JP2010093138A - Reactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reactor for improving workability when assembling into the reactor. <P>SOLUTION: The reactor includes: an assembly wherein a coil 10 is arranged on the outer periphery of a core 150; a case 170 housing the assembly; and a sealing resin 180 charged between these assembly and case 170. The assembly includes a coil molding body 100 and the core. The coil molding body 100 includes: the coil 10 wherein a winding wire is wound in spirals; a resin mold part 20 which holds the coil 10 in a condition where it is constricted shorter than free length; and a core holding part which is so formed of the resin mold part 20 that the core 150 is inserted inside the coil. The sealing resin 180 is a resin whose shock resistance is higher than that of the resin of the resin mold part 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reactor used for components such as a converter.

  2. Description of the Related Art In recent years, converters that perform voltage step-up / step-down are used in hybrid vehicles that are becoming popular, and a reactor described in Patent Document 1 is known as one of the components of the converter.

  This reactor has as its main constituent members an annular core made of a magnetic material and a coil wound in parallel around a part of the outer periphery of the core. In order to assemble this reactor, for example, a coil is formed in advance by winding a rectangular wire edgewise. And the core comprised from a some division | segmentation piece is engage | inserted in the inner periphery of this coil, and an annular core is formed by adhere | attaching division pieces between each division piece via a gap board.

  At the time of this assembly, a resin cylindrical bobbin (inner bobbin) for positioning the coil with respect to the core is interposed between the coil and the core, and a resin frame bobbin (outer bobbin) is disposed at both ends of the coil. ) Is arranged. Usually, a gap is formed between adjacent turns in a coil before assembly by a rectangular springback. Therefore, both ends of the coil are pressed by the frame-shaped bobbin so that the coil after assembly is in a compressed state in which adjacent turns come into contact with each other. The assembly of the core, coil, and each bobbin is housed in a metal case, and a sealing resin is filled between the assembly and the case.

JP 2008-28290 A FIG. 3 and FIG. 4

  However, the above prior art has the following problems.

  First, there is a problem that the number of parts of the reactor is large and assembly workability is poor. Specifically, in order to align the core and the coil, a cylindrical bobbin is required as an independent part. Usually, this cylindrical bobbin is formed in a cylindrical shape by combining a pair of divided pieces having a cross-section] type, and its assembling work is also required.

  Further, since the coil expands and contracts when there is a gap between adjacent turns of the coil, it is difficult to handle the coil during assembly. On the other hand, in order to hold the coil in a compressed state, a frame-shaped bobbin is required as an independent component, and an assembly operation of the frame-shaped bobbin to the coil (core) is also required.

  Secondly, cracks and defects may occur in the sealing resin. Since the sealing resin is disposed close to the heat source, a certain degree of heat resistance is required. Here, if an epoxy resin or the like is used as the sealing resin in consideration of heat resistance, the epoxy resin has a relatively high hardness and is inferior in impact resistance. And defects may occur. If such a defect occurs, not only can the assembly not be securely held in the case, but a gap is formed between the sealing resin and the case, and there is a possibility that heat dissipation from the sealing resin to the case may be insufficient. is there.

  The present invention has been made in view of the above circumstances, and one of its purposes is to provide a reactor capable of reducing the number of parts.

  Another object of the present invention is to provide a reactor having excellent workability when assembled as a reactor.

  Furthermore, another object of the present invention is to provide a reactor having both heat dissipation characteristics and mechanical characteristics.

  The reactor of this invention concerns on a reactor provided with the assembly by which the coil was distribute | arranged to the outer periphery of the core, the case which accommodates this assembly, and sealing resin with which it fills between these assemblies and a case. This assembly includes a coil molded body and a core. The coil molded body includes a coil in which a winding is wound in a spiral shape, a resin mold portion that holds the coil in a compressed state with respect to its free length, and the core is fitted on the inner peripheral side of the coil. And a core holding part formed of a resin mold part. The sealing resin is a resin having higher impact resistance than the resin of the resin mold part.

  According to this configuration, since the coil can be held in a compressed state by the resin mold portion, the coil molded body can be easily handled. In addition, by making the sealing resin a resin having higher impact resistance than the resin of the resin mold part, it is possible to arrange the resin having high impact resistance outside the inside of the assembly. Generation of cracks and defects can be suppressed.

  In the reactor of the present invention, the resin of the resin mold part is preferably a resin having higher heat resistance than the sealing resin.

  According to this configuration, the resin of the resin mold portion is as much as the sealing resin disposed on the outside of the resin mold portion by using a highly heat-resistant resin for the resin of the resin mold portion that is in contact with the coil or core that is a heat source. There is no need to use a highly heat-resistant resin.

  In the reactor of the present invention, the resin of the resin mold part is preferably a resin having a higher thermal conductivity than the sealing resin.

  According to this configuration, efficient heat dissipation from the vicinity of the heat generation source is promoted by using the resin having a high thermal conductivity for the resin of the resin mold portion that is in contact with the coil or the core as the heat generation source. Further, it is not necessary to use a resin having a higher thermal conductivity than the resin of the resin mold part up to the sealing resin disposed outside the resin mold part.

  In the reactor of the present invention, the coil molded body and the case are preferably in surface contact.

  Since the coil molded body and the case are in surface contact, heat conduction from the coil molded body to the case can be efficiently performed.

  In the reactor of the present invention, it is preferable that a heat sink integrated with a contact surface with the case in the resin mold part is further provided.

  According to this configuration, heat can be effectively radiated from the coil molded body to the case via the heat radiating plate.

  In the coil molded body of the present invention, it is preferable that a concave portion is formed on the inner peripheral surface of the core holding portion.

  According to this configuration, when the assembly of the coil molded body and the core is sealed with the sealing resin, the concave portion can be a flow path of the sealing resin, and the wraparound of the sealing resin to the assembly can be improved. it can.

  It is preferable that the recess has a depth corresponding to the gap between the core and the coil.

  According to this configuration, at the time of molding the resin mold portion, by placing the core having a protrusion having a height corresponding to the gap between the core and the coil in the coil and casting the resin, the entire inner circumference of the coil can be obtained. A resin mold portion having a substantially uniform thickness can be easily formed over the circumference.

  In the reactor of the present invention, it is preferable that at least one of a concave portion and a convex portion is formed on the surface of the resin mold portion on the outer periphery of the coil.

  According to this configuration, when the assembly of the coil molded body and the core is sealed with the sealing resin, the flow path of the sealing resin can be formed in the concave portion or between the convex portions, and the sealing resin wraps around the assembly. Can be improved.

  According to the reactor of this invention, workability | operativity at the time of assembling to a reactor can be improved by hold | maintaining a coil in a compression state by a resin mold part. Moreover, it can be set as the reactor excellent in mechanical characteristics, especially impact resistance by making resin with the characteristic from which the resin of a resin mold part and sealing resin differ.

  The reactor of this invention is equipped with an assembly, a case, and sealing resin, and is further provided with a heat sink as needed. Among these, the assembly includes a coil molded body and a core. Furthermore, a coil molded object is provided with a coil and a resin mold part. This reactor does not require a cylindrical bobbin conventionally used for aligning the coil and the core or a frame bobbin for pressing the coil in a compressed state as an independent part. Hereinafter, each component will be described in more detail.

[Coil molding]
<Coil>
The coil is formed by winding a winding made of a conductor and an insulating coating covering the periphery of the conductor in a spiral shape. A metal material excellent in conductivity such as copper (copper alloy) can be suitably used for the conductor, and enamel can be suitably used for the insulating coating. Various forms such as a circle, an ellipse, and a polygon can be used for the cross section of the winding. If a coil is comprised with a polygonal coil | winding, a space factor will be easy to raise compared with the case where a circular coil | winding is used. When a winding having a rectangular cross section is used, edgewise winding can be suitably used as a winding method of the winding. At the stage where the coil is formed by winding, a gap is usually formed between the turns of the coil with the spring back of the conductive material. The axial length of the coil in the non-compressed state is defined as the free length of the coil.

<Resin mold part>
The resin mold part covers at least a part of the coil and compresses and holds the coil in a state shorter than the free length. In other words, as long as the coil can be held in a compressed state rather than the free length, the entire turn part of the coil may be covered with the resin mold part, or only a part of the coil turn part may be covered with the resin mold part, and the remaining part of the coil may be covered. It may be exposed. By holding the coil in a compressed state by the resin mold portion, the coil molded body can be handled as a single member that does not expand and contract, and the handling properties of the components during reactor assembly can be improved. Moreover, the frame-shaped bobbin conventionally used for pressing the coil is not necessary. However, the ends of the windings that make up the coil need to be pulled out to the terminal block, so that they are exposed from the resin mold.

  The compression state of the coil held by the resin mold part may be shorter than the free length. However, it is preferable to be in a compressed state in which adjacent turns of the coil are in contact with each other. Thereby, the reactor which is further excellent in heat dissipation can be comprised by miniaturizing a coil molded object and preventing resin of a resin mold part from invading between turns.

The resin mold part that holds the coil in a compressed state forms a core holding part that is held so that the core is fitted to the inner periphery of the coil. The core holding part is typically a hollow hole formed in the inner periphery of the coil by curing the resin in the resin mold part, but the core is fitted when the resin in the resin mold part is cured. This includes the case where the core is integrally formed with the fitting portion. In the former case, the core is fitted into the hollow hole after the resin in the resin mold portion is cured. In the latter case, the coil and the core are integrated with the resin of the resin mold part. The core holding part has a function of aligning the coil with the core. Therefore, it is preferable that the thickness of the resin mold portion formed on the inner periphery of the coil is substantially uniform. Thereby, a core and a coil are combined substantially coaxially only by fitting a core in a coil molded object. Of course, the resin mold part formed in the inner periphery of the coil also contributes to ensuring insulation between the core and the coil. The thickness of the resin mold portion formed on the inner periphery of the coil is preferably thin in terms of heat dissipation, and may be, for example, about 2 mm.

  The resin that forms the resin mold part is a material that has heat resistance that does not soften against the maximum temperature of the coil (core) when a coil molded body is used as a reactor, and that can be transfer molded or injection molded Can be suitably used. Moreover, the material excellent in insulation is preferable. In particular, a resin that is superior in at least one of heat resistance and thermal conductivity to a sealing resin described later is preferable. For example, thermosetting resins such as epoxy, and thermoplastic resins such as polyphenylene sulfide (PPS) and liquid crystal polymer (LCP) can be suitably used. In order to increase the thermal conductivity of these resins, a ceramic filler having a high thermal conductivity may be mixed. Examples of the material for the ceramic filler include at least one selected from silicon nitride, alumina, aluminum nitride, boron nitride, and silicon carbide. The form of the filler is preferably a granular material because it is uniformly dispersed in the resin.

  Moreover, it is preferable that the resin mold part in the inner periphery of a coil, ie, the inner peripheral surface of a core holding part, is formed with a recess. The sectional shape of the recess is not particularly limited. This recess can be used as a flow path for the sealing resin when an assembly in which the core is combined with the coil molded body is sealed with the sealing resin, so that the sealing resin can smoothly flow around the coil molded body. Can do. In particular, it is preferable that the recess has a depth corresponding to the gap between the core and the coil. As will be described later, the molding of the resin mold portion is performed by, for example, storing the coil in a compressed state in a mold, and further inserting a core into the inner periphery of the coil and casting the resin. Therefore, if a protrusion having the same height corresponding to the gap between the core and the coil is formed on the outer periphery of the core, a portion corresponding to the protrusion of the core is formed as a concave portion of the resin mold portion. That is, the thickness of the resin mold portion on the inner periphery of the coil can be made substantially uniform, and when the core is inserted into the hollow hole, the gap between the core and the coil is made uniform over the entire circumference of the core (coil). be able to. Therefore, it is not necessary to use the conventionally used cylindrical bobbin in the reactor of the present invention.

  Furthermore, it is preferable to provide at least one of a concave part and a convex part on the outer peripheral side of the coil in the resin mold part. Due to the recesses and protrusions, the coil molded body can have a large surface area and heat dissipation can be improved. In addition, when an assembly in which a core is combined with a coil molded body is sealed with a sealing resin, a space between the concave or convex portions can be used as a flow path for the sealing resin, and a sealing resin is placed around the coil molded body. You can wrap around smoothly. For example, forming the groove | channel along the opening-and-closing direction of the metal mold | die at the time of shape | molding the resin mold part is mentioned in the outer peripheral surface of a resin mold part. The depth of the groove is not particularly limited, and the coil may be exposed from the resin mold part, or the coil may be covered with the resin mold part. In the former case, high heat dissipation can be expected, and in the latter case, the coil at the groove forming portion can also be mechanically protected. The cross-sectional shape of the groove is not particularly limited, and various shapes such as a polygon, a semicircle, and a semi-ellipse can be selected. However, since the bottom surface of the case where the coil molded body is installed is usually configured as a flat surface, the resin molding portion has a groove in order to secure a contact area with the case bottom surface on the installation surface of the coil molded body. It is desirable to form a flat surface without forming. If the coil molded body and the case are in surface contact with a wider area, heat from the coil molded body can be effectively radiated to the case. However, when the installation surface of the coil molded body has irregularities, the coil molded body and the case can be brought into surface contact in a wide range by configuring the bottom surface of the case in a shape that matches the irregularities.

<Manufacturing method of coil molded body>
The method for manufacturing the coil molded body will be described in detail in the embodiments described later. In the mold, the step of arranging the coil in the mold, the step of inserting the core or core in the inner periphery of the coil, A step of holding the coil in a compressed state shorter than the free length, a step of injecting a resin into the mold and solidifying it, forming a molded body in which the coil is held in a compressed state by the resin, and taking out the molded body from the mold A process. In order to hold the coil in a compressed state in the mold, it is possible to press a part of the coil with a rod-like body that can be moved back and forth in the mold to bring the coil into a compressed state.

<Heat sink>
Furthermore, it is preferable to integrate a heat radiating plate excellent in thermal conductivity into the resin mold part. Generally, a reactor is attached to a cooling base through which a refrigerant is circulated. Therefore, if the heat sink is integrated with the surface on the cooling base side (molded body installation surface) in the resin mold portion of the coil molded body, efficient heat dissipation can be performed via the heat sink and the bottom of the case. Moreover, if the heat sink is integrated with the coil molded body, the assembly workability is excellent also when the reactor is combined with the core later. In particular, one surface of the heat radiating plate is in surface contact with the coil, the resin of the resin mold portion is not substantially interposed at the contact interface, and the other surface of the heat radiating plate is exposed from the resin mold portion. It is preferable to integrate them. If it does in this way, the heat of a coil can be rapidly conducted to the exterior of a coil fabrication object via a heat sink.

  This heat radiating plate is preferably made of a material having a thermal conductivity α (W / m · K) of more than 3 W / m · K, particularly 20 W / m · K or more, more preferably 30 W / m · K or more. Further, since the heat radiating plate is disposed in contact with or close to the coil, it is preferable that the whole is made of a non-magnetic material in consideration of magnetic characteristics. The material satisfying such characteristics is preferably a nonmagnetic inorganic material. Nonmagnetic inorganic materials include conductive materials and insulating materials. The constituent material of at least the coil side contact surface in contact with the coil in the heat sink is desired to be electrically insulated from the coil, and therefore is preferably an insulating material. Therefore, the heat dissipation plate may be composed entirely of an insulating inorganic material, or a laminated structure having a layer made of an insulating inorganic material on the surface of a plate-like substrate made of a conductive inorganic material. But you can. Note that “insulating” has an insulating property that can ensure electrical insulation with the coil.

Ceramics can be suitably used as the insulating inorganic material. Specifically, silicon nitride (Si ₃ N ₄ ): about 20 to 150 W / m · K, alumina (Al ₂ O ₃ ): about 20 to ₃₀ W / m · K, aluminum nitride (AlN): 200 to 250 W / at least one selected from about m · K, boron nitride (BN): about 50 to 65 W / m · K, and silicon carbide (SiC): about 50 to 130 W / m · K. Conductivity). That is, a heat dissipation plate made of one type of material may be used, or plate pieces made of a plurality of types of materials may be combined and integrated, and the thermal characteristics may be partially changed. Of the above ceramics, silicon nitride is preferable because it has high thermal conductivity and is superior in bending strength to alumina, aluminum nitride, and silicon carbide.

<Core>
The reactor can be easily configured by inserting the core into the hollow hole of the coil molded body described above, or by integrating the coil and the core with the resin mold portion at the time of molding the resin mold portion.

  The core is typically configured in an annular block shape by combining a plurality of core pieces. This core usually includes a core winding portion (intermediate magnetic member) where the coil is disposed on the outer periphery and an exposed portion (end magnetic member) exposed from the coil. In many cases, the core includes a plurality of magnetic members and a plurality of gap portions, and each magnetic member is joined through the gap portions. As the magnetic member, for example, a compacted body of soft magnetic powder or a laminate of electromagnetic steel sheets can be suitably used. The gap portion is interposed between the magnetic members, is used to adjust the inductance of the core, and is made of a nonmagnetic material. Examples of the material of the gap part include alumina. In addition, it is possible to use a core that is made of a compacted body with adjusted permeability and does not have a gap.

<Case>
The case houses the above-described assembly of the core and the coil molded body, and dissipates heat from the assembly through the case. By using the case, it is easy to mechanically protect the core and the coil molded body. A sealing resin described later is filled between the assembly and the case.

  This case is usually a container having a front, back, left, and right side surfaces and a bottom surface, and an open top. At that time, on the bottom surface, step portions are formed on both end sides, the upper surface of each step portion is used as a support surface of the core, and an intermediate bottom surface lower than the support surface is formed between both step portions. It is preferable that a gap is formed between the coil and the coil molded body. If the case of this form is used, the core can be held in direct contact with the support surface, so that efficient heat dissipation from the core through the case can be performed. In addition, the step between the support surface and the bottom surface of the case described above is larger than the distance from the surface of the core that contacts the support surface to the installation surface of the coil molded body, so A gap for filling the sealing resin described below can be formed between the two. By filling the gap with the sealing resin, it is possible to ensure insulation between the bottom surface of the case and the coil.

  The constituent material of the case is preferably made of a material with high heat dissipation. Specifically, a material excellent in thermal conductivity, particularly a metal material can be suitably used. Aluminum or aluminum alloy is particularly preferable.

<Sealing resin>
The sealing resin covers the periphery of the assembly of the coil molded body and the core, and provides mechanical protection for the assembly. In addition, the function of the sealing resin is to absorb vibration generated when the reactor is excited, and when there is a coil part exposed from the resin mold part, cover the exposed part and protect it mechanically and electrically. Can be mentioned. In addition, when a case is used, the function of further increasing the insulation between the coil and the case, the function of holding the core and the coil molded body, etc., housed in the case, or the heat of the coil molded body It also has the function of conducting the heat to the case.

  The sealing resin is a resin having higher impact resistance than the resin of the resin mold portion. The impact resistance may be evaluated by, for example, a test value of an Izod impact test or a Charpy impact test. The sealing resin is required to have a certain degree of heat resistance, but may not have as high heat resistance as the resin of the resin mold portion. For example, when the resin mold portion requires heat resistance of about 200 ° C., the sealing resin may have heat resistance of about 130 ° C. For example, urethane resin or the like can be suitably used as the sealing resin. Urethane resin is inferior in heat resistance to epoxy used for resin in the resin mold part, but is excellent in impact resistance and economy. As the sealing resin, a porous material that is excellent in absorbing sound generated by the vibration of the reactor can also be used. Specific examples include foamed plastics such as foamed polystyrene, foamed polyethylene, foamed polypropylene, and foamed polyurethane, and foamed rubbers such as foamed chloroprene rubber, foamed ethylene propylene rubber, and foamed silicon rubber.

  In addition, polyamide can be used as the sealing resin. An epoxy resin containing a ceramic filler can be suitably used as the resin of the resin mold part, but this epoxy resin has high hardness but is relatively inferior in impact resistance. Therefore, a reactor excellent in impact resistance can be obtained by covering the coil molded body with a polyamide sealing resin excellent in impact resistance.

<Coil molding>
First, with reference to FIGS. 1-3, the coil molded object 100 which comprises the reactor of this invention is demonstrated. The coil molded body 100 includes a coil 10 in which a winding is wound edgewise in a spiral shape, and a resin mold portion 20 that covers the coil 10, and an intermediate magnetic member 154 of a core 150 (FIG. 3) on the inner periphery of the coil 10. A hollow hole 30 (core holding part) for fitting is formed.

  The coil 10 includes a pair of a first coil 10A and a second coil 10B that are arranged in parallel in a direction orthogonal to the axial direction. The first and second coils 10A and 10B are coils having the same number of turns and a substantially rectangular shape when viewed from the axial direction. Further, both the coils 10A and 10B are constituted by a single winding without a joint. That is, on one end side of the coil 10, the start end 11 and the end end 12 of the winding are drawn upward, and on the other end side of the coil 10, the first coil 10 </ b> A is connected via a bent connecting portion 13 that bends the winding into a U shape. And the second coil 10B. With this configuration, the winding directions of the first coil 10A and the second coil 10B are the same. Each of the coils 10A and 10B is compressed so that adjacent turns are in contact with each other.

  A resin mold portion 20 that holds the coil 10 in a compressed state is formed on the outer periphery of the coil 10. Here, the entire coil 10 is covered with the resin mold part 20 except for the start end 11 and the end end 12 of the winding. The resin mold portion 20 covers the turn portions of both the coils 10A and 10B with a substantially uniform thickness. However, some corners of each of the coils 10A and 10B and the resin mold portion 20 of the bending connecting portion 13 have a portion having a nonuniform thickness. Since the bent connecting portion 13 is formed so as to protrude from the upper center of the coil 10 in the axial direction of each of the coils 10A and 10B, the resin mold portion 20 covering the connecting portion 13 is also projected in an eave shape. . Further, since the adjacent turns of the coils 10A and 10B are in contact with each other, the resin of the resin mold portion 20 does not substantially enter between these turns.

  On the other hand, the hollow hole 30 formed in the inner periphery of each coil 10A, 10B, that is, the inner periphery of the resin mold part 20, is formed by removing the core when the resin mold part 20 is molded, as will be described later. The resulting cross section is a rectangular hole.

<Manufacturing method of coil molded body>
Next, the manufacturing method of such a coil molded object is demonstrated based on FIG. To obtain a coil molded body, first, the coil 10 is placed in the mold 50. At that time, a certain gap is formed between the mold surface and the coil 10. A mold 50 used for molding is composed of a pair of a first mold 51 and a second mold 52 that are opened and closed. The first mold 51 includes an end plate 51A located on one end side (start end / end end side) of the coil 10 and a core 51B inserted into the inner periphery of each coil 10. On the other hand, the second mold 52 includes an end plate 52A located on the other end side (bending connecting portion side) of the coil, and a side wall 52B covering the periphery of the coil 10.

  The first and second molds 51 and 52 are provided with a plurality of rod-like bodies 53 that can be advanced and retracted inside the mold 50 by a drive mechanism (not shown). Here, a total of eight rod-like bodies 53 are used, and the coils 10 are compressed by pressing almost the corners of the coils 10A and 10B. However, since it is difficult to push the bent connecting portion 13 with the rod-like body 53, the lower portion of the connecting portion 13 in FIG. The rod-like body 53 is made as thin as possible to reduce the number of places where the coil 10 is not covered with the resin mold portion, but is assumed to have sufficient strength and heat resistance to compress the coil 10. At the stage where the coil 10 is placed in the mold 50, the coil 10 is not yet compressed, and a gap is formed between adjacent turns.

  Next, the mold 50 is closed, and the core 51B is inserted inside the coil 10. At this time, the interval between the core 51B and the coil 10 is made substantially uniform over the entire circumference of the core 51B.

  Subsequently, the rod-shaped body 53 is advanced into the mold 50 to compress the coil 10. By this compression, adjacent turns of the coil 10 are brought into contact with each other, and there is no gap between the turns.

  Thereafter, an epoxy resin is injected into the mold 50 from a resin injection port (not shown). The rod-like body 53 may be retracted from the mold 50 as long as the injected resin is solidified to some extent and the coil 10 can be held in a compressed state.

  When the resin is solidified and a coil molded body that holds the coil 10 in a compressed state is molded, the mold 50 is opened and the molded body is taken out from the mold.

  The obtained molded body is formed in a shape having a plurality of small holes without being covered with the resin mold portion at the portion pressed by the rod-shaped body 53. This small hole may be filled with an appropriate insulating material or the like, or may be left as it is.

<Reactor assembly>
Next, a procedure for constructing a reactor using the above coil molded body will be described with reference to FIGS.

  If the magnetic member is fitted into the hollow hole 30 of the molded body 100 described above to form the annular core 150, the assembly 200 can be configured. For example, the core 150 includes an end magnetic member 152 exposed from the coil molded body 100, an intermediate magnetic member 154 disposed in the hollow hole 30 of each coil and connecting the end magnetic members 152 to each other, and the intermediate magnetic member 154. And a gap plate 156 interposed therebetween. In this example, each of the magnetic members 152 and 154 is made of a powder magnetic material, the end magnetic member 152 is in a trapezoidal block shape, and the intermediate magnetic member 154 is in a rectangular block shape. The gap plate 156 was an alumina plate. The magnetic members 152 and 154 and the gap plate 156 are bonded with an appropriate adhesive to constitute an annular core 150.

  Such an assembly 200 of the molded body 100 and the core 150 is housed in a case 170 as shown in FIG. Here, unlike FIG. 3, an assembly 200 having a configuration in which a part of the coil 10 is exposed from the resin mold portion 20 is shown. In order to fix the assembly 200 to the case 170, a plate spring or a presser fitting (not shown) that holds the upper part of the core as appropriate may be used. As shown in FIG. 1, a concave groove portion is formed on the bottom surface of the coil molded body 100 of this example at a position corresponding to between the coils 10 </ b> A and 10 </ b> B, but this concave groove portion is formed on the bottom surface of the case 170. A protrusion (see FIG. 5) is formed to be fitted into the. Therefore, when the assembly 200 is stored in the case 170, the entire bottom surface of the coil molded body 100 and the bottom surface of the case are brought into surface contact. When the assembly 200 is stored in the case 170, a sealing resin is filled between the assembly 200 and the case 170. At this time, it is preferable that the sealing resin does not enter between the coil molded body 100 and the bottom surface of the case. Thereby, heat radiation from the coil molded body 100 to the case 170 is improved.

  The sealing resin was polyurethane which was inferior to epoxy resin in heat resistance and thermal conductivity, but excellent in impact resistance. FIG. 5 shows a cross section filled with the sealing resin. As shown in this figure, the coil 10 is molded with a resin mold part 20 having excellent heat resistance and thermal conductivity, and between the outside and the case 170 is a polyurethane sealing resin 180 having excellent impact resistance. It is sealed. After the sealing resin 180 is cured, the case 170 may be fixed to a cooling base (not shown). A cooling medium is circulated through the cooling base to cool the reactor. In order to fix the case 170 to the cooling base, an appropriate mounting bracket for pressing the case 170 to the cooling base may be used, or a bolt hole may be provided in a part of the case 170 and fixed to the cooling base with a bolt.

  In this example, a pair of end magnetic members 152, a total of six intermediate magnetic members 154, and a total of four gap plates 156 are used, but these numbers can be selected as appropriate. Moreover, the shape of each magnetic member 152,154 is not necessarily limited to the shape of FIG. 3, For example, the edge part magnetic member 152 is good also as a U type.

<Effect>
According to the coil molded body 100 as described above, since the coil 10 can be a component that is held in a compressed state, handling of the component at the time of reactor assembly can be improved, and it has been used to hold the coil with a conventional reactor. The frame bobbin can be omitted. Further, since the inner peripheral surface of the coil 10 is covered with the resin mold portion 20 with a substantially uniform thickness, if the core is inserted into the hollow hole 30, the core and the coil 10 can be aligned coaxially. The cylindrical bobbin used in the conventional reactor can be omitted. Furthermore, the insulation between the coil 10 and the core 150 can be ensured by the resin mold portion 20. And, by configuring the resin mold part 20 with an epoxy resin having excellent heat resistance and thermal conductivity, and by configuring the sealing resin 180 with polyurethane having excellent impact resistance, the inner side closer to the heat source has better heat dissipation, The outer side can be configured to have better impact resistance. Therefore, it is possible to configure a reactor that achieves both heat dissipation characteristics and mechanical characteristics.

<Modification 1>
As a modification of the coil molded body of the first embodiment, as shown in FIG. 6, a heat radiating plate is provided on the lower surface of the coil molded body 100, that is, the surface that becomes the cooling base when the molded body 100 is housed in the case. 60 may be integrated. In this modification, one heat sink 60 made of silicon nitride is used, and the upper surface of the heat sink 60 is in contact with the coil and the lower surface is exposed from the resin mold portion 20.

  According to this modification, the heat of the coil can be efficiently conducted to the cooling base side through the heat radiating plate 60 having excellent thermal conductivity, and the heat dissipation of the reactor can be improved. In particular, by making the entire lower surface of the heat radiating plate in contact with the bottom surface of the case, it is possible to provide a reactor having further excellent heat radiation characteristics. In addition, a total of two heat sinks may be integrated with each of the lower surfaces of the first and second coils by a resin mold portion.

  Next, a preferred embodiment will be described with reference to FIG. 7 in order to easily equalize the thickness of the resin mold portion on the inner periphery of the coil. Since the basic configuration of the second embodiment is the same as that of the first embodiment, the following description will be focused on differences from the first embodiment.

  In the coil molded body 100 of this example, as shown in FIG. 7A, a concave groove 22 (concave portion) along the coil axis direction is formed in the resin mold portion 20 on the inner periphery of the coil. The depth of the concave groove 22 corresponds to the gap between the core and the coil, and a total of four locations are provided on the upper, lower, left and right of each inner peripheral surface of the molded body 100. That is, the portion where the concave groove 22 is formed is exposed without the coil 10 being covered with the resin mold portion 20.

  In order to obtain such a molded body, as shown in FIG. 7B, a core 51B having a substantially cross-shaped cross section is used. In other words, the protrusions 510 having a rectangular cross section are provided along the longitudinal direction of the core 51B on the upper, lower, left, and right side surfaces of the core 51B, and the height of the protrusions 510 corresponds to the gap between the core and the coil 10. . If the resin mold portion 20 is molded using such a core 51B, a molded body in which a hollow hole 30 (FIG. 7A) having a concave groove 22 is formed is obtained. At the time of molding, the position of the coil in the mold can be easily determined, and the thickness of the resin mold portion 20 on the inner circumference of the coil of the obtained molded body can be made substantially uniform. Therefore, if the core is fitted into the hollow hole 30 of the coil molded body 100 of this example, the core and the coil can be easily aligned coaxially. Further, when such a molded body is combined with a core to form an assembly and the assembly is sealed with a sealing resin, the concave groove 22 can be a flow path of the sealing resin, and the sealing resin around the molded body Can be improved.

  As a modification of this example, as shown in FIG. 8, the cross-sectional shape of the core 51B can be changed. For example, fan-shaped protrusions 512 having a cross section are provided at a pair of corners whose cross section is at a diagonal position of a rectangular core. Even when this core 51B is used, if the height of the ridge 512 is made to correspond to the gap between the core and the coil, the resin is filled in the area other than the ridge 512. Can be made substantially uniform in thickness.

  Further, as another modification of this example, a core with a protrusion and a cross-section is used, but the protrusion of the core may be lower than the gap between the core and the coil. In this case, the bottom surface of the concave groove 22 is also covered with the resin mold portion 20, and the coil is not exposed. Even in that case, the concave groove 22 can be used as the flow path of the sealing resin described above.

  Next, a coil molded body having further excellent heat dissipation will be described with reference to FIG. Since the basic configuration of the third embodiment is the same as that of the first embodiment, the following description will be focused on differences from the first embodiment.

  The molded body 100 of this example includes a plurality of concave grooves 24 along the axial direction of the coil on the left and right side surfaces and the upper surface. By forming the concave grooves 24, the surface area of the coil molded body 100 can be increased, and a reactor with higher heat dissipation can be constructed. In particular, in this example, the concave groove 24 is formed so that the coil is exposed from the resin mold portion 20 (the coil exposed state is not shown), and the heat dissipation from the coil 10 is further enhanced. On the other hand, no concave groove is provided on the lower surface of the molded body 100. Thus, when the molded body 100 is stored in the case as an assembly, a contact area between the molded body 100 and the case is ensured.

  Such a molded body may be provided with protrusions having a rectangular cross section on the inner side of the side wall 52B of the second mold shown in FIG. A portion corresponding to the protrusion becomes a concave groove 24 of the resin mold portion. When the molded body and the core of this example constitute an assembly and the periphery of the assembly is covered with a sealing resin, the concave groove 24 can also be used as a flow path for the sealing resin.

  In addition, as a modification of this example, a configuration in which this example and Example 3 are combined may be employed. That is, it is the structure which provided the ditch | groove in the inner periphery of the molded object, and also provided the ditch | groove in the outer periphery. According to this configuration, the accuracy of alignment between the core and the coil can be improved, and the heat dissipation or the wraparound of the sealing resin around the molded body can be improved.

  Next, a modification of the present invention using a coil having a configuration different from those of the first to third embodiments will be described with reference to FIG. In FIG. 10, only the shape of the coil is shown, and the resin mold part is omitted.

  In Examples 1 to 3, a coil having a single winding and having a bent connecting portion was used. However, the first and second coils 10A and 10B were formed by different windings, and both the coils 10A and 10B were welded. May be joined. In this example, the end of the second coil 10B is bent toward the first coil 10A, and the two coils 10A and 10B are joined by overlapping and welding the end of the first coil 10A.

  According to such a coil 10, it is possible to obtain a coil molded body in which the winding end of each of the coils 10A and 10B and the welded portion are protruded from the resin mold portion. It is possible to eliminate the resin mold portion that protrudes from the surface. Alternatively, the first coil and the second coil may be individually held in a compressed state by the resin mold portion, and then the ends of the windings of the pair of molded bodies may be joined by welding.

  In addition, this invention is not limited to each Example mentioned above, Each Example can be changed suitably, without deviating from the summary of this invention.

  The reactor of this invention can be utilized as components, such as a converter. In particular, it can be suitably used as a reactor for automobiles such as hybrid cars and electric cars.

It is a see-through | perspective perspective view of the coil molded object which comprises this invention reactor of Example 1. FIG. It is explanatory drawing which shows the shaping | molding method of the molded object of FIG. It is a disassembled perspective view which shows the assembly procedure of the assembly which comprises the reactor of Example 1. FIG. It is explanatory drawing of the assembly procedure of the reactor of Example 1. FIG. It is sectional drawing of the reactor of Example 1. FIG. It is explanatory drawing which shows the modification of the coil molded object of FIG. (A) is a perspective view which shows the coil molded object which comprises this invention reactor of Example 2, (B) is explanatory drawing which shows a part of shaping | molding procedure of the molded object. 6 is a cross-sectional view showing a modification of the core used for forming the coil molded body of Example 2. FIG. It is a perspective view which shows the coil molded object which comprises this invention reactor of Example 3. FIG. It is a perspective view of the coil used for the coil molded object which comprises this invention reactor of Example 4. FIG.

Explanation of symbols

100 coil molded body
10 coils
10A 1st coil 10B 2nd coil
11 Start 12 End 12 Bend joint
20 Resin mold part
22 groove 24 groove
30 hollow holes
50 molds
51 First mold 51A End plate 51B Core
52 Second mold 52A End plate 52B Side wall
53 Rod 510 510 Projection 512 Projection
60 Heat sink
150 core
152 End magnetic member 154 Intermediate magnetic member 156 Gap plate
170 cases
180 Sealing resin
200 assembly

Claims (8)

A reactor comprising an assembly in which a coil is arranged on the outer periphery of the core, a case for storing the assembly, and a sealing resin filled between the assembly and the case,
The assembly includes a coil molded body and a core,
This coil molding is
A coil with a spiral winding,
A resin mold part that holds this coil in a compressed state than its free length;
A core holding part formed of a resin mold part so that the core is fitted to the inner peripheral side of the coil,
The reactor, wherein the sealing resin is a resin having higher impact resistance than the resin of the resin mold part.   The reactor according to claim 1, wherein the resin of the resin mold portion is a resin having higher heat resistance than the sealing resin.   The reactor according to claim 1, wherein the resin of the resin mold portion is a resin having a higher thermal conductivity than the sealing resin.   The reactor according to any one of claims 1 to 3, wherein the coil molded body and the case are in surface contact.   Furthermore, the reactor of any one of Claims 1-4 provided with the heat sink integrated in the contact surface with the case in the said resin mold part.   The reactor according to any one of claims 1 to 5, wherein a concave portion is formed on an inner peripheral surface of the core holding portion.   The reactor according to claim 1, wherein the recess has a depth corresponding to a gap between the core and the coil.   The reactor according to claim 1, wherein at least one of a concave portion and a convex portion is formed on a surface of the resin mold portion on the outer periphery of the coil.

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