JP7049207B2 - Reactor manufacturing method - Google Patents

Description

The techniques disclosed herein relate to methods of making reactors.

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

Japanese Unexamined Patent Publication No. 2018-41919

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 or the protrusions for other purposes are formed by injection molding at the same time as the resin cover. The mold is composed of a lower mold and an upper mold provided so as to be movable in the vertical direction with respect to the lower mold. When a protrusion protruding upward or laterally from the resin cover is provided on the resin cover, a cavity portion (protrusion cavity portion) for forming the protrusion is provided on the upper mold of the mold. When the 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 drop sufficiently, and the protrusion is released from the protrusion cavity when the upper mold is opened. It may be torn off from the resin cover without doing so. The present specification relates to a method for manufacturing a reactor provided with a resin cover having protrusions protruding upward or laterally, a technique for preventing the protrusions from being torn off when opening the upper mold without significant cost increase. offer.

The techniques disclosed herein include a core, windings wound around the core, and a resin cover that covers the core and windings and has protrusions that project upward or laterally. Regarding the manufacturing method of the prepared reactor. The protrusion is used, for example, in a terminal block for fixing the end of a winding (leader wire) and another conductor. The mold for filling the molten resin to form the resin cover includes an upper mold and a lower mold. The upper mold can move relatively in the vertical direction with respect to the lower mold. The upper mold is provided with a protrusion upper cavity portion that forms the upper part of the protrusion. The lower mold has a core pressing portion and a protrusion 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 protrusion lower cavity portion is connected to the core pressing portion and can move forward and backward together with the core pressing portion. The lower protrusion cavity portion is a portion that forms the lower part of the protrusion. A groove extending in the advancing / retreating direction of the core pressing portion is provided on the side surface of the protrusion lower cavity portion. When molding the resin cover, after the molten resin in the mold is solidified, the core pressing portion and the protrusion lower cavity portion are retracted after opening the upper mold.

According to the above manufacturing method, the molten resin is also filled in the groove of the cavity portion below the protrusion. The resin portion formed by the groove becomes a rib protruding from the side surface of the protrusion. When opening the upper mold, the rib is caught in the groove of the protrusion lower cavity portion provided in the lower mold, and the protrusion is separated from the rising upper mold. The core pressing portion, which is supported so as to be able to move forward and backward with respect to the side surface of the core and fixes the core when filling the molten resin, is originally provided in the lower mold. The technique disclosed herein utilizes a slide-type core pressing portion originally provided in the lower mold to hold the protrusion when opening the upper mold and then retract the slide-type protrusion lower cavity. Parts can be added at low cost. That is, it is possible to prevent the protrusions from being torn off when the upper mold is opened without a large cost increase. The techniques disclosed herein make it possible to inexpensively manufacture reactors including resin covers with protrusions that project upward or laterally.

Details and further improvements to the techniques disclosed herein will be described in the "Modes for Carrying Out the Invention" section below.

It is a perspective view of the reactor to be manufactured (with a resin cover). It is a perspective view of the reactor to be manufactured (without a resin cover). It is a cross-sectional view of a mold in which a core and a winding are set (corresponding to the cross section III-III of FIG. 2). It is a partial cross-sectional view of the lower mold. It is sectional drawing of a mold (resin injection process). It is a cross-sectional view of a mold (the process of opening the upper mold). It is a cross-sectional view of a mold (the process of retracting a slide block).

Before explaining the manufacturing method of the Example, the reactor will be described. FIG. 1 shows a perspective view of the reactor 10, and FIG. 2 shows a perspective view of the core and winding assembly 10a (reactor without a resin cover). The reactor 10 is a passive element using an inductor. The 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 places of the ring-shaped core 14, and constitutes the coils 11a and 11b. That is, the two coils 11a and 11b are made of one winding 11, and electrically form one coil. The end of the winding 11 corresponds to the lead wires 12a and 12b. Leaders 12a and 12b are connected to other conductors. In FIGS. 1 and 2, the drawings from the middle of the leader lines 12a and 12b are omitted.

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 on the resin cover 20, and the coils 11a and 11b are also exposed from the window 25. Tabs 29 extend from four locations on the resin cover 20. The tab 29 is provided with a hole through which a bolt for fixing the reactor 10 to the housing of the voltage converter is passed.

A protrusion 21 is provided over the upper surface 20a and the side surface 20b that cover the core 14 of the resin cover 20. The protrusion 21 projects upward from the upper surface 20a of the resin cover 20 and also protrudes horizontally from the side surface 20b 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 protrusion 21. A rib 23 extending in the horizontal direction is provided on the side surface of the protrusion 21. The rib 23 fulfills its function in the step of injection molding the resin cover 20 having the protrusion 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 in an injection molding process. Hereinafter, the resin cover forming process, which is a part of the manufacturing process of the reactor 10, will be described. FIG. 3 shows a partial cross-sectional view of the mold 30 for forming the resin cover 20. The cross section of FIG. 3 corresponds to the cross section of the reactor 10 along line III-III of FIG. FIG. 3 shows a state in which the reactor (that is, the assembly 10a of the core 14 and the winding 11) before forming the resin cover 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 is composed of an upper mold 31 and a lower mold 32. The upper die 31 is supported so as to be movable in the vertical direction with respect to the lower die 32. The + Z direction of the coordinate system in the figure corresponds to the top. In the figure, the mechanism for supporting the upper die 31 is not shown. The upper mold 31 includes a protrusion upper cavity portion 311 forming 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 die portion other than the slide block 33 is drawn by a virtual line. The lower mold 32 includes a side cavity surface 321 facing the side surface of the core 14. The slide block 33 includes 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 move forward and backward from the side cavity surface 321. The mechanism for advancing and retreating the slide block 33 is not shown. The side cavity surface 321 is also provided with a recess 329 for forming a tab 29 (see FIG. 1) of the resin cover 20.

The 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 can move forward and backward with respect to the side surface of the core 14.

Although not shown, the lower mold 32 is provided with another slide block on the opposite side of the slide block 33 with the core 14 interposed therebetween, and the slide block also has a core pressing portion facing the core 14. The two slide blocks each advance and retreat 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 (projection lower cavity portion 333) for forming the lower portion of the protrusion 21. A core pressing portion 332 and a protrusion lower cavity portion 333 are provided on one slide block 33. Therefore, in other words, the protrusion lower cavity portion 333 is connected to the core pressing portion 332, and moves back and forth 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 protrusion lower cavity portion 333. The groove 334 extends horizontally along the side surface of the protrusion lower cavity portion 333. A part of the groove 334 extends along the advancing / retreating direction (X direction in the figure) of the slide block 33.

Hereinafter, the 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 the core 14 is supported by the core pressing portion 332 (and the core pressing portion on the opposite side) (FIG. 5). .. Note that FIG. 5A is a cross section corresponding to FIG. 3, and FIG. 5B shows a cross section along the line BB of FIG. 5A. By supporting the core 14 by 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 positions of the core 14 and the resin cover 20 are determined. When the molten resin hardens, it becomes the resin cover 20.

(Step of opening the upper mold) When the molten resin is solidified, the upper mold 31 is moved upward (FIG. 6). In other words, the upper mold 31 is opened. 6 (A) is a cross section corresponding to FIG. 3, and FIG. 6 (B) shows a cross section along the line BB of FIG. 6 (A). When the upper mold 31 is opened, the slide block 33 of the lower mold 32 is not moved. The rib 23 of the protrusion 21 is fitted into the groove 334 of the slide block 33, and the protrusion 21 is prevented from sticking to the rising upper mold 31 and being torn off from the resin cover 20.

(Step of retracting the slide block) After opening the upper mold 31, the slide block 33 (core pressing portion 332 and protrusion 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 is in contact with the core 14 corresponds to the hole 24 in FIG.

The advantages of the above-mentioned manufacturing method will be described. 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. The protrusion lower cavity portion 333 is provided with a groove 334 extending in the horizontal direction. A rib 23 is formed on the protrusion 21 corresponding to the groove 334. When the upper mold 31 is opened after the molten resin is solidified in the cavity, the protrusion 21 may be torn off from the resin cover 20 unless the protrusion 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 protrusion upper cavity portion 311 is completely lowered. If the temperature of the protrusion upper cavity portion 311 is not sufficiently lowered, the upper mold 31 will open before the protrusion 21 is sufficiently solidified. The protrusion 21 that is not sufficiently solidified is difficult to separate from the upper mold 31, but is easily torn off from the resin cover 20. The groove 334 provided in the protrusion lower cavity portion 333 of the lower mold 32 serves to hold down the protrusion 21 when the upper mold 31 is opened. When the groove 334 and the rib 23 engage with each other and the upper die 31 rises, the protrusion 21 is separated from the upper die 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 groove 334 extending in the horizontal direction cannot be removed from the resin cover 20 unless it retracts in the direction away from the resin cover 20. The protrusion lower cavity portion 333 is connected to a core pressing portion 332 that advances and retreats to fix the core 14. That is, the protrusion lower cavity portion 333 advances and retreats 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 / retreat mechanism of the core pressing portion 332 originally possessed by the mold. It is possible to add a mechanism for pressing the protrusion without adding a new mechanism for advancing and retreating the protrusion lower cavity portion 333. That is, the protrusion lower cavity portion 333 that advances and retreats can be realized at low cost.

As shown in FIG. 6, the protrusion upper cavity portion 311 of the upper die 31 is provided with a protrusion 312 for forming a pilot hole of the screw hole 22 (see FIG. 1). The protrusion 312 extends in the vertical direction and is located inside the protrusion 21. When the upper mold 31 has the protrusion 312, the protrusion 21 becomes difficult to cool when the mold 30 is continuously used, and the possibility that the protrusion 21 is further torn off increases. Since the groove 334 of the protrusion lower cavity portion 333 works to hold the rib 23 extending around the side surface of the protrusion 21, the protrusion 21 can be firmly held. Therefore, when the protrusion upper cavity portion 311 (upper mold 31) provided with the protrusion 312 is raised, the protrusion 21 is prevented from being pulled by the upper mold 31 and being torn off from the resin cover 20.

The points to be noted regarding the technique described in the examples will be described. The manufacturing method disclosed herein is not limited to the manufacturing method of a reactor having a ring-shaped core. For example, it can be applied to a method for manufacturing a reactor having a rod-shaped core and a single coil. The protrusion 21 included in the resin cover 20 is not limited to the terminal block connecting the leader wire and the conductor. The protrusion provided on the resin cover 20 may be used for another purpose.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of claims. The techniques described in the claims include various modifications and modifications of the specific examples exemplified above. The technical elements described herein or in the drawings exhibit their 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 techniques exemplified in the present specification or the drawings can achieve a plurality of purposes at the same time, and achieving one of the purposes itself has technical usefulness.

10: Reactor 10a: Assembly 11: Winding 11a, 11b: Coil 12a, 12b: Leader 14: Core 20: Resin cover 21: Protrusion 22: Screw hole 23: Rib 30: Mold 31: Upper mold 32: Lower mold 33: Slide block 311: Projection upper cavity portion 321: Side cavity surface 331: Core facing surface 332: Core pressing portion 333: Projection lower cavity portion 334: Groove CA: Cavity space

Claims (1)

A method for manufacturing a reactor including a core, a winding wound around the core, and a resin cover covering the core and the winding and having a protrusion protruding upward or laterally. And
The mold for filling the molten resin to form the resin cover is provided with an upper mold and a lower mold.
The upper mold is movable in the vertical direction relative to the lower mold, and has a protrusion upper cavity portion forming the upper portion of the protrusion.
The lower mold is
A core pressing portion that is provided so as to be able to move forward and backward with respect to the side surface of the core and presses the core when filling the molten resin, and a core pressing portion.
A protrusion lower cavity portion that is connected to the core pressing portion and forms the lower portion of the protrusion and has a groove on the side surface of the protrusion lower cavity portion, and a protrusion lower cavity portion.
Equipped with
A method for manufacturing a reactor in which the core pressing portion and the protrusion lower cavity portion are retracted after the molten resin in the mold has solidified and then the upper mold is opened.

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