JP2017073936A - Rotor, permanent magnet dynamo-electric machine and manufacturing method for rotor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rotor that can be manufactured simply with small manhours, while achieving high torque and sufficient reduction of cogging torque, and to provide a permanent magnet dynamo-electric machine including the rotor, and a manufacturing method of the rotor.SOLUTION: A rotor 20 includes a rotor core 21 having multiple magnet slots 23, multiple solid permanent magnets 24 having dimensions smaller than those of the multiple magnet slots 23, respectively, and inserted into the multiple magnet slots 23, respectively, to form gaps 25 between respective magnet slots 23, and a filler 26 filling respective gaps 25 of the multiple magnet slots 23, and containing permanent magnet powder having a remanent magnetic flux density, in the filling state, lower than that of the solid permanent magnets 24.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a rotor, a permanent magnet type rotating electrical machine including the rotor, and a method for manufacturing the rotor, and in particular, can be manufactured easily and with less man-hours, and can realize a high torque and a sufficient reduction in cogging torque. The present invention relates to a rotor, a permanent magnet type rotating electrical machine including the rotor, and a method for manufacturing the rotor.

In general, it is well known that a kind of torque pulsation called cogging torque occurs in a permanent magnet type rotating electrical machine. In a permanent magnet type rotating electrical machine, when the cogging torque is large, there is a problem that the control performance is deteriorated or noise is generated.
This cogging torque is generated because the magnetic energy changes as the rotor rotates. Therefore, the cogging torque can be reduced if the change in magnetic energy due to the rotation of the rotor is reduced.

Conventionally, for example, a method disclosed in Patent Document 1 is known as a method for reducing the cogging torque by devising the structure.
The method shown in Patent Document 1 is to obtain a permanent magnet type rotating electrical machine with a small torque ripple by reducing the cogging torque by skewing the rotor. In other words, in a permanent magnet type rotating electrical machine, a permanent magnet divided into a plurality of parts in the axial direction is embedded in a rotor core divided into a plurality of parts in the same axial direction, and the plurality of rotor cores are shifted in the rotational direction to rotate the shaft. The rotor is formed integrally with the direction. Thereby, since the harmonic component can be canceled out of the magnetomotive force generated by the magnetic flux from the permanent magnet, which is one of the factors that determine the magnetic energy, the cogging torque can be reduced.

Japanese Patent Laid-Open No. 10-80079

However, the conventional cogging torque reduction method disclosed in Patent Document 1 has the following problems.
That is, there are cases where the cogging torque cannot be sufficiently reduced even if the rotor is skewed in order to reduce the cogging torque.
In addition, when the rotor is skewed, a complicated process including management of the skew angle is required, and the fundamental wave component of the magnetomotive force that contributes to the steady-state torque of the rotating electrical machine partially cancels out. There is a problem that torque also decreases.
Accordingly, the present invention has been made to solve this conventional problem, and the object of the present invention is to provide a rotor that can be manufactured easily and with less man-hours, and that can achieve high torque and sufficient reduction of cogging torque. An object of the present invention is to provide a permanent magnet type rotating electrical machine equipped with this rotor and a method of manufacturing the rotor.

  To achieve the above object, a rotor according to an aspect of the present invention has a rotor core having a plurality of magnet slots, a size smaller than each of the plurality of magnet slots, and the plurality of the plurality of magnet slots. A plurality of solid permanent magnets that are inserted into each of the magnet slots to form a gap between each of the magnet slots, and a residual magnetic flux density in the filled state that is filled in each of the gaps of the plurality of magnet slots is The gist of the present invention is to provide a filler containing a permanent magnet powder lower than the solid permanent magnet.

A permanent magnet type rotating electrical machine according to another aspect of the present invention includes a stator having an exciting coil wound thereon, and the above-described rotation, which is rotatably arranged to face the stator with a predetermined gap therebetween. The gist is to have a child.
Furthermore, a method of manufacturing a rotor according to another aspect of the present invention includes a step of forming a rotor core having a plurality of magnet slots, and a size smaller than the size of each magnet slot in each of the plurality of magnet slots. Each of a plurality of solid permanent magnets having a plurality of solid permanent magnets is inserted and a gap is formed between each of the magnet slots, and a residual magnetic flux density in a filled state is provided in each of the gaps of the plurality of magnet slots. And a step of filling a filler containing permanent magnet powder lower than the magnet.

  According to the rotor, the permanent magnet type rotating electrical machine and the method of manufacturing the rotor according to the present invention, the rotor that can be manufactured easily and with less man-hours, and that can realize high torque and sufficient reduction of the cogging torque, and this rotation A permanent magnet type rotating electrical machine having a child and a method for manufacturing the rotor can be provided.

It is sectional drawing which shows schematic structure of the permanent magnet type rotary electric machine provided with the rotor which concerns on 1st Embodiment of this invention. It is sectional drawing of the rotor in the permanent magnet type rotary electric machine shown in FIG. It is sectional drawing which shows the magnetic pole which is the principal part of the rotor which concerns on 2nd Embodiment of this invention. It is sectional drawing which shows the magnetic pole which is the principal part of the rotor which concerns on a modification. It is a graph which shows the magnetomotive force waveform in the permanent-magnet-type rotary electric machine of a prior art example. It is a graph which shows the magnetomotive force waveform in the permanent magnet type rotary electric machine shown in FIG.

Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
A permanent magnet type rotating electrical machine having a rotor according to a first embodiment of the present invention is shown in FIG. 1, and the permanent magnet type rotating electrical machine 1 is a 4 pole 24 slot embedded magnet type synchronous motor. . Note that the present invention is not limited by the number of poles, the number of slots, dimensions of other parts, and the like.
As shown in FIG. 1, the permanent magnet type rotating electrical machine 1 includes a stator 10 and a rotor 20 that is rotatably arranged opposite to the inner peripheral side of the stator 10 with a predetermined gap G therebetween. I have.

Here, the stator 10 includes a cylindrical frame 2 and a cylindrical stator core 11 disposed on the inner peripheral side of the frame 2. On the inner peripheral surface side of the stator core 11, 24 slots 12 and 24 magnetic pole teeth 13 formed at equal intervals in the circumferential direction are formed. An excitation coil 14 wound in the slot 12 is wound around each magnetic pole tooth 13.
The rotor 20 includes a columnar rotor core 21 formed of a laminated iron core and four magnetic poles 22 provided on the rotor core 21. The rotor 20 is rotated by a rotating shaft 3 that is fitted and fixed to the center portion of the rotor core 21.

  Each of the four magnetic poles 22 includes a magnet slot 23 formed with a through hole penetrating to both ends of the rotor core 21 in the axial direction. As shown in FIG. 2, each magnet slot 23 includes a rectangular hole portion that is elongated and extends linearly, and a pair of inclined hole portions that extend obliquely outward from both longitudinal ends of the rectangular hole. In each magnet slot 23, a solid permanent magnet 24 having a rectangular cross section smaller than each magnet slot 23 is inserted, and a gap 25 is formed between each magnet slot 23. That is, the solid permanent magnet 24 is inserted into the rectangular hole portion of each magnet slot 23, and a pair of inclined hole portions on both sides of the rectangular hole portion forms the gap 25. One inclined hole portion of the gap 25 constitutes a first gap 25 a formed on one side of the solid permanent magnet 24, and the other inclined hole portion of the gap 25 is formed on the other side of the solid permanent magnet 24. A second gap 25b is formed. The solid permanent magnet 24 is fixed to the rectangular hole of each magnet slot 23 with an adhesive or the like. The solid permanent magnets 24 are arranged differently between the adjacent magnetic poles 22 of the rotor 20.

  Here, the solid permanent magnet 24 may be composed of a single permanent magnet or may be composed of a plurality of permanent magnets. When a plurality of permanent magnets are used as the solid permanent magnet 24, the eddy current path flowing in the magnet can be cut off, and thus the magnet loss can be reduced. The solid permanent magnet 24 can be a sintered magnet, a bonded magnet, or the like, but a sintered magnet having a high residual magnetic flux density is preferable for increasing the torque. As the material of the solid permanent magnet 24, various materials such as Nd—Fe—B, Sm—Co, and ferrite can be used.

Further, the gaps 25 of the magnet slots 23 are filled with a filler 26 containing permanent magnet powder whose residual magnetic flux density in the filled state is lower than that of the solid permanent magnet 24. That is, the filler 26 is filled in each of the first gap 25 a and the second gap 25 b of the gap 25.
As described above, FIG. 5 and FIG. 6 show the advantages of filling the gaps 25 of the magnet slots 23 with the filler 26 containing permanent magnet powder whose residual magnetic flux density in the filled state is lower than that of the solid permanent magnet 24. The description will be given with reference. FIG. 5 is a graph showing a magnetomotive force waveform in a conventional permanent magnet type rotating electrical machine. FIG. 6 is a graph showing a magnetomotive force waveform in the permanent magnet type rotating electrical machine shown in FIG. 5 and 6, the angle θ is a rotation angle in the circumferential direction with reference to a predetermined position in the circumferential direction of the rotor 20, as shown in FIG.

First, the conventional permanent magnet type rotating electric machine showing the magnetomotive force waveform shown in FIG. 5 will be described with reference to FIG. 2. Only the solid permanent magnets 24 are fixed to the magnet slots 23, and the gaps 25 are used as spaces. 22 is configured. In this case, the magnetomotive force waveform generated by the magnetic flux from the solid permanent magnet 24 has a rectangular wave shape indicated by symbol A as shown in FIG.
On the other hand, the filler 26 containing permanent magnet powder whose residual magnetic flux density in the filled state is lower than that of the solid permanent magnet 24 in the gap 25 (the first gap 25a and the second gap 25b) of each magnet slot 23. When each magnetic pole 22 is configured by filling, magnetic flux is generated not only from the solid permanent magnet 24 but also from the permanent magnet powder of the pair of fillers 26 disposed on both sides of the solid permanent magnet 24, and the solid permanent magnet 24. As shown in FIG. 6, the waveform of the magnetomotive force generated by the magnetic flux from the permanent magnet powder is indicated by the symbol B created by the magnetic flux of the permanent magnet powder on both sides of the rectangular wave shape indicated by the symbol A created by the magnetic flux of the solid permanent magnet 24. It becomes the shape which added the small rectangular wave shape shown. That is, the waveform of the magnetomotive force generated by the magnetic flux from the solid permanent magnet 24 and the permanent magnet powder approaches a sine wave shape.

Thus, when the waveform of the magnetomotive force generated by the magnetic flux from the solid permanent magnet 24 and the permanent magnet powder approaches a sine wave shape, the fundamental wave component of the magnetomotive force increases and the harmonic component decreases. Increasing the fundamental component increases torque, and decreasing the harmonic component decreases cogging torque and torque ripple. Therefore, by filling the gap 25 with the filler 26 containing permanent magnet powder whose residual magnetic flux density in the filled state is lower than that of the solid permanent magnet 24, high torque and sufficient reduction of the cogging torque are realized. be able to.
In addition, the method of filling the gap 25 with the filler 26 containing the permanent magnet powder is only required to fill the gap 25 with a small number of steps and the method is simple. Even if the gap 25 has a complicated shape, it can be easily manufactured by filling the gap 25 with the filler 26. In addition, when using the method of inserting a solid permanent magnet separately in the clearance gap 25, it will be necessary to prepare the solid permanent magnet of complicated shape according to the shape of the clearance gap 25 of the magnet slot 23 for every model. .

  Here, the filler 26 may be composed of only one kind of permanent magnet powder, or only a permanent magnet powder obtained by mixing a plurality of kinds, or may be mixed with a permanent magnet powder and a binder. As the raw material for the permanent magnet powder, various materials such as Nd—Fe—B, Sm—Co, and ferrite can be used. One guideline for selecting the permanent magnet powder is to make the residual magnetic flux density in the filled state lower than the residual magnetic flux density of the solid permanent magnet 4. When the residual magnetic flux density in the filled state of the permanent magnet powder is higher than the residual magnetic flux density of the solid permanent magnet 4, the magnetomotive force waveform generated by the magnetic flux from the solid permanent magnet 24 and the permanent magnet powder is shown in FIG. A rectangular wave shape having a magnetomotive force larger than A is added to both sides of the rectangular wave shape indicated by symbol A. That is, the waveform of the magnetomotive force generated by the magnetic flux from the solid permanent magnet 24 and the permanent magnet powder is a waveform obtained by adding a rectangular wave shape having a large magnetomotive force on both sides of A, and the fundamental wave component increases without approaching the sine wave shape. In addition, harmonic components are not reduced.

Further, when the filler 26 contains a binder, when the filler 26 is filled into the gaps 25 of the magnet slots 23, the filler 26 can be removed from the gaps 25 only by curing the binder as necessary. Since the gaps 25 of the magnet slots 23 can be easily filled, the filler 26 can be easily filled. Further, by adjusting the ratio of the binder contained in the filler 26, it is possible to adjust the amount of magnetic flux for making the magnetomotive force close to a sine wave.
Furthermore, the coercive force of the permanent magnet powder contained in the filler 26 is preferably higher than the coercive force of the solid permanent magnet 24. As a result, the coercive force is selectively increased only for the end portion of the entire magnet that is most likely to be demagnetized, that is, only the portion filled with the filler 26 containing permanent magnet powder, and thus other characteristics are impaired as much as possible. Without increasing the demagnetization resistance. In general, since the residual magnetic flux density and the coercive force of the permanent magnet are in a trade-off relationship, if the coercive force of the solid permanent magnet 24 is increased, there is a disadvantage that the torque is reduced due to the decrease of the residual magnetic flux density.

Next, a method for manufacturing the rotor 20 will be described.
In manufacturing the rotor 20, first, the rotor core 21 having a plurality of magnet slots 23 is formed (rotor core forming step).
The rotor core 21 is constructed by laminating a structural material such as an electromagnetic steel plate or SPCC punched into a desired shape so as to form magnet slots 23 at four predetermined locations, and fixing the lamination between welding and caulking or the like. To do. Alternatively, the rotor core 21 is configured by cutting a lump-shaped soft magnetic structural material such as S45C into a desired shape so as to form magnet slots 23 at four predetermined locations.

Next, each of the plurality of solid permanent magnets 24 having a size smaller than the size of each magnet slot 23 is inserted into each of the plurality of magnet slots 23 to form a gap 25 between each of the magnet slots 23 (solid). Magnet insertion process).
Here, the solid permanent magnet 24 is inserted into a rectangular hole portion of each magnet slot 23, and a pair of inclined hole portions on both sides of the rectangular hole portion forms a gap 25. One inclined hole portion of the gap 25 constitutes a first gap 25 a formed on one side of the solid permanent magnet 24, and the other inclined hole portion of the gap 25 is formed on the other side of the solid permanent magnet 24. A second gap 25b is formed. The solid permanent magnet 24 is fixed to the rectangular hole of each magnet slot 23 with an adhesive or the like. The solid permanent magnets 24 are arranged differently between the adjacent magnetic poles 22 of the rotor 20.

As described above, the solid permanent magnet 24 may be composed of one permanent magnet, or may be composed of a plurality of permanent magnets. The solid permanent magnet 24 can be a sintered magnet, a bonded magnet, or the like, but a sintered magnet having a high residual magnetic flux density is preferable for increasing the torque. As the material of the solid permanent magnet 24, various materials such as Nd—Fe—B, Sm—Co, and ferrite can be used.
Next, each gap 25 of the plurality of magnet slots 23, that is, each of the first gap 25a and the second gap 25b is filled with permanent magnet powder having a residual magnetic flux density lower than that of the solid permanent magnet 24 in the filled state. The material 26 is filled (filler filling step).

  Here, as described above, the filler 26 may be composed of only one type of permanent magnet powder or only a permanent magnet powder obtained by mixing a plurality of types, or a mixture of the permanent magnet powder and a binder. Good. As the raw material for the permanent magnet powder, various materials such as Nd—Fe—B, Sm—Co, and ferrite can be used. As described above, as a guide for selecting the permanent magnet powder, it is possible to make the residual magnetic flux density in the filled state lower than the residual magnetic flux density of the solid permanent magnet 4. Further, as described above, it is preferable to select a permanent magnet powder whose coercive force of the permanent magnet powder contained in the filler 26 is higher than that of the solid permanent magnet 24. In addition to an adhesive, an epoxy resin, a phenol resin, or the like can be used as the binder.

When the filler 26 is composed of only one type of permanent magnet powder or a mixture of multiple types of permanent magnet powder, the gap 25 is covered after filling so that the magnet powder does not jump out. There is a need. The lid may be filled with, for example, a resin having a shape matching the gap 25 of the magnet slot 23, or may be solidified by applying an adhesive or the like. When the rotor 20 is pressed and fixed from both sides in the axial direction by the end plate, a part of the end plate may be used as a substitute for the lid.
In addition, when the filler 26 contains a binder, heat treatment for curing the binder is performed as necessary.
Finally, the rotor 20 on which the solid permanent magnet 24 and the filler 26 containing permanent magnet powder are arranged is magnetized by external magnetization (magnetization step).
The rotating shaft 3 is attached to the rotor core 21 by pressing the rotating shaft 3 into the rotor core 21 immediately after the rotor core 21 is formed. The rotating shaft 3 may be press-fitted into the rotor core 21 after the filler 26 is disposed.
And the permanent-magnet-type rotary electric machine 1 can be obtained by combining the stator 10 with the rotor 20 manufactured by the above methods.

(Second Embodiment)
Next, a rotor according to a second embodiment of the present invention will be described with reference to FIG. FIG. 3 shows a magnetic pole 22 that is a main part of the rotor according to the second embodiment of the present invention.
The rotor according to the second embodiment has the same basic configuration as the rotor 20 according to the first embodiment, but a plurality of first gaps 25a and second gaps 25b are divided by the partition wall 21a of the rotor core 21. According to the first embodiment, the gap portion 25c or 25d is divided into two (in this embodiment), and the filler 26 is filled in each of the plurality of gap portions 25c or 25d. This is different from the rotor 20.

  Here, the filling material 26 filled in each of the gap portions 26c or 26d divided into a plurality is such that the residual magnetic flux density in the filled state of the permanent magnet powder gradually decreases as the distance from the solid permanent magnet 24 side increases. Preferably, it is configured. That is, when the first gap 25a is considered, the residual magnetic flux density in the filled state of the permanent magnet powder of the filler 26 filled in the gap portion 26c on the side away from the solid permanent magnet 24 is equal to the solid permanent magnet 24 side. It is preferable to make it lower than the residual magnetic flux density in the filling state of the permanent magnet powder of the filler 26 filled in the gap portion 26c.

Thereby, the waveform of the magnetomotive force generated by the magnetic flux from the solid permanent magnet 24 and the permanent magnet powder is filled in the gap portion 26c on the solid permanent magnet 24 side on both sides of the rectangular wave shape generated by the magnetic flux of the solid permanent magnet 24. A small rectangular wave shape created by the magnetic flux of the permanent magnet powder of the filling material 26 is added, and the permanent material of the filling material 26 filled in the gap portion 26c on the side away from the solid permanent magnet 24 on both sides of the small rectangular wave shape. A smaller rectangular wave shape created by the magnetic flux of the magnet powder is added. For this reason, the waveform of the magnetomotive force generated by the magnetic flux from the solid permanent magnet 24 and the permanent magnet powder is closer to a sine wave shape than in the case of the first embodiment.
As a result, the fundamental wave component of the magnetomotive force further increases and the harmonic component decreases, so that further increase in torque and sufficient reduction in cogging torque can be realized.
As mentioned above, although embodiment of this invention has been described, this invention is not limited to this, A various change and improvement can be performed.

For example, the gap 25 is not necessarily formed by a pair of the first gap 25a and the second gap 25b formed on both sides of the solid permanent magnet 24. For example, as shown in FIG. 4, only one side of the solid permanent magnet 24 is provided. It may be formed. In this case, the filler 26 is filled in the gap 25 formed only on one side of the solid permanent magnet 24.
The gap 25 does not necessarily need to be an inclined hole extending from the end of the rectangular hole into which the solid permanent magnet 24 is inserted, and can take any shape extending from the end of the rectangular hole. For example, as shown in FIG. 4, the shape of the rectangular hole may be extended as it is.
Furthermore, the coercive force of the permanent magnet powder contained in the filler 26 is not necessarily higher than the coercive force of the solid permanent magnet 24.

DESCRIPTION OF SYMBOLS 1 Permanent-magnet-type rotary electric machine 2 Frame 3 Rotating shaft 10 Stator 11 Stator core 12 Slot 13 Magnetic pole teeth 14 Excitation coil 20 Rotor 21 Rotor core 21a Partition wall 22 Magnetic pole 23 Magnet slot 24 Solid permanent magnet 25 Gap 25a 1st Gap 25b Second gap 25c Gap part 25d Gap part 26 Filler

Claims (8)

A rotor core having a plurality of magnet slots;
A plurality of solid permanent magnets having a size smaller than the size of each of the plurality of magnet slots, and being inserted into each of the plurality of magnet slots to form a gap between the magnet slots;
A rotor comprising: a filling material filled in the gaps of each of the plurality of magnet slots and containing permanent magnet powder having a residual magnetic flux density in a filled state lower than that of the solid permanent magnet.   The rotor according to claim 1, wherein the filler includes a binder.   The rotor according to claim 1 or 2, wherein the coercive force of the permanent magnet powder contained in the filler is higher than the coercive force of the solid permanent magnet.   The gap includes a first gap and a second gap formed on both sides of the solid permanent magnet, and the filler is filled in each of the first gap and the second gap. Item 4. The rotor according to any one of Items 1 to 3.   Each of the first gap and the second gap is divided into a plurality of gap portions by a partition wall of the rotor core, and the filler is filled in each of the divided gap portions. The rotor according to claim 4.   The filler filled in each of the gap portions divided into a plurality is configured such that the residual magnetic flux density in the filled state of the permanent magnet powder gradually decreases as the distance from the solid permanent magnet side increases. The rotor according to claim 5.   A stator having an exciting coil wound thereon, and the rotor according to any one of claims 1 to 6, which is rotatably arranged opposite to the stator with a predetermined gap therebetween. A permanent magnet type rotating electrical machine. Forming a rotor core having a plurality of magnet slots;
Inserting a plurality of solid permanent magnets each having a size smaller than the size of each magnet slot into each of the plurality of magnet slots to form a gap between each magnet slot; and
Filling the gap in each of the plurality of magnet slots with a filler containing a permanent magnet powder whose residual magnetic flux density in a filled state is lower than that of the solid permanent magnet. Production method.

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