JP2000295797A - Permanent magnet motor and manufacture of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve productivity without relation to the shape of a rotor core and a rotor magnet. SOLUTION: A permanent magnet motor 21 is composed of a stator 24 that is formed by winding a plurality of coils 23 to a stator core 22 and a rotor 27 that is formed by providing a rotor magnet 26 to a rotor core 25. The rotor core 25 of rotor 27 is formed of a molding material that is formed by injection mold of a kneaded material of an iron-based soft magnet material and a thermosetting resin. The rotor magnet 26 loaded at the external circumference area of the rotor core 25 is formed of a molding material that is formed by injection mold of kneaded material of the ferrite or rare earth based hard magnetic material and thermosetting resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent magnet motor having an improved rotor structure and a method for manufacturing the same.

[0002]

Conventionally, as a permanent magnet motor, there is one having a structure shown in FIGS. The permanent magnet motor 1 has a configuration in which a stator 4 in which a plurality of coils 3 are wound around a stator core 2, and a rotor 7 in which a rotor magnet 6 is provided on a rotor core 5. The rotor core 5 of the rotor 7 is made of an iron-based soft magnetic material. In this case, the rotor core 5 is formed to have a unique planar shape in order to reduce cogging torque. The rotor magnet 6 made of, for example, a bonded magnet is mounted on an outer peripheral portion of the rotor core 5. Further, as the rotor core, there is a rotor core having a configuration in which silicon steel plates 8a are laminated as in a rotor core 8 shown in FIG.

FIG. 3 shows a rotor having another structure.
There is also a rotor 9 shown at 4 and 35. The rotor core 10 of the rotor 9 has a configuration in which the bond magnet 11 is accommodated and disposed inside, and also has a unique shape. The rotor core 10
Is formed of an iron-based soft magnetic material. As a rotor core of this kind, there is a rotor core 12a laminated like a rotor core 12 shown in FIG.

[0004] However, FIGS.
Alternatively, in FIGS. 34 and 35, the rotor core has to be formed by shaving a material material, which is extremely troublesome and time-consuming.
In particular, when the shape is a peculiar shape, there is a problem that the productivity is even worse. 33 or 36, since the silicon steel plates are laminated, the lamination and the bonding between the steel plates are troublesome, and an error occurs at the time of lamination. There was a problem that there was a lot of variation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to omit a shaving process of a material material and to omit a lamination process and a bonding process of a silicon steel plate, and to obtain a rotor core and a rotor core as a whole. It is an object of the present invention to provide a permanent magnet motor which can be easily manufactured regardless of the shape of the rotor magnet, can eliminate variations in axial length, and can improve manufacturing accuracy, and a method of manufacturing the same.

[0006]

According to a first aspect of the present invention, there is provided a permanent magnet motor including a stator having a plurality of coils wound around a stator core and a rotor having a rotor core provided with a rotor magnet. Wherein the rotor core is formed from a molded body formed by kneading a soft magnetic material and a resin, and the rotor magnet is formed from a molded body formed by kneading a ferrite or rare earth hard magnetic material and a resin. It has features in its configuration. In this configuration, since the rotor core and the rotor magnet contain resin, the rotor core and the rotor magnet can be molded by molding dies, respectively, and after molding these rotor cores, the rotor magnet can be integrally molded therewith. It is also possible to mold the rotor magnet and then integrally mold the rotor core with it.This eliminates the need to cut out the integrally molded material material, as well as the lamination process and bonding of silicon steel sheets. No process is required, making it easy to manufacture regardless of the shape of the rotor core and rotor magnet,
Further, the variation in the axial length can be eliminated, and the production accuracy can be improved. Further, since resin is contained in the rotor core and the rotor magnet, eddy current can be suppressed, and unlike the silicon steel sheet laminated structure, it is possible to contribute to improvement of motor characteristics while improving manufacturability.

In this case, the rotor may have a configuration in which a rotor magnet is provided on the outer peripheral portion of the rotor core. Further, a configuration in which a rotor magnet is provided on the inner peripheral portion of the rotor core may be adopted (the invention of claim 3). Further, the rotor may be located outside the stator (the invention of claim 4) or may be located inside the stator (the invention of claim 5). The soft magnetic material in the rotor core may be an iron-based soft magnetic material, and the resin in the rotor core may be a thermoplastic resin (the invention of claim 6). Furthermore, the resin in the rotor magnet may be a thermoplastic resin (the invention of claim 7).

According to an eighth aspect of the present invention, there is provided a method of manufacturing a permanent magnet motor, comprising: a stator having a plurality of coils wound around a stator core; and a rotor having a rotor core provided with a rotor magnet. In the method, the rotor core is injection-molded by injection-injecting and solidifying a kneaded product of a soft magnetic material and a resin into a molding die,
With the rotor core compact left in the mold,
By injecting and kneading a kneaded product of ferrite or rare earth hard magnetic material and resin into this mold, and solidifying it,
It is characterized in that the rotor magnet is injection-molded integrally with the rotor core. In this method, the rotor core and the rotor magnet can be molded by one molding die, so that the configuration of the molding die can be simplified and the time required for manufacturing the rotor can be shortened.

In this case, a rotor magnet is injection molded by injecting and solidifying a kneaded product of a ferrite or rare earth hard magnetic material and a resin into a molding die, and solidifying the rotor magnet. The rotor core may be injection-molded integrally with the rotor magnet by injecting and kneading a kneaded product of a soft magnetic material and a resin into the mold in a state where the rotor core is left (the invention according to claim 9). ).

In this method, the rotor magnet is formed first, but the rotor magnet and the rotor core can be formed by one forming die, thereby simplifying the structure of the forming die and manufacturing the rotor. The time can be shortened.

According to a tenth aspect of the present invention, there is provided a method for manufacturing a permanent magnet motor including a stator having a stator core wound with a plurality of coils and a rotor having a rotor core provided with a rotor magnet. ,
The rotor core is injection-molded by injection-injecting and solidifying a kneaded product of a soft magnetic material and a resin into a molding die, and the molded body of the rotor core is arranged in another molding die. It is characterized in that the rotor magnet is integrally molded with the rotor core by injection-injecting and solidifying a kneaded product of a rare-earth hard magnetic material and a resin. In this method, the rotor magnet can be integrally formed with the separately formed rotor core, and the bonding step is not required.

In this case, a rotor core is injection-molded by injection-injecting and solidifying a kneaded product of a soft magnetic material and a resin into a molding die, and a molded body of the rotor core is arranged in another molding die. The rotor magnet may be injection-molded integrally with the rotor core by injecting and solidifying a kneaded product of a ferrite or a rare earth-based hard magnetic material and a resin into a molding die and solidifying the mixture (invention 11). . In this method, the same effect can be obtained.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a plan view of a permanent magnet motor. The permanent magnet motor 21 has a configuration in which a stator 24 in which a plurality of coils 23 are wound around a stator core 22 and a rotor 27 in which a rotor magnet 26 is provided on a rotor core 25 are provided. The rotor 27 is located inside the stator 24 and has an inner rotor shape. The rotor core 25 of the rotor 27 is formed from a molded product obtained by injection molding a kneaded product of an iron-based soft magnetic material and a thermoplastic resin. In this case, the planar shape is unique in order to reduce cogging torque. It is formed to have a shape.

A rotor magnet 26 made of, for example, a bond magnet is mounted on an outer peripheral portion of the rotor core 25. The rotor magnet 26 is formed by kneading a ferrite or rare earth hard magnetic material and a thermoplastic resin. It is composed of a molded article obtained by injection molding.

A method of manufacturing the rotor 27 will be described with reference to FIGS. First, the molding apparatus 28 will be described. In FIG. 3 showing the mold open state, the table 28a is movable in the direction of arrow A and the opposite direction, and is rotatable about the shaft 28b in the direction of arrow B and in the opposite direction. This table 28a
Molding dies 29 and 30 having the same configuration and serving as both a rotor core and a rotor magnet are attached to one surface side. The molding dies 29, 30 are formed with cavities 29a, 30a having the same size as the entire rotor, respectively, and are provided with ejector pins 29b, 30b, respectively.

In FIG. 3, an injection mold 31 for a rotor core is provided at a position P1 facing the molding die 29.
A protrusion 31b having a shape that matches the shape of the rotor magnet to be formed is formed on the pressing surface (left side in the figure) of the pressing die 31a of the rotor core injection die 31. The protruding portion 31b is for forming a space for the rotor core in the cavities 29a and 30a.

In FIG. 3, an injection mold 32 for a rotor magnet is provided at a position P2 facing the molding die 30. On the pressing surface (left side in the figure) of the pressing die 32a of the rotor magnet injection die 32, the protruding portion 31b is provided.
Is not formed, and is a flat surface.

The procedure for manufacturing the rotor 27 will now be described. First, from the state shown in FIG. 3, the table 28a is moved in the direction of the arrow A so that the molding die 29 and the casting die 31 are matched, and the molding die 30 and the casting die 32 are matched. At this time, the protruding portion 31b of the injection mold 31 is fitted to the inner surface of the cavity 29a of the molding die 29 on the large diameter side, and the cavity 29a has a rotor core-shaped space S25.
Is formed. Then, first, the kneaded material 25p for the rotor core 25 is passed through an injection mold 31 from an injection device (not shown).
The injection is injected into the space S25 of the cavity 29a of the mold 29. The kneaded material 25p is obtained by kneading a powder of a soft magnetic material of an Fe-Si-based metal and a melt of a nylon-based thermoplastic resin.

When the kneaded material 25p is solidified, the solidified material becomes a molded body 25r of the rotor core 25. After the mold is opened, the table 28a is rotated by 180 °. This state is shown in FIG. By the above mold opening,
The protruding portion 31b is retracted from the cavity 29a of the molding die 29, so that the space S26 for molding the rotor magnet is formed.
Appears. Then, by the rotation, the molding 2
The mold 29 in which 5r remains and the space S26 exists faces the injection mold 32, and the mold 30 faces the injection mold 31.

The mold is adjusted from the state shown in FIG. 5, and as shown in FIG. 6, the kneaded material 25p having the above-described composition is injected and injected from the injection mold 31, and the kneaded material 26p for the rotor magnet is injected from the injection mold 32. Is injected into the space S26. The kneaded material 26p is obtained by kneading a powder of a hard magnetic material of a rare earth alloy or a ferrite alloy and a melt of a nylon-based thermoplastic resin. By solidifying the kneaded material 26p, the molded body 26r of the rotor magnet is injection-molded integrally with the molded body 25r of the rotor core, whereby the molded body 27r of the rotor is molded. Thereafter, the mold is opened as shown in FIG. 7 and the molded body 27r of the rotor is taken out. Thereafter, the table 28a is rotated to the original position (see FIG. 8), and FIG. 6 (mold matching and injection / injection), FIG.
The rotation of a by 180 ° is repeated. The rotor magnet compact 26r of the rotor compact 27r taken out is to be subjected to required magnetization. Thus, the rotor 27 having the rotor core 25 and the rotor magnet 26 is manufactured.

In this configuration, since the rotor core 25 and the rotor magnet 26 contain a thermoplastic resin, the rotor core 25 and the rotor magnet 26 can be injection-molded by the molding apparatus 28, respectively.
This eliminates the necessity of shaving the material and eliminates the need for lamination and bonding of silicon steel sheets, making it easier to manufacture as a whole and eliminating variations in axial length. The accuracy can be improved. Further, since the rotor core 25 and the rotor magnet 26 contain a thermoplastic resin, eddy current can be suppressed, and unlike the silicon steel sheet laminated structure, it is possible to improve manufacturability and contribute to improvement of motor characteristics.

According to this embodiment, the rotor core 25
Is first injection-molded with a molding die 29 (or 30),
Since the rotor magnet 26 is injection-molded integrally with the rotor core 25 while the molded body of the rotor core 25 is left in the molding die 29 (or 30), the rotor core 25 is formed by one molding die 29 (or 30).
And the rotor magnet 26 can be molded, so that the configuration of the molding apparatus 28 can be simplified and the rotor 2
7 can be shortened.

More specifically, the cavities 29a and 30a of the molding dies 29 and 30 have a common rotor configuration, and one injection mold 31 is formed with a protrusion 31b for forming a cavity of a rotor magnet, and the other injection mold 31 is formed with the other injection mold. 32 to the projection 3
1b, the molding apparatus 2 capable of simultaneously molding the rotor core 25 and the rotor magnet 26.
8 could be simplified.

FIGS. 9 to 14 show a second embodiment of the present invention. This embodiment differs from the first embodiment in the following points. That is, in the molding die device 40, the injection mold 4 for the rotor magnet located at the position P1.
On the pressing surface (left side in the figure) of the pressing die 41a, a protrusion 41 having a shape matching the shape of the rotor core to be formed is provided.
b is formed. The protruding portion 41b is for forming a space for the rotor magnet in the cavities 29a and 30a. At the position P2, a rotor core injection mold 42 is provided.
Does not have such a portion as the protrusion 41b.

The procedure for manufacturing the rotor 27 using the above-described molding apparatus 40 will be described. First, the table 28a is moved in the direction of arrow A from the state of FIG.
The mold 29 and the casting mold 41 are matched, and the mold 30 and the casting mold 42 are matched. At this time, the projecting portion 41b of the injection mold 41 is
a in the center portion of the rotor magnet-shaped space S26.
Is formed. Then, first, the kneaded material 26p for the rotor magnet 26 is passed from the injection device (not shown) through the injection mold 41 to the space S26 of the cavity 29a of the mold 29.
(See FIG. 10).

When the kneaded material 26p is solidified, the solidified material becomes a molded body 26r of the rotor magnet 26. After the mold is opened, the table 28a is rotated by 180 °. This state is shown in FIG. Due to the opening of the mold, the protrusion 41
b recedes, so that the space S2 for forming the rotor core is formed.
5 appears. Then, due to the rotation, the molding die 29 in which the molded body 26r remains and the space S25 exists faces the injection mold 42, and the molding die 30 faces the injection mold 41.

The mold is matched from the state shown in FIG.
As shown in FIG. 12, the above kneaded material 26
p is injected and the kneaded material 25p for the rotor magnet is injected and injected from the injection mold 42 into the space S25 of the cavity 29a. The kneaded material 25p is solidified to form a compact 25r, and the rotor core compact 2r is formed.
5r is integrally formed with the molded body 26r of the rotor magnet by injection molding, whereby the molded body 27r of the rotor 27 is molded. Thereafter, the mold is opened as shown in FIG. 13 and the molded body 27r of the rotor is taken out. After this, Table 2
Rotating 8a to its original position (see FIG. 14), FIG. 12 (mold matching and injection injection), FIG. 13 (mold opening and removal), and 180 ° rotation of table 28a are repeated. The rotor magnet molded body 26r of the rotor molded body 27r taken out is subjected to required magnetization.
Thus, the rotor core 25 and the rotor magnet 2
6 is manufactured.

In this embodiment, first, a rotor magnet 26 is injection-molded by a molding die 29 (or 30), and a molded body of the rotor magnet 26 is formed by the molding die 2 (or 30).
Since the rotor core 25 is integrally formed with the rotor magnet 26 while being left at 9 (or 30), the rotor core 25 and the rotor magnet 26 can be formed by one molding die 29 (or 30). As a result, the configuration of the molding apparatus 28 can be simplified, and the manufacturing time of the rotor 27 can be reduced.

Also in this embodiment, the molding die 2
The cavities 29a and 30a of the rotors 9 and 30 have a common rotor-shaped configuration, and a projection 41b for forming a cavity of the rotor magnet is formed in the injection mold 41 for the rotor magnet.
Since the rotor core injection mold 42 does not have the protrusion 41b, the molding apparatus 28 can be simplified.

FIGS. 15 to 20 show a third embodiment of the present invention. In this embodiment, the rotor core 25 is first injection-molded by a molding apparatus 51 dedicated to the rotor core, and the rotor core 25 is separated. 55a of a molding die 55 of a molding die device 52 dedicated to two-stage molding, which is a molding die of
And the rotor magnet 26 is integrally formed by injection molding.

That is, as shown in FIGS. 15 and 16, the mold apparatus 51 has a mold 53 in which a cavity 53a conforming to the shape of the rotor core to be molded is formed and also has an injection mold 54. ing. Another mold apparatus 52 is, as shown in FIGS. 18 and 19, provided with a cavity 5 corresponding to the overall shape of the rotor to be molded.
5a is formed, and the injection mold 56 is provided.
Is configured.

The manufacturing procedure will be described. As shown in FIG. 17, a molding 25r of the rotor core is injection-molded by the molding apparatus 51, and the molding 25 of the rotor core is formed.
r is placed in a cavity 55a of a mold 55 of another mold apparatus 52 as shown in FIG. With this arrangement, a space S26 for the rotor magnet is formed in the cavity 55a. Then, as shown in FIG. 20, the kneaded material 26p is injected and injected into this space S26, solidified, and injection-molded into a molded body 27r of the rotor. According to this embodiment, the rotor magnet 26 can be integrally molded with the separately formed rotor core 25 (this is the molded body 25r), and the bonding step is not required.

FIGS. 21 to 26 show a fourth embodiment of the present invention.
6 is first injection-molded by a molding apparatus 61 dedicated to a rotor magnet, and the rotor magnet 26 is arranged in a cavity 65a of a molding die 65 of a molding apparatus 62 dedicated to two-stage molding, which is another molding die. Are integrally formed by injection molding.

That is, as shown in FIG. 21, the molding apparatus 61 has a molding die 63 in which a cavity 63a conforming to the shape of a rotor magnet to be molded is formed and also has an injection mold 64. I have. As shown in FIG. 24, another mold apparatus 62 includes a mold 65 having a cavity 65a that matches the overall shape of the rotor to be molded, and has an injection mold 66.

The manufacturing procedure will be described. As shown in FIG. 23, a molded body 26r of a rotor magnet is injection-molded by the molding apparatus 61, and the molded body 26r of the rotor magnet is separated as shown in FIG. In the cavity 65a of the molding die 65 of the molding die device 62. With this arrangement, a space S25 for the rotor core is formed in the cavity 65a. And this space S2
The kneaded material 25p is injection-injected into 5, and solidified to injection-mold a molded body 27r of the rotor. According to this embodiment, the separately formed rotor magnet 26 (which is
r), the rotor core 25 can be integrally formed,
No bonding process is required.

The present invention is not limited to the above embodiments, but may be, for example, a rotor 71 as shown in FIGS. 27 and 28 as a fifth embodiment of the present invention. The rotor 71 has rotor magnet housing portions 72a formed at four positions of a rotor core 72, and the rotor magnet housing portions 72a are formed.
This is a configuration in which a rotor magnet 73 is filled and disposed in a.
In this case, the rotor core 72 is made of Fe-
It is molded from a kneaded material obtained by kneading a Si-based metal powder and a melt of a nylon-based thermoplastic resin,
The rotor magnet 73 is formed by kneading a rare earth alloy or ferrite alloy powder and a melt of a nylon-based thermoplastic resin. With this, basically, the same effect as that of the first embodiment can be obtained.

Further, in each of the above embodiments, the inner rotor type permanent magnet motor is exemplified, and the present invention is applied to an outer rotor type permanent magnet motor 81 as shown in FIG. 29 shown as a sixth embodiment of the present invention. Is also good. That is, the rotor 83 is located outside the stator 82, and the rotor 83 has the rotor magnet 85 disposed inside the rotor core 84.

The present invention is not limited to the above embodiments. For example, Fe-S
In addition to i-based metals, Fe-Si-B-based metals, Fe-Si-
Al-based metal or Fe-Ni-based metal may be used.

[0039]

As is clear from the above description, the present invention can omit the shaving process of the material and can omit the laminating step and the bonding step of the silicon steel sheet.
Regardless of the shape of the rotor core and rotor magnet,
It has the advantages of facilitating fabrication, eliminating variations in axial length, improving fabrication accuracy, and reducing eddy currents. Play.

[Brief description of the drawings]

FIG. 1 is a plan view of a motor according to a first embodiment of the present invention.

FIG. 2 is a plan view of a rotor.

FIG. 3 is a longitudinal sectional side view showing a molding apparatus.

FIG. 4 is a view for explaining a molding procedure.

FIG. 5 is a view for explaining a molding procedure.

FIG. 6 is a view for explaining a molding procedure.

FIG. 7 is a view for explaining a molding procedure.

FIG. 8 is a diagram for explaining a molding procedure.

FIG. 9 is a longitudinal sectional side view of a molding apparatus showing a second embodiment of the present invention.

FIG. 10 is a longitudinal sectional side view of a mold apparatus for explaining a molding procedure.

FIG. 11 is a longitudinal sectional side view of a molding apparatus for explaining a molding procedure.

FIG. 12 is a longitudinal sectional side view of a molding apparatus for explaining a molding procedure.

FIG. 13 is a longitudinal sectional side view of a molding apparatus for explaining a molding procedure.

FIG. 14 is a longitudinal side view of a molding apparatus for explaining a molding procedure.

FIG. 15 is a longitudinal sectional side view of a molding apparatus showing a third embodiment of the present invention.

FIG. 16 is a plan view of a molding die.

FIG. 17 is a longitudinal sectional side view of a molding apparatus showing a state of molding.

FIG. 18 is a longitudinal sectional side view of another mold apparatus.

FIG. 19 is a plan view of a molding die.

FIG. 20 is a longitudinal sectional side view of a molding apparatus showing a state of molding.

FIG. 21 is a longitudinal sectional side view of a molding apparatus showing a fourth embodiment of the present invention.

FIG. 22 is a plan view of a molding die.

FIG. 23 is a longitudinal sectional side view of a molding apparatus showing a state of molding.

FIG. 24 is a longitudinal sectional side view of another mold apparatus.

FIG. 25 is a plan view of a molding die.

FIG. 26 is a longitudinal sectional side view of a molding apparatus showing a state of molding.

FIG. 27 is a plan view of a motor according to a fifth embodiment of the present invention.

FIG. 28 is a plan view of a rotor.

FIG. 29 is a plan view of a motor according to a sixth embodiment of the present invention.

FIG. 30 is a plan view of a motor showing a conventional example.

FIG. 31 is a plan view of a rotor.

FIG. 32 is a perspective view of a rotor core.

FIG. 33 is a perspective view of a rotor core showing a different conventional example.

FIG. 34 is a plan view of a rotor showing a different conventional example.

FIG. 35 is a perspective view of a rotor core.

FIG. 36 is a perspective view of a rotor core showing a different conventional example.

[Description of References] 21 is a permanent magnet motor, 22 is a stator core, 23 is a coil, 24 is a stator, 25 is a rotor core, 26 is a rotor magnet, 27 is a rotor, 28 is a molding apparatus, 2
9 and 30 are molds, 31 is an injection mold for rotor core, 31b
Is a protrusion, 32 is a rotor magnet injection mold, 41 is a rotor magnet injection mold, 41b is a protrusion, 42 is a rotor core injection mold, 51 is a rotor core dedicated molding apparatus,
52 is a molding device dedicated to two-stage molding, 61 is a molding device dedicated to rotor magnet, 62 is a molding device dedicated to two-stage molding, 71 is a rotor, 72 is a rotor core, 73 is a rotor magnet, and 81 is a permanent magnet motor. , 82 are stators, 8
Reference numeral 3 denotes a rotor, 84 denotes a rotor core, and 85 denotes a rotor magnet.

Claims (11)

[Claims] 1. A permanent magnet motor comprising: a stator having a stator core wound with a plurality of coils; and a rotor having a rotor core provided with a rotor magnet, wherein the rotor core comprises a soft magnetic material and a resin. A permanent magnet motor, comprising: a molded body obtained by molding a kneaded product; and the rotor magnet comprising a molded product obtained by molding a kneaded product of a ferrite or rare earth-based hard magnetic material and a resin. 2. The permanent magnet motor according to claim 1, wherein the rotor has a configuration in which a rotor magnet is provided on an outer peripheral portion of a rotor core. 3. The permanent magnet motor according to claim 1, wherein the rotor has a structure in which a rotor magnet is disposed on an inner peripheral portion of a rotor core. 4. The permanent magnet motor according to claim 1, wherein the rotor is located outside the stator. 5. The permanent magnet motor according to claim 1, wherein the rotor is located inside the stator. 6. The permanent magnet motor according to claim 1, wherein the soft magnetic material in the rotor core is an iron-based soft magnetic material, and the resin in the rotor core is a thermoplastic resin. 7. The permanent magnet motor according to claim 1, wherein the resin in the rotor magnet is a thermoplastic resin. 8. A method of manufacturing a permanent magnet motor including a stator having a stator core wound with a plurality of coils and a rotor having a rotor core provided with a rotor magnet, wherein a kneaded product of a soft magnetic material and a resin is provided. The rotor core is injection-molded by injection-injection into a molding die and solidified, and while the molded body of the rotor core is left in the molding die, a ferrite or rare-earth hard magnetic material and a resin are added to the molding die. A method for manufacturing a permanent magnet motor, characterized in that the rotor magnet is injection-molded integrally with the rotor core by injection-injecting and solidifying the kneaded material. 9. A method of manufacturing a permanent magnet motor including a stator having a plurality of coils wound around a stator core and a rotor having a rotor core provided with a rotor magnet, the method comprising the steps of: The rotor magnet is injection-molded by injecting and kneading a kneaded product with a resin into a molding die, and while the molded body of the rotor magnet remains in the molding die, a soft magnetic material and a resin are added to the molding die. Wherein the rotor core is injection-molded and solidified by injection-injecting the kneaded material with the rotor core to integrally form the rotor core with the rotor magnet. 10. A kneaded product of a soft magnetic material and a resin in a method of manufacturing a permanent magnet motor including a stator having a plurality of coils wound around a stator core and a rotor having a rotor core provided with a rotor magnet. The rotor core is injection-molded by injection-injection into a molding die and solidified, the molded body of this rotor core is arranged in another molding die, and a ferrite or rare earth hard magnetic material and a resin are placed in this another molding die. Wherein the kneaded material is injected and solidified to injection-mold the rotor magnet integrally with the rotor core. 11. A method of manufacturing a permanent magnet motor including a stator having a plurality of coils wound around a stator core and a rotor having a rotor core provided with a rotor magnet, the method comprising: using a ferrite or rare earth hard magnetic material; The rotor magnet is injection-molded by injecting and kneading the kneaded product with a resin into a molding die, and the molded body of the rotor magnet is arranged in another molding die. A method for manufacturing a permanent magnet motor, characterized in that the rotor core is injection-molded integrally with the rotor magnet by injection-injecting and solidifying a kneaded material of the rotor and the resin.