Patent ID: 12217895

DETAILED DESCRIPTION TO EXECUTE THE INVENTION

Further miniaturization of reactors is desired. The miniaturization of a reactor here means a small installation area of the reactor and a small interval between an assembly and a case. Further improvement in the productivity of reactors is also desired. In the reactor described in Patent Document 1, the resin introduction path for filling the sealing resin is provided in the side wall portion of the case. However, as a matter of practice, if the resin introduction path is provided in the side wall portion of the case, the manufacturing cost of the case may increase due to a need for special processing to form the resin introduction path and the like. If the resin introduction paths are provided in four corners of the case as described in Patent Document 1, it may lead to the enlargement of the case. Therefore, a structure is desired which can satisfactorily fill the sealing resin while realizing the miniaturization of the reactor.

One object of the present disclosure is to provide a reactor small in size and excellent in productivity.

Effect of Present Disclosure

The reactor of the present disclosure is small in size and excellent in productivity.

Description of Embodiments of Present Disclosure

First, embodiments of the present disclosure are listed and described.

(1) A reactor according to an embodiment of the present disclosure is provided with a coil including a pair of winding portions arranged in parallel, a magnetic core to be arranged inside and outside the winding portions, a holding member for specifying mutual positions of the coil and the magnetic core, a case for accommodating an assembly including the coil, the magnetic core and the holding member, and a sealing resin portion to be filled into the case, wherein the case includes a bottom plate portion, the assembly being placed on the bottom plate portion, a side wall portion in the form of a rectangular tube for surrounding the assembly, and an opening facing the bottom plate portion, the side wall portion includes a pair of long side parts facing each other and a pair of short side parts facing each other, the assembly is so accommodated into the case that an axial direction of each winding portion is along a depth direction of the case, the magnetic core includes an outer core portion to be arranged outside the winding portions and on the opening side, the holding member includes an outer wall portion for covering at least a part of an outer peripheral surface of the outer core portion and a protruding portion projecting from the outer wall portion toward one of the short side parts, and a clearance is provided between at least one of the long side parts and the protruding portion when the case is viewed from above.

In the reactor of the present disclosure, the assembly is so accommodated into the case that the axial direction of each winding portion in the coil is along the depth direction of the case. This arrangement mode is called an upright type below. On the other hand, in the reactor described in Patent Document 1, the assembly is so accommodated into the case that the parallel direction of the pair of winding portions and the axial direction of each winding portion are parallel to a bottom plate portion. This arrangement mode is called a horizontally placed type below. If the arrangement mode of the assembly is the upright type, an installation area of the assembly with respect to the bottom plate portion of the case can be reduced as compared to the horizontally placed type. This is because a length of an assembly along a direction orthogonal to both a parallel direction of a pair of winding portions and axial directions of the both winding portions is generally shorter than a length of the assembly along the axial directions of the both winding portions. Thus, the reactor of the present disclosure is thin and small in size. Therefore, the reactor of the present disclosure can reduce an area of the bottom plate portion and reduce the installation area.

Further, if the arrangement mode of the assembly is the upright type, a large facing area of the both winding portions and the case can be secured as compared to the horizontally placed type. Thus, in the reactor of the present disclosure, the case can be efficiently utilized as a heat dissipation path. Therefore, the reactor of the present disclosure easily dissipates the heat of the coil to the case and is excellent in heat dissipation.

In the reactor of the present disclosure, the holding member located on the opening side of the case includes the protruding portion projecting toward the one short side part in the side wall portion. The reactor of the present disclosure includes the clearance between at least one of the long side parts and the protruding portion when the case is viewed from above. In the reactor of the present disclosure, by providing the clearance between the long side part and the protruding portion, a resin, which will become the sealing resin portion, can be filled into the case through the clearance with the assembly accommodated into the case in forming the sealing resin portion. For example, the resin can be filled into the case by inserting a nozzle for injecting the resin into the clearance and injecting the resin from the bottom plate portion side of the case through the nozzle.

The size of the clearance can be adjusted according to the size of the protruding portion and a clearance enabling the insertion of a nozzle having a large diameter can also be easily formed. If the diameter of the nozzle is large, an operation of filling the resin, which will become the sealing resin portion, can be efficiently performed. Thus, the reactor of the present disclosure is excellent in productivity.

Besides, in the reactor of the present disclosure, the following effects can be expected by providing the protruding portion on the holding member and providing the clearance between the long side part and the protruding portion.

(a) In forming the sealing resin portion, the resin can be injected by inserting the nozzle into the clearance. Thus, it is not necessary to provide a resin introduction path in the side wall portion of the case, and the case needs not be specially processed. Therefore, the manufacturing cost of the case can be reduced.

(b) The protruding portion is provided on the holding member only on the side of the one short side part, and the clearance is formed only on the side of the one short side part. Thus, the case can be reduced in size as compared to the case where the protruding portion is also provided on the side of the other short side part and the clearances are formed on the sides of the both short side parts.

(c) In the case of injecting the resin by inserting the nozzle into the clearance, the resin is injected from the side of the one short side part and flows toward the side of the other short side part. Specifically, the resin injected from the nozzle flows from the side of the one short side part between the assembly and the long side parts and merges on the side of the other short side part. Thus, a merging point of the resin is created at a location distant from a location where the resin was injected. In this case, air bubbles mixed into the resin float up and the air bubbles in the resin are easily removed while the resin is flowing from the side of the one short side part toward the side of the other short side part. Thus, by injecting the resin from the side of the one short side part, the remaining of air bubbles in the sealing resin portion can be reduced. Further, if the resin is injected from the side of the one short side part, the merging point of the resin is one location on the side of the other short side part. Since the entrainment of air bubbles easily occurs at the merging point of the resin, less merging points are preferable. Since the resin merges at one location by injecting the resin from the side of one short side part, the remaining of air bubbles is easily reduced.

(2) As one form of the above reactor, a tip of the protruding portion in a projecting direction is in contact with an inner surface of the short side part.

In the reactor of the present disclosure, the assembly can be positioned with respect to the case since the holding member includes the protruding portion. Particularly, by the contact of the protruding portion with the inner surface of the short side part, a position shift of the assembly caused by the flow of the resin can be suppressed when the resin, which will become the sealing resin portion, is filled into the case. Thus, because of the contact of the protruding portion with the inner surface of the short side part, the reactor of the present disclosure is more excellent in the productivity.

(3) As one form of the above reactor, the protruding portion has a first surface located on the bottom plate portion side, a second surface located on the opening side, and a hole penetrating through the first and second surfaces, and the sealing resin portion includes a first resin portion to be filled into the hole and a second resin portion continuous with the first resin portion, the second resin portion being provided in contact with the first and the second surfaces.

In the reactor of the present disclosure, the protruding portion includes the hole and a part of the sealing resin portion is filled into that hole, whereby the protruding portion and the sealing resin portion can be firmly joined and, consequently, the assembly and the sealing resin portion can be firmly joined. This is because the first resin portion filled in the hole and the second resin portion provided in contact with the first and second surfaces are hooked to the protruding portion. Besides, in the reactor of the present disclosure, a filled state of the resin on the side of the one short side part can be confirmed through the hole in forming the sealing resin portion since the protruding portion includes the hole. Further, in the reactor of the present disclosure, air bubbles mixed into the resin filled on the side of the one short side part can be removed from the hole in forming the sealing resin portion since the protruding portion includes the hole. That is, the hole provided in the protruding portion functions as a confirmation hole used to confirm the filled state of the resin in forming the sealing resin portion and as a vent for removing air bubbles mixed into the resin. The hole provided in the protruding portion functions as a hooking structure for joining the assembly and the sealing resin portion after the sealing resin portion is formed.

(4) As one form of the above reactor, the short side part includes a mounting seat for supporting the protruding portion, and the protruding portion and the mounting seat are fastened.

In the above form, the assembly can be firmly fixed to the case since the protruding portion of the holding member is fastened to the mounting seat. In the above form, the detachment of the assembly from the case, for example, due to an impact, vibration or the like can be avoided.

Details of Embodiments of Present Disclosure

Specific examples of reactors according to embodiments of the present disclosure are described below with reference to the drawings. The same reference signs in the drawings denote the same components. Components may be shown in a partially exaggerated or simplified manner in the drawings for the convenience of description. A dimension ratio of each part in the drawings may be different from an actual one. Note that the present invention is not limited to these illustrations and is intended to be represented by claims and include all changes in the scope of claims and in the meaning and scope of equivalents.

First Embodiment

Summary

A reactor1A according to a first embodiment is described with reference toFIGS.1A to4B. As shown inFIG.1B, the reactor1A includes a coil2, a magnetic core3, holding members41,42, a case5and a sealing resin portion6. As shown inFIG.1B, the coil2includes a pair of winding portions21,22arranged in parallel. The magnetic core3includes inner core portions31,32to be arranged inside the winding portions21,22and outer core portions33to be arranged outside the winding portions21,22. The holding members41,42specify mutual positions of the coil2and the magnetic core3. The case5accommodates an assembly10including the coil2, the magnetic core3and the holding members41,42. The sealing resin portion6is filled into the case5. One of features of the reactor1A is that an arrangement mode of the assembly10is an upright type to be described later. Another feature of the reactor1A is that the holding member41to be arranged on the side of an opening55of the case5includes a protruding portion45. As shown inFIG.1A, clearances46are formed between the protruding portion45and at least one long side part541,542in a side wall portion52when the case5is viewed from above.

The sealing resin portion6is not shown inFIG.1A.FIGS.1B and1Cshow the case5and the sealing resin portion6in section to make an internal structure of the reactor1A easily understandable.FIG.1Bis a partial section along B-B inFIG.1A.FIG.1Bshows the appearance of the assembly10in the case5viewed from the side of a side surface and shows cross-sections of the case5and the sealing resin portion6cut by a plane parallel to the side surface.FIG.1Cis a partial section along C-C inFIG.1A.FIG.1Cshows the appearance of the assembly10in the case1viewed from the side of a front surface and shows cross-sections of the case5and the sealing resin portion6cut by a plane parallel to the front surface. If there are separate figuresFIGS.1A,1B and1C, all the separate figures may be collectively referred to asFIG.1Ato1C. The same applies to figures including other separate figures. In the following description, the side of a bottom plate portion51of the case5is a lower side and the side of the opening55opposite to the bottom plate portion51is an upper side. This vertical direction is a height direction. The height direction is a depth direction of the case5. Further, a direction orthogonal to the height direction and along the long side parts541,542of the side wall portion52is a length direction. A direction orthogonal to the height direction and along the short side parts531,532of the side wall portion52in the case5is a width direction. The vertical direction is a vertical direction ofFIGS.1B and1C. The length direction is a lateral direction ofFIGS.1A and1B. The width direction is a vertical direction ofFIG.1Aand a lateral direction ofFIG.1C.

The configuration of the reactor1A is described in detail below.

Coil

As shown inFIG.1B, the coil2includes the pair of winding portions21,22. The winding portions21,22are formed by spirally winding a winding wire. The both winding portions21,22are so arranged side by side that the axial directions thereof are parallel. The axial directions of the both winding portions21,22coincide with the height direction. The both winding portions21,22of the coil2may be constituted by one continuous winding wire or may be constituted by separate winding wires. If the winding portions21,22are constituted by one continuous winding wire, the winding wire is, for example, bent and folded on the other end side and the other winding portion22is formed after one winding portion21is formed. If the respective winding portions21,22are constituted by separate winding wires, end parts of the winding wires may be connected on the other end sides of the respective winding portions21,22after the respective winding portions21,22are formed by the respective winding wires. A joining method such as welding, crimping, soldering or brazing can be utilized for this connection. End parts of the winding wires on one end sides of the winding portions21,22are pulled out to outside from the side of the opening55of the case5. Unillustrated terminal fittings are mounted on the tips of the pulled out winding wires. An unillustrated external device such as a power supply is connected to the terminal fittings. Note that only the winding portions21,22are shown and end parts of the winding wires and the like are not shown inFIGS.1A to1Cand the like.

The winding wire may be a coated wire including a conductor wire and an insulation coating. A constituent material of the conductor wire may be copper or the like. A constituent material of the insulation coating may be a resin such as polyamide-imide. The coated wire may be a coated flat rectangular wire having a rectangular cross-sectional shape, a coated round wire having a circular cross-sectional shape or the like.

The both winding portions21,22of this example are made of the winding wires having the same specifications and have the same shape, size, winding direction and number of turns. Further, the winding portion21,22of this example is an edge-wise coil in the form of a rectangular tube formed by winding a coated flat rectangular wire in an edge-wise manner. Although the winding portion21,22has a rectangular tube shape in this example, there is no particular limitation. The winding portion21,22may have, for example, a hollow cylindrical shape, a hollow elliptical cylindrical shape or a hollow oval cylindrical shape. Further, the specifications of the winding wires forming the both winding portions21,22and the shapes of the both winding portions21,22may be different.

In this example, the winding portion21,22has a rectangular end surface shape when viewed from the axial direction. That is, the winding portion21,22has four flat surfaces and four corner parts. The corner parts of the winding portion21,22are rounded. The outer peripheral surface of the winding portion21,22is substantially constituted by flat surfaces. Thus, flat surfaces are facing each other between the outer peripheral surface of the winding portion21,22and the inner peripheral surface of the side wall portion52of the case5as shown inFIGS.1B and1C. Accordingly, a large facing area of the outer peripheral surface of the winding portion21,22and the inner peripheral surface of the side wall portion52in the case5is easily secured. Further, an interval between the outer peripheral surface of the winding portion21,22and the inner peripheral surface of the side wall portion52in the case5tends to become smaller.

As shown inFIG.1B, the coil2is so arranged that the respective axial directions of the both winding portions21,22are orthogonal to the bottom plate portion51of the case5and a parallel direction of the both winding portions21,22is along the long side parts541,542in the side wall portion52of the case5. That is, the both winding portions21,22are arranged side by side in the length direction of the case5. In this example, one winding portion21is arranged on the side of one short side part531, i.e. on a left side inFIG.1B, and the other winding portion22is arranged on the side of the other short side part532, i.e. on a right side inFIG.1B.

Magnetic Core

As shown inFIG.1B, the magnetic core3includes inner core portions31,32and a pair of outer core portions33,33. The inner core portions31,32mainly constitute parts to be arranged inside the respective winding portions21,22. End parts in the axial direction of the inner core portions31,32project from end surfaces of the winding portions21,22. The outer core portions33,33are arranged outside the both winding portions21,22. The outer core portions33,33are provided to connect end parts of the both inner core portions31,32. In this example, as shown inFIG.3, the outer core portions33,33are respectively arranged to sandwich the both inner core portions31,32from both ends. The magnetic core3is formed into an annular shape by connecting the respective end surfaces of the both inner core portions31,32and respective inner end surfaces33e(FIG.3) of the outer core portions33,33. When the coil2is excited, a magnetic flux flows in the magnetic core3to form a closed magnetic path.

Inner Core Portions

The inner core portions31,32are shaped to substantially correspond to the inner peripheral shapes of the winding portions21,22. Clearances are present between the inner peripheral surfaces of the winding portions21,22and the outer peripheral surfaces of the inner core portions31,32. A resin for constituting molded resin portions8to be described later is filled into these clearances. In this example, the inner core portions31,32have a quadrangular prism shape, more specifically a rectangular parallelepiped shape and have a rectangular end surface shape when viewed from the axial direction. Corner parts of the inner core portions31,32are rounded to extend along the corner parts of the winding portions21,22. The both inner core portions31,32have the same shape and size. Both end parts of the inner core portions31,32projecting from the end surfaces of the winding portions21,22are inserted into through holes43of the holding members41,42to be described later (see alsoFIG.3).

In this example, each of the inner core portions31,32is constituted by one column-like core piece. Each core piece constituting the inner core portion31,32has a length substantially equal to the entire length in the axial direction of the winding portion21,22. That is, the inner core portion31,32is not provided with a magnetic gap member. Note that the inner core portion31,32may be constituted by a plurality of core pieces and magnetic gap member(s) interposed between adjacent ones of the core pieces.

Outer Core Portions

The shapes of the outer core portions33,33are not particularly limited as long as the outer core portions33,33are shaped to connect the respective end parts of the both inner core portions31,32. In this example, the outer core portions33,33have a rectangular parallelepiped shape having the inner end surface33efacing the respective end surfaces of the both inner core portions31,32. The both outer core portions33,33have the same shape and size. Each of the outer core portions33,33is constituted by one column-like core piece.

One outer core portion33is arranged outside the winding portions21,22and on the side of the opening55of the case5, i.e. on an upper side inFIG.1B. The other outer core portion33is arranged outside the winding portions21,22and on the side of the bottom plate portion51of the case5, i.e. on a lower side inFIG.1B. The outer end surface of the outer core portion33on the side of the bottom plate portion51is arranged to face the inner bottom surface of the bottom plate portion51.

Constituent Material

The inner core portions31,32and the outer core portions33,33are formed by compacts containing a soft magnetic material. Examples of the soft magnetic material include metals such as iron and iron alloy and non-metals such as ferrite. The iron alloy is, for example, a Fe—Si alloy, a Fe—Ni alloy or the like. Examples of the compact including the soft magnetic material include powder compacts and compacts of composite materials.

A powder compact is obtained by compression-molding a powder made of the soft magnetic material, i.e. a soft magnetic powder. The powder compact has a higher rate of the soft magnetic powder in the core piece than the composite material.

In a compact of a composite material, the soft magnetic powder is dispersed in a resin. The compact of the composite material is obtained by filling a raw material, in which the soft magnetic powder is mixed and dispersed in an unsolidified resin, into a mold and solidifying the resin. Magnetic characteristics, e.g. relative magnetic permeability and saturation flux density of the composite material are easily controlled by adjusting the content of the soft magnetic powder in the resin.

The soft magnetic powder is an aggregate of soft magnetic particles. The magnetic particles may be coated particles having insulation coatings on the surfaces thereof. A constituent material of the insulation coatings may be a phosphate. The resin of the composite material is, for example, a thermosetting resin or thermoplastic resin. Examples of the thermosetting resin include an epoxy resin, a phenol resin, a silicone resin and a urethane resin. Examples of the thermoplastic resin include a polyphenylene sulfide (PPS) resin, a polyamide (PA) resin (e.g. nylon 6, nylon 66, nylon 9T or the like), a liquid crystal polymer (LCP), a polyimide (PI) resin and a fluororesin. The composite material may contain a filler in addition to the resin. By containing the filler, the heat dissipation of the composite material can be improved. A powder made of a nonmagnetic material such as ceramics and carbon nanotubes can be, for example, utilized as the filler. Examples of the ceramics include oxides, nitrides and carbides of metals or non-metals. Examples of the oxides include alumina, silica and magnesium oxide. Examples of the nitrides include silicon nitride, aluminum nitride and boron nitride. Examples of the carbides include silicon carbide.

The constituent material of the inner core portions31,32and that of the outer core portions33,33may be the same or may be different. For example, any of the inner core portions31,32and the outer core portions33,33may be a compact of a composite material and the material and content of the soft magnetic powder in each composite material may be different. In this example, the inner core portions31,32are constituted by compacts of the composite material and the outer core portions33,33are constituted by powder compacts. Further, the magnetic core3of this example includes no magnetic gap member.

Holding Members

The reactor1A of this example includes two holding members41,42. As shown inFIGS.1B and3, the holding member41,42includes a frame plate, which is a part to be arranged to face the respective end surfaces of the both winding portions21,22. Further, the holding member41,42includes a later-described outer wall portion40, which is a part for covering the outer peripheral surface of the outer core portion33. One holding member41is arranged on the side of the opening55of the case5to cover the upper outer core portion33described above. The other holding member42is arranged on the side of the bottom plate portion51of the case5to cover the lower outer core portion33described above. The both holding members41,42ensure electrical insulation between the winding portions21,22of the coil2and the inner core portions31,32and the outer core portions33,33of the magnetic core3. Further, the holding members41,42specify mutual positions of the coil2and the magnetic core3to maintain a positioned state.

The both holding members41,42have the same basic configuration. The holding member41,42of this example includes the frame plate having the through holes43, and the outer wall portion40. The frame plate is interposed between the end surfaces of the winding portions21,22and the inner end part33eof the outer core portion33. The outer wall portion40covers at least a part of the outer peripheral surface of the outer core portion33, in this example, over the entire periphery. In this example, the holding member41,42has a rectangular frame shape in a plan view as shown inFIG.1A. The outer peripheral surface of the outer wall portion40is substantially constituted by flat surfaces. The outer peripheral surface of the outer wall portion40has four flat surfaces facing the short side parts531,532and the long side parts541,542in the side wall portion52of the case5.

The frame plate mainly ensures electrical insulation between the winding portions21,22and the outer core portion33. As shown inFIGS.1B and3, the frame plate includes a pair of the through holes43penetrating through the front and back surfaces of a rectangular plate. The end parts of the inner core portions31,32are inserted into the respective through holes43. The through holes43are shaped to substantially correspond to the outer peripheral shapes of the end parts of the inner core portions31,32. In this example, four corners of the through holes43are formed along the corner parts of the outer peripheral surfaces of the inner core portions31,32. The inner core portions31,32are held in the through holes43by the four corners of these through holes43. Further, with the end parts of the inner core portions31,32inserted in the through holes43, clearances are partially formed between the outer peripheral surfaces of the inner core portions31,32and the inner peripheral surfaces of the through holes43. There clearances communicate with the clearances between the inner peripheral surfaces of the winding portions21,22and the outer peripheral surfaces of the inner core portions31,32.

The outer wall portion40is a rectangular tube surrounding the peripheral edge of the frame plate, and provided to surround the entire periphery of the outer core portion33. The outer wall portion40includes a recess44inside. A part of the outer core portion33on the side of the inner end surface33eis fit into the recess44. In this example, the recess44is provided to form a clearance partially between the outer peripheral surface of the outer core portion33and the inner peripheral surface of the recess44with the outer core portion33fit in the recess44. The resin for constituting the molded resin portion8to be described later is filled into this clearance. The respective outer core portions33,33and the respective holding members41,42are integrated by these molded resin portions8. The holding members41,42of this example are so configured that the clearances between the outer core portions33,33and the recesses44and the aforementioned clearances between the inner core portions31,32and the through holes43communicate. By the communication of these clearances, the resin for constituting the molded resin portions8can be introduced into between the winding portions21,22and the inner core portions31,32when the molded resin portions8are formed.

Further, the holding member41,42of this example includes unillustrated inner interposing portions. The inner interposing portions project toward the insides of the winding portions21,22from peripheral edge parts of the through holes43and are inserted into between the winding portions21,22and the inner core portions31,32. The winding portions21,22and the inner core portions31,32are held at a distance from each other by these inner interposing portions. As a result, electrical insulation between the winding portions21,22and the inner core portions31,32is ensured.

As described above, by inserting the respective end parts of the inner core portions31,32into the respective through holes43of the holding members41,42, the inner core portions31,32are positioned with respect to the holding members41,42. Further, by fitting parts of the outer core portions33,33on the side of the inner end surfaces33einto the recesses44of the holding members41,42, the outer core portions33,33are positioned. Furthermore, the winding portions21,22are positioned by the above inner interposing portions. As a result, the winding portions21,22of the coil2and the inner core portions31,32and the outer core portions33,33of the magnetic core3are held in a positioned state by the holding members41,42.

Protruding Portion

Out of the holding members41,42, the one holding member41located on the side of the opening55of the case5includes the protruding portion45projecting toward one short side part531from the outer wall portion40as shown inFIGS.1A and1B. The protruding portion45is provided to project from a part of the outer peripheral surface of the outer wall portion40facing the short side part531. The protruding portion45is an integrated body integrally molded with the outer wall portion40. The protruding portion45of this example is a solid body not including a through hole453to be described in a second embodiment or the like. As shown inFIG.1A, the clearance46is formed between the protruding portion45and at least one of the long side parts541,542, more specifically, end parts of the long side parts541,542on the side of the short side part531. The position and number of the protruding portion(s)45are not particularly limited. The protruding portion45may be positioned in a center in the width direction of the holding member41or may deviate from the center. It is sufficient to provide at least one protruding portion45and a plurality of protruding portions45may be provided. In this example, one protruding portion45is provided in the center in the width direction of the holding member41.

The shape of the protruding portion45is not particularly limited. In this example, as shown inFIG.1A, the protruding portion45has a rectangular shape in a plan view. The shape of the protruding portion45is not limited to a rectangular shape, but may be a polygonal shape, a semicircular shape, a semielliptical shape or another shape in the plan view. Examples of the polygonal shape include a triangular shape and a trapezoidal shape. The size of the protruding portion45is set to form the clearances46of a predetermined size. For example, a projection length of the protruding portion45is 5 mm or more and 15 mm or less and, further, 6 mm or more and 12 mm or less. If the projection length of the protruding portion45is excessively long, the long side parts541,542become longer and the case5is enlarged. Further, a width of the protruding portion45is smaller than that of the holding member41. The width of the protruding portion45is, for example, so set that an interval between at least one long side part541,542and the outer peripheral surface of the protruding portion45is 5 mm or more and, further, 6 mm or more.

The protruding portion45has such a thickness as not to be easily deformed or broken. The thickness here is a dimension in the height direction, i.e. a dimension in the vertical direction ofFIG.1B. The thickness of the protruding portion45of this example is about slightly less than half the thickness of the holding member41. The thickness of the protruding portion45may be equal to or larger than the thickness of the entire holding member41. For example, the protruding portion45may be in the form of a rod extending from the holding member41toward the other holding member42. Since a used amount of the resin for forming the sealing resin portion6is reduced if the thickness of the protruding portion45is increased, manufacturing cost can be reduced by that much.

The protruding portion45functions to restrict the position in the length direction of the assembly10with respect to the case5. The protruding portion45may be such that the tip thereof in a projecting direction is in contact with the inner surface of the short side part531. The assembly10can be satisfactorily positioned with respect to the case5by the contact of the protruding portion45with the inner surface of the short side part531. Particularly, a position shift of the assembly10due to a flow of the resin can be suppressed when the sealing resin portion6is formed.

Clearances

As shown inFIG.1A, the clearance46is formed between at least one long side part541,542and the protruding portion45when the reactor1A is viewed from above. In this example, the clearances46are provided between the both long side parts541,542and the protruding portion45. That is, the clearances46are provided on both sides of the protruding portion45on the side of the one short side part531. In other words, the clearances46are provided in regions except the protruding portion45, out of a region surrounded by the surface of the holding member41facing the one short side part531, the inner surface of the short side part531and the respective inner surfaces of the long side parts541,542.

In forming the sealing resin portion6, the nozzle65for injecting the resin, which will become the sealing resin portion6, is inserted into the clearance46as shown inFIGS.4A and4B. The size of the clearance46is not particularly limited as long as the nozzle65is insertable thereinto when the reactor1A is viewed from above. The size of the clearance46can be adjusted according to the size of the protruding portion45. Thus, even if a diameter of the nozzle65is large, a clearance into which the nozzle65can be inserted can be easily formed. For example, the clearance46has, for example, a diameter of 4 mm or more and, further, 5 mm or more in a plan view. The clearance46is formed to be continuous from the side of the opening55to the side of the bottom plate portion51of the case5.

Constituent Material

Examples of a constituent material of the holding members41,42include electrically insulating materials. Resins are typical examples of the electrically insulating materials. Specific examples of resins include thermosetting resins and thermoplastic resins. Examples of thermosetting resins include an epoxy resin, a phenol resin, a silicone resin, a urethane resin and an unsaturated polyester resin. Examples of thermoplastic resins include a PPS resin, a PA resin, an LCP, a PI resin, a fluororesin, a polytetrafluoroethylene (PTFE) resin, a polybutylene terephthalate (PBT) resin and an acrylonitrile-butadiene-styrene (ABS) resin. The constituent material of the holding members41,42may contain a filler in addition to the resin. By containing the filler, the heat dissipation of the holding members41,42can be improved. A filler similar to the one used in the aforementioned composite material can be utilized as this filler. In this example, the constituent material of the holding members41,42is the PPS resin.

Molded Resin Portions

The assembly10of this example includes, as shown inFIG.1B, the molded resin portions8. The molded resin portions8cover at least parts of the outer peripheral surfaces of the outer core portions33,33and are interposed between the inner peripheral surfaces of the winding portions21,22and the outer peripheral surfaces of the inner core portions31,32. The inner core portions31,32and the outer core portions33are integrally held by these molded resin portions8, and the winding portions21,22of the coil2and the inner core portions31,32and the outer core portions33of the magnetic core3are integrated. Thus, the coil2and the magnetic core3can be handled as an integrated body. Further, the respective outer core portions33,33and the respective holding members41,42are integrated by the molded resin portions8. That is, in this example, the coil2, the magnetic core3and the holding members41,42are integrated by the molded resin portions8. Thus, the assembly10can be handled as an integrated object. Note that the outer peripheral surfaces of the winding portions21,22are not covered by the molded resin portions8and are exposed from the molded resin portions8.

The molded resin portions8only have to be able to integrally hold the inner core portions31,32and the outer core portions33,33and only have to be formed to cover the outer peripheral surfaces along a circumferential direction of at least end parts of the inner core portions31,32. That is, the molded resin portions8may not extend up to axially central parts of the inner core portions31,32. In view of the function of the molded resin portions8to integrally hold the inner core portions31,32and the outer core portions33,33, it is sufficient for formation ranges of the molded resin portions8to extend up to the vicinities of the end parts of the inner core portions31,32. Of course, the molded resin portions8may extend up to the axially central parts of the inner core portions31,32. In this case, the molded resin portions8cover the outer peripheral surfaces of the inner core portions31,32over the entire length and are formed from one outer core portion33to the other outer core portion33.

Constituent Material

The resin for constituting the aforementioned holding members41,42can be used as the resin for constituting the molded resin portions8. A constituent material of the molded resin portions8may contain the aforementioned filler in addition to the resin. In this example, the molded resin portions8are made of a PPS resin.

Case

By accommodating the assembly10as shown inFIGS.1A to1C, the case5can mechanically protect the assembly10and protect the assembly10from an external environment. Protection from the external environment aims to improve corrosion resistance and the like. The case5of this example is made of metal. Metals are higher in thermal conductivity than resins. Thus, the case5made of metal easily dissipates the heat of the assembly10to outside via the case5. Therefore, the case5made of metal contributes to an improvement in the heat dissipation of the assembly10.

As shown inFIGS.1A to1C, the case5includes the bottom plate portion51, the side wall portion52and the opening55. The bottom plate portion51is a flat plate member, on which the assembly10is placed. The side wall portion52is a rectangular tube body for surrounding the assembly10. The case5is a bottomed tubular container in which an accommodation space for the assembly10is formed by the bottom plate portion51and the side wall portion52and the opening55is formed on the side facing the bottom plate portion51. In this example, the bottom plate portion51and the side wall portion52are integrally formed. The side wall portion52has a height equal to or more than that of the assembly10.

The bottom plate portion51of this example is in the form of a rectangular plate. In the bottom plate portion51, the inner bottom surface on which the assembly10is placed is substantially constituted by a flat surface. The side wall portion52of this example is in the form of a rectangular tube. The side wall portion52includes the pair of long side parts541,542facing each other and the pair of short side parts531,532facing each other. In the case of this example, out of the inner peripheral surface of the side wall portion52, the surfaces of the long side parts541,542and the short side parts531,532facing the winding portions21,22are substantially constituted by flat surfaces. Further, a part of the inner peripheral surface of the short side part531facing the protruding portion45is also substantially constituted by a flat surface. Parts connected from the short side part531to the both long side parts541,542are constituted by curved surfaces.

As shown inFIG.1A, the side wall portion52of this example has a substantially rectangular tube shape in a plan view. The substantially rectangular tube shape means that the inner peripheral surface of the side wall portion52has a substantially rectangular shape when the case5is viewed from above. The rectangular shape here may not be rectangular in a geometrically strict sense and may include a range of rectangular shapes regarded to be substantially rectangular, including shapes having rounded corner parts and chamfered corner parts. For example, a shape having corner parts formed by curved surfaces having a relatively large radius of curvature like the side wall portion52of this example is also included.

The inner peripheral surface of the side wall portion52may be inclined to widen from the side of the bottom plate portion51toward the side of the opening55. More specifically, at least either the inner surfaces of the long side parts541,542or the inner surfaces of the short side parts531,532of the side wall portion52are inclined to be more spaced apart from each other from the side of the bottom plate portion51toward the side of the opening55. That is, at least one of the inner surfaces of the long side parts541,542and the inner surfaces of the short side parts531,532of the side wall portion52may be inclined outwardly of the case5with respect to a perpendicular direction to the inner bottom surface of the bottom plate portion51. Note that the above perpendicular direction is equivalent to the height direction of the case5.

If the respective inner surfaces of the long side parts541,542and the short side parts531,532are inclined to be more spaced apart from each other from the side of the bottom plate portion51toward the side of the opening55, the assembly10is easily accommodated into the case5in the manufacturing process of the reactor1. Further, in the case of manufacturing the case5made of metal by die casting, the case5is easily removed from a mold if at least one of the respective inner surfaces of the long side parts541,542and the short side parts531,532is inclined. In this example, as shown inFIGS.1B and1C, all the inner surfaces of the long side parts541,542and the short side parts531,532are inclined to widen the inner peripheral surface of the side wall portion52from the side of the bottom plate portion51toward the side of the opening55.

Angles of inclination between the respective inner surfaces of the long side parts541,542and the short side parts531,532and a perpendicular to the inner bottom surface of the bottom plate portion51can be appropriately selected. The angles of inclination are, for example, 0.5° or more and 5° or less and, further, 1° or more and 2° or less. If the angles of inclination are excessively large, the interval between the outer peripheral surface of the assembly10and the inner peripheral surface of the side wall portion52becomes larger on the side of the opening55. However, if the interval is excessively large, the heat of the assembly10on the side of the opening55is less likely to be transferred to the case5. Thus, excessively large angles of inclination are not preferable also in terms of heat dissipation. Therefore, an upper limit of the angles of inclination is set to be 5° or less and, further, 2° or less.

A length of the case5is, for example, 80 mm or more and 120 mm or less and, further, 90 mm or more and 115 mm or less. A width of the case5is, for example, 30 mm or more and 80 mm or less and, further, 35 mm or more and 70 mm or less. A height of the case5is, for example, 70 mm or more and 140 mm or less and, further, 80 mm or more and 130 mm or less. The length of the case5is a length in the lateral direction ofFIGS.1A and1B. The width of the case5is a length in the vertical direction ofFIG.1A. The height of the case5is a length in the vertical direction ofFIG.1B. A volume of the case5is, for example, 120 cm2or more and 1200 cm3or less and, further, 200 cm2or more and 900 cm3or less. The case5of this example has the length larger than the width and has the height larger than the width. Thus, an area obtained by the length×width of the case5is smaller than an area obtained by the length×height of the case5.

Constituent Material

The case5is made of nonmagnetic metal. Examples of nonmagnetic metal include aluminum, alloys thereof, magnesium and alloys thereof, copper and alloys thereof, silver and alloys thereof and austenite-based stainless steels. These metals are relatively high in thermal conductivity. Thus, the case5can be used as a heat dissipation path, and the heat of the assembly10is efficiently dissipated to outside via the case5. Therefore, the heat dissipation of the assembly10is improved. Besides metals, resins and the like can be used as the material for constituting the case5.

The case5made of metal can be, for example, manufactured by die casting. The case5of this example is constituted by a die cast product made of aluminum.

Arrangement Mode of Assembly

An arrangement mode of the assembly10with respect to the case5is the upright type. In this case, as shown inFIG.1B, the assembly10is so accommodated into the case5that the respective axial directions of the both winding portions21,22are orthogonal to the inner bottom surface of the bottom plate portion51. Further, the assembly10of this example is so accommodated into the case5that the parallel direction of the both winding portions21,22is along the long side parts541,542. In the case of this example, since the holding member41includes the protruding portion45on the side of the one short side part531, the assembly10is arranged closer to the other short side part532with respect to the case5. If the arrangement mode of the assembly10is the upright type, an installation area of the assembly10with respect to the bottom plate portion51can be reduced as compared to the aforementioned horizontally placed type. In the horizontally placed type, an assembly is so accommodated in a case that a parallel direction and axial directions of both winding portions are parallel to a bottom plate portion. Generally, the length of the assembly10along a direction orthogonal to both the parallel direction of the both winding portions21,22and the axial directions of the both winding portions21,22is shorter than the length of the assembly10along the axial directions of the both winding portion21,22. That is, in the case of the upright type, the installation area of the assembly10is smaller as compared to the horizontally placed type. Therefore, if the arrangement mode of the assembly10is the upright type, an area of the bottom plate portion51can be reduced and the installation area of the reactor1A can be reduced.

Further, if the outer peripheral surfaces of the winding portions21,22are substantially constituted by flat surfaces as in this example, a large facing area of the winding portions21,22and the side wall portion52is ensured. Further, the intervals between the outer peripheral surfaces of the winding portions21,22and the inner peripheral surface of the side wall portion52tend to become smaller. In the case of this example, the intervals between the outer peripheral surfaces of the winding portions21,22and the inner surfaces of the long side parts541,542and the interval between the outer peripheral surface of the winding portion22and the inner surface of the short side part532tend to become smaller. Thus, in the reactor1A, the case5can be efficiently utilized as a heat dissipation path. Therefore, the reactor1A easily dissipates the heat of the coil2to the case5and is excellent in the heat dissipation of the assembly10.

The interval between the outer peripheral surface of the assembly10and the inner peripheral surface of the side wall portion52is, for example, 0.5 mm or more and 1.5 mm or less and, further, 0.5 mm or more and 1 mm or less. This interval is an interval between the outer peripheral surface of the outer wall portion40of the other holding member42located on the side of the opening55and the long side parts541,542and the short side part532of the side wall portion52. The reason for this is that, out of the assembly10, a closest member to the side wall portion52, except the protruding portion45, is the holding member42. If the respective inner surfaces of the long side parts541,542and the short side parts531,532of the side wall portion52are inclined as described later, a minimum value may be adopted as the above interval. If this interval is 0.5 mm or more, the resin, which will become the sealing resin portion6, easily flows between the assembly10and the side wall portion52. On the other hand, if the above interval is 1.5 mm or less and, further, 1 mm or less, the case5is easily reduced in size. Further, if the above interval is 1.5 mm or less and, further, 1 mm or less, the intervals between the outer peripheral surfaces of the winding portions21,22and the inner peripheral surface of the side wall portion52become smaller. Thus, the heat dissipation of the assembly10can be improved.

Sealing Resin Portion

The sealing resin portion6is filled into the case5and seals at least a part of the assembly10. The assembly10can be mechanically protected and protected from an external environment by the sealing resin portion6. Protection from the external environment aims to improve corrosion resistance and the like.

In this example, the sealing resin portion6is filled up to the opening end of the case5and the entire assembly10is embedded in the sealing resin portion6. Only a part of the assembly10may be sealed by the sealing resin portion6. For example, a part of the assembly10up to the height of the upper end surfaces of the winding portions21,22may be sealed by the sealing resin portion6. Further, the sealing resin portion6is interposed between the winding portions21,22of the coil2and the side wall portion52of the case5. In this way, the heat of the coil2can be transferred to the case5via the sealing resin portion6and the heat dissipation of the assembly10is improved.

Constituent Material

Examples of the resin of the sealing resin portion6include thermosetting resins and thermoplastic resins. Examples of thermosetting resins include an epoxy resin, a urethane resin, a silicone resin and an unsaturated polyester resin. Examples of thermoplastic resins include a PPS resin. The sealing resin portion6of this example is made of silicone resin, more specifically, silicone gel. The higher the thermal conductivity of the sealing resin portion6, the more preferable. The reason for this is that the heat of the coil2is easily transferred to the case5. Thus, the material for constituting the sealing resin portion6may contain, for example, a filler as described above in addition to the above resin. Components of the above material may be adjusted to enhance the thermal conductivity of the sealing resin portion6. The thermal conductivity of the sealing resin portion6is, for example, preferably 1 W/m·K or more and, further, 1.5 W/m·K or more.

Besides, an unillustrated adhesive layer may be provided between the assembly10and the bottom plate portion51. The adhesive layer can firmly fix the assembly10to the case5. The adhesive layer may be made of electrically insulating resin. Examples of the electrically insulating resin for constituting the adhesive layer include thermosetting resins and thermoplastic resins. Examples of thermosetting resins include an epoxy resin, a silicone resin and an unsaturated polyester resin. Examples of thermoplastic resins include a PPS resin and an LCP. The constituent material of the adhesive layer may contain the aforementioned filler in addition to the above resin. The adhesive layer may be formed, utilizing a commercially available adhesive sheet or commercially available adhesive.

Manufacturing Method

Mainly with reference toFIGS.4A and4B, an example of a manufacturing method of the reactor1A described above is described. The reactor1A can be manufactured by a manufacturing method including the following first to third steps.

In the first step, the assembly10and the case5are prepared.

In the second step, the assembly10is accommodated into the case5.

In the third step, the sealing resin portion6is formed in the case5.

FIG.4Ashows an arrangement position of the nozzle65in a step of forming the sealing resin portion6.FIG.4Bis a partial section along B-B inFIG.4A.FIG.4Bshows the appearance of the assembly10in the case5viewed from the side of a side surface as inFIG.1Band shows a cross-section of the case5cut by a plane parallel to the side surface.

First Step

In the first step, the assembly10and the case5are prepared. As shown inFIG.3, the assembly10is fabricated by assembling the coil2, the magnetic core3and the holding members41,42. Further, in this example, the molded resin portions8are formed, and the coil2, the magnetic core2and the holding members41,42are integrated by the molded resin portions8as shown inFIG.4B. Specifically, the molded resin portions8are formed to cover the outer peripheral surfaces of the outer core portions33with the coil2and the magnetic core3held at predetermined positions by the holding members41,42. At this time, part of the resin for constituting the molded resin portions8is filled between the winding portions21,22and the inner core portions31,32through the clearances between the outer core portions33and the recesses44and the clearances between the inner core portions31,32and the through holes43. Thus, the molded resin portions8are formed to be interposed between the winding portions21,22and the inner core portions31,32.

The prepared case5is, for example, made of nonmagnetic metal. In this example, the case5is a die-cast product made of aluminum.

Second Step

In the second step, the assembly10is accommodated into the case5through the opening55of the case5. The assembly10is so accommodated into the case5that the arrangement mode of the assembly10is the upright type. In this example, as shown inFIG.4B, the assembly10is so accommodated into the case5that the respective axial directions of the both winding portions21,22are orthogonal to the bottom plate portion51and the parallel direction of the both winding portions21,22is along the long side parts541,542(FIG.4A). In the case of this example, the assembly10can be positioned with respect to the case5by the protruding portion45of the holding member41.

Third Step

In the third step, the resin is filled into the case5to form the sealing resin portion6shown inFIG.1B. Specifically, as shown inFIGS.4A and4B, the resin, which will become the sealing resin portion6, is filled with the assembly10accommodated into the case5. In this example, the nozzle65for injecting the resin is used. In this example, the resin, which will become the sealing resin portion6, is a silicone resin, more specifically, a silicone gel.

As shown inFIG.4A, the resin is filled by inserting the nozzle65into the clearance46formed between the long side part541,542of the side wall portion52and the protruding portion45of the holding member41. Then, as shown inFIG.4B, the resin in a fluid state is injected from the side of the bottom plate portion51through the nozzle65. For example, a thermosetting resin may be injected by being mixed and stirred. Here, a case where the nozzle65is inserted into one clearance46on the side of the long side part541is illustrated as shown inFIG.4A. The diameter of the nozzle65is, for example, 3.5 mm or more and 5 mm or less. The tip of the nozzle65preferably reaches the vicinity of the bottom plate portion51. The tip of the nozzle65may not reach the vicinity of the bottom plate portion51.

If the resin is caused to flow from the side of the opening55of the case5, air bubbles tend to be included in the resin and tend to remain in the sealing resin portion6. Particularly, air bubbles tend to remain in the sealing resin portion6on the side of the bottom plate portion51. If the nozzle65is inserted into the clearance46and the resin is injected from the side of the bottom plate portion51to the side of the opening55, air bubbles are hardly included in the resin and hardly remain in the sealing resin portion6. Particularly, it can be avoided that air bubbles remain in the sealing resin portion6on the side of the bottom plate portion51. Thus, the sealing resin portion6can be satisfactorily filled into the case5.

In the case of this example, a state where the assembly10is positioned with respect to the case5can be maintained by the contact of the protruding portion45of the holding member41with the short side part531of the side wall portion52. Thus, a position shift of the assembly10can be effectively suppressed when the resin, which will become the sealing resin portion6, is filled.

If the nozzle65is inserted into the clearance46provided on the side of the one short side part531as shown inFIG.4A, the resin flows from the side of the short side part531toward the side of the other short side part532. As shown by white arrows inFIG.4A, the resin injected from the nozzle65flows between the assembly10and the long side parts541,542from the side of the one short side part531and merges on the side of the other short side part532. Thus, a merging point of the resin is created at a location distant from a location where the resin was injected. In this case, air bubbles mixed into the resin float up while the resin is flowing from the side of the one short side part531toward the side of the other short side part532, and the air bubbles in the resin are easily removed. Thus, the remaining of the air bubbles in the sealing resin portion6can be reduced by injecting the resin from the side of the one short side part531. Further, if the resin is injected from the side of the one short side part531, the merging point of the resin is one location on the side of the other short side part532. Since the entrainment of air bubbles easily occurs at the merging point of the resin, less merging points are preferable. Since the resin merges at one location by injecting the resin from the one short side part531, the remaining of air bubbles is easily reduced.

AlthoughFIG.4Aillustrates the case where the nozzle65is inserted into one clearance46on the side of the long side part541and the resin is injected, there is no limitation to this. A nozzle may be also inserted into the clearance46on the side of the long side part542and the resin may be injected from two nozzles.

The resin is preferably filled by placing the case5accommodating the assembly10in a vacuum tank and injecting the resin in a vacuum state. The generation of air bubbles in the sealing resin portion6can be suppressed by injecting the resin in the vacuum state.

By solidifying the resin after the resin is filled into the case5, the sealing resin portion6shown inFIG.1Bis formed. The resin may be solidified under appropriate conditions according to the used resin.

Main Effects

The reactor1A of the first embodiment achieves the following effects.

Since the arrangement mode of the assembly10is the upright type, the installation area of the assembly10with respect to the bottom plate portion51of the case5is reduced. Thus, the reactor1A can be reduced in size. Further, if the arrangement mode of the assembly10is the upright type, the facing area of the winding portions21,22and the side wall portion52tend to increase and the intervals between the winding portions21,22and the side wall portion52tend to become smaller. Thus, reactor1A easily dissipates the heat of the coil2to the case5and can improve the heat dissipation of the assembly10.

In the reactor1A, one holding member41includes the protruding portion45and the clearances46are formed between the long side parts541,542and the protruding portion45. Thus, in forming the sealing resin portion6, the resin, which will become the sealing resin portion6, can be filled by inserting the nozzle65into the clearance46. The size of the clearance46can be adjusted according to the size of the protruding portion45. Thus, even if the diameter of the nozzle65is large, the clearance46corresponding to the diameter of the nozzle65can be easily formed. If the diameter of the nozzle65is large, the resin filling operation can be efficiently performed. Therefore, the reactor1A is excellent in productivity.

Further, since the holding member41includes the protruding portion45, the assembly10can be positioned with respect to the case5. Thus, when the resin, which will become the sealing resin portion6, is filled into the case5, a position shift of the assembly10can be suppressed by the contact of the tip of the protruding portion45with one short side part531. This point contributes to an improvement of productivity.

Besides, the following effects can be expected for the reactor1A of the first embodiment.

In forming the sealing resin portion6, the resin can be injected by inserting the nozzle65into the clearance46. Since it is not necessary to provide a resin introduction path in the side wall portion52of the case5, the case5needs not be specially processed. Thus, the processing labor and manufacturing cost of the case5can be reduced.

The protruding portion45is provided only on the side facing the one short side part531, out of the outer peripheral surface of the holding member41, and the clearances46are formed only on the side of the one short side part531. Thus, the case5can be reduced in size as compared to the case where the protruding portion45is also provided on the side of the other short side part532and the clearances46are formed on the sides of the both short side parts531,532.

In the case of injecting the resin by inserting the nozzle65into the clearance46, the resin is injected from the side of the one short side part531and flows toward the side of the other short side part532. In this case, the merging point of the resin is created at the location distant from the location where the resin was injected. Thus, air bubbles in the resin are easily removed. By injecting the resin from the side of the one short side part531, the remaining of air bubbles in the sealing resin portion6can be reduced. Further, if the resin is injected from the side of the one short side part531, the merging point of the resin is one location on the side of the other short side part532. Since the merging point of the resin is one location, the remaining of air bubbles is easily reduced.

By injecting the resin from the side of the bottom plate portion51by inserting the nozzle65into the clearance46, air bubbles are hardly mixed into the resin and the remaining of air bubbles in the sealing resin portion6can be avoided. Thus, the sealing resin portion6is satisfactorily filled into the case5.

Use Application

The reactor1A can be used as a component of a circuit for performing a voltage stepping-up operation and a voltage stepping-down operation. The reactor1A can be used, for example, as a constituent component of various converters and power conversion devices. Examples of converters include in-vehicle converters to be installed in vehicles, typically DC-DC converters and converters of air conditioners. Example of the vehicles include hybrid vehicles, plug-in hybrid electric vehicles, electric vehicles and fuel cell vehicles.

Second Embodiment

A reactor1B according to a second embodiment is described with reference toFIGS.5A and5B. The reactor1B has a basic configuration similar to that of the reactor1A of the first embodiment. The reactor1B of the second embodiment differs from the reactor1A of the first embodiment in that a protruding portion45includes a through hole453and a part of a sealing resin portion6is filled into this through hole453. The following description is centered on points of difference from the first embodiment and similar matters are not described.

FIG.5Bis a partial section along B-B inFIG.5Ashowing the vicinity of the protruding portion45.FIG.5Bshows the appearance of an assembly10in a case5viewed from the side of a side surface as inFIG.1Band shows cross-sections of the case5and the sealing resin portion6cut by a plane parallel to the side surface.

Protruding Portion

As shown inFIG.5B, the protruding portion45has a first surface451located on the side of a bottom plate portion51(FIG.1B) of the case5and a second surface452located on the side of an opening55of the case5. The protruding portion45includes the through hole453penetrating through the first and second surfaces451,452as shown inFIGS.5A and5B. In this example, one through hole453is provided in a widthwise center of the protruding portion45. The protruding portion45may be provided with a plurality of the through holes453.

An axial direction in the through hole453is parallel to axial directions of through holes43provided in a frame plate of a holding member41. The through hole453of this example is formed by a circular hole having a uniform diameter. A cross-sectional shape of the through hole453is not limited to a circular shape, and may be a polygonal shape or the like. The through hole453may also be formed into a tapered shape having a diameter gradually reduced from the side of the first surface451toward the second surface452. A part of the sealing resin portion6is filled into the through hole453. Thus, by forming the through hole453into a tapered shape, a large contact area of the protruding portion45and the sealing resin portion6is easily secured. Further, by forming the through hole453into a tapered shape, the sealing resin portion6is easily hooked in a region continuous from a tapered surface to the first surface451.

Sealing Resin Portion

The sealing resin portion61includes a first resin portion61to be filled into the through hole453provided in the protruding portion45and a second resin portion62provided in contact with the first and second surfaces451,452. The first and second resin portions61,62constitute a continuously provided integrated body.

In the reactor1B of the second embodiment, the protruding portion45includes the through hole453and a part of the sealing resin portion6is filled into the through hole453, whereby the protruding portion45and the sealing resin portion6can be firmly joined and, consequently, the assembly10and the sealing resin portion6can be firmly joined. This is because the first resin portion61filled in the through hole453and the second resin portion62provided in contact with the first and second surfaces451,452are hooked to the protruding portion45.

Besides, in the reactor1B of the second embodiment, a filled state of the resin on the side of one short side part531can be confirmed through the through hole453in forming the sealing resin portion6since the protruding portion45includes the through hole453. Further, in the reactor1B of the second embodiment, air bubbles mixed into the resin filled on the side of the one short side part531can be removed from the through hole453in forming the sealing resin portion6since the protruding portion45includes the through hole453.

Third Embodiment

A reactor1C according to a third embodiment is described with reference toFIGS.6A,6B and7. The reactor1C of the third embodiment differs from the reactor1A of the first embodiment in that a short side part531includes a mounting seat56for supporting a protruding portion45of a holding member41and the protruding portion45and the mounting seat56are fastened. The following description is centered on points of difference from the first embodiment and similar matters are not described.

FIG.6Bis a partial section along B-B inFIG.6A.FIG.6Bshows the appearance of an assembly10in a case5viewed from the side of a side surface as inFIG.1Band shows cross-sections of the case5and a sealing resin portion6cut by a plane parallel to the side surface.

Mounting Seat

As shown inFIG.6B, the mounting seat56projects into the case5from the short side part531and supports a part of the protruding portion45on the side of a bottom plate portion51. As shown inFIG.6A, the mounting seat56is provided to overlap the protruding portion45when the reactor1C is viewed from above. In this example, the mounting seat56is formed to extend along the inner surface of the short side part531from the bottom plate portion51. The mounting seat56includes a screw hole57in an upper surface on the side of an opening55of the case5.

Protruding Portion

As shown inFIGS.6A and6B, the protruding portion45includes a through hole49penetrating through a first surface located on the side of the bottom plate portion51of the case5and a second surface located on the side of the opening55of the case5. The through hole49of this example is formed by embedding a collar490made of metal in the protruding portion45. The through hole49is provided at a position overlapping the screw hole57of the mounting seat56when the reactor1C is viewed from above.

The protruding portion45may include another unillustrated through hole in addition to the through hole49overlapping the screw hole57of the mounting seat5. A part of the sealing resin portion6is filled into the other through hole. The other through hole into which a part of the sealing resin portion6is filled has the function of the through hole453described in the second embodiment.

In this example, as shown inFIG.6B, the protruding portion45and the mounting seat56are fastened by a bolt59. The bolt59is not shown inFIG.6A. The bolt59is inserted into the through hole49of the protruding portion45from the side of the opening55of the case5and screwed into the screw hole57of the mounting seat56. A head part of the bolt59is located inwardly of the opening55of the case5. Thus, the head part of the bolt59does not project from the opening55of the case5. In this example, the head part of the bolt59is embedded in the sealing resin portion6and not exposed from the sealing resin portion6.

In the reactor1C of the third embodiment, the assembly10can be firmly fixed to the case5by fastening the protruding portion45of the holding member41to the mounting seat56. Thus, the detachment of the assembly10from the case5, for example, due to an impact, vibration or the like can be avoided in the reactor1C. Further, in this example, the mounting seat56is formed to extend along the inner surface of the short side part531from the bottom plate portion51. Since the mounting seat56is present in the case5in the reactor1C, a volume of the case5is smaller as compared to the reactor1A of the first embodiment. Thus, a used amount of the resin, which will become the sealing resin portion6, is reduced in the reactor1C than in the reactor1A. Therefore, the manufacturing cost of the reactor1C can be reduced by as much as the used amount of the resin, which will become the sealing resin portion6, is reduced.

Fourth Embodiment

A reactor1D according to a fourth embodiment is described with reference toFIGS.8A and8B. The reactor1D has a basic configuration similar to that of the reactor1A of the first embodiment. The reactor1D of the fourth embodiment differs from the reactor1A of the first embodiment in that an outer wall portion40of a holding member41includes projections47,48. The following description is centered on points of difference from the first embodiment and similar matters are not described.

FIG.8Bis a partial section along B-B inFIG.8A.FIG.8Bshows the appearance of an assembly10in a case5viewed from the side of a side surface as inFIG.1Band shows cross-sections of the case5and a sealing resin portion6cut by a plane parallel to the side surface.

Projections

The projections47,48are provided to project toward the inner peripheral surface of the case5from the outer wall portion40as shown inFIGS.8A and8B. First projections47are provided on surfaces facing long side parts541,542of the case5. A second projection48is provided on a surface facing a short side part532of the case5. That is, the second projection48is provided on the surface of the outer wall portion40facing a protruding portion45.

The number, positions and shapes of the projections47,48are not particularly limited and can be appropriately selected. For example, one projection47may be provided or a plurality of the projections47may be provided. In this example, two first projections47are provided at an interval in a length direction on each of the surfaces of the outer wall portion40facing the both long side parts541,542as shown inFIG.8A. Further, one second projection48is provided in a widthwise center on the surface of the outer wall portion40facing the short side part532. The projections47,48have a semispherical shape. Projection amounts of the projections47,48can be appropriately set according to intervals between the outer peripheral surface of the outer wall portion40and the long side parts541,542and the short side part532of a side wall portion52. The projection amounts of the projections47may be, for example, 0.5 mm or more and 1.5 mm or less.

In the reactor1D of the fourth embodiment, intervals between winding portions21,22and the long side parts541,542and an interval between the winding portion22and the short side part532are easily properly maintained by providing the projections47,48on the outer wall portion40. The projections47,48may be in contact with the surfaces facing the outer wall portion40. By the contact of the projections47with the respective inner surfaces of the long side parts541,542, the assembly10is easily positioned in a width direction with respect to the case5. Further, by the contact of the projection48with the inner surface of the short side part532, the assembly10is easily positioned in the length direction with respect to the case5. Particularly, if the inner peripheral surface of the side wall portion52is inclined to widen from the side of a bottom plate portion51toward the side of an opening55, excessive inclination of the assembly10in the case5can be suppressed by the contact of the projections47,48with the respective inner surfaces of the long side parts541,542and the short side part532.

LIST OF REFERENCE NUMERALS

1A,1B,1C,1D reactor10assembly2coil21,22winding portion3magnetic core31,32inner core portion33outer core portion,33einner end surface41,42holding member40outer wall portion43through hole,44recess45protruding portion451first surface,452second surface,453through hole46clearance47,48projection49through hole490collar5case51bottom portion52side wall portion531,532short side part541,542long side part55opening56mounting seat57screw hole59bolt6sealing resin portion61first resin portion,62second resin portion65nozzle8molded resin portion