WO2011125209A1

WO2011125209A1 - Rotor and manufacturing method for same

Info

Publication number: WO2011125209A1
Application number: PCT/JP2010/056396
Authority: WO
Inventors: 靖西隈; 靖治竹綱; 勝彦建部; 晋吾雪吹; 智裕竹永
Original assignee: トヨタ自動車株式会社
Priority date: 2010-04-08
Filing date: 2010-04-08
Publication date: 2011-10-13

Abstract

A rotor is provided with: a rotor core; a plurality of slots formed in the rotor core; and permanent magnets which are mounted to each of the plurality of slots. The permanent magnets are provided with an outer layer magnet, and an inner layer magnet, which is on the inside of the outer layer magnet, with the strength of the outer layer magnets being set so as to be less than the strength of the inner layer magnets. The width of the inner layer magnets is less than the width of the slots, and the overall width of the permanent magnets, including the outer layer magnets, is greater than the width of the slots. The permanent magnets are fixed inside the slots by being in contact with the inner walls of the slots, with part of the outer layer magnet being shaved off.

Description

Rotor and method for manufacturing the same

The present invention relates to a rotor that is one of the components of a motor, and relates to a rotor including a rotor core and field permanent magnets assembled to each of a plurality of slots formed in the rotor core, and a method of manufacturing the same.

Generally, a rotor having a permanent magnet for a field is known in which a permanent magnet is accommodated in a plurality of slots formed in a rotor core and fixed with an adhesive. In this type of rotor, the permanent magnet fixing operation requires steps such as degreasing, cleaning, applying an adhesive, and curing the rotor core and permanent magnet, and the number of manufacturing steps is large. In addition, the fixed position in the surface direction of the permanent magnet in the slot may vary, and the motor characteristics may be deteriorated. Furthermore, if the rotor becomes hot when the motor is used, the adhesive force of the adhesive is weakened, and there is a problem in quality that the position of the permanent magnet is shifted. Further, when an adhesive is used for fixing the permanent magnet, it becomes difficult to separate and disassemble the rotor core and the permanent magnet when the rotor is discarded, and there is a problem in terms of recyclability. Here, a method is known in which the rotor is placed in a furnace to weaken the adhesive force of the adhesive, and the rotor core and the permanent magnet are separated and disassembled. However, such a dismantling operation requires many steps, and the adhesive may remain on the rotor core.

Therefore, conventionally, several techniques have been proposed in which the manufacturing process of the rotor is reduced, the permanent magnet is firmly fixed to the slot of the rotor core, and recyclability is taken into consideration. As an example, Patent Document 1 below describes that a permanent magnet made of a bonded magnet is press-fitted into a slot of a rotor core and fixed while cutting the outermost periphery.

On the other hand, the following Patent Document 2 describes a rotor in which a permanent magnet whose outer periphery is wrapped with resin is fitted in a slot of a rotor core. Patent Document 3 discloses a method in which a permanent magnet is coated with a coating material made of resin to form a coating layer, and a projection is formed on the outer surface of the coating layer. It is described that the permanent magnet is press-fitted into the slot while engaging the portion while cutting the portion.

Japanese Patent Laid-Open No. 2003-070194 Japanese Utility Model Publication No. 58-172376 Japanese Patent No. 3677486 JP 2005-012859 A JP 2008-130781 A

However, in the rotor described in Patent Document 1, the permanent magnet is composed of a bond magnet having a weak magnetic force. Therefore, it can be considered that the permanent magnet is composed of a rare earth sintered magnet having a strong magnetic force. However, if a permanent magnet made of a rare earth sintered magnet is press-fitted into the slot, the permanent magnet may be cracked due to stress during press-fitting, and the magnet performance may be reduced. In addition, if a part of the permanent magnet falls off due to cracking, the magnet performance may be further deteriorated. Accordingly, it is conceivable to reduce the press-fitting allowance of the permanent magnet so that it is difficult to break. However, in this case, the accuracy of the slot shape and the outer dimensions of the permanent magnet must be increased, which increases the manufacturing effort.

On the other hand, in the rotors described in

Patent Documents

2 and 3, since the resin coating layer is interposed between the inner wall of the slot and the permanent magnet, the magnetic force of the permanent magnet is weakened accordingly. Therefore, if the permanent magnet is increased in order to ensure the magnetic force, the slot also increases, and the outer diameter of the rotor core increases. This is contrary to the demand for miniaturization of the rotor, and thus the motor.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a rotor capable of securely fixing a permanent magnet to a slot of a rotor core while ensuring magnet performance, and a method for manufacturing the same. There is to do.

(1) In order to achieve the above object, according to a first aspect of the present invention, there is provided a rotor including a rotor core, a plurality of slots formed in the rotor core, and a permanent magnet assembled to each of the plurality of slots. The permanent magnet includes an outer layer magnet and an inner layer magnet provided inside the outer layer magnet, and the strength of the outer layer magnet is set to be smaller than the strength of the inner layer magnet. It is intended to be fixed in the slot by contacting the inner wall of the slot.

According to the configuration of the invention described above, in order to assemble the permanent magnet into the slot, the outer layer magnet having low strength is brought into contact with the inner wall of the slot and the permanent magnet is press-fitted into the slot while shaving a part. At this time, the outer layer magnet having a low strength is scraped, so that the press-fit load of the permanent magnet becomes relatively small. Further, the strong inner layer magnet is accommodated in the slot without being cut. The permanent magnet is fixed in the slot by contacting the inner wall of the slot with the outer layer magnet cut away.

(2) In order to achieve the above object, in the configuration of (1), the width of the inner layer magnet is smaller than the width of the slot, and the entire width of the permanent magnet including the outer layer magnet is larger than the width of the slot. desirable.

According to the configuration of the invention, in addition to the operation of the configuration of (1) above, the inner layer magnet is accommodated in the slot without contacting the inner wall of the slot because the width of the inner layer magnet is smaller than the width of the slot. Since the width of the permanent magnet including the outer layer magnet is larger than the width of the slot, the outer layer magnet is scraped by the larger width.

(3) In order to achieve the above object, in the configuration of the above (1) or (2), the inner wall of the slot contacting the outer layer magnet may be formed in a cross-sectional sawtooth shape with irregularities extending in the axial direction of the slot. desirable.

According to the configuration of the present invention, in addition to the operation of the configuration of (1) or (2) above, the inner wall of the slot that contacts the outer layer magnet is formed in a sawtooth cross section, so that when the permanent magnet is press-fitted into the slot The outer layer magnet that comes into contact with the inner wall of the slot is easily scraped, and the press-fitting load of the permanent magnet is further reduced. Further, the contact area between the inner wall of the slot and the outer layer magnet increases in the state where the permanent magnet is assembled in the slot.

(4) In order to achieve the above object, another aspect of the present invention provides a method for manufacturing a rotor including a rotor core, a plurality of slots formed in the rotor core, and a permanent magnet assembled to each of the plurality of slots. A permanent magnet manufacturing step of manufacturing a permanent magnet comprising an outer layer magnet and an inner layer magnet provided inside the outer layer magnet, the strength of the outer layer magnet being smaller than the strength of the inner layer magnet, and the permanent magnet in each slot. And a permanent magnet assembling step in which a part of the outer layer magnet is pressed into contact with the inner wall of the slot while being cut.

According to the configuration of the above invention, in the permanent magnet manufacturing step, a permanent magnet is manufactured that includes an outer layer magnet and an inner layer magnet provided inside the outer layer magnet, and the strength of the outer layer magnet is smaller than that of the inner layer magnet. In the permanent magnet assembling step, the permanent magnet is press-fitted into each slot while scraping a part of the outer layer magnet in contact with the inner wall of the slot. Accordingly, when the permanent magnet is press-fitted into the slot, the outer layer magnet having a low strength is scraped, so that the press-fitting load becomes relatively small. At this time, the strong inner layer magnet is accommodated in the slot without being cut. In the state where the permanent magnet is assembled in the slot, the outer layer magnet is interposed between the inner layer magnet and the inner wall of the slot, and there is no gap between the permanent magnet and the inner wall of the slot.

(5) In order to achieve the above object, in the configuration of (4), the width of the inner layer magnet is smaller than the width of the slot, and the entire width of the permanent magnet including the outer layer magnet is larger than the width of the slot. desirable.

According to the configuration of the invention, in addition to the operation of the configuration of (4) above, the inner layer magnet is accommodated in the slot without contacting the inner wall of the slot because the width of the inner layer magnet is smaller than the width of the slot. Since the width of the permanent magnet including the outer layer magnet is larger than the width of the slot, the outer layer magnet is scraped by the larger width.

According to the present invention, the permanent magnet can be securely fixed to the rotor core slot while ensuring the magnet performance.

The top view which concerns on 1st Embodiment and shows a rotor. FIG. 2 is a sectional view taken along line 2-2 of FIG. 1 showing the rotor according to the same embodiment. The top view which expands and shows the part of the permanent magnet enclosed with the chain-line ellipse of FIG. 1 about the rotor concerning the embodiment. A top view showing a rotor core before assembling a permanent magnet according to the embodiment. The top view which expands and shows the part of the slot enclosed with the chain-line ellipse of FIG. 4 about the rotor core concerning the embodiment. FIG. 6 is a sectional view taken along line 6-6 of FIG. 5 showing a portion of one slot of the rotor core according to the same embodiment. The top view which concerns on the same embodiment and shows a permanent magnet. FIG. 8 is a cross-sectional view taken along line 8-8 of FIG. 7 showing the permanent magnet according to the embodiment. The flowchart which concerns on the embodiment and shows the manufacturing method of a rotor. FIG. 4 is a schematic diagram showing one process of a “permanent magnet manufacturing process” according to the embodiment. FIG. 4 is a schematic diagram showing one process of a “permanent magnet manufacturing process” according to the embodiment. FIG. 4 is a schematic diagram showing one process of a “permanent magnet manufacturing process” according to the embodiment. FIG. 4 is a schematic diagram illustrating a process of a “permanent magnet assembly process” according to the embodiment. FIG. 4 is a schematic diagram illustrating a process of a “permanent magnet assembly process” according to the embodiment. FIG. 4 is a schematic diagram illustrating a process of a “permanent magnet assembly process” according to the embodiment. The top view according to FIG. 3 which concerns on 2nd Embodiment and expands and shows the part of a permanent magnet about a rotor. FIG. 6 is a plan view similar to FIG. 5 showing an enlarged slot portion of the rotor core according to the same embodiment; The top view which concerns on another embodiment and shows a permanent magnet.

<First Embodiment>
Hereinafter, a rotor and a manufacturing method thereof according to the first embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a plan view showing the rotor 11 of this embodiment. FIG. 2 shows the rotor 11 by a cross-sectional view taken along line 2-2 of FIG. As shown in FIGS. 1 and 2, this rotor 11 includes a rotor core 12 having a cylindrical shape, a single shaft fastening hole 13 formed at the center of the rotor core 12, and a rotor shaft assembled to the shaft fastening hole 13. 14.

In this embodiment, as shown in FIG. 2, the rotor core 12 is configured by laminating a plurality of electromagnetic steel plates 22. As shown in FIGS. 1 and 2, a plurality of slots 15 that are arranged at equiangular intervals and penetrate in the axial direction of the rotor core 12 are formed on the outer periphery of the rotor core 12. The plurality of slots 15 are arranged along the outer peripheral edge of the rotor core 12, and are arranged so that two adjacent slots 15 form a “C” shape or “reverse C shape”. In each slot 15, a permanent magnet 16 for field is assembled and fixed. In the rotor core 12, a plurality (“8” in this embodiment) of lightening holes 17 are formed around the shaft tightening hole 13 between the shaft tightening hole 13 and the plurality of slots 15. . These thinning holes 17 have a substantially trapezoidal shape in plan view and penetrate the rotor core 12 in the axial direction. These thinning holes 17 are arranged one by one between two pairs of slots 15 having an “inverted C shape”.

1 and 2, the rotor shaft 14 has a cylindrical shape, and a flange 14a that engages with the rotor core 12 is formed on the outer periphery thereof. In this embodiment, the rotor shaft 14 is formed by forging a metal material. The rotor shaft 14 is assembled to the shaft tightening hole 13 of the rotor core 12 by intermediate fitting or press fitting.

FIG. 3 is an enlarged plan view of the portion of the permanent magnet 16 surrounded by the chain ellipse S1 of FIG. A first bridge portion 18 is formed between two adjacent slots 15 having an “inverted C shape” as a meat portion that divides both slots 15. Further, a second bridge portion 19 as a flesh portion is formed between each slot 15 and the outer peripheral edge of the rotor core 12. In order for the rotor 11 to be assembled with a stator (not shown) in order to constitute a motor, the second permanent magnet 16 in each slot 15 is moved closer to the stator located around the rotor 11. It is necessary to make the width of the bridge portion 19 as small as possible.

As shown in FIG. 3, in this embodiment, a permanent magnet 16 having a rectangular shape in plan view is assembled to the slot 15. In the permanent magnet 16, all of the two long sides and a part of the two short sides are in contact with the

inner walls

15 a and 15 b of the slot 15.

FIG. 4 is a plan view showing the rotor core 12 before the permanent magnet 16 is assembled. FIG. 5 is an enlarged plan view of the portion of the slot 15 surrounded by the chain ellipse S2 in FIG. FIG. 6 shows a portion of one slot 5 by a sectional view taken along line 6-6 in FIG.

FIG. 7 is a plan view showing the permanent magnet 16. FIG. 8 shows the permanent magnet 16 by a cross-sectional view taken along line 8-8 in FIG. The permanent magnet 16 includes a pair of

outer layer magnets

16a and 16b and an inner layer magnet 16c provided inside the

outer layer magnets

16a and 16b. The strength of the

outer layer magnets

16a and 16b is set smaller than the strength of the inner layer magnet 16c. In this embodiment, the permanent magnet 16 has an inner layer magnet 16c sandwiched between two

outer layer magnets

16a and 16b. The inner layer magnet 16c has the same strength and magnetic force as a general permanent magnet conventionally used for a rotor. The basic materials constituting the inner layer magnet 16c and the

outer layer magnets

16a and 16b are the same. Here, in order to reduce the strength of the

outer layer magnets

16a and 16b, the particle size of the material of the

outer layer magnets

16a and 16b can be increased, or the material can be made into a blending component that hardly melts and solidifies at the grain boundaries. . The permanent magnet 16 is fixed in the slot 15 by contacting the

inner walls

15a and 15b of the slot 15 with the

outer layer magnets

16a and 16b shaved off. Here, the width W1 of the inner layer magnet 16c shown in FIGS. 7 and 8 is set smaller than the width W2 of the slot 15 shown in FIG. Further, the entire width W3 of the permanent magnet 16 including the

outer layer magnets

16a and 16b shown in FIGS. 7 and 8 is set larger than the width W2 of the slot 15 shown in FIG.

Next, a method for manufacturing the rotor 11 according to this embodiment will be described with reference to FIGS. FIG. 9 is a flowchart showing this manufacturing method. 10 to 12 schematically show a series of processes constituting the “permanent magnet manufacturing process”. 13 to 15 are sectional views showing a series of processes constituting the “permanent magnet assembling step”.

First, in the “electromagnetic steel sheet forming step” shown in (1) of FIG. 9, a plurality of electromagnetic steel sheets 22 are formed into the same shape. The electromagnetic steel plate 22 is formed by pressing a thin plate material of about “0.3 mm”.

Next, in the “rotor core manufacturing process” shown in (2) of FIG. 9, the rotor core 12 is manufactured by laminating the plurality of electromagnetic steel sheets 22 formed in the above process. The electromagnetic steel plates 22 stacked one above the other are joined together by “caulking”.

Further, in the “permanent magnet manufacturing process” shown in (3) of FIG. 9, a plurality of permanent magnets 16 are manufactured. In this step, a permanent magnet is produced by forming a magnet material into a predetermined shape by a well-known method and then firing it. This step can be performed in parallel with each step described above.

Here, the “permanent magnet manufacturing process” will be described in detail. First, as shown in FIG. 10, a material 26a constituting one outer layer magnet 16a is filled in a lower die 31 for molding, and the upper die 32 is clamped and compressed, whereby the material 26a is flattened. To form. Next, as shown in FIG. 11, the material 26a in the lower mold 31 is filled with the material 26c constituting the inner layer magnet 16c, and the upper mold 32 is clamped and compressed, whereby the material 26c is compressed. The material 26a is integrally formed with a flat plate shape. Next, as shown in FIG. 12, the material 26b in the lower mold 31 is further filled with the material 26b constituting the other outer layer magnet 16b, and the upper mold 32 is clamped and compressed. The material 26b is integrally formed with the

materials

26a and 26c into a flat plate having a three-layer structure. Thereafter, the work formed into the three-layer structure is fired to complete the production of the permanent magnet 16.

Next, in the “permanent magnet assembling step” shown in FIG. 9 (4), the permanent magnet 16 manufactured as described above is assembled in each slot 15 of the rotor core 12 manufactured as described above. Fix it. That is, as shown in FIG. 13, the permanent magnets 16 are aligned and press-fitted into the slots 15 of the rotor core 12. At this time, as shown in FIG. 14, the permanent magnet 16 is press-fitted while the

outer layer magnets

16 a and 16 b located on both sides of the inner layer magnet 16 c are partly brought into contact with the

inner walls

15 a and 15 b of the slot 15 and shaved. When the press-fitting is completed as shown in FIG. 15, the permanent magnet 16 is fixed in the slot 15 by contacting the

inner walls

15a, 15b of the slot 15 with the

outer layer magnets

16a, 16b being partially cut away. Is done. In other words, the permanent magnet 16 is fixed in the slot 15 with the

outer layer magnets

16 a and 16 b interposed between the inner layer magnet 16 c and the

inner walls

15 a and 15 b of the slot 15.

In the “rotor shaft manufacturing step” shown in FIG. 9 (5), the rotor shaft 14 is manufactured by a well-known forging method. This step can be performed in parallel with each step described above.

In the “rotor shaft assembling step” shown in FIG. 9 (6), the rotor shaft 14 is assembled by intermediate fitting or press fitting into the shaft fastening hole 13 shown in FIG. In this way, the manufacture of the rotor 11 shown in FIGS. 1 and 2 can be completed.

According to the rotor 11 of this embodiment described above, in order to assemble the permanent magnet 16 into the slot 15, the

outer layer magnets

16 a and 16 b having low strength are brought into contact with the

inner walls

15 a and 15 b of the slot 15 to be permanently cut away. The magnet 16 is press-fitted into the slot 15. In this embodiment, since the width W3 of the permanent magnet 16 including the

outer layer magnets

16a and 16b is larger than the width W2 of the slot 15, the

outer layer magnets

16a and 16b are scraped by the larger width W3. At this time, the

outer layer magnets

16a and 16b having low strength are scraped, so that the press-fit load of the permanent magnet 16 becomes relatively small. For this reason, the equipment for press-fitting the permanent magnet 16 into the slot 15 can be made small and inexpensive.

In this embodiment, since the width W1 of the inner layer magnet 16c is smaller than the width W2 of the slot 15, the inner layer magnet 16c is accommodated in the slot 15 without contacting the

inner walls

15a, 15b of the slot 15. That is, the strong inner layer magnet 16c is accommodated in the slot 15 without being cut. For this reason, breakage such as a crack does not occur in the inner layer magnet 16c having the same magnet performance as a general permanent magnet. In this sense, the magnet performance of the permanent magnet 16 in the slot 15 can be ensured.

Further, in this embodiment, when the permanent magnet 16 is assembled in the slot 15, the

outer layer magnets

16 a and 16 b are interposed between the inner layer magnet 16 c and the

inner walls

15 a and 15 b of the slot 15. There is no gap (air gap) between the

inner wall

15a, 15b of the slot 15. For this reason, the permanent magnet 16 can be reliably fixed to the slot 15. Further, the magnetic performance of the permanent magnet 16 can be improved as compared with the case where there is an air gap between the inner wall of the slot and the permanent magnet.

Thus, in the rotor 11 of this embodiment, the permanent magnet 16 can be reliably fixed while securing the magnet performance in the slot 15 of the rotor core 12.

Further, in this embodiment, since the

outer layer magnets

16a and 16b of the permanent magnet 16 are brought into contact with the

inner walls

15a and 15b of the slot 15, the cutting allowance can be set appropriately. In this sense, the formation accuracy of the slots 15 and the permanent magnets 16 can be relaxed, and their processing costs can be reduced.

According to the rotor manufacturing method described above, in the “permanent magnet manufacturing step”, the

outer layer magnets

16 a and 16 b and the inner layer magnet 16 c provided inside the

outer layer magnets

16 a and 16 b are provided, and the strength of the

outer layer magnets

16 a and 16 b is increased. The permanent magnet 16 is made smaller than the strength of the inner layer magnet 16c. In the “permanent magnet assembling step”, the permanent magnet 16 is press-fitted into each slot 15 while a part of the

outer layer magnets

16 a and 16 b is in contact with the

inner walls

15 a and 15 b of the slot 15. Accordingly, when the permanent magnet 16 is press-fitted into the slot 15, the

outer layer magnets

16a and 16b having a low strength are scraped, so that the press-fitting load of the permanent magnet 16 becomes relatively small. For this reason, the equipment for press-fitting the permanent magnet 16 into the slot 15 can be made small and inexpensive. At this time, the strong inner layer magnet 16c is accommodated in the slot 15 without being cut. For this reason, breakage such as a crack does not occur in the inner layer magnet 16c having magnet performance equivalent to that of a general permanent magnet. In this sense, the magnet performance of the permanent magnet 16 in the slot 15 can be ensured. In the state where the permanent magnet 16 is assembled in the slot 15, the

outer layer magnets

16 a and 16 b are interposed between the inner layer magnet 16 c and the

inner walls

15 a and 15 b of the slot 15. No air gap between 15b. For this reason, the permanent magnet 16 can be reliably fixed to the slot 15. Further, the magnetic performance of the permanent magnet 16 can be improved as compared with the case where there is an air gap between the inner wall of the slot and the permanent magnet.

Thus, in the rotor manufacturing method of this embodiment, the permanent magnet 16 can be reliably fixed while securing the magnet performance in the slot 15 of the rotor core 12.

Second Embodiment
Next, a second embodiment in which the rotor of the present invention is embodied will be described in detail with reference to the drawings. In this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and different points are mainly described.

This embodiment is different from the first embodiment in the shape of each slot 15. FIG. 16 is an enlarged plan view of the permanent magnet 16 of the rotor 11 according to FIG. FIG. 17 is an enlarged plan view of the slot 15 of the rotor core 12 according to FIG.

In this embodiment, as shown in FIGS. 16 and 17, the

inner walls

15 a and 15 b of the slot 15 that come into contact with the

outer layer magnets

16 a and 16 b of the permanent magnet 16 are formed in a sawtooth cross-section extending in the axial direction of the slot 15. The

Therefore, according to the rotor 11 of this embodiment, the

inner walls

15a and 15b of the slot 15 that come into contact with the

outer layer magnets

16a and 16b are formed in a sawtooth cross section, so that when the permanent magnet 16 is press-fitted into the slot 15, the outer layer A part of the

magnets

16a and 16b is easily scraped, and the press-fit load is further reduced. For this reason, the working efficiency of the “permanent magnet assembling step” can be improved. In addition, the effect of preventing damage such as cracking of the permanent magnet 16 can be enhanced.

In this embodiment, as shown in FIG. 16, in the state where the permanent magnet 16 is assembled in the slot 15, the contact area between the

inner walls

15a, 15b of the slot 15 and the

outer layer magnets

16a, 16b increases. For this reason, the fixing performance of the permanent magnet 16 with respect to the slot 15 can be improved.

In addition, this invention is not limited to each said embodiment, A part of structure can also be changed suitably and implemented in the range which does not deviate from the meaning of invention.

(1) In each of the above embodiments, the

outer magnets

16a and 16b are provided on the two opposing surfaces of the inner magnet 16c for the permanent magnet 16. However, the above two magnets are arranged in accordance with the magnetic performance of the permanent magnet and the processing convenience. An outer layer magnet may be provided on a surface other than the surface. For example, as shown in FIG. 18, the permanent magnet 16 can be configured by providing outer layer magnets 16d on the four outer peripheral surfaces of the inner layer magnet 16e.

(2) The number of slots 15 and permanent magnets 16 can be appropriately increased or decreased with respect to each of the above embodiments.

(3) In each of the above embodiments, the rotor core 12 is configured by laminating a plurality of electromagnetic steel plates 22, but the configuration of the rotor core is not limited to this, for example, the rotor core is formed by forging. You can also

The present invention can be used for manufacturing a motor used in an electric vehicle or the like.

11 Rotor 12 Rotor core 15 Slot

15a Inner wall

15b Inner wall 16 Permanent magnet

16a Outer magnet

16b Outer magnet

16c Inner magnet

16d Outer magnet 16e Inner magnet W1 Inner magnet width W2 Slot width W3 Permanent magnet width

Claims

Rotor core,
A plurality of slots formed in the rotor core;
In a rotor including a permanent magnet assembled to each of the plurality of slots,
The permanent magnet includes an outer layer magnet and an inner layer magnet provided inside the outer layer magnet, and the strength of the outer layer magnet is set smaller than the strength of the inner layer magnet,
The permanent magnet is fixed in the slot by contacting the inner wall of the slot with the outer layer magnet cut away.
The rotor according to claim 1, wherein a width of the inner layer magnet is smaller than a width of the slot, and an entire width of the permanent magnet including the outer layer magnet is larger than a width of the slot.
The rotor according to claim 1 or 2, wherein an inner wall of the slot that contacts the outer layer magnet is formed in a sawtooth shape having a cross section extending in the axial direction of the slot.
Rotor core,
A plurality of slots formed in the rotor core;
A method of manufacturing a rotor comprising a permanent magnet assembled to each of the plurality of slots,
A permanent magnet production step of producing a permanent magnet comprising an outer layer magnet and an inner layer magnet provided inside the outer layer magnet, the strength of the outer layer magnet being smaller than the strength of the inner layer magnet;
A method of manufacturing a rotor, comprising: a step of pressing a permanent magnet into each slot while pressing a part of the outer layer magnet in contact with the inner wall of the slot while scraping the permanent magnet.
The method for manufacturing a rotor according to claim 4, wherein a width of the inner layer magnet is smaller than a width of the slot, and an entire width of the permanent magnet including the outer layer magnet is larger than a width of the slot.