JP5931467B2 - Manufacturing method of laminated iron core - Google Patents

Description

The present invention relates to a method of manufacturing a laminated core in which permanent magnets are respectively inserted into the magnet insertion holes formed in the laminated core body and sealed with resin. Specifically, the magnet insertion holes of the laminated core body are covered with the surface of the laminated core body. The present invention relates to a method of injecting resin through a worn dummy plate and resin-sealing a permanent magnet.

Conventionally, a rotor laminated core used in a motor is manufactured by a method in which an unmagnetized permanent magnet is inserted into a magnet insertion hole formed according to the number of magnetic poles in an annular laminated core body and resin-sealed. In the resin sealing, a laminated core with a permanent magnet inserted is sandwiched between an upper mold and a lower mold, and a thermosetting resin is filled from a resin reservoir pot provided in the upper mold or the lower mold through a runner. In the manufacturing process, as described in Patent Document 1, in order to eliminate the work of cleaning the surface of the laminated iron core by removing the resin that has adhered to the entrance portion of the magnet insertion hole and cured after resin sealing, A method has been adopted in which a dummy plate is disposed between a laminated core body into which a permanent magnet is inserted and an upper die or a lower die, and after the resin is sealed, the resin soot is removed from the laminated iron core together with the dummy plate.

Japanese Patent No. 4441417

However, in recent years, motors used in automobiles and the like have a tendency to increase in size in order to obtain a large output, and the total height is also high. Therefore, when the permanent magnet is resin-sealed in the above-described manufacturing method on the laminated iron core whose height is increased in accordance with such a motor, the resin 18 has the magnet insertion hole 13 and the permanent magnet 14 as shown in FIG. This causes a problem that the gap is not sufficiently filled. This is because the resin 18 is hardened in the middle of the resin injection because the resin injection speed is not sufficient although the volume of the resin core 18 is increased due to the increase in the total height of the laminated core 10. Thus, the resin 18 cannot be injected within the determined resin injection time, and the unfilled portion 21 is formed.

As a countermeasure against this problem, it is conceivable to increase the resin injection speed by widening the injection area of the resin injection hole arranged in the dummy plate, but when the injection area of the resin injection hole is widened, as shown in FIG. When the dummy plate 19 is removed from the laminated iron core 10 after the resin 18 is cured, the surface of the filled resin 18 is peeled off together with the resin ridge 23 on the dummy plate 19 side, and a resin stagnation portion 22 is generated. .

The present invention has been made in view of such circumstances, and an object thereof is to prevent unfilling of the resin injected into the gap between the magnet insertion hole and the permanent magnet, and to prevent the resin surface from curling.

The method for manufacturing a laminated core according to the first aspect of the present invention is formed by laminating a plurality of core pieces, and in each of the magnet insertion holes of a laminated core body having a plurality of magnet insertion holes in the circumferential direction. After inserting the permanent magnet, in a state where the laminated core body is pressed between the upper die and the lower die, the magnet is removed from the resin reservoir pot provided in one of the upper die and the lower die. In the method of manufacturing a laminated core in which the insertion hole is filled with resin and the permanent magnet is fixed,
A mold the resin reservoir pot is formed, between the laminated core body, a plurality of resin injection holes leading from the resin reservoir pot the resin to one of the magnet insertion holes, one of the resin injection hole After placing a dummy plate having an arrangement such that a part or the whole fits within the range of the resin reservoir pot in plan view, after injecting the resin into the magnet insertion hole through the resin injection hole and curing it, The dummy plate is removed from the laminated core body.

Here, although the laminated iron core is a rotor laminated iron core, the present invention is applied to any of the inner rotor type and the outer rotor type.
The dummy plate is preferably a metal plate made of stainless steel, steel, aluminum or the like, alloy tool steel, or carbon steel. Also good.
Furthermore, it is preferable that the dummy plate is previously subjected to a surface treatment having a high releasability from the sealing resin by nickel plating or chrome plating in addition to coating with a fluorine resin such as Teflon (registered trademark) or silicon resin.
Further, as the shape of the resin injection hole of the dummy plate, various shapes can be adopted in addition to a circle and a rectangle in plan view. Furthermore, the cross section of the resin injection hole may be formed in a tapered shape, and this taper facilitates the removal of the resin soot remaining in the resin injection hole and improves the workability.

In the method for manufacturing a laminated core according to the second invention, the resin injection hole is formed on the outline of the magnet insertion hole in plan view.

In the method for manufacturing a laminated core according to the present invention, by providing a plurality of resin injection holes for one magnet insertion hole, the injection area of the entire resin injection hole can be reduced without changing the injection area of one resin injection hole. Can be wide. This makes it possible to increase the resin injection speed without causing the surface of the resin filled when removing the dummy plate after resin sealing, thereby preventing unfilling of the resin.

Moreover, the some or all of the resin injection hole is arranged so as to fall within the scope of the plan view to the resin pot, a runner is injected directly into the resin magnet insertion hole without being formed, shortened resin injection time In addition, the amount of resin required for filling can be reduced.

Furthermore, since the resin injection hole is formed on the outline of the magnet insertion hole in plan view, a corner is formed at the entrance of the cured resin magnet insertion hole, and the corner is removed when the dummy plate is removed. The stress is concentrated on the resin, and the resin crack generated there propagates along the entrance surface of the magnet insertion hole and breaks the resin.

It is sectional drawing which shows the manufacturing method of the laminated core which concerns on one embodiment of this invention. It is a top view of the laminated iron core which mounted the dummy board. It is sectional drawing which shows the manufacturing method of the laminated core which concerns on a prior art example. It is a top view of the laminated iron core which mounted the dummy board. It is explanatory drawing of the manufacturing method of the laminated core.

Subsequently, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
As shown in FIGS. 1 and 2, a method for manufacturing a laminated iron core (for example, a rotor laminated iron core) according to an embodiment of the present invention is formed by laminating a plurality of iron core pieces 11. After the permanent magnet 14 is inserted into each magnet insertion hole 13 of the laminated iron core 10 having a plurality of pairs of magnet insertion holes 13 around it, the laminated iron core 10 is joined to an upper mold 15 and a lower mold 16 (both of which are molds). In an example), a resin 18 (usually a thermosetting resin) is poured into a magnet insertion hole 13 from a resin reservoir pot 17 having a circular cross section provided in the upper mold 15 or the lower mold 16 and pressed permanently. This is a method of injecting the resin 18 into the magnet insertion hole 13 using a dummy plate 19 when fixing the magnet 14. This will be described in detail below.

First, an electromagnetic steel sheet having a thickness of, for example, about 0.5 mm or less is punched in a ring shape, and a plurality of punched iron core pieces 11 are sequentially laminated to form a laminated iron core 10. As a method of laminating the plurality of iron core pieces 11, any one or two or more of caulking, welding, and adhesion can be used in combination, but they may be simply stacked.
Thereby, a plurality of magnet insertion holes 13 penetrating in the vertical direction are formed around the shaft hole 12 of the laminated core 10. In addition, the arrangement position and shape of the magnet insertion hole 13 are not limited to this, For example, a conventionally well-known arrangement position or shape may be sufficient.

Next, the shaft hole 12 is fitted into a pole (not shown) provided in the lower mold 16. As a result, the accuracy of the laminated core 10 is determined on the basis of the inner diameter.
Subsequently, after inserting the permanent magnet 14 into the magnet insertion hole 13 formed in the laminated core 10, the dummy plate 19 is placed on the surface of the laminated core 10. The dummy plate 19 is formed with a plurality of resin injection holes 20 for injecting a liquid resin through the resin reservoir pot 17 and the magnet insertion hole 13 in a region overlapping the magnet insertion hole 13 in plan view. Yes.
Here, the dummy plate 19 uses a plate material made of an alloy tool steel of about 1 to 5 mm, and the surface is coated with a coating of Teflon (registered trademark) in order to improve the peelability.

In this manner, the laminated iron core 10 on which the dummy plate 19 is placed is preliminarily heated to around 170 ° C. by the preheating device. Then, the laminated iron core 10 that has been heated is transferred to the resin sealing device, and is pressed between the upper mold 15 and the lower mold 16 provided with the resin reservoir pot 17. At this time, the upper mold 15 and the lower mold 16 have already been heated to around 170 ° C.
Next, the resin 18 heated in the resin reservoir pot 17 and liquefied is pushed out toward the magnet insertion hole 13 by a plunger 24 driven by a cylinder (not shown). The resin 18 is injected from one resin reservoir pot into the magnet insertion hole 13 through the resin injection hole 20 provided in the dummy plate 19 and hardens, thereby fixing the permanent magnet 14 to the laminated core 10.
Since the dummy plate 19 is provided with a plurality of resin injection holes 20 for one magnet insertion hole 13, the entire resin injection hole 20 with respect to one magnet insertion hole 13 has a large injection area and sufficient resin injection. Speed can be secured. Thus, the resin 18 can be filled into the magnet insertion hole 13 before the resin 18 is cured, and the unfilled portion 21 is prevented from being formed.

Further, in the conventional manufacturing method, as shown in FIGS. 3 and 4, a runner 25 is formed from the resin reservoir pot 17, and the resin 18 is injected through the resin injection hole 20 provided in the runner 25 and the dummy plate 19. However, in the present invention, part or all of the resin injection hole 20 is arranged so as to be within the range of the resin reservoir pot 17 in plan view, and the runner 25 is not formed, so that the resin injection time is reduced. Is shortened, and the amount of the resin 18 required to fill the magnet insertion hole 13 can be reduced.

After the magnet insertion hole 13 is sealed with resin and the resin 18 is cured, the dummy plate 19 is removed from the laminated core 10. The resin injection hole 20 is formed on the contour line of the magnet insertion hole 13 in plan view, so that a corner portion 26 is formed in the filled resin 18. As a result, when the dummy plate 19 is removed, the stress applied to the resin 18 is concentrated on the corner portion 26 and a resin crack is generated. The crack propagates along the entrance surface of the magnet insertion hole 13 and the resin 18 Break occurs. Due to this effect, the resin 18 is not further bent.
Thereafter, by removing the resin cage 23 from the dummy plate 19, the dummy plate 19 becomes usable again. Thus, the resin sealing can be efficiently and economically implemented by repeatedly using the dummy plate 19 for production.

As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and the matters described in the scope of claims. Other embodiments and modifications conceivable within the scope are also included.
In the above embodiment, the resin reservoir pot is provided in the upper mold and the resin is injected from the upper side. However, the present invention is not limited thereto, and it is also possible to provide the resin reservoir pot in the lower mold and inject the resin from the lower side. .
Moreover, in the said embodiment, although the thermosetting resin was used as a resin member, a thermoplastic resin can also be used.
In the embodiment, the case where the magnet insertion holes are a plurality of pairs has been described. However, the present invention is applied even when the magnet insertion holes are not a pair.

10: laminated iron core, 11: iron core piece, 12: shaft hole, 13: magnet insertion hole, 14: permanent magnet, 15: upper mold, 16: lower mold, 17: resin reservoir pot, 18: resin, 19: dummy plate 20: Resin injection hole, 21: Unfilled part, 22: Drown part, 23: Resin crease, 24: Plunger, 25: Runner, 26: Corner part

Claims (2)

After a permanent magnet is inserted into each magnet insertion hole of a laminated core body formed by laminating a plurality of iron core pieces and having a plurality of magnet insertion holes in the circumferential direction, the laminated core body is formed into an upper mold and a lower mold. A laminated iron core for fixing the permanent magnet by filling the magnet insertion hole with a resin from a resin reservoir pot provided in one of the upper mold and the lower mold in a state of being sandwiched and pressed In the manufacturing method,
A mold the resin reservoir pot is formed, between the laminated core body, a plurality of resin injection holes leading from the resin reservoir pot the resin to one of the magnet insertion holes, one of the resin injection hole After placing a dummy plate having an arrangement such that a part or the whole fits within the range of the resin reservoir pot in plan view, after injecting the resin into the magnet insertion hole through the resin injection hole and curing it, A method of manufacturing a laminated core, wherein the dummy plate is removed from the laminated core body. 2. The method for manufacturing a laminated core according to claim 1 , wherein the resin injection hole is formed on a contour line of the magnet insertion hole in a plan view.

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