JP2012119454A - Reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reactor that has a reduced weight and a reduced number of components.SOLUTION: A reactor 100 includes a coil 110 and an annular core 120. The core 120 has a pair of intermediate cores 121 inserted in the coil 110 (coil elements 111, 112) and a pair of end core pieces 122 coupling ends of the pair of intermediate cores 121 juxtaposed, and the pair of intermediate cores 121 (main core sections) and the pair of end core pieces 122 (coupling core sections) combine annularly. The intermediate cores 121 each comprise a plurality of intermediate core pieces 123 and are each a member in which the intermediate core pieces 123 are arranged alternately with gap members 124. The intermediate core pieces 123 each have an insulating coating layer covering all the peripheral surfaces. The insulating coating layer is formed of an acrylic resin or silicone resin.

Description

  The present invention relates to a reactor used for a component of an in-vehicle DC-DC converter mounted on a vehicle such as a hybrid vehicle or an electric vehicle.

  One of the components of the circuit that performs the step-up operation or the step-down operation is a reactor. The reactor is mainly composed of a coil formed by winding a winding and a core that forms a closed magnetic circuit. As the form of the reactor, for example, the following two forms may be mentioned depending on the shape of the core.

  As a 1st form, the reactor provided with the cyclic | annular core formed by combining several core pieces is mentioned (for example, refer patent document 1). The core described in Patent Document 1 is formed in an annular shape by two opposing linear portions and two opposing curved portions, and each core piece forming the linear portion and the curved portion (the linear portion core body and the curved portion). A gap is provided between each of the core bodies. A gap material is disposed in each gap, and the gap material is fixed to the core piece with an adhesive. In addition, a coil is wound around each linear portion, and each linear portion is inserted into the coil.

  As a 2nd form, the reactor provided with the pot-type core formed by combining several core pieces is mentioned (for example, refer patent document 2). The core described in Patent Document 2 connects an inner core portion and an outer core portion that cover both ends of the coil, an inner core portion disposed inside the coil, an outer core portion disposed outside the coil, and both ends of the coil. A connecting core part. The inner core portion, the outer core portion, and the connecting core portion are each a laminate formed by laminating electromagnetic steel sheets, a compact formed by pressing a soft magnetic powder having an insulating coating on the surface, a soft magnetic powder and a binder resin. It is a core piece comprised from the molded object (molding hardening body) etc. of the mixture which mixed.

  In many cases, the coil is attached to the core while being wound around the bobbin (for example, see Patent Document 3). In the reactor described in Patent Document 3, each linear portion of the core on which the coil is disposed is covered with an inner bobbin, the coil is wound around the inner bobbin, and the linear portion of the core is inserted into the inner bobbin. It has become a state. In this reactor, outer bobbins are attached to both ends of the coil, and both ends of the coil are sandwiched between the outer bobbins.

JP 2006-351679 A JP 2009-033051 A JP 2008-028290 A

  In-vehicle parts such as recent hybrid vehicles are strongly required to be small and light, reduce the number of parts, and reduce the cost. However, since the conventional reactor uses a bobbin, it is difficult to reduce the weight, and the number of parts is large, so there is a problem in cost reduction.

  When the bobbin is not used, it is difficult to reliably ensure insulation between the coil (winding) and the core. Although it is conceivable to use a conductor having an insulation coating (eg, enameled wire) for the coil winding, there is a risk of the insulation coating peeling off when the winding is wound. It is necessary to thicken the insulation coating. However, when the insulation coating of the winding is made thick, it is difficult to wind and it is difficult to reduce the weight.

  This invention is made | formed in view of the said situation, and one of the objectives is to provide the reactor which can aim at weight reduction and reduction of a number of parts.

  The reactor of this invention is equipped with the coil formed by winding a coil | winding, and the core formed by combining a some core piece. And a core has a main core part penetrated in a coil, and a connection core part connected with this main core part, and it combines so that a closed magnetic circuit may be formed in both core parts. Further, at least one core piece constituting the main core portion includes an insulating coating layer covering the entire peripheral surface.

  According to this configuration, since the entire peripheral surface of the core piece constituting the main core portion is covered with the insulating coating layer, the coil (winding) and the core (main core portion) can be used without using a bobbin. It is possible to reliably ensure insulation between the two. The thickness of the insulating coating layer may be determined so as to ensure adequate insulation between the coil and the core, and can be made thinner than the bobbin. In addition, the insulating coating layer on the end surface of the core piece (the surface facing the adjacent core piece when used as a core) can also function as a gap material. Therefore, it is possible to reduce the weight of the reactor and reduce the number of parts.

  Here, the main core part and the connection core part in the case of the above-described annular core and pot type core will be described. In the case of an annular core, each straight portion corresponds to the main core portion referred to in the present invention, and both curved portions correspond to the connecting core portion referred to in the present invention. In the case of a pot-type core, the inner core portion corresponds to the main core portion referred to in the present invention, and the outer core portion and the connected core portion correspond to the connected core portion referred to in the present invention.

  In the reactor of the present invention, the insulating coating layer is preferably formed of a material satisfying at least one of the following characteristics, and more preferably formed of a material satisfying all of the following characteristics.

(1) Dielectric breakdown strength is 1 kV / mm or more (2) Thermal conductivity is 0.02 W / m · K or more (3) Rubber hardness is 10 or more and 70 or less

  The insulating coating layer is formed of an insulating material, and the insulating property can be increased by increasing the thickness. When the insulation coating layer is formed of a material having a dielectric breakdown strength of 1 kV / mm or more, the insulation coating layer can be made thin while ensuring insulation from the coil. Moreover, it is possible to ensure heat dissipation by making the insulating coating layer thin.

  When the insulation coating layer is made of a material with a thermal conductivity of 0.02 W / m · K or more, heat dissipation can be improved, and the heat of the core piece is transferred to the adjacent core piece (especially the core piece constituting the connecting portion). It is easy to convey to and can efficiently dissipate heat.

  When the reactor is driven, vibration due to magnetostriction of the core pieces themselves, vibration due to electromagnetic attraction between adjacent core pieces, and noise due to these vibrations are generated. When the insulating coating layer is formed of a material having a rubber hardness of 10 or more and 70 or less, it is possible to absorb the vibration when the reactor is driven, and to effectively reduce the vibration and the noise caused thereby. Further, when the rubber hardness is 10 or more and 70 or less, it is hard to be deformed to some extent, and it is easy to function as a gap material while maintaining a distance from an adjacent core piece. The rubber hardness referred to in the present invention is the Asker C hardness defined in the Japan Rubber Association Standard (SRIS 0101).

  In the reactor of the present invention, the insulating coating layer is preferably formed of at least one kind of acrylic resin and silicone resin.

  All the characteristics of (1) to (3) above ((1) Dielectric breakdown strength is 1 kV / mm or more, (2) Thermal conductivity is 0.02 W / m · K or more, and (3) Rubber hardness is 10 or more and 70. Examples of materials that satisfy the following) include acrylic resins and silicone resins. By forming the insulating coating layer from at least one of acrylic resin and silicone resin, it is possible to improve insulation, heat dissipation, and vibration control (silence).

  The insulating coating layer can be formed of a kind of material so as to cover the entire peripheral surface of the core piece. Moreover, you may form the outer peripheral surface (surface which opposes and contacts the inner peripheral surface of a coil) side of a core piece, and the end surface side of a core piece with a dissimilar material. For example, of the entire peripheral surface of the core piece, the outer peripheral surface side may be formed of a material having high dielectric breakdown strength (insulation), and the end surface side may be formed of a material having high thermal conductivity (heat dissipation).

  In the reactor of the present invention, the insulating coating layer preferably has a thickness of 0.02 mm to 6 mm.

  By setting the thickness of the insulating coating layer to 0.02 mm or more and 6 mm or less, it is easy to ensure sufficient heat dissipation of the core piece while ensuring sufficient insulation with the coil.

  The insulating coating layer may have a uniform thickness over the entire peripheral surface of the core piece, or may vary in thickness between the outer peripheral surface side of the core piece and the end surface side of the core piece. For example, among the entire peripheral surfaces of the core piece, the end surface side that functions as the gap material may be made thicker than the outer peripheral surface side. For example, the thickness on the outer peripheral surface side is 0.02 mm to 2 mm, the thickness on the end surface side is 1 mm to 6 mm, and the outer peripheral surface side is made thinner than the end surface side in consideration of heat dissipation while ensuring insulation.

  The insulating coating layer may contain a filler. By containing a filler, insulation, heat dissipation, and vibration control (silence) can be improved. The filler is selected from, for example, at least one kind of ceramic particles selected from silicon nitride, alumina, aluminum nitride, boron nitride, and silicon carbide, copper, zinc, tin, tungsten, lead, and alloys thereof. At least one metal particle can be used alone or in combination. For example, when the above-described ceramic particles are used for the filler, the heat conductivity of the ceramic is high, so that the heat dissipation can be improved while maintaining the insulation. On the other hand, when the above-described metal particles are used for the filler, the vibration damping property can be improved and the heat radiation property can be improved because the metal particles are heavier than the above-described ceramic particles.

  When a resin is used as the material for the insulating coating layer, examples of the method for forming the insulating coating layer include outsert molding and powder coating. As the powder coating, a fluid dip coating method can be used. In addition, even if an insulating coating layer is formed by sticking or winding this sheet (tape) material around the entire peripheral surface of the core piece using a sheet (tape) -like resin having one surface having adhesiveness Good. In this case, by using a sheet (tape) material of a different material, it is easy to form the outer peripheral surface side of the core piece and the end surface side of the core piece from different materials. Also, the thickness of the insulation coating layer can be controlled by sticking or winding this sheet (tape) material in multiple layers, so the thickness varies between the outer peripheral surface side of the core piece and the end face side of the core piece. It is also easy to make it. For such a sheet (tape) material, a commercially available thermal conductive sheet (acrylic thermal conductive sheet, silicone thermal conductive sheet) can be used (for example, a sheet-like thermal conductive gel manufactured by Taika Co., Ltd.). COH series (λGEL: registered trademark), Hypersoft heat dissipation material 5580H, 5589H manufactured by Sumitomo 3M Limited). When the insulating coating layer is formed by the above-described forming method, the insulating coating layer can be adhered to the core piece.

  As the core piece, a laminate of electromagnetic steel sheets, a compacted compact, and a compact (molded and cured product) of a mixture of a powder made of a magnetic material and a resin can be used.

  For example, in the above-described pot-type core, the core piece constituting the main core part is formed by a compacting body, and the core piece constituting the connection core part is formed by a molded cured body, and the magnetic flux saturation density of the main core part is determined by the connection core part. It is known that the cross-sectional area of the main core portion can be reduced and the reactor can be downsized by making the height higher (see Patent Document 2). Here, when the core piece constituting the main core part is a green compact, vibration due to the magnetostriction of the core piece itself is likely to occur. Can be expected.

  In addition to a conductor having an insulation coating (eg, enameled wire), a bare conductor having no insulation coating can be used for the coil winding. In the present invention, since the entire peripheral surface of the core piece constituting the main core portion is covered with the insulating coating layer, sufficient insulation can be ensured even if the winding is a bare conductor. When the winding is a bare conductor having no insulation coating, it can be easily wound and the reactor can be reduced in weight because there is no insulation coating.

  The reactor of this invention can aim at the weight reduction of a reactor, and reduction of a number of parts because the at least 1 core piece which comprises a main core part is equipped with an insulation coating layer.

1 is a schematic perspective view of a reactor according to a first embodiment. 2 is a schematic exploded perspective view of a core provided in the reactor according to Embodiment 1. FIG. It is the schematic of the reactor which concerns on Embodiment 2, (A) is the perspective view, (B) is the longitudinal cross-sectional view. FIG. 6 is a schematic exploded perspective view of a reactor according to a second embodiment. It is a schematic longitudinal cross-sectional view of the reactor which concerns on the modification 2-1 of Embodiment 2. FIG. It is the schematic of the reactor which concerns on the modification 2-4 of Embodiment 2, (A) is the perspective view, (B) is a longitudinal cross-sectional view of the arrow BB of (A). It is a schematic exploded perspective view of the reactor which concerns on the modification 2-4 of embodiment. It is the schematic of the reactor which concerns on the modification 2-5 of Embodiment 2, (A) is the longitudinal cross-sectional view of the example, (B) is a longitudinal cross-sectional view of another example.

  Embodiments of the present invention will be described below with reference to the drawings. In addition, the same code | symbol in a figure shows the same or an equivalent part.

[Embodiment 1]
In Embodiment 1, an embodiment including an annular core will be described.

  A basic configuration of the reactor according to the first embodiment will be described with reference to FIGS. A reactor 100 shown in FIG. 1 includes a coil 110 and an annular core 120 having a main core portion inserted into the coil 110 and a connecting core portion connected to the main core portion. Hereinafter, each configuration will be described in more detail.

  The coil 110 is formed by edgewise winding a rectangular winding having a rectangular cross section. In this example, a bare rectangular copper wire without an insulating coating is used for the winding. The coil 110 has a pair of coil elements 111 and 112 arranged in parallel and connected to each other, and both the coil elements 111 and 112 are formed in a rectangular tube shape with a single winding. Specifically, the winding portion is bent in a U-shape on the other end side of the coil 110 so that the starting end and the terminal end of the winding are located on one end side in the axial direction of the coil 110 to form the connecting portion 113. Thus, both coil elements 111 and 112 are formed by a single winding.

  As shown in FIG. 2, the core 120 includes a pair of intermediate cores 121 inserted into the coil 110 (coil elements 111 and 112) and a pair of ends connecting the ends of the pair of intermediate cores 121 arranged in parallel. Part core piece 122. The pair of intermediate cores 121 corresponds to the main core portion, and the pair of end core pieces 122 corresponds to the connecting core portion. The pair of intermediate cores 121 (main core portions) and the pair of end core pieces 122 (connection core portions) are combined to form an annular shape. The intermediate core 121 and the end core piece 122 may be joined with, for example, an adhesive.

  The intermediate core 121 includes a plurality of intermediate core pieces 123. In this example, the intermediate core 121 is a rectangular parallelepiped member in which gap members 124 and I-shaped intermediate core pieces 123 are alternately arranged and bonded with an adhesive. is there. On the other hand, the end core piece 122 is opposed to the end faces of both the intermediate cores 121, and the end face connected (connected) to both the intermediate cores 121 is a single plane, and the width increases from this end face toward the opposite end face. It is a member having a D-shaped section that narrows.

  The intermediate core piece 123 and the end core piece 122 are formed of a green compact. The gap member 124 is a plate-like member made of a nonmagnetic material, and is formed of ceramics such as glass epoxy resin or alumina, for example.

  In this example, the surface on the installation side of the end core piece 122 (the surface facing the installation target when the reactor 100 is installed on the installation target. The surface on the lower side in FIG. 2) is the surface on the installation side of the intermediate core 121. Than protruding. Thereby, the thickness of the end core piece 122 (the axial distance of the coil 110) can be reduced, and the projected area of the core 120 can be reduced. Therefore, the reactor 100 can be expected to be downsized. Since the end core piece 122 is formed of a green compact, the protruding portion can also be used for the magnetic path.

  The intermediate core piece 123 includes an insulating coating layer that covers the entire circumferential surface. The insulating coating layer is formed of an acrylic resin or a silicone resin. This resin may contain ceramic or metal particles (fillers). Moreover, the thickness of the insulating coating layer is, for example, 0.02 mm to 6 mm.

  The insulating coating layer can be formed by, for example, winding a sheet material around the entire peripheral surface of the intermediate core piece 123 using a sheet-like resin having one surface having adhesiveness. A commercially available sheet material can be used for this sheet material. Examples of other methods for forming the insulating coating layer include outsert molding and powder coating.

  The insulating coating layer may have a uniform thickness over the entire peripheral surface of the intermediate core piece 123, or the thickness may be changed between the outer peripheral surface side and the end surface side of the intermediate core piece 123. For example, the outer peripheral surface side of the entire peripheral surface of the intermediate core piece 123 may be thinner than the end surface side. Further, the insulating coating layer may be formed of a kind of material, and the material may be changed between the outer peripheral surface side and the end surface side of the intermediate core piece 123.

  In this example, the insulating coating layer is formed individually for each of the intermediate core pieces 123 constituting the intermediate core 121. However, the intermediate coating pieces 123 and the gap material 124 are collectively formed to form an insulating coating layer. Also good. Even in this case, the entire peripheral surface of the intermediate core piece 123 is covered with the insulating coating layer. In this case, the labor of joining the intermediate core piece 123 and the gap member 124 with an adhesive can be saved. Further, for example, a plurality of intermediate core pieces 123 are gathered together with a gap (gap) provided between the core pieces, and the gap portion between the core pieces is filled with the resin of the insulating coating layer by insert molding. An insulating coating layer may be formed and integrated.

  In this example, the three intermediate core pieces 123 and the four gap members 124 constitute the intermediate core 121. However, the number and arrangement of the intermediate core pieces 123 and the gap members 124 satisfy the required specifications. Can be changed as appropriate. For example, an intermediate core may be configured with one intermediate core piece, or a gap material may not be disposed at both ends of the intermediate core (that is, no gap material is interposed between the intermediate core piece and the end core piece). Good.

  Furthermore, in this example, the gap material 124 is used. However, when the insulating coating layer is formed of a nonmagnetic material, the insulating coating layer on the end face side of the intermediate core piece 123 can function as the gap material. Therefore, it is possible to control the thickness of the insulating coating layer on the end face side and omit the gap material. The acrylic resin and the silicone resin are both nonmagnetic.

  In the reactor 100 described above, the entire peripheral surface of the intermediate core piece 123 that constitutes the intermediate core 121 is covered with an insulating coating layer, so that the coil 110 (winding) and the core 120 (intermediate core 121) are separated. It is possible to ensure sufficient insulation. In addition, vibration and noise reduction effects can be expected. Furthermore, the reactor 100 can reduce the weight and the number of parts by not using a bobbin.

(Modification 1-1)
In the first embodiment described above, the case where the bare conductor (flat copper wire) having no insulation coating is used as the winding of the coil 110 has been described as an example. ), Or a coil molded body in which the coil 110 is molded with an insulating resin and the coil 110 and the resin are integrated. In this case, the insulation between the coil 110 and the core 120 can be further enhanced. For example, an epoxy resin, a polyphenylene sulfide (PPS) resin, a liquid crystal polymer (LCP), or the like can be used as the resin forming the coil molded body. Further, when this resin contains at least one kind of ceramic particles (filler) selected from silicon nitride, alumina, aluminum nitride, boron nitride, and silicon carbide, heat dissipation can be improved.

(Modification 1-2)
In the first embodiment described above, the case where the insulating coating layer is formed on the intermediate core piece 123 constituting the intermediate core 121 has been described as an example. However, the insulating coating layer is also formed on the entire peripheral surface of the end core piece 122. May be. In this case, since the entire peripheral surface of the end core piece 122 that may come into contact with the axial end surface of the coil 110 is covered with the insulating coating layer, the insulation between the coil 110 and the end core piece 122 is achieved. Can also be adequately secured. Further, when the reactor 100 is housed in the case, even if the end core piece 122 may come into contact with the inner peripheral surface of the case, the end core piece 122 includes an insulating coating layer, thereby reducing vibration and noise. Can be expected.

(Modification 1-3)
Although the reactor 100 according to the first embodiment described above can be used as it is, the reactor 100 may be molded with an insulating resin and provided with a resin coating portion. In this case, the reactor 100 can be protected from the external environment or mechanically protected. Examples of the resin forming the resin coating include epoxy resin, urethane resin, polyphenylene sulfide (PPS) resin, polybutylene terephthalate (PBT) resin, acrylonitrile-butadiene-styrene (ABS) resin, and unsaturated polyester resin. Can be used. Further, when the resin contains the above-described ceramic particles (filler), the heat dissipation can be improved.

  Alternatively, the reactor 100 may be housed in a case formed of a metal such as aluminum and its alloy, magnesium and its alloy, and the case may be filled with a resin and sealed. The material forming the case is preferably nonmagnetic. For example, a urethane resin, an epoxy resin, a silicone resin, or the like can be used as the sealing resin. Further, when the resin contains the above-described ceramic particles (filler), the heat dissipation can be improved.

  The case described above may be formed of a resin such as polybutylene terephthalate (PBT) resin, urethane resin, polyphenylene sulfide (PPS) resin, acrylonitrile-butadiene-styrene (ABS) resin. In general, many non-metals such as resin have high electrical insulation, so that sufficient insulation between the coil 110 and the case can be secured. Further, non-metals are lighter in specific gravity than the above-described metals, and can be expected to be lighter. When the resin forming the case contains the above-described ceramic particles (filler), heat dissipation can be improved. When the case is formed of a resin, injection molding can be used as the forming method.

[Embodiment 2]
In the above-described first embodiment, the embodiment including the annular core has been described. In the second embodiment, the embodiment including the pot-type core will be described.

  A basic configuration of the reactor according to the second embodiment will be described with reference to FIGS. A reactor 200 shown in FIGS. 3 and 4 includes a coil 210 and a pot-type core 220 having a main core portion inserted into the coil 210 and a connecting core portion connected to the main core portion. Hereinafter, each configuration will be described in detail.

  The coil 210 is formed in a cylindrical shape by edgewise winding a rectangular winding having a rectangular cross section. In this example, an insulating rectangular copper wire having an insulating coating is used for the winding.

  The core 220 connects the inner core piece 221 inserted through the coil 210, the outer core piece 222 arranged outside the coil 210, and the inner core piece 221 and the outer core piece 222 covering both ends of the coil 210. And a pair of connecting core pieces 223. The inner core piece 221 corresponds to the main core portion, and the outer core piece 222 and the pair of connecting core pieces 223 correspond to the connecting core portion. The inner core piece 221 (main core portion), the outer core piece 222 and the pair of connecting core pieces 223 (connecting core portion) are combined to form a pot shape. Note that the inner core piece 221 and the two connecting core pieces 223, and the outer core piece 222 and the two connecting core pieces 223 may be bonded to each other with, for example, an adhesive.

  In this example, the inner core piece 221 has a cylindrical shape, the outer core piece 222 has a cylindrical shape, and each connecting core piece 223 has a disk shape, and the inner core piece 221 and the outer core piece 222 are arranged on a concentric circle. The core piece 222 and the connecting core pieces 223 have substantially the same outer diameter. Further, the upper and lower end surfaces of the outer core piece 222 are provided with notches for drawing out the start end and the end of the winding of the coil 210, respectively. Each of these core pieces 221, 222, 223 is formed of a compacted body.

  The inner core piece 221 includes an insulating coating layer 225 that covers the entire circumferential surface (see FIG. 3B). The material, thickness, formation method, and the like of the insulating coating layer are the same as those described in the first embodiment. That is, the insulating coating layer can be formed by, for example, using a sheet-like resin with one surface sticking and winding the sheet material around the entire peripheral surface of the inner core piece 221. In addition, the insulating coating layer may have a uniform thickness over the entire peripheral surface of the inner core piece 221, and the thickness may be changed between the outer peripheral surface side and the end surface side of the inner core piece 221. Of the entire peripheral surface of the piece 221, the outer peripheral surface side may be thinner than the end surface side, and the insulating coating layer is formed of a kind of material, and the outer peripheral surface side and the end surface side of the inner core piece 221 You may change the material.

  The reactor 200 described above has sufficient insulation between the coil 210 (winding) and the core 220 (inner core piece 221) by covering the entire peripheral surface of the inner core piece 221 with an insulating coating layer. Can be secured. In addition, vibration and noise reduction effects can be expected. Furthermore, the reactor 200 can reduce the weight and the number of parts by not using a bobbin.

(Modification 2-1)
In the second embodiment described above, the case where the insulating coating layer is formed on the inner core piece 221 has been described as an example, but the insulating coating layer may also be formed on the entire peripheral surface of the outer core piece 222 and the connecting core piece 223. Good. For example, as shown in FIG. 5, an insulating coating layer 225 may be formed on the entire peripheral surface of the outer core piece 222 and both connecting core pieces 223, and all the core pieces 221, 222, 223 constituting the core 220 may be provided with an insulating coating layer. Good. In this case, the entire outer peripheral surface of the outer core piece 222 that may be in contact with the outer peripheral surface of the coil 210 and the entire peripheral surface of the connection core piece 223 that may be in contact with the axial end surface of the coil 210 are insulating coating layers. The insulation between the coil 210 and the outer core piece 222 and the connecting core piece 223 can be sufficiently ensured. Further, a bare conductor (flat copper wire) having no insulating coating may be used for the winding of the coil 210. Furthermore, since the outer core piece 222 and the connecting core piece 223 are provided with an insulating coating layer, a vibration / noise reduction effect can be expected.

(Modification 2-2)
In the above-described second embodiment, the case where an insulated flat copper wire having an insulating coating is used as the winding of the coil 210 has been described as an example. However, as described in the modification 1-1 of the first embodiment. Alternatively, a coil molded body in which the coil 210 is molded with an insulating resin and the coil 210 and the resin are integrated may be used. In this case, the insulation between the coil 210 and the core 220 can be further enhanced.

(Modification 2-3)
In the second embodiment described above, the case where the connecting core portion is configured by the three core pieces of the outer core piece 222 and the pair of connecting core pieces 223 has been described as an example. However, the outer core piece 222 and one of the connecting core pieces 223 are described. Or the outer core piece 222 is divided, and a part of the outer core piece 222 and one of the connecting core pieces 223 are integrally formed, and the remaining part of the outer core piece 222 and the other connecting core piece 223 may be integrally formed. In this case, the number of core pieces constituting the connecting core portion can be reduced.

(Modification 2-4)
In above-mentioned Embodiment 2, although the case where the compacting body was used for the core piece which comprises a connection core part was demonstrated to the example, you may use a shaping | molding hardening body for the core piece which comprises a connection core part. Hereinafter, the reactor in this case will be described with reference to FIGS.

  A reactor 300 shown in FIGS. 6 and 7 includes a coil 310 and a pot-type core 320 having a main core portion inserted into the coil 310 and a connecting core portion connected to the main core portion.

  The coil 310 is formed in a cylindrical shape by edgewise winding a rectangular winding having a rectangular cross section. In this example, an insulating rectangular copper wire having an insulating coating is used for the winding.

  The core 320 includes an inner core piece 321 (corresponding to a main core portion) that is inserted into the coil 310, and a connecting core portion 322 that is formed so as to cover the assembly of the inner core piece 321 and the coil 310. . This core 320 has partially different magnetic properties. Specifically, the inner core piece 321 is formed of a green compact and the connecting core portion 322 is formed of a molded and hardened body, and the inner core piece 321 has a higher saturation magnetic flux density than the connecting core portion 322.

  In this example, the inner core piece 321 is cylindrical. The inner core piece 321 is housed in the case 330 with one end surface abutting against the bottom surface of the case 330 so that the axial direction of the coil 310 is substantially orthogonal to the bottom surface of the case 330 (FIG. 6B). reference). Further, the axial length of the inner core piece 321 is longer than the length of the coil 310, and one end portion of the inner core piece 321 projects from the end surface of the coil 310.

  The inner core piece 321 includes an insulating coating layer 325 that covers the entire circumferential surface (see FIG. 6B). The material, thickness, formation method, etc. of the insulating coating layer are the same as those described in the first and second embodiments.

  The connecting core portion 322 is a core piece made of a molded hard body that forms a closed magnetic path with the inner core piece 321, and is connected to the inner core piece 321. In this example, as will be described later, the connecting core portion 322 is formed by using the case 330 as a mold. As shown in FIG. 6 (B), the connecting core portion 322 has substantially the entire surface of the assembly of the coil 310 and the inner core piece 321, that is, the outer peripheral surface and both end faces of the coil 310, and the other of the inner core piece 321. It is formed in a rectangular parallelepiped shape so as to substantially cover the end surface (the end surface opposite to the one end surface in contact with the bottom surface of case 330). Specifically, the outer shape of the connecting core portion 322 is the same as the shape of the space formed by the inner peripheral surface of the case 330. The inner core piece 321 and the connection core part 322 are integrated by a resin that forms the connection core part 322 (molded and cured body).

  The connection core portion 322 of the molded cured body is prepared by, for example, mixing a soft magnetic powder of a magnetic material and a fluid binder resin, pouring the mixture into the case 330 with a predetermined pressure, and then filling the resin. It can be obtained by solidifying. Alternatively, the mixture may be injected and filled into the case 330 without applying pressure to solidify the resin. Moreover, you may add nonmagnetic particle | grains (filler), such as above-mentioned ceramics, to a mixture as needed. As the binder resin, for example, a thermosetting resin such as an epoxy resin, a phenol resin, or a silicone resin can be suitably used. When a thermosetting resin is used as the binder resin, the resin is thermally cured by heating together with the mold (case 330). As the binder resin, a room temperature curable resin or a low temperature curable resin may be used. In this case, the resin can be cured while being kept at a room temperature to a relatively low temperature. Since the molded hardened body (connected core portion 322) contains a large amount of non-magnetic binder resin, even if the same soft magnetic powder as that of the green compact (inner core piece 321) is used, The saturation magnetic flux density is low and the magnetic permeability is also low. Further, since the connecting core portion 322 includes a resin component, the coil 310 and the inner core piece 321 can be protected from the external environment and mechanical stress such as moisture and dust.

  The case 330 can be made of metal or resin, as described in Modification 1-3 of Embodiment 1.

  The reactor 300 can be manufactured as follows, for example. In addition, an inner core piece 321 made of a coil 310 and a green compact is prepared, and the inner core piece 321 is inserted into the coil 310 to produce an assembly of the coil 310 and the inner core piece 321 (see FIG. 7). ). Next, the assembly of the coil 310 and the inner core portion 321 is stored in a predetermined position in the case 330. At this time, the coil 310 is supported so that a predetermined gap is formed between one end surface of the coil 310 (an end surface facing the bottom surface of the case 330) and the bottom surface of the case 330.

  Next, the case 330 containing the above-described assembly is filled with the material of the connecting core portion 322, that is, a mixture of soft magnetic powder and binder resin, and the resin is cured to integrally form the connecting core portion 322. . Note that the connecting core portion 322 may be formed in multiple steps, and an intermediate molded product of the connecting core portion 322 in the middle stage may be used for positioning the height position of the coil 310. Specifically, in a state where the coil 310 is not housed in the case 330, the case 330 is filled with a part of the mixture and cured, and only a part of the connecting core portion 322 is molded, and then the intermediate molded product is placed on the intermediate molded product. A coil 310 is disposed. Thereafter, the remaining portion of the connecting core portion 322 is molded, and the remaining portion and the intermediate molded product are integrated with resin to completely form the connecting core portion 322.

  The reactor 300 described above can enhance the insulation between the coil 310 and the core 320 (inner core piece 321) by covering the entire peripheral surface of the inner core piece 321 with an insulating coating layer. In addition, vibration and noise reduction effects can be expected. Further, when the saturation magnetic flux density of the inner core piece 321 is higher than that of the connecting core portion 322, when the same saturation magnetic flux density as that of the homogeneous core is obtained as a whole, the cross-sectional area of the inner core piece 321 (the cross-sectional area orthogonal to the magnetic flux) ) Can be reduced. By reducing the size of the inner core piece 321, the core 320 can be reduced in size, and further reduction in size and weight can be achieved.

(Modification 2-5)
In Modification 2-4, the axial length of the inner core piece 321 is longer than the length of the coil 310, and one end of the inner core piece 321 protrudes from the end surface of the coil 310. The length of the piece 321 may be changed as appropriate. For example, as shown in FIG. 8A, both end portions of the inner core piece 321 may be protruded from both end surfaces of the coil 310. For example, as shown in FIG. 8B, the length of the inner core piece 321 may be substantially equal to the length of the coil 310. In the latter case, in a state where the assembly of the coil 310 and the inner core piece 321 is not housed in the case 330, the case 330 is filled with a part of the mixture of the soft magnetic powder and the binder resin and cured, and the connecting core portion After molding only a part of 322, the braid is placed on the intermediate molding. Thereafter, the remaining portion of the connecting core portion 322 is molded, and the remaining portion and the intermediate molded product are integrated with resin to completely form the connecting core portion 322.

  The above-described embodiment can be appropriately changed without departing from the gist of the present invention, and is not limited to the above-described configuration.

The reactor of this invention can be utilized for the component of the vehicle-mounted DC-DC converter mounted in vehicles, such as a hybrid vehicle, an electric vehicle, and a fuel cell vehicle, for example. When the reactor is used for such applications, the energization conditions are the maximum current (DC): about 100A to 1000A, the average voltage: about 100V to 1000V, the operating frequency: about 5kHz to 100kHz, for example, the following specifications It is good to design so that it may satisfy.
Inductance: 10μH ~ 1mH
Volume: 200cm ^{3 to} 1000cm ³

  The reactor of the present invention can be suitably used as a component part of an in-vehicle DC-DC converter mounted on a vehicle such as a hybrid vehicle, an electric vehicle, or a fuel cell vehicle.

100,200,300 reactor
110,210,310 coil
111,112 Coil element 113 Connecting part
120 core (annular core)
121 Intermediate core 122 End core piece
123 Intermediate core piece 124 Gap material
220 core (pot type core)
221 Inner core piece 222 Outer core piece 223 Linked core piece
225 Insulation coating layer
320 core (pot type core)
321 Inner core piece 322 Connecting core
325 Insulation layer
330 cases

Claims (9)

A reactor comprising a coil formed by winding a winding and a core formed by combining a plurality of core pieces,
The core is
A main core portion inserted into the coil;
A connecting core portion connected to the main core portion,
Combined to form a closed magnetic circuit at both cores,
At least one core piece which comprises the said main core part is equipped with the insulation coating layer which covers all the surrounding surfaces, The reactor characterized by the above-mentioned.   The reactor according to claim 1, wherein the insulating coating layer is made of a material having a dielectric breakdown strength of 1 kV / mm or more.   The reactor according to claim 1, wherein the insulating coating layer is made of a material having a thermal conductivity of 0.02 W / m · K or more.   The insulating coating layer is formed of a material having a rubber hardness (Asker C hardness defined in Japan Rubber Association Standard (SRIS 0101)) of 10 or more and 70 or less. The reactor according to claim 1.   The reactor according to any one of claims 1 to 4, wherein the insulating coating layer is made of at least one resin selected from an acrylic resin and a silicone resin.   The reactor according to any one of claims 1 to 5, wherein the insulating coating layer has a thickness of 0.02 mm to 6 mm.   The reactor according to any one of claims 1 to 6, wherein the core piece constituting the main core portion is a compacted body.   The reactor according to any one of claims 1 to 7, wherein the core piece constituting the connecting core portion is a molded body of a mixture of a powder made of a magnetic material and a resin.   The reactor according to claim 1, wherein the winding is a bare conductor having no insulating coating.

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