JP2013115140A - Reactor and manufacturing method therefor - Google Patents

Abstract

Provided is a technique for suppressing generation of burrs in an exposed portion of a core without forming unnecessary holes in a cover that covers the core when manufacturing a reactor.
The present specification discloses a method of manufacturing a reactor. The reactor includes a core member and a coil wound around the core member. The core member includes a core and a resin cover that covers the core. At least a part of the cover is formed with an exposed portion where the exposed surface of the core is exposed. The method includes a step of forming a cover integrally with the core by insert molding to obtain a core member, and a step of assembling the core member and a coil to obtain a reactor. In the method, in the step of obtaining the core member, the core is supported through the contact surface provided on the mold corresponding to the exposed surface, and the resin is injected from the gate disposed on the back side of the exposed surface of the core. .
[Selection] Figure 6

Description

  The present invention relates to a reactor and a manufacturing method thereof.

  In recent years, electric vehicles such as hybrid vehicles and electric vehicles have been put into practical use and are spreading. Power conversion devices for electric vehicles often include a reactor. The reactor includes a core and a coil wound around the core. In many cases, in order to prevent the core from being rusted and to ensure insulation between the core and the coil, the periphery of the core is covered with a resin cover, and the coil is wound outside the cover. The cover that covers the core is formed integrally with the core by insert molding. Such a reactor is described in Patent Document 1, for example.

JP 2004-314338 A

  In the case where an exposed portion where the core is exposed is formed on a part of the cover, the resin is injected with the exposed surface of the core in close contact with the mold. At this time, if the core is not strongly pressed against the mold, the resin enters between the core and the mold, and burrs are generated.

  If the resin is injected while pressing the jig against the core as in the technique of Patent Document 1, the resin can be prevented from entering between the core and the mold. However, in this case, a hole corresponding to the jig is formed in the molded cover. If such holes are present, the rust prevention performance of the core is lowered and the strength of the cover is lowered. A technique that can prevent the occurrence of burrs in the exposed portion of the core without forming unnecessary holes in the cover is expected.

  In this specification, the technique which solves said subject is provided. In this specification, when manufacturing a reactor, the technique which can suppress generation | occurrence | production of the burr | flash in the exposed part of a core is formed, without forming an unnecessary hole in the cover which covers a core.

  This specification discloses the manufacturing method of a reactor. The reactor includes a core member and a coil wound around the core member. The core member includes a core and a resin cover that covers the core. At least a part of the cover is formed with an exposed portion where the exposed surface of the core is exposed. The method includes a step of forming a cover integrally with the core by insert molding to obtain a core member, and a step of assembling the core member and a coil to obtain a reactor. In the method, in the step of obtaining the core member, the core is supported through the contact surface provided on the mold corresponding to the exposed surface, and the resin is injected from the gate disposed on the back side of the exposed surface of the core. .

  In the above method, when forming a cover that covers the core by insert molding, the core is supported via a contact surface provided on the mold corresponding to the exposed surface, and the back side of the exposed surface of the core (core Resin is injected from the gate located on the opposite side of the exposed surface as viewed from the side. Since the core is pressed against the contact surface by the pressure received from the injected resin, the exposed surface of the core and the contact surface of the mold are in close contact with each other, and the injected resin does not enter between them. According to said method, generation | occurrence | production of a burr | flash can be suppressed, without forming an unnecessary hole in a cover.

  In the above method, the core preferably has two or more exposed surfaces, and the gate is preferably disposed in the vicinity of the corner of the core where the back surfaces of the exposed surfaces intersect.

  According to said method, each exposed surface of a core can be pressed against a metal mold | die with the pressure of the resin inject | poured from one gate. With simple equipment, it is possible to form a cover that does not have unnecessary holes and has no burrs.

  In the above method, it is preferable that a groove is formed in the vicinity of the gate of the mold along the direction in which the resin flows.

  Depending on the shape of the cover to be formed, there may be an imbalance in the resin injection between the part where the resin tends to flow and the part where the resin does not flow easily during insert molding, and the force pressing the core against the contact surface may be insufficient There is. In the above method, by forming a groove along the direction in which the resin flows in the vicinity of the gate of the mold, it is possible to sufficiently inject the resin even in a region where the resin does not flow easily, thereby eliminating the imbalance of the resin injection. it can. The core is surely pressed against the contact surface, and the adhesion between the exposed surface of the core and the contact surface of the mold is further ensured.

  In the above method, it is preferable that a magnet for attracting the core is disposed on the contact surface (including the vicinity thereof) of the mold.

  By arranging the magnet on the contact surface of the mold, in addition to pressing the core against the contact surface by the pressure of the injected resin, the core can be attracted to the contact surface by the magnet's adsorption force. The position of the core with respect to the mold can be firmly fixed.

  The present specification also discloses a reactor manufactured by the above method. The reactor includes a core member and a coil wound around the core member. The core member includes a core and a resin cover that covers the core. At least a part of the cover is formed with an exposed portion where the exposed surface of the core is exposed. The reactor has a gate mark on the back side of the exposed surface of the core of the cover.

  When the core has two or more exposed surfaces, the reactor is arranged near the corner of the core where the back surfaces of the exposed surfaces intersect each other.

  In addition, when a groove portion is formed in the vicinity of the gate of the mold along the direction in which the resin flows, the reactor manufactured by the above method is aligned in the direction in which the resin flows in the vicinity of the gate mark. Ribs are formed.

  According to the technology disclosed in the present specification, when a reactor is manufactured, the generation of burrs in the exposed portion of the core can be suppressed without forming unnecessary holes in the cover that covers the core.

1 is an exploded perspective view of a reactor 10. FIG. 1 is a perspective view of a reactor 10. FIG. It is the perspective view which looked at the core member 12a from the downward direction. It is a figure which shows the state which mounted the core 24a in the lower mold | type 40. FIG. It is a figure which shows the state which closed the lower mold | type 40 and the upper mold | type 38. FIG. It is a figure which shows the state which has inject | poured resin in the cavity. It is a figure which shows the state which injection | pouring of the resin to the cavity 52 was completed. It is a figure showing the state where injection of resin became imbalanced. It is a figure which shows the state which provided the flow leader 54 in the lower mold | type 40. FIG. FIG. 6 is a perspective view of a core member 12a including a flow leader rib 56.

  FIG. 1 shows an exploded perspective view of the reactor 10 of this embodiment, and FIG. 2 shows a perspective view of the reactor 10. The reactor 10 is used, for example, in a power conversion device of a hybrid vehicle or an electric vehicle.

  As shown in FIG. 2, the reactor 10 includes a ring-shaped reactor core 12 and a coil 14 wound at two locations of the reactor core 12.

  The coil 14 is wound between flanges 16 a and 16 b formed on the reactor core 12. As well shown in FIG. 1, the coil 14 is formed using a rectangular wire. A flat wire is a conducting wire having a rectangular cross section. The coil 14 is wound into a shape having two insertion holes 18a and 18b.

  As shown in FIG. 1, the reactor core 12 is divided into two U-shaped core members 12a and 12b. When manufacturing the reactor 10, the core member 12 a is inserted into the insertion holes 18 a and 18 b from one side of the coil 14, the core member 12 b is inserted into the insertion holes 18 a and 18 b from the other side of the coil 14, and the core is inserted via the spacers 20 and 22. The reactor core 12 around which the coil 14 is wound is formed by joining the member 12a and the core member 12b. The spacers 20 and 22 are made of a nonmagnetic material. The material of the spacers 20 and 22 is, for example, alumina ceramics.

  The core member 12a and the core member 12b have the same structure. Hereinafter, the core member 12a will be described in detail as an example. As shown in FIG. 3, the core member 12a includes a core 24a and a cover 26a that covers the periphery of the core 24a. In the present embodiment, the core 24a is a dust core made of ferrite, which is a magnetic material. The core 24a is formed in a U shape. The cover 26a is an insulating resin member in which the core 24a is insert-molded. A flange 16a is formed on the cover 26a. The cover 26a is formed with an adhesive portion 28a and a cooling portion 30a as exposed portions from which the core 24a is exposed. In the bonding portion 28a, the bonding surface 32a of the core 24a is exposed. The adhesive surface 32a is used for applying an adhesive to the spacers 20 and 22 for surface bonding. In the cooling unit 30a, the cooling surface 34a of the core 24a is exposed. The cooling surface 34a is used to cool the core 24a by surface contact with an external cooling mechanism (not shown) when the coil 10 is energized to operate the reactor 10.

  Below, the manufacturing method of the reactor 10 is demonstrated. When manufacturing the reactor 10, the core members 12a and 12b and the coil 14 are prepared first.

  The core members 12a and 12b are manufactured by the same manufacturing method. Hereinafter, the manufacturing method will be described using the core member 12a as an example.

  First, as shown in FIG. 4, the core 24 a is set in the mold 36. The mold 36 includes an upper mold 38 and a lower mold 40. The upper die 38 and the lower die 40 are formed with cavity surfaces corresponding to the outer shape of the cover 26a to be molded. The upper mold 38 is formed with a resin injection path 42 for injecting resin. The resin injection path 42 communicates with a gate 44 provided on the cavity surface of the upper mold 38. The lower mold 40 includes a lower contact surface 46 and a side contact surface 48. The shape of the lower contact surface 46 matches the shape of the cooling surface 34a of the core 24a exposed in the core member 12a. The shape of the side contact surface 48 matches the shape of the bonding surface 32a of the core 24a exposed in the core member 12a. The core 24 a is supported by the lower mold 40 in a state in which both the lower contact surface 46 and the side contact surface 48 are in contact.

  In this embodiment, in order to firmly fix the core 24a to the lower mold 40, a magnet 50 is provided in the vicinity of the side contact surface 48 of the lower mold 40 as shown in FIG. The core 24 a is attracted to the side contact surface 48 by the magnetic force of the magnet 50, and the core 24 a can be strongly fixed to the lower mold 40.

  Thereafter, as shown in FIG. 5, the upper mold 38 and the lower mold 40 are closed. As a result, a cavity 52 corresponding to the shape of the cover 26 a is formed around the core 24 a inside the mold 36.

  Thereafter, as shown in FIG. 6, the resin is injected through the resin injection path 42. As a result, the resin flowing in from the gate 44 is filled into the cavity 52 around the core 24a.

  In the present embodiment, when viewed from the core 24a, the gate 44 is located on the opposite side of the cooling surface 34a (the back side of the cooling surface 34a) and on the opposite side of the bonding surface 32a (the back side of the bonding surface 32a). Has been placed. Accordingly, the core 24 a is pressed against the lower contact surface 46 and the side contact surface 48 by the pressure of the resin injected from the gate 44. Thereby, the position of the core 24a is not shifted. Further, due to the pressure of the resin injected from the gate 44, the lower contact surface 46 of the mold 36 and the cooling surface 34a of the core, and the side contact surface 48 of the mold 36 and the adhesive surface 32a of the core are in close contact with each other. The molten resin does not enter between the surfaces. Therefore, no burr occurs. According to the present embodiment, the position of the core 24a can be fixed without pressing a positioning jig against the core 24a. The cover 26a can be formed without pressing a jig against the core 24a. At the same time, the generation of burrs can be suppressed.

  As shown in FIG. 7, when the filling of the resin into the cavity 52 is completed, the resin is cooled and cured. By the above, the cover 26a which covers the core 24a is formed, and the core member 12a can be manufactured. The core member 12a manufactured as described above is the opposite side of the cooling surface 34a (the back side of the cooling surface 34a) and the opposite side of the bonding surface 32a (the back side of the bonding surface 32a) when viewed from the core 24a. There is a gate mark at the position.

  After manufacturing the core members 12a and 12b, the reactor 10 can be manufactured by assembling the core members 12a and 12b to the coil 14 in a wound state as shown in FIG.

  As shown in FIG. 6, when the resin is filled in the cavity 52, depending on the shape of the core member 12 a, an imbalance may occur in the resin injection between the location where the resin easily flows and the location where the resin does not flow easily. There is. In the example illustrated in FIG. 8, the resin easily flows at a location along the upper surface of the core 24 a, and the resin hardly flows at a location along the side surface of the core 24 a. In the example shown in FIG. 8, there is a possibility that the side surface of the core 24 a is not sufficiently filled with the resin and the entire cavity 52 is not filled with the resin uniformly. Further, the force for pressing the core 24a against the side contact surface 48 may be insufficient.

  In such a case, as shown in FIG. 9, a flow leader 54 is provided in the vicinity of the gate 44 so that the resin can be sufficiently injected into a portion where the resin does not flow easily. The flow leader 54 is a groove provided in the mold 36 for promoting the flow of the resin along the direction in which the resin flows. By providing the flow leader 54 in the vicinity of the gate 44, the resin is sufficiently injected even in a location where the resin is difficult to flow, and the imbalance of the resin injection is eliminated. Thereby, the core 24a can be reliably pressed against the side contact surface 48, and the position of the core 24a can be firmly fixed. Moreover, generation | occurrence | production of the burr | flash of the resin in the side contact surface 48 can be suppressed. In addition, as shown in FIG. 10, the flow leader rib 56 corresponding to the flow leader 54 is formed in the core member 12a manufactured in this way. The flow leader rib 56 is formed in the vicinity of the gate mark of the cover 26a.

  In the above embodiment, the case where a dust core is used as the core 24a has been described as an example. However, the core 24a may be another type of core such as a laminated core.

  In the above embodiment, the case where a flat wire is used as the coil 14 has been described as an example, but the coil 14 may be another type of coil.

  In the above-described embodiment, the case where the reactor 10 is manufactured by assembling the U-shaped two core members 12a and 12b to the coil 14 wound in advance has been described. For example, the ring core 12 is used as one core member. After manufacturing, the reactor 10 may be manufactured by winding the coil 14 from the outside.

  Specific examples of the present invention have been described in detail above, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology exemplified in this specification or the drawings can achieve a plurality of objects at the same time, and has technical usefulness by achieving one of the objects.

DESCRIPTION OF SYMBOLS 10 Reactor 12 Reactor core 12a, 12b Core member 14 Coil 16a, 16b Flange 18a, 18b Insertion hole 20, 22 Spacer 24a, 24b Core 26a, 26b Cover 28a, 28b Adhesion part 30a, 30b Cooling part 32a, 32b Adhesive surface 34a, 34b Cooling surface 36 Mold 38 Upper die 40 Lower die 42 Resin injection path 44 Gate 46 Lower contact surface 48 Side contact surface 50 Magnet 52 Cavity 54 Flow leader 56 Flow leader rib

Claims (7)

A reactor manufacturing method comprising:
The reactor includes a core member and a coil wound around the core member,
The core member includes a core and a resin cover that covers the core,
An exposed portion where the exposed surface of the core is exposed is formed on at least a part of the cover,
The method is
Forming the cover integrally with the core by insert molding to obtain the core member;
Assembling the core member and the coil to provide the reactor;
In the step of obtaining the core member, the core is supported through a contact surface provided on the mold corresponding to the exposed surface, and resin is injected from a gate disposed on the back side of the exposed surface of the core. A method for manufacturing a reactor. The core has two or more exposed surfaces;
The method of manufacturing a reactor according to claim 1, wherein the gate is disposed in the vicinity of a corner of the core where the back surfaces of the exposed surfaces intersect.   The method for manufacturing a reactor according to claim 1, wherein a groove portion is formed in the vicinity of the gate of the mold along a direction in which resin flows.   The method for manufacturing a reactor according to any one of claims 1 to 3, wherein a magnet for attracting the core is disposed on the contact surface of the mold. A reactor comprising a core member and a coil wound around the core member,
The core member includes a core and a resin cover that covers the core,
An exposed portion where the exposed surface of the core is exposed is formed on at least a part of the cover,
A reactor having a gate mark on the back side of the exposed surface of the core of the cover. The core has two or more exposed surfaces;
The reactor according to claim 5, wherein the gate mark is disposed in the vicinity of a corner of the core where the back surfaces of the exposed surfaces intersect.   The reactor of Claim 5 or 6 in which the rib along the direction through which resin flows is formed in the vicinity of the said gate trace.

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