la and the core piece 3a described in the first embodiment.
(1) The size (length) of the base portion 32a in the coil axis direction can be reduced while keeping the volume of the core 3 the same as compared with the case where the protruding portion 32c is not provided. Further, the end face on the coil side of the projecting portion 32c is not flush with the end face on the coil side of the base portion 32a, and the projecting portion 32c is provided only on the side away from the coil 2 on the upper surface of the base portion 32a. 2r and the protrusion part 32c do not interfere. As described above, the reactor 1b can be a small reactor without excessively increasing the length or height.

(2) When the upper surface of the projecting portion 32c is flush with the upper surface of the coil 2, for example, a cooling member such as a heat sink that is in contact with both the coil 2 and the projecting portion 32c is provided on the upper portion of the reactor 1b. The heat generated in the core piece 3b can be radiated from the reactor 1b through the protrusion 32c and the cooling member.

  For example, the coil facing surface of the protrusion 32c may be an inclined surface corresponding to the end surface of the coil element coupling portion 2r. By doing in this way, while being able to reduce the dead space of the reactor 1b, the volume of the protrusion part 32c can be enlarged more. As a result, the length of the reactor 1b in the coil axis direction can be further shortened. Further, since the area of the upper surface of the protruding portion 32c is increased, the area in contact with the cooling member and the like is increased, and the heat radiation efficiency from the reactor 1b can be improved.

(3) By providing draft angle in the coil arrangement | positioning parts 31 and 31, the defect | deletion of the core piece 3b can be suppressed and productivity can be improved. When the core piece 3b is removed (extracted) from the mold in the process of producing the core piece 3b, the core piece 3b may be damaged due to friction with the inner peripheral surface of the mold. In this embodiment, since the split surface is provided so that the movable extraction direction is the longitudinal direction (coil axis direction) of the leg portions (here, the coil placement portions 31 and 31), the leg portions may be damaged. There is. Therefore, the core circumferential surface provided in the coil arrangement portion 31 is an inclined surface that is inclined from the end surface on the exposed portion 32 side of the coil arrangement portion 31 toward the end surface on the opposite side. By providing such an inclined surface (so-called draft angle) in the mold for manufacturing, friction between the coil placement portion 31 and the inner peripheral surface of the mold can be reduced, and the core piece 3b can be easily demolded. it can. Thereby, breakage of the core piece 3b can be prevented and yield (productivity) can be improved. The draft angle may be provided in accordance with the design of the mold for manufacturing the core, and is not limited to the case where the draft angle is provided on the leg portion.

  As described above, the reactor 1b and the core piece 3b of the second embodiment have been described. However, the core piece 3b can be manufactured by the same method as that of the first embodiment.

<Embodiment 3>
In the third embodiment, a reactor 1c including a core piece 3c having a configuration different from that of the first embodiment and a core 3 obtained by combining the core pieces 3c will be described with reference to FIGS. A reactor 1c according to the third embodiment forms a core 3 by combining a pair of so-called E-type core pieces 3c.

[Reactor]
As shown in FIG. 8, the reactor 1 c of the present embodiment includes a coil 2 and a plurality of core pieces 3 c and 3 c constituting the core 3. Each core piece 3c, 3c is comprised with the composite material containing magnetic body powder and resin. Each of the core pieces 3c, 3c includes a coil placement portion 31 and an exposed portion 32 that are integrally formed with each other, as will be described later. The exposed portion 32 includes a base portion 32a and outer leg portions 32d and 32d. Then, a chamfered portion 33a is provided at a corner portion constituted by the base portion 32a and the coil placement portion 31, and a chamfered portion 33d is provided at a corner portion constituted by the base portion 32a and the outer leg portions 32d and 32d.

[coil]
The coil 2 provided in the reactor 1c shown in FIG. 8 includes only one coil element 2C. Each end of the winding is drawn upward from one end side and the other end side of this one coil element 2C. Further, the end face shape of each coil element 2C is a shape in which each of the outer corner and the inner corner of the rectangular frame is rounded like the coil elements 2A and 2B of the first embodiment.

[core]
As shown in FIGS. 8 and 9, the core piece 3c of the present embodiment has a substantially E shape when viewed from above. The core piece 3 c includes a coil placement portion 31, an exposed portion 32, and a chamfered portion 33. The exposed portion 32 includes a base portion 32a and a pair of outer leg portions 32d and 32d. A two-dot chain line in the figure is a boundary between the base portion 32a and the leg portions (the coil placement portion 31 and the pair of outer leg portions 32d and 32d). In the reactor 1c, the coil arrangement portions 31 of the two core pieces 3c and 3c are inserted into the coil element 2C from both ends of the coil element 2C, respectively. At this time, the core facing surfaces of the opposing coil placement portions 31 and the core facing surfaces of the opposing outer leg portions 32d and 32d are joined to each other to form an integral core 3 and form a closed magnetic path in the reactor 1c. can do. Hereinafter, each part with which the core piece 3c mentioned above is provided is demonstrated.

(Coil placement part)
In this embodiment, the coil arrangement | positioning part 31 is made into the substantially rectangular parallelepiped shape similarly to Embodiment 1,2. Further, the end face shape, the axial length, and the corner drop portion are the same as in the first and second embodiments.

(Exposed part)
The exposed portion 32 in the present embodiment has a substantially] shape. The exposed portion 32 includes a base portion 32a and an outer leg portion 32d. Hereinafter, the outer leg portion 32d will be described.

(Outside leg)
The outer leg portion 32 d is a part of the exposed portion 32. In other words, it refers to a portion of the core leg that covers a part of the outer peripheral side surface of the coil 2. In the present embodiment, the outer leg portions 32d and 32d are substantially rectangular parallelepiped portions that are parallel to the coil placement portion 31 with the coil 2 interposed therebetween, and the length in the coil axial direction is the same as that of the coil placement portion 31. It is about half the length. Therefore, as described above, a plurality of core pieces 3c, 3c are combined to form an integral core 3. The magnetic flux generated by the coil 2C combined with the core 3 passes through the coil placement portion 31, and the base portion 32a of one core piece 3c, the outer legs 32d and 32d of the core piece 3c, and the outer legs of the other core piece 3c. It returns to the coil arrangement | positioning part 31 through the part 32d and 32d and the base 32a of this core piece 3c in order. Therefore, a closed magnetic circuit can be formed in the reactor 1c. Further, a corner drop portion is formed on a part of the periphery of the outer leg portions 32d, 32d facing the core circumferential surface of the coil placement portion 31.

(Chamfered part)
In the present embodiment, the chamfered portion 33 includes a chamfered portion 33a, a chamfered portion 33d, and a chamfered portion 33r. The chamfered portion 33a is formed at a corner portion of the outer peripheral surface of the coil placement portion 31 that is configured by an inner surface facing the outer leg portions 32d and 32d and a coil facing surface of the base portion 32a. The chamfered portion 33d is formed at a corner portion constituted by an inner side surface facing the coil placement portion 31 and a coil facing surface of the base portion 32a among the outer peripheral surfaces of the outer side leg portions 32d and 32d. The chamfered portion 33r is formed at both ends of the chamfered portion 33a and an upper end portion of the chamfered portion 33d.

  In the present embodiment, the core piece 3c includes six chamfered portions 33r. Of the peripheral edge of the core circumferential surface of the coil placement portion 31, four sides facing the corner R portion of the coil 2 are corner dropping portions that are corner-dropped along the shape of the corner R portion. By chamfering the area in the vicinity of the base portion 32a in the four corner dropping portions, four chamfered portions 33r are formed. Similarly, of the sides constituting the upper surfaces of the outer leg portions 32d and 32d, two sides facing the coil placement portion 31 are corner dropping portions. Two chamfered portions 33r are formed by chamfering the area near the base 32a of the corner dropping portion. The shape and size of the chamfer can be the same as those in the first embodiment. It should be noted that the outer leg portions 32d, 32d are not corner-dropped at the periphery on the lower surface side (not a corner-dropping portion). Thereby, when this lower surface is connected to the cooling base side, the lower surface can be utilized as a wide heat dissipation path.

<Modification 1>
Hereinafter, with reference to FIG. 10, the modification 1 which changed Embodiment 1 is demonstrated.

[Reactor]
Although the reactor 1d of this modification is the same as that of the first embodiment in that it includes a coil 2 including a pair of coil elements 2A and 2B, it has the same shape as the inner core pieces 3d and 3d having the same shape. The point which is set as the core 3 which combined two outer core pieces 3e and 3e differs from the reactor of Embodiment 1. FIG. Hereinafter, the inner core piece 3d and the outer core piece 3e, which are different from the reactor 1a of the first embodiment, will be described.

[Inner core piece]
The inner core pieces 3 d and 3 d are cores that are inserted into the coil 2 and are part of the coil placement portion 31. Further, when assembled to the coil 2, at least one of both end faces in the coil axial direction is located inside the coil end face. The inner core pieces 3 d and 3 d of the present modification are cores disposed in the coil elements 2 </ b> A and 2 </ b> B, and both end surfaces in the axial direction of the coil 2 are located inside the both end surfaces of the coil 2. In addition, the inner core pieces 3d and 3d of the present modified example have a rounded core circumference. That is, the inner core pieces 3d, 3d have a substantially rectangular parallelepiped shape in which a part of the periphery is dropped. By doing in this way, the defect | deletion of the periphery of the inner core pieces 3d and 3d can be prevented.

  As the inner core pieces 3d and 3d, not only composite materials but also powder compacts formed by press-molding magnetic powder and laminates obtained by laminating electromagnetic steel sheets may be used. In this modification, the inner core pieces 3d and 3d are formed of a compacted body. Hereinafter, the green compact will be described in detail.

[Green compact]
Typically, the compacting body constituting the inner core pieces 3d, 3d in the present embodiment can be manufactured by press-molding a magnetic powder having an insulating coating on the surface and then appropriately performing a heat treatment. it can. In the compacted body material, the coating powder having an insulating coating on the surface of particles made of a magnetic powder such as an iron-based material or an alloy containing a rare earth metal, an additive such as a resin such as a thermoplastic resin or a higher fatty acid The use of a mixed material to which (disappeared by the heat treatment or changed into an insulator) is used. According to the above manufacturing method, a compacted body in which the periphery of the magnetic particles is covered with an insulating coating (for example, a phosphate compound, a silicon compound, a zirconium compound, an aluminum compound, a boron compound, etc.) and an insulator is interposed between the particles. Is obtained. The green compact provided with an insulating coating is excellent in insulation and can reduce eddy current loss. Moreover, you may use the powder of a ferrite as a magnetic body powder for the material of a compacting body. When ferrite is used as a material, the insulation is excellent even if an insulating coating is not provided.

  The average particle size of the magnetic powder to be used is preferably 1 μm or more and 1000 μm or less, more preferably 10 μm or more and 500 μm or less. The magnetic powder may be a mixture of a plurality of powders with different average particle diameters, a mixture of a plurality of powders with different materials, or a mixture of a plurality of powders with different average particle diameters and materials. It may be good. In addition, the magnitude | size of the magnetic body powder in the compacting body and the powder used for the material is substantially the same (maintained).

  The content of the magnetic powder (magnetic component) in the green compact is preferably 70% by volume or more and 80% by volume or more when the green compact is 100% by volume. More desirable. The adjustment of the content of the magnetic powder in the green compact is, for example, the thickness of the insulating coating formed on the surface of the magnetic particles, and the amount of resin or additive added to the magnetic powder during the production of the green compact Can be adjusted by.

  As can be seen from the content of the magnetic powder, since the magnetic component is overwhelmingly larger than the insulating component in the powder compact, the powder compact has a high relative permeability compared to the composite material described above, and High saturation magnetic flux density. It is desirable that the powder compact has a relative permeability of 50 to 500, a saturation magnetic flux density of 1.0 T or more, and a thermal conductivity of 10 W / m · K or more. The magnetic properties of the green compact can be adjusted by changing the content of the magnetic powder. Of course, the magnetic properties of the green compact can also be adjusted by changing the material of the magnetic powder. In addition, the magnetic characteristics (particularly, the saturation magnetic flux density) of the green compact can be changed by adjusting the molding pressure during pressure molding. In that case, a compacting body with a high saturation magnetic flux density can be obtained by increasing the molding pressure. The relative magnetic permeability and magnetic flux density of the green compact can be obtained by the same method as that for the composite material described above.

[Outer core piece 3e]
The outer core pieces 3e and 3e in the present modification are core pieces that constitute the annular core 3 by being connected to the inner core pieces 3d and 3d, and are made of a composite material. Here, the outer core piece 3e according to the present modification has the same configuration as the core piece 3a according to the first embodiment, but the length of the coil placement portion 31 in the coil axial direction is the core piece 3a according to the first embodiment. The point which is shorter than that of the coil arrangement | positioning part 31 with which it comprises is different. If it demonstrates in detail, the length of the axial direction of the coil arrangement | positioning parts 31 and 31 of the outer core piece 3e will be the core piece which concerns on Embodiment 1 by the part of the length of the inner core pieces 3d and 3d in the coil axial direction. It is shorter than the coil arrangement parts 31 and 31 of 3a. Then, the inner core pieces 3d and 3d are inserted into the coil 2, the core facing surfaces of the inner core pieces 3d and 3d located inside the coil 2, and the core facing surfaces of the outer core pieces 3e and 3e (outer cores). The core 3 of the leg portion of the piece 3e is joined to form an annular core 3, and a closed magnetic circuit can be formed.

  According to the present embodiment, it is possible to reduce the leakage magnetic flux generated from the corner portion formed by the coil placement portions 31 and 31 and the base portion 32a included in the outer core pieces 3e and 3e. Further, by combining the inner core pieces 3d and 3d and the outer core pieces 3e and 3e into an integral core 3, the magnetic permeability of the coil placement portion 31 is made different between the central portion and both end portions of the coil 2. Is easy. Therefore, a reactor 1d having various characteristics can be realized.

<Embodiment 4>
In the fourth embodiment, a converter and a power conversion device according to the embodiment will be described with reference to FIGS. 11 and 12. The converter and the power conversion device include the reactor shown in the first to third embodiments and the first modification.

  In the reactors shown in Embodiments 1 to 3 and Modification 1, the energization conditions are, for example, maximum current (DC): about 100 A to 1000 A, average voltage: about 100 V to 1000 V, and usage frequency: about 5 kHz to 100 kHz. It can be used as a component of a converter mounted on a vehicle such as an electric vehicle or a hybrid vehicle, typically, or a component of a power conversion device including this converter. In this application, it is expected that an inductance satisfying 10 μH or more and 2 mH or less of the inductance when the DC current is 0 A and 10% or more of the inductance when the maximum current is applied is 10% or more can be suitably used.

  For example, a vehicle 1200 such as a hybrid vehicle or an electric vehicle is driven by a main battery 1210, a power conversion device 1100 connected to the main battery 1210, and power supplied from the main battery 1210 as shown in FIG. The motor (load) 1220 is provided. The motor 1220 is typically a three-phase AC motor, which drives the wheel 1250 when traveling and functions as a generator during regeneration. In the case of a hybrid vehicle, vehicle 1200 includes an engine in addition to motor 1220. In addition, in FIG. 11, although an inlet is shown as a charge location of the vehicle 1200, it is good also as a form provided with a plug.

  Power conversion device 1100 includes converter 1110 connected to main battery 1210 and inverter 1120 connected to converter 1110 and performing mutual conversion between direct current and alternating current. Converter 1110 shown in this example boosts the DC voltage (input voltage) of main battery 1210 of about 200V to 300V to about 400V to 700V and supplies power to inverter 1120 when vehicle 1200 is traveling. In addition, converter 1110 steps down DC voltage (input voltage) output from motor 1220 via inverter 1120 to DC voltage suitable for main battery 1210 during regeneration, and causes main battery 1210 to be charged. The inverter 1120 converts the direct current boosted by the converter 1110 into a predetermined alternating current when the vehicle 1200 is running, and supplies the motor 1220 with electric power. During regeneration, the alternating current output from the motor 1220 is converted into direct current and output to the converter 1110. doing.

  As shown in FIG. 12, the converter 1110 includes a plurality of switching elements 1111, a drive circuit 1112 that controls the operation of the switching elements 1111, and a reactor L, and converts input voltage by ON / OFF repetition (switching operation). (In this case, step-up / down pressure) is performed. For the switching element 1111, a power device such as FET or IGBT is used. The reactor L has the function of smoothing the change when the current is going to increase or decrease by the switching operation by utilizing the property of the coil that prevents the change of the current to flow through the circuit. As this reactor L, the reactor as described in the said embodiment and modified embodiment is used. By using these lightweight and easy-to-handle reactors, the power converter 1100 (including the converter 1110) can be reduced in weight.

  Here, the vehicle 1200 is connected to the converter 1110, the power supply converter 1150 connected to the main battery 1210, and the sub-battery 1230 and the main battery 1210 that are power sources of the auxiliary devices 1240. Auxiliary power supply converter 1160 for converting the high voltage 1210 to a low voltage is provided. The converter 1110 typically performs DC-DC conversion, while the power supply device converter 1150 and the auxiliary power supply converter 1160 perform AC-DC conversion. Some power supply device converters 1150 perform DC-DC conversion. The reactors of the power supply device converter 1150 and the auxiliary power supply converter 1160 have the same configuration as the reactors of the above-described embodiments and modifications, and a reactor whose size and shape are appropriately changed can be used. Further, the reactor of the above-described embodiment or the modified example can be used for a converter that performs conversion of input power and that only performs step-up or converter that performs only step-down.

  In addition, this invention is not limited to embodiment mentioned above, It can change suitably in the range which does not deviate from the summary of this invention. For example, an insulating member such as a bobbin may be interposed between the coil and the core. Further, the projecting portion of the core may be provided not only in the vertical direction of the base portion but also in all directions in the direction orthogonal to the coil axis direction so as to cover all the coil end faces.

Regarding the above description, the following additional notes are disclosed.
(Appendix 1)
A reactor comprising a core and a coil,
The core piece constituting at least a part of the core is composed of a composite material containing magnetic powder and resin,
The core piece is
A base disposed outside the coil so as to cover at least a part of the coil end surface;
The base is formed integrally with the base, and includes a leg that protrudes in a direction intersecting the base,
The leg portion includes a coil placement portion that is inserted inside the coil,
A reactor having a chamfered portion formed at a corner portion constituted by the leg portion and a portion facing at least a part of a coil end surface of the base portion.

  The reactor of the present invention can reduce loss. Therefore, it can be used for a component part of a power converter such as a bidirectional DC-DC converter mounted on a vehicle such as a hybrid vehicle, an electric vehicle, or a fuel cell vehicle. The core piece for a reactor according to the present invention can reduce loss generated in the reactor. Therefore, it is suitable as a core piece constituting the core provided in the reactor. The converter and the power converter of the present invention can be suitably used for in-vehicle components and the like by including the reactor of the present invention with reduced loss and excellent productivity.

1a, 1b, 1c, 1d reactor 2, coil 2A, 2B, 2C coil element 2r coil element connecting part 2a, 2b end 3 core 3a, 3a ', 3b, 3c core piece 3d inner core piece 3e outer core piece 31, 31A, 31B Coil arrangement portion 32 Exposed portion 32a Base portion 32b, 32c Protruding portion 32d Outer leg portion 32m Injection trace 33, 33a, 33b, 33d, 33r Chamfered portion B Burr S Envelope contour 1100 Power converter 1110 Converter 1111 Switching element 1112 Drive Circuit L Reactor 1120 Inverter 1150 Power supply converter 1160 Auxiliary power supply converter 1200 Vehicle 1210 Main battery 1220 Motor 1230 Sub battery 1240 Auxiliary equipment 1250 Wheel

Claims (11)

A reactor comprising a core and a coil,
The core piece constituting at least a part of the core is composed of a composite material containing magnetic powder and resin,
The core piece is
A coil placement portion inserted inside the coil;
An exposed portion that is molded integrally with the coil placement portion and is arranged outside the coil so as to cover at least a part of the coil end surface;
A reactor comprising a chamfered portion formed at a corner portion formed by the coil placement portion and a portion facing at least a part of a coil end surface of the exposed portion. The exposed portion is
A base having a portion facing at least a portion of the coil end surface;
An outer leg that covers a portion of the outer periphery of the coil;
The reactor of Claim 1 provided with the chamfered part formed in the corner comprised by the part which opposes at least one part of the coil end surface of the said base, and the said outer leg part.   The reactor according to claim 1 or 2, wherein a shape of the chamfered portion is an arc shape, and a radius R of the arc is 0.5 mm or more. The coil includes a pair of coil elements, and each coil element is arranged in parallel with each other in the axial direction.
The reactor according to any one of claims 1 to 3, wherein the coil placement portion is inserted inside each of the pair of coil elements. When the reactor is installed so that the axial direction of the coil is parallel to the installation target,
The exposed portion includes a protruding portion protruding in at least one direction of the installation target side of the reactor and the opposite side thereof,
The reactor of any one of Claims 1-4 provided with the chamfering part formed in the corner part which the said protrusion part and the said coil arrangement | positioning part comprise.   The reactor according to claim 5, wherein the protrusion includes an injection mark of the composite material.   The reactor according to any one of claims 1 to 6, wherein the coil placement portion includes an inclined surface that is inclined from an end surface side to an inner side of the coil.   The reactor according to any one of claims 1 to 7, wherein a periphery of at least one of the coil placement portion, the exposed portion, and the chamfered portion is dropped. A coil placement portion inserted inside the coil;
An exposed portion that is molded integrally with the coil placement portion and is arranged outside the coil so as to cover at least a part of the coil end surface;
A chamfered portion formed at a corner formed by the coil placement portion and a portion facing at least a part of the coil end surface of the exposed portion;
A core piece for a reactor composed of a composite material including magnetic powder and resin.   A converter provided with the reactor of any one of Claims 1-8.   A power converter device comprising the converter according to claim 10.

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