JP2007300754A - Rotor of motor and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the cost of manufacturing a rotor embedding permanent magnets. <P>SOLUTION: A plurality of magnetic pieces 1 to 4 are formed by polarizing a plurality of divided pieces 101 to 104 made of magnetic material (a first polarizing process). Next, the plurality of magnetic pieces 1 to 4 are disposed so as to have different polarities from those of adjacent pieces each other, and integrated by attraction of the magnetic pieces 1 to 4 (an integrating process). Then, the integrated magnetic pieces 1 to 4 are embedded in a rotor core 10 (an embedding process). Subsequently, the embedded magnetic pieces 1 to 4 are re-polarized (a second polarizing process). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a rotor for an electric motor having a permanent magnet embedded therein, and the rotor.

  As this type of rotor, there is known a rotor in which a plurality of divided permanent magnets are embedded in a rotor core in order to reduce eddy currents generated in the permanent magnets (see, for example, Patent Document 1). The thing of this patent document 1 is embed | buried in a rotor core in the state which bonded and integrated magnet pieces with the adhesive agent.

Japanese Patent Laid-Open No. 2003-164083

  However, if the magnet pieces are bonded to each other using an adhesive, the material cost is excessive and the cost is increased.

In the method for manufacturing a rotor of an electric motor according to the present invention, a plurality of divided pieces made of a magnetic material are magnetized to form a plurality of magnet pieces, and a plurality of magnet pieces are adjacent to each other with different polarities. And an integration step of integrating the magnet pieces by the attraction force, an embedding step of embedding the integrated magnet pieces in the rotor core, and a second attachment for re-magnetizing the embedded magnet pieces And a magnetic process.
It is preferable to manufacture the rotor of the electric motor by such a manufacturing method.

  According to the present invention, a plurality of magnet pieces can be integrated and embedded in the rotor core without adhering the magnet pieces, and the manufacturing cost can be reduced.

-First embodiment-
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a diagram showing a part of the manufacturing process of the method for manufacturing a rotor for an electric motor according to the first embodiment, particularly an assembling procedure of magnet pieces 1 to 4 embedded in a rotor core 10 (FIG. 3). is there. In the present embodiment, four magnet pieces 1 to 4 having an elongated, substantially rectangular parallelepiped shape are integrated into the rotor core 10. Hereinafter, the vertical direction, the horizontal direction, and the length direction of the magnet pieces 1 to 4 are defined by a, b, and c, respectively, as illustrated.

(A) Pre-magnetization step First, a magnetic field is applied to the divided pieces 101 to 104 formed of a magnetic material to form the magnet pieces 1 to 4. In this case, the magnetic field is applied (pre-magnetization) by applying a magnetic field in the magnetization difficult direction indicated by the arrow in FIG. Thereby, for example, magnet pieces 1 to 4 having an N pole and an S pole in the b direction are formed. The magnet pieces 1 to 4 may be made of any material such as a ferrite magnet or a rare earth magnet.

(B) Integration Step Next, as shown in FIG. 1B, the magnet pieces 1 to 4 are arranged in the same direction as the magnetization direction (b direction) so that the N pole and S pole of the magnet pieces 1 to 4 are adjacent to each other. Sort by. In this state, an attractive force acts between adjacent magnet pieces, and the magnet pieces 1 to 4 can be integrated by the attractive force. At this time, as shown in FIG. 2, a sheet-like insulating material 5 such as insulating paper is sandwiched between the contact surfaces of the magnet pieces 1 to 4, and the magnet pieces can be electrically insulated.

(C) Embedding step Next, magnet pieces 1 to 4 (which are referred to as integral magnets) integrated by attractive force are embedded in the rotor core. FIG. 3 is a perspective view showing a main configuration of the rotor. As shown in FIG. 3, the rotor core 10 is configured by laminating a plurality of steel plates, and the rotor core 10 has a predetermined number (four in the drawing) of substantially rectangular insertion holes 11 at equal intervals in the circumferential direction. Has been. The dimensions of the insertion hole 11 are substantially equal to the external dimensions of the integrated magnets 1 to 4, and the integrated magnets 1 to 4 are inserted into the insertion hole 11 from the axial direction. In this case, since the magnet pieces 1 to 4 are formed by being magnetized in the hard axis direction, the magnetic force of the integral magnet is weak and easy to insert into the insertion hole 11.

(D) End plate attachment process After inserting the integrated magnets 1 to 4, the substantially circular plate-like end plates 21 and 22 are attached to both end faces of the rotor core 10 to close the entire insertion hole 11. The end plates 21 and 22 are attached by, for example, through bolts that penetrate the rotor core 10 and the end plates 21 and 22. A rotation shaft is provided at the center (hole) of the rotor, and a stator around which a winding is wound is provided on the outer side in the radial direction of the rotor. However, these are not shown in FIG. .

(E) Post-magnetization step After the above steps are completed, N poles and S poles are formed along the long side of the insertion hole 11 as shown in FIG. 3, and adjacent integrated magnets are different from each other. Thus, the integrated magnets 1 to 4 are magnetized (post-magnetization). As a result, a four-pole IPM rotor is formed.

  In this case, as shown in FIG. 1C, the integrated magnets 1 to 4 are magnetized in the easy magnetization axis direction (direction a), so that the integrated magnets 1 to 4 can obtain a strong magnetic force. In this state, since the N poles and the S poles of the magnet pieces 1 to 4 are adjacent to each other, a repulsive force acts on the magnet pieces 1 to 4 and a gap is generated between the contact surfaces of the magnet pieces. Therefore, an adhesive can be injected between the contact surfaces of the magnet pieces 1 to 4 and the magnet pieces can be insulated from each other by the adhesive.

  For example, as shown in FIG. 4A, if one end plate 22 is opened with a through hole 22a facing the insertion hole 11 and smaller than the insertion port 11, and an adhesive is injected through the through hole 22a. Good. Since the through hole 22a only needs to have a minimum size for injecting the adhesive, as shown in FIG. 4B, which is a cross-sectional view taken along the line bb of FIG. A guide portion 22b may be provided at the edge of the through hole 22a, and the front surface of the through hole 22a may be covered with the guide portion 22b. In addition, since the adhesive is not for bonding the magnet pieces, the adhesive layer has a very small thickness, and the increase in material cost can be minimized.

  Another modification of the end plate 22 is shown in FIG. 5A is a front view of the end plate 22, and FIG. 5B is a cross-sectional view taken along the line bb of FIG. 5A. As shown in FIG. 5, the end hole 22 is provided with a protrusion 22 c that protrudes in a V shape toward the insertion hole 11. The protrusion 22c functions as an elastic body that can be elastically deformed. As a result, the end surfaces of the integrated magnets 1 to 4 are elastically supported, and the backlash of the magnet inside the hole 11 can be prevented and the magnet can be prevented from cracking. Moreover, when the repulsive force after magnetization arises in the integral magnets 1-4, the deformation | transformation of the magnet pieces 1-4 by the repulsive force can be absorbed, and the crack of the magnet pieces 1-4 can be prevented. .

According to the above 1st Embodiment, there can exist the following effects.
(1) Magnet pieces 1 to 4 are formed by pre-magnetization, the magnet pieces 1 to 4 are arranged so that the N pole and the S pole are adjacent to each other, and the magnet pieces 1 to 4 are integrated by an attractive force and integrated. The magnets 1 to 4 are inserted into the holes 11 of the rotor core 10. Thereby, the several magnet pieces 1-4 can be embed | buried in the rotor core 10 at once, and a man-hour can be reduced. Moreover, the trouble of bonding the magnet pieces 1 to 4 with an adhesive or the like is saved, and the manufacturing cost is reduced. Since the magnet pieces 1 to 4 are integrated, it is not necessary to insert the elongated magnet pieces 1 to 4 into the holes 11 one by one, and the insertion is easy.

(2) Since there is no need to interpose an adhesive layer for adhering the magnet pieces between the contact surfaces of the magnet pieces 1 to 4, it is possible to prevent a decrease in the space factor of the magnet, which is good Rotor characteristics can be obtained.
(3) Since the magnetic poles of the magnet pieces 1 to 4 can be inserted in a regularly aligned state, uniform magnet characteristics can be obtained by the post-magnetization process.
(4) Since the magnet is preliminarily magnetized in the hard axis direction, the attractive force to the rotor core 10 does not increase, and the magnets 1 to 4 can be easily incorporated. Moreover, since the attractive force between the magnet pieces is weak, it is possible to prevent the magnet from being broken by the attractive force.

(5) If the magnet pieces are integrated with each other through the insulating material 5 (FIG. 2), the magnet pieces are electrically insulated from each other, and eddy current can be reduced.
(6) If the through hole 22a is provided in the end plate 22 facing the insertion hole 11 (FIG. 4), an adhesive is injected between the contact surfaces of the magnet pieces 1 to 4 on which a repulsive force acts after magnetization. The magnet pieces can be insulated from each other.
(7) If the projection 22c is provided on the end plate 22 toward the insertion hole 11 (FIG. 5), the magnet can be prevented from rattling and the magnet can be prevented from cracking.

-Second Embodiment-
A second embodiment of the present invention will be described with reference to FIG.
FIG. 6 is a diagram illustrating a part of the manufacturing process of the rotor manufacturing method according to the second embodiment. In addition, the same code | symbol is attached | subjected to the location same as FIGS. 1-5, and the difference with 1st Embodiment is mainly demonstrated below.

  The second embodiment differs from the first embodiment in the arrangement of the magnet pieces 1 to 4 when assembled to the rotor core 10. That is, in the second embodiment, first, as shown in FIG. 6A, a plurality of divided pieces are magnetized in a predetermined direction (direction a) to form magnet pieces 1a to 4a and 1b to 4b (front wearing). Magnetic process). The a direction is, for example, the easy axis direction of magnetization. It should be noted that it is sufficient that the magnetic pieces 1a to 4a and 1b to 4b have a magnetic force enough to integrate the magnetic pieces, and pre-magnetization is performed so that a magnetic force larger than necessary is not applied.

  Next, as shown in FIG. 6 (b), the magnet pieces 1a to 4a and 1b to 4b have their N poles and S poles alternately reversed from top to bottom in a direction (b direction) orthogonal to the magnetization direction of the previous magnetization. Magnet pieces 1a to 4a and 1b to 4b are arranged (integration step). Thereby, the different poles of the magnet pieces are adjacent to each other, and an attractive force acts on the magnet pieces, so that the magnet pieces 1a, 2b, 3a, 4b and 1b, 2a, 3b, 4a can be integrated.

  Thereafter, the integrated magnet pieces 1a, 2b, 3a, 4b and 1b, 2a, 3b, 4a are embedded in the insertion hole 11 of the rotor core 10 (embedding step). In this state, since the magnetic force acting on the magnet piece is small, embedding in the rotor core 10 is easy.

  Next, after attaching the end plates 21 and 22 to both axial end faces of the rotor core 10 (end plate attaching step), a magnetic field stronger than the pre-magnetization is applied in the direction a (post-magnetizing step). That is, the magnet piece is magnetized in the same direction as or opposite to the magnetization direction (a direction) of the pre-magnetization. Thereby, as shown in FIG.6 (c), each magnet piece is each formed with the S pole and the N pole on the same side.

  Also in the second embodiment, the magnet pieces 1a to 4a and 1b to 4 are integrated and inserted into the hole 11 of the rotor core 10 by the attractive force of the magnet. Can be reduced.

  Note that the magnetization direction of the pre-magnetization step (first magnetization step) and the magnetization direction of the post-magnetization step (second magnetization step) are not limited to the above-described examples. In the integration step, the number and shape of the magnet pieces are not limited to those described above as long as a plurality of magnet pieces magnetized in advance are arranged so that the different poles are adjacent to each other. In FIG. 4, the end plate 22 is provided with a through hole 22a, and in FIG. 5, the end plate 22 is provided with a protrusion 22c.

  That is, as long as the features and functions of the present invention can be realized, the present invention is not limited to the rotor manufacturing method and the rotor according to the embodiment. The above description is merely an example, and when interpreting the invention, there is no limitation or restriction on the correspondence between the items described in the embodiment and the items described in the claims.

The figure which shows a part of manufacturing process of the rotor which concerns on 1st Embodiment. The figure which shows the modification of the integration process of FIG. The perspective view which shows the principal part structure of the rotor which concerns on 1st Embodiment. The figure which shows the modification of FIG. The figure which shows the modification of an end plate. The figure which shows a part of manufacturing process of the rotor which concerns on 2nd Embodiment.

Explanation of symbols

1-4, 1a-4a, 1b-4b Magnet piece 10 Rotor core 11 Insertion holes 21, 22 End plate 22a Through-hole 22c Projection part 101-104 Split piece

Claims (7)

A first magnetizing step of magnetizing a plurality of divided pieces made of a magnetic material to form a plurality of magnet pieces;
An integration step of arranging the plurality of magnet pieces so that different poles are adjacent to each other, and integrating them by the attractive force of the magnet pieces;
An embedding step of embedding the integrated magnet piece in a rotor core;
A method of manufacturing a rotor for an electric motor, comprising: a second magnetization step of re-magnetizing the embedded magnet piece. The method for manufacturing a rotor for an electric motor according to claim 1,
In the first magnetizing step, the divided pieces are magnetized in the hard axis direction,
In the integration step, the plurality of magnet pieces are arranged in parallel in the same direction as the magnetization direction in the first magnetization step,
In the second magnetizing step, remagnetization is performed in a direction different from the hard magnetization axis. The method for manufacturing a rotor for an electric motor according to claim 1,
In the integration step, the plurality of magnet pieces are alternately arranged upside down in a direction perpendicular to the magnetization direction of the first magnetization step,
In the second magnetizing step, remagnetization is performed in the same direction as or opposite to the magnetization direction in the first magnetizing step. In the rotor manufacturing method of the electric motor according to any one of claims 1 to 3,
In the integration step, a sheet-like insulating member is interposed between the contact surfaces of the magnet pieces for integration, and the rotor manufacturing method for an electric motor is characterized. In the rotor manufacturing method of the electric motor according to any one of claims 1 to 4,
Furthermore, an end plate attaching step of attaching an end plate so as to cover both end faces of the magnet pieces embedded in the embedding step,
And a step of injecting an adhesive between the contact surfaces of the magnet pieces through an opening provided in the end plate after the second magnetizing step. Production method. In the rotor manufacturing method of the electric motor according to any one of claims 1 to 4,
Furthermore, it has an end plate attaching step for attaching an end plate so as to cover both end faces of the magnet piece embedded in the embedding step,
The rotor manufacturing method, wherein the end plate is provided with a pressing portion that presses an end face of the magnet piece with an elastic force.   The rotor manufactured by the rotor manufacturing method of the electric motor of any one of Claims 1-6.

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