JP2020021806A - Manufacturing method for reactor - Google Patents

Abstract

To provide a manufacturing method appropriate for a reactor having a projection on a resin cover.SOLUTION: A resin cover covering a core and a coil of a reactor has a projection. A mold filled with molten resin to form the resin cover has an upper mold and a lower mold. The upper mold is vertically movable with respect to the lower mold. The upper mold has a projection top cavity part for forming a projection top. The lower mold has a core pressing part and a projection bottom cavity part. The core pressing part is provided so as to be movable forward/backward with respect to a side surface of the core placed in the mold and presses the core when the mold is filled with the molten resin. The projection bottom cavity part is coupled to the core pressing part and is movable forward/backward together with the core pressing part. A side surface of the projection bottom cavity part has a groove extending along the forward/backward movement direction of the core pressing part. After the molten resin in the mold is solidified, the core pressing part and the projection bottom cavity part are moved backward after the upper mold is opened.SELECTED DRAWING: Figure 6

Description

  The technology disclosed in the present specification relates to a method for manufacturing a reactor.

  There is known a reactor including a core, a winding wound around the core, and a resin cover covering the core and the winding (Patent Document 1). The resin cover of the reactor of Patent Literature 1 is provided with a terminal fixing portion for connecting and fixing a lead wire of a winding and another copper body.

JP 2018-41919 A

  Generally, the resin cover is made by injection molding. More specifically, the resin cover is made by filling a mold containing a core and winding assembly with molten resin. The protrusions corresponding to the terminal fixing portions described above or protrusions for other uses are formed simultaneously with the resin cover by injection molding. The mold includes a lower mold and an upper mold that is provided so as to be vertically movable with respect to the lower mold. When a protrusion projecting upward or laterally from the resin cover is provided on the resin cover, a cavity (projection cavity) for forming the protrusion on the upper mold of the mold is provided. If a resin cover is continuously produced in a short cycle with a mold equipped with such an upper mold, the temperature of the protrusion cavity of the upper mold does not fall sufficiently, and the protrusion is released from the protrusion cavity when the upper mold is opened. Otherwise, it may be torn off from the resin cover. The present specification relates to a method of manufacturing a reactor having a resin cover having a protrusion protruding upward or sideways, and relates to a technique for preventing the protrusion from being torn when opening the upper mold without increasing the cost. provide.

  The technology disclosed in the present specification includes a core, a winding wound around the core, and a resin cover that covers the core and the winding and has a protrusion that projects upward or laterally. The present invention relates to a method for manufacturing a reactor provided with the reactor. The projection is used, for example, in a terminal block for fixing an end of the winding (lead wire) and another conductor. A mold for filling a molten resin to form a resin cover includes an upper mold and a lower mold. The upper mold is movable in the vertical direction relative to the lower mold. The upper mold has a projection upper cavity portion that forms the upper portion of the projection. The lower mold has a core pressing portion and a projection lower cavity portion. The core pressing portion is provided so as to be able to advance and retreat with respect to the side surface of the core placed in the mold, and presses the core when filling the molten resin. The projection lower cavity portion is connected to the core pressing portion, and can move forward and backward together with the core pressing portion. The protrusion lower cavity portion is a portion that forms the lower portion of the protrusion. A groove extending along the direction in which the core pressing portion moves forward and backward is provided on the side surface of the projection lower cavity portion. When the resin cover is formed, after the molten resin in the mold has solidified, the upper mold is opened, and then the core pressing portion and the lower cavity portion of the protrusion are retracted.

  According to the above-described manufacturing method, the molten resin is also filled in the groove in the lower cavity portion of the projection. The resin portion formed by the groove becomes a rib protruding from the side surface of the projection. When the upper mold is opened, the rib is caught in the groove of the lower cavity of the projection provided in the lower mold, and the projection is separated from the ascending upper mold. A core pressing portion which is supported on the side surface of the core so as to be capable of moving forward and backward and fixes the core when filling the molten resin is originally provided in the lower mold. The technology disclosed in this specification utilizes a slide-type core pressing portion originally provided in the lower die to hold down the protrusion when opening the upper die, and then to retreat afterward with a slide-type lower protrusion cavity. Parts can be added at low cost. That is, it is possible to prevent the protrusion from being torn when the upper mold is opened, without increasing the cost. According to the technology disclosed in the present specification, a reactor including a resin cover having a protrusion protruding upward or laterally can be manufactured at low cost.

  The details and further improvements of the technology disclosed in this specification will be described in the following “Detailed description of the invention”.

FIG. 3 is a perspective view of a reactor to be manufactured (with a resin cover). FIG. 3 is a perspective view of a reactor to be manufactured (without a resin cover). FIG. 3 is a sectional view of a mold in which a core and a winding are set (corresponding to a section taken along line III-III in FIG. 2). It is a partial sectional view of a lower model. It is sectional drawing of a metal mold (resin injection process). It is sectional drawing of a metal mold | die (process of opening an upper mold | die). FIG. 3 is a cross-sectional view of a mold (a step of retracting a slide block).

  Before describing the manufacturing method of the embodiment, the reactor will be described. FIG. 1 shows a perspective view of the reactor 10, and FIG. 2 shows a perspective view of a core and winding assembly 10a (reactor without a resin cover). The reactor 10 is a passive element using an inductor. Reactor 10 is incorporated in, for example, a voltage conversion circuit. The main components of the reactor 10 are the core 14 and the winding 11. The winding 11 is wound around two portions of a ring-shaped core 14 to form coils 11a and 11b. That is, the two coils 11a and 11b are made of one winding 11, and electrically constitute one coil. The ends of the winding 11 correspond to the leads 12a and 12b. The lead lines 12a and 12b are connected to other conductors. In FIGS. 1 and 2, illustration of the leading lines 12 a and 12 b is omitted from the middle.

  The core 14 and the winding 11 are covered with a resin cover 20. The lower portions of the coils 11a and 11b are exposed from the resin cover 20. A window 25 is provided in the resin cover 20, and the coils 11 a and 11 b are also exposed from the window 25. Tabs 29 extend from four places of the resin cover 20. The tab 29 is provided with a hole for passing a bolt for fixing the reactor 10 to the housing of the voltage converter.

  A protrusion 21 is provided over the upper surface 20 a and the side surface 20 b of the resin cover 20 covering the core 14. The protrusion 21 protrudes upward from the upper surface 20 a of the resin cover 20 and also protrudes horizontally from the side surface 20 b of the resin cover 20. The protrusion 21 serves as a terminal block for connecting the lead wire 12a to another conductor. A screw hole 22 for fixing a screw is provided on the upper surface of the projection 21. A rib 23 extending horizontally is provided on a side surface of the projection 21. The ribs 23 perform their function in the step of injection molding the resin cover 20 having the projections 21. A hole 24 is provided below the protrusion 21 of the resin cover 20. The core 14 is exposed from the hole 24.

  The resin cover 20 is made by an injection molding process. Hereinafter, a resin cover forming process which is a part of the manufacturing process of the reactor 10 will be described. FIG. 3 is a partial sectional view of a mold 30 for forming the resin cover 20. The cross section in FIG. 3 corresponds to the cross section of the reactor 10 along the line III-III in FIG. FIG. 3 shows a state in which a reactor (that is, an assembly 10 a of the core 14 and the winding 11) before the resin cover is formed is set inside the mold 30. The resin filled in the cavity space CA inside the mold 30 forms the resin cover 20.

  FIG. 3 is a cross-sectional view of a portion for forming the protrusion 21. The mold 30 includes an upper mold 31 and a lower mold 32. The upper die 31 is supported so as to be vertically movable with respect to the lower die 32. The + Z direction of the coordinate system in the figure corresponds to the upper direction. In the figure, a mechanism for supporting the upper die 31 is omitted. The upper die 31 includes a protrusion upper cavity portion 311 that forms the upper portion of the protrusion 21.

  The lower mold 32 includes a slide block 33 that slides in the X direction in the drawing. FIG. 4 shows a perspective view of the slide block 33. In FIG. 4, the lower mold portion other than the slide block 33 is drawn by a virtual line. The lower mold 32 has a side cavity surface 321 facing the side surface of the core 14. The slide block 33 has a core facing surface 331 that is flush with the side cavity surface 321. The slide block 33 is supported by the lower mold 32 so as to be able to advance and retreat from the side surface cavity surface 321. A mechanism for moving the slide block 33 forward and backward is not shown. The side cavity surface 321 is also provided with a depression 329 for forming the tab 29 (see FIG. 1) of the resin cover 20.

  A core pressing portion 332 projects horizontally from the core facing surface 331. The core pressing portion 332 faces the side surface of the core 14 in the cavity (see FIG. 3). The core pressing portion 332 faces the side surface of the core 14 set in the cavity space CA, and is capable of moving forward and backward with respect to the side surface of the core 14.

  Although not shown, the lower mold 32 includes another slide block on the opposite side of the slide block 33 with the core 14 interposed therebetween, and the slide block also includes a core pressing portion facing the core 14. Each of the two slide blocks advances and retreats with respect to the core 14 so as to sandwich the core 14. That is, the core pressing portion 332 (the core pressing portion on the opposite side) sandwiches and fixes the core 14 in the cavity.

  The slide block 33 includes a portion (a lower projection cavity portion 333) for forming a lower portion of the projection 21. One slide block 33 is provided with a core pressing portion 332 and a projection lower cavity portion 333. Therefore, in other words, the protrusion lower cavity portion 333 is connected to the core pressing portion 332 and moves forward and backward with respect to the core 14 together with the core pressing portion 332. A groove 334 corresponding to the rib 23 described above is provided on the side surface of the projection lower cavity portion 333. The groove 334 extends horizontally along the side surface of the projection lower cavity portion 333. A part of the groove 334 extends along the direction in which the slide block 33 moves (X direction in the figure).

  Hereinafter, a resin cover molding process using the mold 30 will be described.

  (Resin Injection Step) The assembly 10a is set inside the mold 30, and the molten resin is injected into the cavity space CA while supporting the core 14 with the core pressing part 332 (and the core pressing part on the opposite side) (FIG. 5). . Note that FIG. 5A is a cross section corresponding to FIG. 3, and FIG. 5B is a cross section taken along line BB of FIG. 5A. By supporting the core 14 with the core pressing portion 332 (and the core pressing portion on the opposite side), the position of the core 14 is determined inside the cavity space CA, and the relative position of the core 14 and the resin cover 20 is determined. When the molten resin solidifies, it becomes the resin cover 20.

  (Step of Opening Upper Die) When the molten resin is solidified, the upper die 31 is moved upward (FIG. 6). In other words, the upper mold 31 is opened. FIG. 6A is a cross section corresponding to FIG. 3, and FIG. 6B is a cross section taken along line BB of FIG. 6A. When the upper mold 31 is opened, the slide block 33 of the lower mold 32 is not moved. The ribs 23 of the projections 21 are fitted into the grooves 334 of the slide block 33, and the projections 21 are fixed to the upper mold 31 that rises and are prevented from being torn off from the resin cover 20.

  (Step of Retracting Slide Block) After the upper die 31 is opened, the slide block 33 (the core pressing portion 332 and the projection lower cavity portion 333) is retracted (FIG. 7). Then, the reactor 10 on which the resin cover 20 is formed is taken out from the lower mold 32. The portion where the core pressing portion 332 has contacted the core 14 corresponds to the hole 24 in FIG.

  The advantages of the above manufacturing method will be described. In order to form the protrusion 21 of the resin cover 20, the upper mold 31 is provided with the protrusion upper cavity portion 311, and the lower mold 32 is provided with the protrusion lower cavity portion 333. A groove 334 extending in the horizontal direction is provided in the projection lower cavity portion 333. A rib 23 is formed on the projection 21 corresponding to the groove 334. When the upper mold 31 is opened after the molten resin is solidified in the cavity, the projection 21 may be torn off from the resin cover 20 unless the projection 21 is separated from the upper mold 31. In particular, when the mold 30 is repeatedly used in a short cycle, the upper mold 31 may be opened before the temperature of the projection upper cavity portion 311 has completely decreased. If the temperature of the projection upper cavity portion 311 is not sufficiently lowered, the upper mold 31 is opened before the projections 21 are sufficiently solidified. The protrusions 21 that are not sufficiently solidified are difficult to separate from the upper mold 31 while being easily torn off from the resin cover 20. The groove 334 provided in the projection lower cavity portion 333 of the lower mold 32 plays a role of pressing the projection 21 when the upper mold 31 is opened. When the groove 334 and the rib 23 are engaged and the upper mold 31 rises, the projection 21 is separated from the upper mold 31. The groove 334 provided on the side surface of the protrusion lower cavity portion 333 prevents the protrusion 21 from being torn off from the resin cover 20 when the upper mold 31 is opened.

  The protrusion lower cavity portion 333 having the horizontally extending groove 334 cannot be removed from the resin cover 20 unless it retreats away from the resin cover 20. The projection lower cavity portion 333 is connected to a core pressing portion 332 that moves forward and backward to fix the core 14. That is, the projection lower cavity portion 333 moves forward and backward together with the core pressing portion 332. In other words, in the manufacturing method of the embodiment, the protrusion lower cavity portion 333 is also advanced and retracted by using the advance and retreat mechanism of the core pressing portion 332 originally included in the mold. A mechanism for holding down the protrusion can be added without adding a new mechanism for moving the protrusion lower cavity portion 333 forward and backward. That is, the protrusion lower cavity portion 333 that moves forward and backward can be realized at low cost.

  As shown in FIG. 6, a protrusion 312 for forming a pilot hole of the screw hole 22 (see FIG. 1) is provided in the protrusion upper cavity portion 311 of the upper die 31. The protrusion 312 extends in the up-down direction, and is located inside the protrusion 21. When the upper mold 31 has the projections 312, the projections 21 are hardly cooled when the mold 30 is continuously used, and the possibility that the projections 21 are further torn off increases. The groove 334 of the projection lower cavity portion 333 functions to press the rib 23 extending around the side surface of the protrusion 21, so that the protrusion 21 can be pressed firmly. Therefore, when the protrusion upper cavity portion 311 (the upper mold 31) provided with the protrusion 312 moves upward, the protrusion 21 is prevented from being pulled by the upper mold 31 and being torn off from the resin cover 20.

  Points to keep in mind regarding the technology described in the embodiment will be described. The manufacturing method disclosed in the present specification is not limited to the method for manufacturing a reactor having a ring-shaped core. For example, the present invention can be applied to a method for manufacturing a reactor having a rod-shaped core and a single coil. The protrusion 21 provided on the resin cover 20 is not limited to the terminal block that connects the lead wire and the conductor. The protrusion provided on the resin cover 20 may be used for another purpose.

  As described above, the specific examples of the present invention have been described in detail, 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 the present 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 illustrated in the present specification or the drawings can simultaneously achieve a plurality of objects, and has technical utility by achieving one of the objects.

10: Reactor 10a: Assembly 11: Windings 11a, 11b: Coil 12a, 12b: Lead wire 14: Core 20: Resin cover 21: Projection 22: Screw hole 23: Rib 30: Die 31: Upper die 32: Lower die 33: slide block 311: protrusion upper cavity portion 321: side cavity surface 331: core facing surface 332: core pressing portion 333: protrusion lower cavity portion 334: groove CA: cavity space

Claims (1)

A method for manufacturing a reactor comprising a core, a winding wound around the core, and a resin cover covering the core and the winding, the resin cover having a protrusion protruding upward or laterally. And
A mold for filling the molten resin to form the resin cover includes an upper mold and a lower mold,
The upper mold is relatively movable in the vertical direction with respect to the lower mold, and includes a protrusion upper cavity portion forming an upper portion of the protrusion,
The lower mold,
A core pressing portion that is provided to be able to advance and retreat with respect to the side surface of the core, and presses the core when filling the molten resin,
A projection lower cavity portion connected to the core pressing portion and forming a lower portion of the projection, wherein a groove is provided on a side surface of the projection lower cavity portion;
With
A method for manufacturing a reactor, wherein after the molten resin in the mold is solidified, the upper mold is opened, and then the core pressing portion and the lower cavity portion of the protrusion are retracted.

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