Reactor and method for manufacturing the same

Abstract

To provide a reactor which is reduced in the size while reducing separation of a split core, and a method for manufacturing the reactor.SOLUTION: A reactor 1 includes a coil 2, a core 3, and a mold resin 5. The coil 2 is formed by winding a conductive wire 21, the core 3 is mounted with the coil 2 and is formed by connecting a plurality of split cores 41, and a mold resin 5 coats and is integrated with the coil 2 and the core 3. Each of the mold resin 5 and the split cores 41 has a recess 6 and a projection 7 for connecting the split cores 41 through the mold resin 5 by fitting. The recess 6 is deep in a direction orthogonal to arrangement of the split cores 41, and the projection 7 projects in a direction orthogonal to arrangement of the split cores 41, and is distributed and fit into the mold resin 5 side and the split cores 41 side.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a reactor having a coil and a core, and a method for manufacturing the reactor. [Background technology]

[0002] A reactor mainly consists of a coil and a core. When electricity is passed through the coil, it generates magnetic flux according to the number of turns. The core acts as a closed magnetic circuit that allows the magnetic flux generated by the coil to pass through with a magnetic permeability higher than that of a vacuum. In other words, a reactor is an electromagnetic component that converts electrical energy into magnetic energy and stores and releases it.

[0003] Such reactors are used in a wide variety of applications, and representative examples include boost reactors, series reactors, parallel reactors, current limiting reactors, starting reactors, shunt reactors, neutral point reactors, and arc suppression reactors.

[0004] Boost reactors are incorporated into on-board boost circuits such as those used in the drive systems of hybrid and electric vehicles. Series reactors are connected in series to motor circuits to limit the current during short circuits. Parallel reactors stabilize the current sharing between parallel circuits. Current-limiting reactors limit the current during short circuits and are connected to them. Starting reactors are connected in series to motor circuits to protect the machine and limit the starting current. Shunt reactors are connected in parallel to transmission lines to compensate for leading reactive power and suppress abnormal voltages. Neutral reactors are connected between the neutral point and the ground to limit the ground fault current that flows in the event of a ground fault in the power system. Arc-suppression reactors automatically extinguish the arc that occurs when a single-line ground fault occurs in a three-phase power system.

[0005] This reactor is provided with a molded resin that simultaneously covers and integrates the coil and the core. By integrating the coil and the core, the molded resin suppresses vibration of the reactor and further protects the insulating coating that protects the conductive wire of the coil.

[0006] Also, the core may be divided into multiple pieces and formed by joining the divided cores together (see, for example, Patent Document 1). The divided surfaces of the divided cores are joined together with an adhesive or the like, but this requires time and effort to apply and dry the adhesive, which increases the number of manufacturing steps and time.

[0007] Therefore, this molding resin extends to the back surface of the split core region that is furthest from the adjacent split core along the direction in which the split cores are arranged, and holds the core in a sandwiched manner from the direction in which the split cores are arranged. This prevents the split cores from separating or vibrating individually even if they are not joined together, and reduces the number of manufacturing steps and time. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2019-110232 A Summary of the Invention [Problem to be solved by the invention]

[0009] In recent years, as can be seen particularly in automotive applications, the integration of circuit components has progressed rapidly, and further miniaturization of reactors is expected. The molding resin forms the outermost shell of the reactor. Therefore, if it is possible to limit the area of ​​the coil and core covered by the molding resin, it will contribute to miniaturization of the reactor.

[0010] However, if the split cores are not joined, and the molded resin cannot hold the cores in a sandwiched manner in the direction in which the split cores are aligned, the split cores will collide with each other due to vibration, which will become a source of noise, and in the worst case, the split cores will separate and the magnetic permeability of the cores will change.Even if the split cores are joined, if the molded resin cannot hold the cores in a sandwiched manner in the direction in which the split cores are aligned, the adhesive will come off and the split cores will collide with each other due to vibration, which will become a source of noise, and in the worst case, the split cores will separate and the magnetic permeability of the cores will change.

[0011] The present invention has been proposed to solve the above-mentioned problems, and has an object to provide a reactor that is miniaturized while reducing the risk of separation of the split cores, and a method for manufacturing the reactor. [Means for solving the problem]

[0012] In order to achieve the above-mentioned object, a reactor according to an embodiment of the present invention comprises a coil formed by winding a conductive wire, a core to which the coil is attached and which is formed by connecting a plurality of split cores, and a molded resin that covers and integrates the coil and the core, wherein the molded resin and the split cores each have a recess and a protrusion that connect the split cores to each other via the molded resin by fitting together, the recess is deep in a direction perpendicular to the arrangement of the split cores, the protrusion protrudes in a direction perpendicular to the arrangement of the split cores, and the recess and the protrusion are distributed and fitted on the molded resin side and the split core side.

[0013] The split core may have a back surface that is farthest from the adjacent split core along the arrangement direction of the adjacent split core, and the molding resin may expose the entire back surface of the split core.

[0014] The core may have a ring shape formed by connecting the split cores, the molded resin may cover a boundary region of the inner ring surface of the core that includes the boundaries of the split cores, and the recess and the protrusion may be formed on the boundary region on the split core side and on the outer peripheral surface that covers the boundary region on the molded resin side.

[0015] The molding resin may have a flange that covers an edge of the annular surface of the core that contacts an inner peripheral surface of the core.

[0016] The molding resin may expose an outer circumferential surface of the core.

[0017] The split cores may be connected together without being joined.

[0018] The split core may have a split core body through which the magnetic flux passes and a split core coating resin that coats the split core body, and the concave or convex portion distributed on the split core side may be formed on the surface of the split core coating resin.

[0019] The manufacturing method of a reactor is also one aspect of an embodiment of the present invention, and in order to achieve the above-mentioned object, the manufacturing method of a reactor according to an embodiment of the present invention includes a core molding process in which a split core body that allows magnetic flux to pass is coated with a split core coating resin to produce a split core, and a secondary molding process in which molded resin is formed around a core made of a series of split cores and a coil attached to the core, wherein in the core molding process, a deep recess is formed in the split core coating resin in a direction perpendicular to the arrangement of the split cores, and in the secondary molding process, a convex portion that fits into the recess is formed in the molded resin using a mold having a gate hole at a position facing the recess or near the recess. Effect of the Invention

[0020] According to the present invention, even if the areas of the coil and core covered with the molding resin are limited, the risk of the split cores being separated can be reduced, and the reactor can be made smaller. [Brief description of the drawings]

[0021] [Figure 1] FIG. 2 is a perspective view of the reactor with the molding resin omitted. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a perspective view showing a reactor including a mold resin. [Figure 4] FIG. 2 is a top view showing a reactor including a mold resin. [Diagram 5] FIG. [Figure 6] 4 is a cross-sectional view of the core taken along the direction in which the split cores are arranged. FIG. [Figure 7] 1A and 1B are perspective views of a molded resin, in which (a) is a perspective view seen from one direction, and (b) is a perspective view seen from a direction rotated 90 degrees from the perspective view of (a). [Figure 8] 4 is a cross-sectional view of the reactor taken along the arrangement direction of the split cores. FIG. [Figure 9] 11A to 11C are perspective views showing a process of forming a molding resin. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, a reactor according to an embodiment of the present invention will be described with reference to the drawings. In each drawing, thickness, dimensions, positional relationship, ratio, shape, and the like may be emphasized for ease of understanding, but the present invention is not limited to such emphasis.

[0023] FIG. 1 is a perspective view showing the main configuration of the reactor of this embodiment, and for convenience of explanation, the molded resin 5 (see FIG. 3, etc.) is omitted. The reactor 1 includes a coil 2 and a core 3. The coil 2 is fitted into the core 3. When current is applied to the coil 2, the coil 2 generates a magnetic flux according to the number of turns. The core 3 is a closed magnetic circuit through which the magnetic flux generated by the coil 2 passes with a magnetic permeability higher than that of a vacuum. In other words, the reactor 1 is an electromagnetic component that converts electric energy into magnetic energy and stores and releases it. The core 3 is provided with fixing portions 49 extending at multiple locations, through which bolts can be inserted, and the reactor 1 is mounted on a circuit via the fixing portions 49.

[0024] The coil 2 is a winding body in which a conductive wire 21 such as a copper wire is wound into a cylindrical shape. The conductive wire 21 is coated with an insulating coating such as enamel coating. The coil 2 is formed by winding the conductive wire 21 in a spiral shape along a winding axis while shifting the winding position for each turn. The conductive wire 21 is drawn out from the beginning and end of the winding of the coil 2. The conductive wire 21 drawn out from the coil 2 is welded to a bus bar 22 which is a conductive member. The bus bar 22 is, for example, a long plate of copper, and a terminal block 23 which is connected to an external circuit is formed at the tip of the bus bar 22. The coil 2 is supplied with current from the outside via the bus bar 22, and generates a magnetic flux which penetrates along the winding axis.

[0025] The core 3 is formed by two split cores 41 connected together with their end faces 44 facing each other. The two split cores 41 are not bonded. That is, the end faces 44 are butted together without any adhesive applied, and the end faces 44 are simply in contact with each other, and the two split cores 41 are not bonded. In addition to butting the end faces 44 of the split cores 41 together without adhesive, "not bonded" also includes a mode in which an air gap is formed between the split core bodies 42 and the split core coating resins 43 are in contact with each other without being bonded.

[0026] FIG. 2 is an exploded perspective view of the core 3. As shown in FIG. 2, the core 3 includes a center leg 31, two outer legs 32, and a pair of yokes 33. The center leg 31 has a smaller diameter than the inner diameter of the coil 2, extends the same as or slightly longer than the entire length of the coil 2, and the coil 2 is fitted into the center leg 31. The outer legs 32 extend on both sides of the center leg 31 and are parallel to the center leg 31 on the same plane as the center leg 31. The yokes 33 are arranged separately at both ends of the center leg 31 and both outer legs 32, and are perpendicular to the center leg 31 and both outer legs 32, connecting the center leg 31 and both outer legs 32. Such a core 3 has an approximate θ shape in which two ring shapes with the center leg 31 in common are connected.

[0027] Both split cores 41 are formed by dividing the center leg 31 and both outer legs 32 of the core 3 at their centers so that the center leg 31 and both outer legs 32 are perpendicular to each other, and have a roughly E-shape. The core 3 is formed by connecting both split cores 41 with their end faces 44 facing each other and their back faces 48 separated from each other. Each split core 41 includes a split core body 42 and a split core coating resin 43.

[0028] The divided core body 42 includes a magnetic material such as a dust core, a ferrite core, a metal composite core, or a laminated steel plate. A dust core is a powder compact obtained by compressing magnetic powder and annealing it. The magnetic powder is mainly composed of iron, and examples of the magnetic powder include pure iron powder, permalloy (Fe-Ni alloy) mainly composed of iron, Si-containing iron alloy (Fe-Si alloy), sendust alloy (Fe-Si-Al alloy), amorphous alloy, nanocrystalline alloy powder, and a mixture of two or more of these powders. A metal composite core is a core formed by kneading magnetic powder and resin and molding them.

[0029] The split core body 42 also has an E-shape to match the shape of the split core 41. The split core body 42 may have an E-shape as a seamless, one-piece body, or may be further divided into a plurality of blocks, and the blocks may be connected together to form an E-shape to match the shape of the split core 41.

[0030] The split core body 42 is coated with the split core coating resin 43, except for the end faces 44 of the split core body 42, and this split core coating resin 43 is E-shaped to match the shape of the split core 41. This split core coating resin 43 has insulating properties and heat resistance, and a thermally conductive filler may be mixed into the split core coating resin 43.

[0031] Examples of the material for the split core coating resin 43 include epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), PBT (Polybutylene Terephthalate), and a composite of these.

[0032] Fig. 3 is a perspective view showing the reactor 1 including the molded resin 5, and Fig. 4 is a top view showing the reactor 1 including the molded resin 5. As shown in Fig. 3 and Fig. 4, the reactor 1 further includes the molded resin 5 that covers and integrates the coil 2 and the core 3. The molded resin 5 has insulating properties and heat resistance, and a thermally conductive filler may be mixed into the molded resin 5.

[0033] Examples of the material of the molding resin 5 include epoxy resin, unsaturated polyester resin, urethane resin, BMC (Bulk Molding Compound), PPS (Polyphenylene Sulfide), PBT (Polybutylene Terephthalate), and a composite of these.

[0034] This molded resin 5 is formed by injection molding with the coil 2 and core 3 accommodated in a metal mold. This molded resin 5 flows around the coil 2 and covers the entire surface including the inner and outer periphery of the coil 2. However, it is not necessary to cover the entire surface of the coil 2 with the molded resin 5. A flat plate 53 may be placed on a portion of the surface of the coil 2 and covered with this flat plate 53. The molded resin 5 adheres closely to the entire periphery of the flat plate 53 while covering the other entire surface of the coil 2.

[0035] Moreover, the molded resin 5 covers the inner peripheral surface 45 (see FIG. 2) of the core 3, which does not affect the size of the reactor 1. The inner peripheral surface 45 of the core 3 is defined by one surface of the outer leg 32 facing the center leg 31, two surfaces of the center leg 31 facing the outer leg 32, and one surface of the yoke 33 sandwiched between these surfaces. Among these, the molded resin 5 covers at least one surface of the outer leg 32 facing the center leg 31.

[0036] Furthermore, the molded resin 5 has a flange 51 that covers an edge region of the annular surface 46 (see FIG. 2) of the core 3 that contacts the inner peripheral surface 45 of the core 3 to provide a countermeasure against vibration that oscillates in a direction perpendicular to the center leg 31 and both outer legs 32. The annular surface 46 of the core 3 is a surface parallel to the plane on which the center leg 31 and the outer legs 32 are aligned.

[0037] However, in order to reduce the size of reactor 1, molded resin 5 leaves the entire area of ​​back surface 48 (see FIG. 2) of split core 41 exposed and does not cover it. Back surface 48 is the surface that is farthest from other split cores 41 along arrangement direction 9 of split cores 41. Preferably, in order to further reduce the size of reactor 1, molded resin 5 also leaves the entire area of ​​outer circumferential surface 47 (see FIG. 2) of core 3 exposed and does not cover it. Outer circumferential surface 47 of core 3 is the surface located opposite inner circumferential surface 45.

[0038] Here, FIG. 5 is a perspective view showing the core 3, and FIG. 6 is a cross-sectional view of the core 3 cut along the arrangement direction 9 of the split cores 41. As shown in FIGS. 5 and 6, the split cores 41 have recesses 6. One recess 6 is formed on the inner peripheral surface 45 of each split core 41 near the end faces 44 of both outer legs 32, and extends in a groove shape to connect both annular surfaces 46. As a whole, the core 3 has four recesses, two on each outer leg 32, sandwiching the end face 44 between them. The recesses 6 are deeper in a direction perpendicular to the arrangement direction 9 of the split cores 41. That is, the recesses 6 have an inner wall surface perpendicular to the arrangement direction 9 of the split cores 41.

[0039] 7 is a perspective view of the molded resin, where (a) is a perspective view seen from one direction, and (b) is a perspective view seen from a direction rotated 90 degrees from the perspective view of (a). As shown in FIG. 7, the molded resin 5 has a protrusion 7. The protrusion 7 protrudes in a direction perpendicular to the arrangement direction 9 of the split cores 41. The protrusion 7 is formed on the outer peripheral surface 52 that covers the inner peripheral surface 45 of the outer leg 32 of the split core 41, and protrudes toward this inner peripheral surface 45.

[0040] 8, which is a cross-sectional view of reactor 1 cut along arrangement direction 9 of split cores 41, convex portion 7 of molded resin 5 fits into each concave portion 6 of each split core 41. Therefore, each split core 41 is fixed in position in arrangement direction 9 of split cores 41 based on molded resin 5. Therefore, even if split cores 41 are not joined to each other and molded resin 5 does not extend to embrace both back surfaces 48 of core 3, the risk of distance changes, such as approaching or separating, of split cores 41 along arrangement direction 9 is suppressed.

[0041] In this way, the recesses 6 and the protrusions 7 can be formed on any of the surfaces of the core 3 covered by the molded resin 5 in order to maintain the connected state of the split cores 41 via the molded resin 5. For example, the recesses 6 may be formed on the annular surface 46 or the outer peripheral surface 47 of the core 3, and the molded resin 5 may have the protrusions 7 at locations corresponding to the recesses 6 while covering the annular surface 46 and the outer peripheral surface 47. This also allows the reactor to be made smaller than a reactor in which the molded resin 5 extends to embrace both back surfaces 48 of the core 3.

[0042] However, it is particularly preferable to cover inner peripheral surface 45 of core 3 with molded resin 5 and to provide recessed portions 6 and protruding portions 7 on inner peripheral surface 45 of core 3 and outer peripheral surface 52 of molded resin 5. This is because even if inner peripheral surface 45 of core 3 is covered with molded resin 5, reactor 1 does not become larger, and reactor 1 can be further miniaturized.

[0043] The above-described reactor 1 is manufactured through a core molding process in which split cores 41 are fabricated, and a secondary molding process in which split cores 41 are joined together to form core 3, and coil 2 and core 3 are integrated with molding resin 5.

[0044] In the core molding process, the split core body 42, or in addition, if a metal collar or the like is inserted in the fixing portion 49, is accommodated in the mold for the split core coating resin 43, and the resin material for the split core coating resin 43 is injected into the mold. This produces the split core 41 in which the split core body 42 is coated with the split core coating resin 43 in which the recess 6 is formed.

[0045] Furthermore, if the split core body 42 is, for example, a powder magnetic core, the split core body 42 is produced by forming a single layer or multiple types of multiple layers of insulating coating, etc. on soft magnetic powder, then press-molding it into the shape of the split core body 42, and sintering the press-molded body.

[0046] In the secondary molding process, the bus bar 22 is welded to the coil 2, and the coil 2 and the bus bar 22 are fitted into the split core 41, and the split core 41 is then arranged and housed in a mold for the molded resin 5. A flat plate 53 is placed on the coil 2. The mold for the molded resin 5 is composed of an upper mold and a lower mold, and the flat plate 53 is interposed between the coil 2 and the upper mold as a buffer material to prevent the surface of the coil 2 from being damaged by the mold. When the mold is closed, the coil 2 is pressed by the mold through the flat plate 53, and is supported so as to suppress positional deviation within the mold, and also unevenness and twists on the surface of the coil 2 are corrected.

[0047] 9 is a perspective view showing the coil 2 and core 3 housed in a die for molding resin 5, and illustrating the process of forming the molding resin 5. As shown in FIG. 9, when the die is closed, the resin material of the molding resin 5 is injected into the die. The gate hole 8 for injecting the resin material of the molding resin 5 can be arranged in various positions, but can at least be arranged to correspond to the recessed portion 6 formed in the split core 41.

[0048] The gate hole 8 faces the opening of the recess 6 on the annular surface 46 side, and the resin material of the molded resin 5 is efficiently poured into the recess 6. As a result, the molded resin 5 forms a protrusion 7 that is in close contact with the recess 6 with no gaps. Therefore, the split cores 41 are precisely fitted together and fixed without any rattling. It is sufficient for this gate hole 8 to be located in the vicinity of the recess 6 as long as it can efficiently pour the resin material of the molded resin 5 into the recess 6, and it is not necessary for the gate hole 8 to be precisely positioned opposite the opening of the recess 6 on the annular surface 46 side.

[0049] Due to the presence of these gate holes 8, dome-shaped gate marks 54 are generated at both ends of each protrusion 7, expanding so as to catch on the annular surface 46 of the core 3 (see, for example, Figures 3 and 7). These gate marks 54 make it difficult for cracks to form in the protrusion 7 even when subjected to vibration, and prevent the protrusion 7 from breaking and coming off the recess 6. Note that the gate marks 54 may be formed in a dome shape or in a cone shape with a concave center.

[0050] As described above, the reactor 1 of this embodiment includes the coil 2, the core 3, and the molded resin 5. The coil 2 is formed by winding the conductive wire 21, the core 3 is formed by connecting a plurality of split cores 41 together with the coil 2 attached thereto, and the molded resin 5 covers and integrates the coil 2 and the core 3. At this time, the molded resin 5 and the split cores 41 each have a recess 6 and a protrusion 7 that connect the split cores 41 to each other via the molded resin 5 by fitting them together. The recess 6 is deep in a direction perpendicular to the arrangement of the split cores 41, and the protrusion 7 protrudes in a direction perpendicular to the arrangement of the split cores 41, and is distributed and fitted to the molded resin 5 side and the split core 41 side.

[0051] As a result, even if the back surface 48 which is farthest from the adjacent split core 41 along the alignment direction 9 of the split core 41 is not embraced by the molded resin 5 but is entirely exposed, the risk of the split core 41 separating can be reduced, and the reactor 1 can be made smaller.

[0052] In this embodiment, the core 3 is formed in a substantially θ-shape by joining two E-shaped split cores 41 together, but the shape and split manner of the core 3 are not limited to this. For example, the core 3 may be formed by a split core 41 that becomes the center leg 31, a split core 41 that becomes the outer leg 32, and a split core 41 that becomes the yoke 33. The arrangement direction 9 is determined for each pair of adjacent two split cores 41.

[0053] For example, recesses 6 may be provided in each of center leg 31 and yoke 33 so as to be perpendicular to arrangement direction 9 of split core 41 of center leg 31 and split core 41 of one yoke 33, and protrusions 7 may be formed in molded resin 5 covering center leg 31 and yoke 33 to fit into these recesses 6. Furthermore, molded resin 5 may be provided with protrusions 7 to fit into recesses 6 of outer leg 32 and recesses 6 of the other yoke 33.

[0054] Also, the core 3 may be composed of, for example, a total of three split cores 41, the first to third, and the third split core 41 may be connected in a direction perpendicular to the arrangement direction 9 of the first and second split cores 41. In this case, deep recesses 6 and protrusions 7 in the direction perpendicular to the arrangement direction 9 of the first and second split cores 41 may be distributed among the first and second split cores 41 and the molded resin 5. Furthermore, another deep recesses 6 and protrusions 7 in the direction perpendicular to the arrangement direction 9 in which the third split core 41 and the first or second split core 41 are connected may be distributed among the third split core 41, the first or second split core 41, and the molded resin 5.

[0055] In addition, in this embodiment, the split core 41 is formed with the recess 6, and the molded resin 5 is provided with the protrusion 7, but this is not limited to the above. That is, the split core 41 may be formed with the protrusion 7, and the molded resin 5 may be provided with the recess 6. Alternatively, one split core 41 may be provided with the recess 6, the molded resin 5 may be provided with the protrusion 7 for fitting with this split core 41, and the other split core 41 may be provided with the recess 6 for fitting with this split core 41.

[0056] Further, the core 3 has a ring shape formed by connecting the split cores 41, and the recessed portion 6 and the protruding portion 7 are formed on the inner peripheral surface 45 of the split cores 41 and the outer peripheral surface 52 of the molded resin 5. Even if the inner peripheral surface 45 of the core 3 is covered with the molded resin 5, the reactor 1 does not become larger, and it is possible to satisfactorily achieve both miniaturization of the reactor 1 and prevention of separation of the split cores 41. That is, for example, the molded resin 5 exposes the outer peripheral surface 47 of the core 3 in addition to exposing the back surface 48 of the split cores 41, thereby making it possible to further miniaturize the reactor 1.

[0057] In order to prevent the split cores 41 from separating, it is sufficient that the molding resin 5 covers only the area of ​​the inner circumferential surface 45 of the core 3 where the fitting structure is to be formed by the recesses 6 and the protrusions 7. The area of ​​the inner circumferential surface 45 of the core 3 where the fitting structure is to be formed by the recesses 6 and the protrusions 7 is preferably the boundary area of ​​the inner circumferential surface 45 of the core 3 where the split cores 41 separate, which can further prevent the split cores 41 from separating.

[0058] The boundary of separation of split core 41 is the portion where end faces 44 face each other. The boundary region is a region that extends on both sides along outer leg 32 across this boundary of separation, and does not have to extend over the entire length of outer leg 32. In other words, it is not essential that molded resin 5 cover the entire outer leg 32 portion of inner circumferential surface 45, it is not essential that molded resin 5 cover the region of inner circumferential surface 45 that is the yoke 33, and further it is not essential that molded resin 5 cover the region of inner circumferential surface 45 that is the center leg 31.

[0059] Furthermore, the molded resin 5 has a flange 51 that covers the edge of the annular surface 46 of the core 3 that contacts the inner peripheral surface 45 of the core 3. This makes it possible to suppress the vibration amplitude in the direction perpendicular to the annular surface 46 of the core 3 even if the area of ​​the molded resin 5 is reduced to make the reactor 1 smaller.

[0060] In this embodiment, the split cores 41 are connected without being joined. Unjoined split cores 41 are easy to separate, which is particularly useful for reactor 1 having recessed portion 6 and protruding portion 7, but split cores 41 may be joined. Even if end faces 44 of split cores 41 are joined with adhesive, there is a risk that the adhesive will come off due to vibration and split cores 41 will separate. Therefore, even in reactor 1 in which split cores 41 are joined, it is possible to reduce the size while suppressing the risk of split cores 41 separating.

[0061] Here, non-joining includes not only butting the end faces 44 of the split cores 41 together without adhesive, but also a configuration in which an air gap is formed between the split core bodies 42 and the split core coating resins 43 are butted together.

[0062] The manufacturing method of the reactor 1 includes a core molding process and a secondary molding process. In the core molding process, a split core body 42 through which magnetic flux passes is coated with a split core coating resin 43 to produce a split core 41. In the secondary molding process, a molded resin 5 is formed on a core 3 in which the split cores 41 are aligned and a coil 2 attached to the core 3. In this core molding process, a deep recess 6 is formed in the split core coating resin 43 in a direction perpendicular to the arrangement of the split cores 41, and in the secondary molding process, a protrusion 7 that fits into the recess 6 is formed in the molded resin 5 using a die having a gate hole 8 at a position facing the recess 6 or in the vicinity of the recess 6.

[0063] This allows the resin material of the mold resin 5 to be sufficiently filled in the recess 6, and the protrusion 7 can be formed to fit tightly with the recess 6 without any gaps. This reduces the risk of rattling of the split core 41 and noise generation from the reactor 1.

[0064] The above-mentioned embodiment of the present invention is presented as an example, and the present invention is not limited to the above-mentioned embodiment. The above-mentioned embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the scope of the invention. The embodiment and its modifications are included in the scope of the present invention. [Explanation of symbols]

[0065] 1 Reactor 2 Coil 21 Conductive wire 22 Busbar 23 Terminal block 3 Cores 31 Middle legs 32 Outer legs 33 York 41 Split Core 42 Split core body 43 Split core coating resin 44 End face 45 Inner surface 46 Annular Surface 47 Outer surface 48 Back 49 Fixed part 5. Mold Resin 51 Flange 52 Outer surface 53 flat plate 54 Gate Remains 6 Recess 7 Convex 8 Gate hole 9. Layout Direction

Claims

1. A coil formed by winding a conductive wire; a core having an annular shape with an outer leg and a yoke, the coil being attached to the core, the core being made up of a plurality of divided cores connected together and dividing the outer leg; a molding resin that covers and integrates the coil and the core; Equipped with At least some of the divided cores are connected together without being joined, the mold resin and the split cores each have a recess and a protrusion that connect the split cores to each other via the mold resin by fitting them together, the recessed portion is deep in a direction perpendicular to the arrangement of the split cores, and the protruding portion protrudes in the direction perpendicular to the arrangement of the split cores, the molding resin covers a boundary region of an annular inner peripheral surface of the core, the boundary region including the boundary between the divided cores; the recessed portion and the protruding portion are formed in the boundary region of the split core and in the molding resin covering the boundary region, the boundary region includes the boundary of the divided core, does not extend over the entire length of the outer leg, and does not extend over the inner peripheral surface of the yoke; A reactor characterized by the above.

2. The split core has a back surface that is farthest from the adjacent split core along an arrangement direction of the adjacent split cores, the molding resin exposes the entire back surface of the split core; The reactor according to claim 1 .

3. the molding resin has a flange covering an edge of the annular surface of the core that is in contact with an annular inner peripheral surface of the core; The reactor according to claim 1 .

4. the molding resin exposes an outer circumferential surface of the core; The reactor according to any one of claims 1 to 3,

5. The split core includes a split core body through which magnetic flux passes and a split core coating resin that coats the split core body, the concave portion or the convex portion distributed on the split core side is formed on a surface of the split core coating resin; The reactor according to any one of claims 1 to 4,

6. a core molding process in which a split core body through which magnetic flux passes is coated with a split core coating resin to produce a plurality of split cores; a core forming step of connecting at least some of the plurality of split cores without joining them to form a ring-shaped core having an outer leg and a yoke; a secondary molding step of mounting a coil on the core and forming a molding resin on the core and the coil; Including, In the core molding step, a deep recess is formed in the split core coating resin at a boundary region of the split core in a direction perpendicular to an arrangement of the split core, the boundary region includes the boundary of the divided core, does not extend over the entire length of the outer leg, and does not extend over the inner peripheral surface of the yoke, in the secondary molding step, a protrusion that fits into the recess is formed in the molding resin by using a die having a gate hole at a position facing the recess or in the vicinity of the recess; A method for manufacturing a reactor, comprising the steps of:

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