JP2017028923A - Manufacturing method of laminated rotor core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a laminated rotor core in which formation of a thin burr on the upper surface of a bridge can be prevented, in a disc-like steel plate laminated on the uppermost stage.SOLUTION: A manufacturing method of a laminated rotor core includes a step of forming a laminated steel plate 110 by laminating disc-like steel plates in which magnet holes 12a, 12b, flux leakage suppression holes 15a, 15b adjoining the magnet holes 12a, 12b, and a bridge 40 partitioning the magnet holes 12a, 12b and flux leakage suppression holes 15a, 15b are formed, respectively, and a step of resin sealing permanent magnets 22a, 22b inserted into the magnet holes 12a, 12b. In the step of forming a laminated steel plate 110, a disc-like steel plate 90 provided with a pair of steps 40a, in contact with the magnet hole and flux leakage suppression hole respectively, on the upper surface of the bridge 40 is used excepting the uppermost stage, and a disc-like steel plate 190a not provided with a step 40a on the upper surface of the bridge 40 is used in the uppermost stage.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing a laminated rotor core.

  Generally, an electric motor includes a substantially cylindrical stator having a plurality of teeth wound around a coil and projecting to an inner peripheral portion, and a rotor provided rotatably in the stator. The rotor further includes a cylindrical rotor core, a rotating shaft that penetrates the center of the rotor core, an end plate that is disposed in contact with both ends of the rotor core, and the like. Recently, there are many rotors (end plateless rotors) that do not include an end plate.

  A laminated rotor core into which a permanent magnet is inserted is used in an electric motor such as an electric vehicle or a hybrid vehicle. The laminated rotor core is obtained by laminating a plurality of magnetic steel plates (disk-shaped steel plates) press-punched into a disk shape in the axial direction. In order to improve high-speed rotation performance in an electric motor using a laminated rotor core, it is necessary to increase the strength of the disk-shaped steel plate.

  Patent Document 1 discloses a method for manufacturing a laminated rotor core in which the thickness of a peripheral portion of a magnet insertion hole in each disk-shaped steel plate is reduced and the strength is improved by providing a stepped portion.

JP 2005-185081 A

  FIG. 16 is a partial horizontal sectional view showing a schematic configuration of a laminated rotor core 500 under development. FIG. 17 is a cross-sectional view taken along the line XVII-XVII in FIG. 16 and shows a method for manufacturing a laminated rotor. As shown in FIGS. 16 and 17, in the laminated rotor core 500, the magnetic flux leakage suppression hole 14 is provided in the laminated steel sheet 10 in addition to the magnet hole 12 a for inserting the permanent magnet 22 a. The laminated steel plate 10 is a laminate of a plurality of disc-shaped steel plates 90.

  Bridge portions 40 extending in the radial direction are provided at both ends of the magnet leakage suppression hole 14 in order to reinforce the strength of the laminated rotor core 500. That is, between one end of the magnet leakage suppression hole 14 and the radially inner end of the magnet hole 12a, and between the other end of the magnet leakage suppression hole 14 and the radially inner end of the magnet hole 12b. Each of the bridge portions 40 extending in the radial direction is provided.

  Part of the magnetic flux formed by the permanent magnets 22 a and 22 b passes through the bridge portion 40. This magnetic flux is a so-called “leakage magnetic flux” that does not contribute to the rotational motion of the laminated rotor. In order to suppress the leakage magnetic flux passing through the bridge part 40, it is necessary to make the cross-sectional area of the bridge part 140 as small as possible. However, as described above, the disk-shaped steel plate 90 needs to have sufficient strength so that it can withstand even when the electric motor is rotated at high speed.

  In order to reduce the cross-sectional area of the bridge portion 40 without reducing the strength of the disk-shaped steel plate 90, the upper surface of the bridge portion 40 is pressed down by pressing or the like. As shown in FIG.16 and FIG.17, the bridge part 40 has the level | step-difference part 40a extended in a longitudinal direction. The cross-sectional shape of the bridge portion 40 is a convex shape. The bridge portion 40 in which the step portion 40a is formed (work-hardened) by the reduction of the upper surface increases in strength and decreases in cross-sectional area. Thereby, the amount of leakage magnetic flux which passes a bridge part, without reducing the intensity | strength of the radial direction of the disk shaped steel plate 90 can be reduced.

  As shown in FIG. 17, when manufacturing the laminated rotor core 500, the laminated steel sheet 10 with the bridge member 40 inserted is placed on the lower mold 70, and after inserting the permanent magnet 22 a into the magnet hole 12 a, 60 is lowered. And the molten resin 30 is sent into the clearance gap between the magnet hole 12a and the permanent magnet 22a with the plunger 80, and the resin layer 32a is formed. Thereby, the permanent magnet 22a is resin-sealed.

  A stepped portion 40a is formed on the upper surface of the bridge portion 40 that is pressed down by pressing or the like. When the molten resin 30 is fed into the gap between the magnet hole 12a and the permanent magnet 22a, the molten resin 30 also flows into the stepped portion 40a formed on the upper surface of the bridge portion 40. In the disk-shaped steel plate 90a laminated on the uppermost layer of the laminated steel plate 10, the molten resin 30 that has flowed into the stepped portion 40a formed on the upper surface of the bridge portion 40 is solidified to form a thin layer (thin burr). This thin burr is very easy to peel off. In the case of an end plateless rotor, if such a thin burr is formed on the upper surface of the bridge portion of the laminated rotor core, the thin burr may fall off during the rotation of the rotor and the electric motor may be damaged.

  The present invention has been made in view of the above background, and an object of the present invention is to provide a method for manufacturing a laminated rotor core capable of preventing the formation of thin burrs on the upper surface of the bridge portion in the uppermost disk-shaped steel sheet. To do.

  The present invention relates to a disk in which a magnet hole for inserting a magnet body, a magnetic flux leakage suppression hole adjacent to the magnetic hole, and a bridge portion that partitions the magnetic hole and the magnetic flux leakage suppression hole are formed. A step of laminating a plurality of sheet steel plates to form a laminated steel plate, a step of inserting the magnet body into the magnet hole of the laminated steel plate, sandwiching the laminated steel plate with a mold, and sealing the magnet body with resin, In the step of forming the laminated steel sheet, in the step of forming the laminated steel sheet, the disk-shaped steel sheet other than the uppermost stage among the plurality of disk-shaped steel sheets includes the magnet on the upper surface of the bridge portion. A pair of stepped portions that are in contact with the hole and the magnetic flux leakage suppression hole are used, and the uppermost disk-shaped steel plate is one that does not have the stepped portion on the upper surface of the bridge portion. It is.

  According to the present invention, it is possible to prevent a thin burr from being formed on the upper surface of the bridge portion in the uppermost disk-shaped steel plate.

2 is a horizontal cross-sectional view of a laminated rotor core 100 manufactured by the method for manufacturing a laminated rotor core according to the first embodiment. FIG. 1 is a partial horizontal cross-sectional view of a laminated rotor core 100 manufactured by a method for manufacturing a laminated rotor core according to Embodiment 1. FIG. It is sectional drawing (vertical sectional drawing) in alignment with the III-III line | wire in FIG. It is a figure explaining the manufacturing method of the lamination type rotor core concerning Embodiment 1. FIG. It is a figure explaining the manufacturing method of the lamination type rotor core concerning Embodiment 1. FIG. It is a figure explaining the manufacturing method of the lamination type rotor core concerning Embodiment 1. FIG. It is a figure explaining the manufacturing method of the lamination type rotor core concerning Embodiment 1. FIG. It is a figure explaining the manufacturing method of the lamination type rotor core concerning Embodiment 1. FIG. FIG. 6 is a partial horizontal cross-sectional view of a laminated rotor core manufactured by a method for manufacturing a laminated rotor core according to a second embodiment. It is sectional drawing (vertical sectional drawing) in alignment with the XX line in FIG. FIG. 6 is a diagram for explaining a method for manufacturing a laminated rotor core according to a second embodiment. FIG. 6 is a diagram for explaining a method for manufacturing a laminated rotor core according to a second embodiment. It is a partial horizontal sectional view of the lamination type rotor core manufactured by the manufacturing method of the lamination type rotor core concerning Embodiment 3. FIG. It is sectional drawing (vertical sectional drawing) which follows the XIV-XIV line | wire in FIG. It is a figure explaining the manufacturing method of the lamination type rotor core concerning Embodiment 3. FIG. It is a partial horizontal sectional view which shows schematic structure of the lamination type rotor core under development. It is sectional drawing which follows the XVII-XVII line of FIG.

[Embodiment 1]
Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a horizontal cross-sectional view of a laminated rotor core 100 manufactured by a method for manufacturing a laminated rotor core according to the present embodiment. FIG. 2 is a partial horizontal cross-sectional view of the laminated rotor core 100 manufactured by the manufacturing method of the laminated rotor core according to the present embodiment. 3 is a cross-sectional view (vertical cross-sectional view) taken along line III-III in FIG.

  As shown in FIG. 1, the laminated rotor core 100 includes a shaft hole 1 into which a rotating shaft is inserted, a laminated steel plate 110, and permanent magnets (magnet bodies) 21, 22a, 22b. Furthermore, the laminated rotor according to the present embodiment includes a bridge member 140 that partitions between the magnet holes 12a and 12b and the magnetic flux leakage suppression hole 14 shown in FIG. For convenience of illustration, in FIG. 1, the laminated steel sheet 10 is not hatched.

  As shown in FIG. 3, the laminated steel plate 110 is obtained by laminating a plurality of disc-shaped steel plates 190a and 90, which are magnetic steel plates that are press-punched in an annular shape. In FIG. 3, the number of disk-shaped steel plates in the laminated steel sheet 110 is three, but this is merely illustrated as such for convenience and does not represent the actual number of disk-shaped steel plates. As described above, the actual number of stacked disc-shaped steel plates is about several hundred. The thickness dimension of one magnetic steel plate is, for example, about 0.1 to 0.3 mm. Moreover, the lamination | stacking thickness dimension of the laminated steel plate 110 is about 60 mm as an example.

  As shown in FIG. 1, the permanent magnet 21 extends in the circumferential direction at the outer edge of the laminated steel plate 110. Further, a pair of permanent magnets 22 a and 22 b are extended in the radial direction on both sides of the permanent magnet 21. As shown in FIG. 1 surrounded by a one-dot chain fan, the configuration composed of the three permanent magnets 21, 22a and 22b is repeated eight times at a 45 ° pitch along the circumferential direction. In the following description, “radial direction” means the radial direction of the annular laminated steel sheet 10, and “circumferential direction” means the circumferential direction of the annular laminated steel sheet 110.

  FIG. 2 is an enlarged view of the area surrounded by the alternate long and short dash line in FIG. As shown in FIG. 2, the permanent magnet 21 is inserted into the magnet hole 11 extending in the circumferential direction at the outer edge of the laminated steel plate 110 and sealed with the resin layer 31. Further, permanent magnets 22a and 22b are inserted into a pair of magnet holes 12a and 12b extending in the radial direction on both sides of the magnet hole 11, and sealed with resin layers 32a and 32b.

  In the example of FIG. 2, in the permanent magnet 21, the surface on the radially outer side (y axis direction plus side) is an N pole, and the surface on the radially inner side (y axis direction minus side) is an S pole. Further, in the permanent magnets 22a and 22b, the surface closer to the permanent magnet 21 is an N pole, and the surface farther from the permanent magnet 21 is an S pole. In FIG. 2, the lines of magnetic force are indicated by thick dashed arrows.

  As shown in FIG. 2, in order to suppress leakage of magnetic flux from the permanent magnets 21, 22a, 22b between the pair of magnet holes 12a, 12b, the magnetic flux leakage suppression holes 14 are arranged in the circumferential direction (x-axis). Direction). That is, the magnetic flux leakage suppression hole 14 is adjacent to each of the magnet holes 12a and 12b. The magnetic flux leakage suppression hole 14 extends substantially parallel to the magnet hole 11. Further, a pair of magnetic flux leakage suppression holes 15 a and 15 b are formed adjacent to both ends of the magnet hole 11. The magnetic flux leakage suppression holes 15 a and 15 b are formed apart from the magnet hole 11.

  Bridge portions 140 extending in the radial direction are provided at both ends of the magnet leakage suppression hole 14 in order to reinforce the strength of the laminated rotor core 100. That is, between one end of the magnet leakage suppression hole 14 and the radially inner end of the magnet hole 12a, and between the other end of the magnet leakage suppression hole 14 and the radially inner end of the magnet hole 12b. Each of the bridge portions 40 extending in the radial direction is provided.

  Since the disk-shaped steel plates 90 other than the uppermost stage reduce the cross-sectional area of the bridge portion 40 without reducing the strength, the upper surface of the bridge portion 40 is pressed down by pressing or the like. Thereby, a stepped portion 40 a is formed on the upper surface of the bridge portion 40. On the other hand, the upper surface of the bridge portion 140 is not reduced for the disc-shaped steel plate 190a (the uppermost disc-shaped steel plate 190a) stacked in the uppermost stage. That is, the bridge part 140 in the disk-shaped steel plate 190a laminated on the uppermost stage has no step.

  Next, a method for manufacturing the laminated rotor core 100 according to the present embodiment will be described with reference to FIGS. 4, 5, 6, 7, and 8. 4, 5, 6, 7, and 8 are views (all of which are vertical cross-sectional views) illustrating a method for manufacturing the laminated rotor core 100 according to the present embodiment.

  First, as shown in FIG. 4, a laminated steel plate 110 is configured by laminating disc-shaped steel plates. As the uppermost disk-shaped steel plate 190a, a steel plate whose upper surface of the bridge portion 140 is not crushed is used. Then, as shown in FIG. 5, the laminated steel plate 110 is placed on the lower mold 70 of the resin molding apparatus. The lower mold 70 includes a pot plate 71, a runner plate 72, and a gate plate 73. On the gate plate 73, a protrusion 73a for placing the permanent magnet 22a is formed at a predetermined position. In addition, the predetermined position which forms the protrusion 73a is a position of the longitudinal direction both ends of the lower surface of the permanent magnet 22a, for example.

  Next, as shown in FIG. 6, the permanent magnet 22a is inserted into the magnet hole 12a. At this time, the lower end surface of the permanent magnet 22a is supported by the protrusion 73a. Then, as shown in FIG. 7, the upper mold 60 is lowered, and the laminated steel sheet 110 is sandwiched between the mold surfaces of the upper mold 60 and the lower mold 70 (the mold surface of the upper mold 60 is pressed against the upper end surface of the laminated steel sheet 10). . At this time, the upper end surface of the permanent magnet 22 a is pressed by the protrusion 62 a provided on the upper mold 50. That is, the permanent magnet 22 a is supported from below by the protrusions 73 a provided on the gate plate 73 of the lower mold 70, and is pressed by the protrusions 62 a provided on the upper mold 60. Therefore, the permanent magnet 22a is fixed at a predetermined position.

  Next, as shown in FIG. 8, the molten resin 30 is injected into the magnet hole 12 a by the plunger 80 from the lower end surface side of the laminated steel plate 110. Thereby, the permanent magnet 22a is sealed by the resin layer 32a. The permanent magnet 22a is supported from below by the protrusion 73a and pressed from above by the protrusion 62a, so that the upper end surface and the lower end surface are covered by the resin layer 32a. The resin molding method is not particularly limited, but for example, transfer molding is preferable. The resin is preferably a thermosetting resin, but may be a thermoplastic resin.

  There is no step on the upper surface of the bridge portion 140 of the disk-shaped steel plate 190a laminated on the uppermost stage. That is, in the step of forming the laminated steel plate 110, among the plurality of disc-shaped steel plates, the disc-shaped steel plate 90 other than the uppermost stage has a magnet hole 12 a (or magnet hole 12 b) and a magnetic flux leakage suppression hole on the upper surface of the bridge portion 40. 14 is provided with a pair of stepped portions 40a in contact with each other, and the uppermost disc-shaped steel plate 190a is used with no stepped portion provided on the upper surface of the bridge portion 140. For this reason, when the molten resin 30 is poured into the gap between the permanent magnets 22a and 22b and the magnet holes 12a and 12b, a thin burr is generated on the upper surface of the bridge portion 140 of the disk-shaped steel plate 190a stacked at the uppermost stage. Can be suppressed.

[Embodiment 2]
The second embodiment of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the part common to Embodiment 1, and the description is abbreviate | omitted.
FIG. 9 is a partial horizontal cross-sectional view of the laminated rotor core 200 manufactured by the manufacturing method of the laminated rotor core according to the present embodiment. 10 is a cross-sectional view (vertical cross-sectional view) taken along line XX in FIG. In FIG. 10, the number of disk-shaped steel sheets laminated in the laminated steel sheet 210 is three, but this is merely illustrated as such for convenience, and does not represent the actual number of disk-shaped steel sheets stacked.

  In the first embodiment, the uppermost disk-shaped steel plate 190a that does not reduce the upper surface of the bridge portion is used. On the other hand, in the present embodiment, as shown in FIGS. 9 and 10, the uppermost disc-shaped steel plate 90 a is the same as the disc-shaped steel plate 90 other than the uppermost step. In the laminated rotor core 200, the top and bottom disk-shaped steel plates 90a are turned upside down.

Next, a method for manufacturing the laminated rotor core 200 will be described below.
FIG.11 and FIG.12 is a figure explaining the manufacturing method of the lamination | stacking type rotor core 200 concerning this Embodiment. As shown in FIG. 11, first, a laminated steel plate 10 is configured by laminating disc-shaped steel plates 90. About the disk-shaped steel plate 90a laminated | stacked on the uppermost stage, it turns upside down when laminating | stacking. That is, the stepped portion 40a comes to the lower surface of the bridge portion 40 of the disk-shaped steel plate 90a.

  The step of placing the laminated steel sheet 10 on the lower mold 70 of the resin molding apparatus and inserting the magnet 22a and the step of injecting the molten resin 30 into the magnet hole 12a while pressing the upper surface with the upper mold 60 are as follows: This is basically the same as that described with reference to FIGS. 5, 6, 7 and 8 in the first embodiment.

  FIG. 12 is a diagram showing a state immediately after the injection of the molten resin 30 into the magnet hole 12a is completed. As shown in FIG. 10, there is no step on the upper surface of the bridge portion 40 of the uppermost disc-shaped steel plate 90a. For this reason, when the molten resin 30 is poured into the gap between the permanent magnets 22a and 22b and the magnet holes 12a and 12b, it is possible to suppress the occurrence of thin burrs on the upper surface of the bridge portion 40 of the uppermost disk-shaped steel plate 90a. In the first embodiment, the uppermost disk-shaped steel sheet has a bridge portion that is different from the disk-shaped steel sheets stacked on the uppermost layer. On the other hand, in this Embodiment, components common to all the disk-shaped steel plates laminated | stacked can be used.

[Reference form 1]
The third embodiment of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the part common to Embodiment 1, and the description is abbreviate | omitted.
FIG. 13 is a partial horizontal cross-sectional view of a laminated rotor core 300 manufactured by the method for manufacturing a laminated rotor core according to the present embodiment. 14 is a cross-sectional view (vertical cross-sectional view) taken along line XIV-XIV in FIG. In FIG. 14, the number of disk-shaped steel plates laminated in the laminated steel plate 310 is three, but this is merely illustrated as such for convenience, and does not represent the actual number of disk-shaped steel plates.

  As shown in FIGS. 13 and 14, the uppermost disc-shaped steel plate 390 a is the same as the disc-shaped steel plate 390 other than the uppermost step. In the disk-shaped steel plates 390a and 390, a helicopter 340b is formed on the edge of the stepped portion 340a on the side facing the magnet hole 12a.

  In the manufacturing method of laminated rotor core 300 according to the present embodiment, helicopter 340b is formed on the outer edge of the stepped portion 340a facing the magnet hole 12a in the disk-shaped steel plates 390a and 390 constituting the laminated steel plate 310. The bridge portion 340 is pressed down so as to be formed. The laminated steel plate 310 is configured by sequentially stacking the disk-shaped steel plates 390a and 390 formed in this manner so that the stepped portion 340a of the bridge portion 340 becomes the upper surface. The step of placing the laminated steel plate 310 on the lower mold 70 of the resin molding apparatus and inserting the magnet 22a, and the step of injecting the molten resin 30 into the magnet hole 12a while pressing the upper surface with the upper mold 60 are as follows: This is basically the same as that described with reference to FIGS. 5, 6, 7 and 8 in the first embodiment.

  As shown in FIG. 15, when there is a helicopter 340b on the outer edge of the stepped portion 340a facing the magnet hole 12a, the molten resin 30 is poured into the gap between the permanent magnets 22a, 22b and the magnet holes 12a, 12b. At this time, it is possible to suppress the occurrence of a thin burr on the upper surface of the bridge portion 340 of the disk-shaped steel plate 390a laminated on the uppermost stage.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

11, 12a, 12b Magnet hole 14, 15a, 15b Magnetic flux leakage suppression hole 21, 22a, 22b Permanent magnet 40 Bridge portion 40a Stepped portion 100 Laminated rotor core 110 Laminated steel plate 90 Disc-like steel plate other than uppermost layer 190a Uppermost disc shape steel sheet

Claims (1)

A plurality of disk-shaped steel plates in which a magnet hole for inserting a magnet body, a magnetic flux leakage suppression hole adjacent to the magnet hole, and a bridge portion that partitions the magnetic hole and the magnetic flux leakage suppression hole are formed. Laminating and forming a laminated steel sheet;
After inserting the magnet body into the magnet hole of the laminated steel sheet, sandwiching the laminated steel sheet with a mold and resin-sealing the magnet body, and a method for producing a laminated rotor core comprising:
In the step of forming the laminated steel plate, a pair of steps contacting the upper surface of the bridge portion with the magnet hole and the magnetic flux leakage suppression hole in the disk-shaped steel plate other than the uppermost step among the plurality of disk-shaped steel plates. A method of manufacturing a laminated rotor core, wherein the uppermost disc-shaped steel plate is not provided with the stepped portion on the upper surface of the bridge portion.

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