JP2003260596A - Method of manufacturing compact by powder metallurgy, bonded structure of powder molding and rotor for motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To strongly bond two powder materials in a compact comprising a plurality of kinds of powder materials. <P>SOLUTION: The inside of a die 11 is partitioned into a first molding section 41 and a second molding section 42 by disposing a partition plate 15 inside the die 11 which molds the compact, a first powder material 20 is supplied to the first molding section 41, a second powder material 30 is supplied to the second molding section 42, after the partition plate 15 is removed, the first and second powder materials 20, 30 are compacted by an upper punch 13 to obtain a green compact 1', which is sintered to obtain the compact. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a compact by powder metallurgy, a joint structure for powder compacts, and a rotor for a motor molded using these techniques.

[0002]

2. Description of the Related Art Conventionally, the following two methods have been mainly known as a method for joining a molded body made of a plurality of different materials by powder metallurgy. First, as described in JP-A-7-177712, a plurality of powder compacts obtained by compressing and molding powder materials are separately formed for each powder material. In this method, the green compact is sintered in contact with it. In this method, atoms of each green compact are diffused by heat during the sintering of the plural green compacts contacted with each other, whereby the multiple green compacts are joined (hereinafter referred to as "diffusion bonding").

The second is to sinter a green compact obtained by compression molding a powder material to form a molded body separately for each powder material. It is bonded with an adhesive composed of molecules.

[0004]

However, the method for joining the compacts obtained by the above-mentioned powder metallurgy method is as follows.
Since the green compact is molded for each powder material, a die and a punch are required for each powder material, resulting in high manufacturing cost. Moreover, since the reliability of strength is low by either of the methods of diffusion bonding and adhesion, it cannot be used as a mechanical part as it is. Therefore, for example, in a rotor for a motor, in which a magnet made of powder is bonded around a yoke made of powder, it is necessary to attach a cover made of glass fiber reinforced plastic or the like to the outer periphery to improve reliability. However, it is preferable that the air gap between the rotor and the stator of the motor is small in terms of performance. On the other hand, since such a cover is interposed between the magnet and the stator, the performance of the motor is deteriorated.

Further, the motor rotor is made of neodymium which is excellent in residual magnetic flux density, coercive force, maximum energy product, etc.
An iron / boron magnet (Nd-Fe-B based magnet) is used, but the magnetic force of the Nd-Fe-B based magnet is weakened by heat. Therefore, a method of sintering at high temperature for a long time like diffusion bonding is used. Should be avoided as much as possible.

Furthermore, an eddy current is generated in the magnet of the motor rotor during use, and the temperature of the magnet rises due to this current, but the yoke removes this heat to cool the magnet. However, when the yoke and the magnet are bonded with the adhesive, the heat conductivity of the adhesive is poor, so that it was not possible to efficiently transfer heat to the yoke to cool the magnet. Also,
Even when the yoke and the magnet are joined by diffusion joining, it is not possible to eliminate the error in the shape of matching the yoke and the magnet, and the adhesion is not good, so heat transfer from the magnet to the yoke is not sufficiently efficient. I couldn't say it. When the temperature of the magnet rises, the magnetic force in that state also decreases, and since the magnetic force decreases even after repeated heat cycles, it is possible to quickly cool the heat generated by the magnet in order to increase the efficiency of the motor. Is desirable.

In view of the above problems, the present invention has been made. The present invention provides a molded body made of a plurality of dissimilar materials, which is low in cost, highly reliable, and excellent in magnetic properties. It is intended to provide a manufacturing method.

[0008]

In order to solve the above-mentioned problems, according to claim 1 of the present invention, in a method of manufacturing a molded body by powder metallurgy, a partition plate is arranged inside a die for molding the molded body. By dividing the inside of the die into a plurality of molding parts by supplying a first powder material to a first molding part formed on one side of the partition plate, and a second molding part formed on the other side of the partition plate. To the second powder material, and after removing the partition plate, the first and second powder materials are compression molded by a punch to obtain a green compact, and the green compact is sintered to form a compact. It is characterized by obtaining.

According to such a manufacturing method, some particles enter from one of the first powder material and the second powder material to the other when the partition plate is removed. Then, when the particles that have been compressed and formed by the punch are brought into pressure contact with one of the powder materials, a structure in which the first powder material and the second powder material mesh with each other is formed. Therefore, by sintering this green compact, it is possible to obtain a compact in which the first and second powder materials are firmly adhered and joined. Moreover, since only one mold is required, the manufacturing cost of the molded body can be reduced.

Further, in the method for producing a compact by powder metallurgy according to claim 1, a magnetic powder material is used for at least one of the first and second powder materials, and compression molding is performed while applying a magnetic field during compression molding by the punch. You can also do it.

According to such a method for producing a compact, since the magnetic powder material is used as at least one of the first powder material and the second powder material, the compact having a magnetic force following the magnetic field during compression molding. Can be obtained.

Further, in the method for producing this molded article,
When an Nd-Fe-B based magnet is used as the magnetic powder material, a joined body of the Nd-Fe-B based magnet and another member can be molded without using diffusion bonding. Therefore, Nd-F
A molded product can be manufactured while keeping the magnetic force of the e-B magnet high.

Further, the invention of claim 4 is characterized in that one of the first and second powder materials has an average particle size of 0.15 times or less the average particle size of the other. In this way, by setting the average particle size of one of the first and second powder materials to be 0.15 times the average particle size of the other or less, even if the larger particles are arranged in a close-packed structure, the gap You can get inside. Therefore, a small particle powder material
As it penetrates into the powder material of large particles and forms an undercut, the first and second powder materials mesh with each other,
It is firmly joined.

Further, in the above-mentioned method for producing a molded body by powder metallurgy, after the partition plate is removed, before the compression molding of the first and second powder materials by the punch, the first and second powder materials are formed. It is desirable to perform the step of applying vibration to the powder material. By giving vibration in this way,
The powder material mixes in between the second powder materials, ensuring that the first,
Since the second powder material can be intermeshed, the first,
The second powder material is firmly bonded to each other.

Further, in the above-described method for producing a molded body by powder metallurgy, the partition plate is bent so that one of the first and second powder materials enters into the other and one has an undercut cross section. It can also have a cross section.

According to such a manufacturing method, as described above,
In addition to the meshing (undercut portion) of the first and second powder materials at the particle level, one of the first and second powder materials can be meshed in a macro shape with an undercut cross section. The first and second powder materials are firmly bonded. Of course, not only one of the powder materials but also the first and second powder materials may both have an undercut cross section, and may have a shape in which they enter into each other's material.

Further, in claim 7 of the present invention, the first molding part formed by compression molding of the first powder material and the second molding part formed by compression molding of the second powder material are joined and integrally formed. In the joint structure of the formed powder compact, the first,
One of the second powder materials is characterized in that one powder material penetrates between the particles of the other powder material to form an undercut portion.

According to such a joined structure of the powder compacts, one of the first and second powder materials comes into the space between the particles of the other powder material to form the undercut portion. Since the first and second powder materials are intermeshed with each other, they are firmly joined.

According to claim 8 of the present invention, a rotor for a motor molded by using the method for manufacturing a molded body by powder metallurgy according to any one of claims 2 to 6, A ring-shaped yoke is formed using iron-based metal powder as the first powder material, a magnetic powder material is used as the second powder material, and a magnet portion is formed around the yoke.

According to such a rotor for a motor, since the yoke and the magnet can be integrally formed by one die, not only the manufacturing cost can be reduced but also the first and second powder materials can be obtained. Because it is firmly joined,
It is not necessary to fix the outer circumference with a cover or the like, and it is possible to reduce the air gap between the rotor and the stator to provide a rotor that prioritizes motor performance. Also, since the close contact between the yoke and the magnet is good, the heat generated in the magnet can be efficiently transmitted to the yoke to cool the magnet, and in addition, the lines of magnetic force can be efficiently passed. It is also possible to maintain a high magnetic force and increase the efficiency of the motor.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. In the present embodiment, a motor rotor provided with a permanent magnet will be described as an example of a molded body manufactured by using the manufacturing method of the present invention. In the drawings to be referred to, FIG. 1 is a perspective view showing an example of a rotor for a motor.

As shown in FIG. 1, a motor rotor 1 manufactured by the manufacturing method according to the present embodiment has a plurality of (see FIG. 1) around an outer periphery of a ring-shaped yoke 2 containing iron (Fe) as a main component. 8) Neodymium / Iron / Boron (Nd-Fe)
-B) The magnet portions 3 made of a system magnet are joined at equal intervals. The motor rotor 1 is integrally combined with an output shaft (not shown) and is used as a so-called brushless motor rotor.

[Mold 10] FIG. 2 is a cross-sectional view of a mold used in the method of manufacturing the motor rotor of this embodiment, which is a cross section corresponding to line 2-2 of the motor rotor of FIG. ,
(A) a step of supplying a powder material, (b) a step of removing a partition plate, (c) a step of compression molding with a punch,
(D) shows a mold release process.

As shown in FIG. 2 (a), the mold 10 used in this embodiment is a die 11 having a molding portion 40 consisting of a hole having a contour shape in plan view of the motor rotor 1,
A punch corresponding to the contour of the forming unit 40,
0 from the lower side, the lower punch 12 slidable with respect to the molding portion 40, and the upper punch 13 having a contour corresponding to the contour of the molding portion 40 and compressing the powder raw material from the upper portion of the molding portion 40.
(See FIG. 2C). Also, the molding unit 40
Is partitioned by a partition plate 15 into a first molding portion 41 for molding the yoke 2 and a second molding portion 42 for molding each magnet portion 3. The second molding portion 42 is formed at eight locations according to the magnet portion 3. The partition plate 15 is the lower punch 1
It can slide up and down with respect to 2 and retracts into the lower punch 12,
Alternatively, it is configured to be able to advance into the molding unit 40. It should be noted that the partition plate 15 is not configured to be retracted into the lower punch 12 but is formed by, for example, forming a paper piece in a ring shape corresponding to the outer periphery of the yoke 2 and removing it to the upper part of the molding unit 40 after supplying the powder material. May be.

[Powder Material] In this embodiment, an iron-based powder material is used as the first powder material 20 forming the yoke 2, and Nd is used as the second powder material 30 forming the magnet portion 3.
A magnetic powder of a —Fe—B magnet is used. As the magnetic material, it is also possible to use a powder material such as a ferrite magnet or an alnico magnet.

Here, it is desirable that the average particle size of one of the first powder material 20 and the second powder material 30 is not more than 0.15 times the average particle size of the other. This will be described with reference to FIG. FIG. 3 is a diagram schematically showing the arrangement of particles at the interface between the first powder material and the second powder material before compression molding. In FIG. 3, large particles 20
a represents the first powder material 20, and the small particles 30 a represent the second powder material 30. Of course, the actual particles are not spherical, but they are shown in an ideal state in FIG.
When the particles 20a of the first powder material are packed in the closest packed state before compression molding, they are arranged in the same manner as a face-centered cubic lattice or a hexagonal close-packed lattice. Are arranged so that the particles 20a are located at the lattice points of the lattice formed of equilateral triangles as shown in FIG. The largest particle that can enter the gap between the particles 20a in this arrangement is the particle 3
It is shown in FIG. 3 as 0a, and its radius is a. Here, assuming that the radius of the particle 30a is A, geometrically a =
It can be seen that there is a relationship of 0.1547A. Therefore, if the particle size (= 2a) of the particle 30a is 0.15 times or less the particle size (= 2A) of the particle 20a, the particle 30
The particles a can pass through the interstices of the particles 20a at the interface where a is arranged in the closest packed state and enter the interstices of the particles 20a in the first powder material 20.

In the present embodiment, as an example, the average particle size of the first powder material 20 is 70 μm (particle size distribution 40 to 100 μm).
m) and the average particle size of the second powder material 30 is 2 μm (particle size distribution 1 to 3 μm). The magnetic powder material is
It is preferable to use a material having a particle size as small as possible because the magnetic flux density can be improved.

[Manufacturing Method] Next, the mold 10 as described above is manufactured.
A method of manufacturing the motor rotor 1 by using will be described. First, as shown in FIG. 2A, the molding part 40 is divided into a first molding part 41 and a second molding part 42 in a state where the partition plate 15 is advanced into the molding part 40. And
The first powder material 20 is supplied to the first molding part 41, and the second powder material 30 is supplied to the second molding part 42.

Next, as shown in FIG. 2B, the partition plate 1
By lowering 5 into the lower punch 12, it is retracted and removed from the molding section 40, and the first powder material 20 and the second powder material 3 are removed.
Contact with 0. FIG. 4 schematically shows the cross section of the interface between the first powder material 20 and the second powder material at this time. 4 corresponds to a cross section taken along line 4-4 of FIG. 3, and the particles 30a of the second powder material 30 are sufficiently small, and the particle shape is omitted. The upper half of the second powder material 3 in FIG.
0 passes through the minimum gap of the particle 20a and enters the inside of the tetrahedral gap 21a of the particle 20a. Further, it also enters inside a larger gap 21b adjacent to the tetrahedral gap 21a. That is, the particles 30a are the particles 20
Since the minimum gap of a can also pass through, it can further penetrate into the inside of the first powder material 20, spread with a gap wider than the minimum gap, and have an undercut cross section. When the particles in the tetrahedron gaps 21a and 21b here are compression molded and sintered, they become undercut portions.

It is desirable that the surface of the partition plate 15 on the side where the powder material having a large particle size enters, that is, the surface on the side of the first powder material 20 is made slightly rougher than the other surface. The surface roughness at this time is set so that the larger particles are caught. In this way, when the partition plate 15 is removed, the particles 20a roll and the small particles easily enter between the large particles, so that an undercut cross section is easily formed, and the two materials can be more firmly joined. .

Next, as shown in FIG. 2 (c), the inside of the first powder material 20 (yoke 2) is N filled with an electromagnet, for example.
A magnetic field is applied so that the pole and the outside of the second powder material 30 (magnet portion 3) become the S pole, and in this state, the upper punch 13 is pushed in from above to separate the first powder material 20 and the second powder material 30. Compress and mold. By compression molding, the undercut cross section of the first powder material 30 that has entered between the particles 20a of the second powder material 20 is pressed and solidified, and the first powder material 20 and the second powder material 30 are meshed and firmly joined together. .

After the partition plate 15 is removed, before the first and second powder materials 20 and 30 are compression-molded by the upper punch 13, it is preferable to apply vibration to the first and second powder materials 20 and 30. desirable. By applying the vibration in this way, the particles 20a, 30 are generated at the interface between the first and second powder materials 20, 30.
Since a moves and the particles 30a easily enter between the particles 20a, more undercut portions can be formed and the bonding between the two becomes stronger. In addition, as a method of giving vibration, mechanical vibration is given to the mold 10 itself,
It is possible to use a method of producing a sound of a frequency at which these powders are easy to move toward the second powder material 20, 30.

Next, as shown in FIG. 2 (d), the upper punch 13 is raised and the lower punch 12 is further raised to push up the green compact 1'and release it from the die 11.
This green compact 1'is, for example, 1000
The rotor 1 for a motor can be obtained by sintering at 1 ° C. for 1 hour.

In the motor rotor 1 (molded body) obtained by the above-described manufacturing method, the second powder material 30 enters between the particles 20a of the first powder material 20 in the state of the green compact 1 '. Since it has an undercut cross section, the second powder material 30 still has an undercut cross section even after sintering, and the first and second powder materials 20 and 30 mesh with each other and are firmly joined. As a result, the reliability at high temperature and high speed is high, and the cover for pressing down the magnet portion 3 is not required. Therefore, the air gap between the magnet portion 3 and the stator of the motor can be minimized and high efficiency can be achieved. Motor can be configured.

Further, since both are contacted in the form of powder and compression-molded, the adhesion is good and the heat from the magnet portion 3 to the yoke 2 is better than the conventional method of compression-molding and then diffusion-bonding. Good conduction. Therefore, the motor rotor 1 of the present embodiment, when used as a motor component, can quickly transfer the heat generated in the magnet portion 3 to the yoke 2 and prevent the temperature of the magnet portion 3 from rising. A decrease in magnetic force can be prevented, and a highly efficient motor can be obtained. Furthermore, because of the good adhesion between the yoke 2 and the magnet portion 3,
Since the magnetic lines of force of the magnet portion 3 are efficiently passed through the yoke 2, it is possible to construct a highly efficient motor by efficiently utilizing the magnet portion 3. Further, according to the method for manufacturing the molded body of the present embodiment, the magnet part 3 and the yoke 2 are simultaneously compression-molded, so that only one mold is required and the molded body can be manufactured at low cost.

Next, another example of the partition plate 15 will be described. FIG. 5 is a perspective view of a die and a partition plate for explaining another example of the partition plate. In FIG. 5, a partition plate 55 is installed in the die 50 to partition the inside of the die 50 into two parts. After supplying the first powder material 51 to one side and the second powder material 52 to the other side, the partition plate 55 is The removed state is shown. The partition plate 55 is a plate bent so as to have a dovetail-shaped cross section, and after the first and second powder materials 51 and 52 are supplied, the partition plate 55 is removed along the direction of the groove to provide the first and second powder materials. Powder material 5
1, 52 can have a dovetail-shaped cross section. That is,
The second powder material 52 is allowed to enter between the particles of the first powder material 51 at a particle level to form an undercut cross section, and at the same time, the second powder material 52 is allowed to enter the first powder material 51 even in a macro shape. It can be formed to have an undercut cross section. As a result, this partition plate 55
The joined body made by supplying the powder material by using can more firmly join the two powder materials. The cross section of the partition plate 55 is not limited to the dovetail groove type, and may have any shape as long as it has a cross section that extends from one powder material side into the other side, for example, an Ω shape. It may be a cross section. Further, in the partition plate 55, a plurality of bent portions having an undercut cross section may be repeatedly provided.

[0037]

EXAMPLES Next, examples of joining two powder materials by using the method for producing a molded body by powder metallurgy of the present invention will be described. In the figures to be referred to, FIG. 6A is a cross-sectional view of a mold for molding a molded body sample, and FIG.
It is a perspective view of a compact sample. First, length 7mm, width 1
Using a die 60 having a 5 mm rectangular cross-section forming part,
A partition plate (not shown) is installed at the center of this lateral direction, and the die 6
The inside of No. 0 was divided into two molding parts. The average particle size is 70 μm (particle size distribution 40 to 100 μm) in one molding part.
1 g of the iron-based first powder material 65 is supplied, and Nd-Fe having an average particle size of 2 μm (particle size distribution of 1 to 3 μm) is supplied to the other molding part
2g of 2nd powder materials 66 which consist of -B type magnets were supplied.

Then, the partition plate was removed, sandwiched by the lower punch 61 and the upper punch 62 while applying a magnetic field in a magnetic field molding machine, and compression molded at a pressure of 29.4 MPa.
This green compact is taken out and placed in a vacuum firing furnace at 1050 ° C.
Sintering was performed for 2.5 hours to obtain a molded body sample 67 in which iron and an Nd-Fe-B magnet were joined.

An EDS analyzer (energy dispersive X-ray spectroscopic analyzer: OXFORD MODEL6
886) equipped with a scanning electron microscope (JSM-6320F manufactured by JEOL Ltd.), and elemental analysis was performed on a line crossing the interface. The operating conditions of the SEM were an accelerating voltage of 20 kV, a current of 1 × 10 ⁻⁷ A and a WD (working distance) of 15 mm, and the characteristic X-rays detected by the EDS analyzer were Fe emission lines, Kα emission lines, and Nd emission lines. Detected the Lα1 emission line.

The results are shown in FIG. FIG. 7A is an SEM image of the observed molded body, and FIG. 7B is a diagram showing the characteristic X-ray intensity analyzed by the EDS analyzer. Figure 7
In (a), the left side is Fe and the right side is an Nd-Fe-B system magnet, and in this field of view, the result of elemental analysis of the surface across the interface (along the horizontal straight line in the figure) is Figure 7
It is (b). In FIG. 7B, the horizontal axis represents the scanning direction corresponding to FIG. 7A, and the vertical axis represents the intensity of the characteristic X-ray. As can be seen from FIG. 7B, the Kα emission line of Fe is strong on the left side and sharply weak on the right side of the interface.
The Lα1 bright line of d is strong on the right side and sharply weakens on the left side of the interface. From this, it is considered that no diffusion to the opposite phase has occurred at the interface, and it is understood that the two powder materials are geometrically meshed and joined at the interface.

The results of a three-point bending bending test performed on the molded sample will be described. 3
The point bending bending test was performed based on JIS R1601 "Bending strength test method for fine ceramics".

FIG. 8 (a) is a diagram showing the breaking stress of the molded body sample in comparison with the breaking stress of the Nd-Fe-B system magnet and the Fe powder molded body, and FIG. 2 is an SEM image near the fracture surface of the molded body sample of FIG. In addition, Nd-F
The e-B magnet and the Fe powder compact were obtained by compression molding and sintering under the same conditions using the same material as that used in the compact sample (Example). The conditions of the three-point bending bending test are also the same. As shown in FIG. 8A, the fracture stress of the molded sample (Example) is about 60 N.
/ Mm ² , for Nd-Fe-B system magnet, about 90 N / m
The m ² and Fe powder compacts were about 260 N / mm ² . That is, the fracture stress of the molded sample is Nd-Fe-B.
It was found that it was close enough to that of the system magnet and was strongly bonded. Further, in FIG. 8B, Fe is seen on the left side and an Nd-Fe-B system magnet is seen on the right side, but the fracture surface is Nd-F.
It is located in the base material of the e-B system magnet and contains Fe and Nd-F.
It can be seen that the interface (bonding surface) of the e-B magnet is not broken. From this, too, it was found that the two powder materials were strongly bonded by the present invention. Note that FIG. 8 (b)
As shown in FIG. 5, it was also possible to observe the state in which the Nd-Fe-B based magnet entered between Fe particles.

[0043]

As described in detail above, the present invention has the following remarkable effects. According to the method for producing a molded body according to the first aspect, it is possible to obtain a molded body in which the first and second powder materials are firmly adhered and joined. Moreover, since only one mold is required, the manufacturing cost of the molded body can be reduced.

Further, according to the method for producing a molded body according to claim 2, since the magnetic powder material is used for at least one of the first powder material and the second powder material, the magnetic force following the magnetic field during compression molding is used. It is possible to obtain a molded product having

Further, according to the manufacturing method of claim 3, N
A molded product can be manufactured while keeping the magnetic force of the d-Fe-B magnet high.

Further, according to the manufacturing method of the fourth aspect, the powder material of the small particles easily enters the powder material of the large particles, and the two powder materials are more firmly bonded.

According to the manufacturing method of claim 5,
Due to the vibration, the powder material mixes between the first and second powder materials, and the two powder materials are firmly joined.

Further, according to the manufacturing method of the sixth aspect, the two materials can be meshed with each other even in a macro shape, and the two powder materials can be more firmly bonded.

According to the joint structure of the powder compact of claim 7, one of the first and second powder materials is intercalated between the particles of the other powder material to form an undercut portion. And the first and second powder materials mesh with each other, so that they are firmly joined.

According to the motor rotor of the eighth aspect, it is possible to construct a high-efficiency motor at low cost.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a motor rotor.

FIG. 2 is a cross-sectional view of a mold used in the method for manufacturing a motor rotor according to the embodiment, showing the motor rotor of FIG.
It is a cross section corresponding to a line cross section, (a) shows a step of supplying a powder material, (b) shows a step of removing a partition plate, (c) shows a step of compression molding with a punch, and (d) shows a releasing step. .

FIG. 3 is a diagram schematically showing the arrangement of particles at the interface where the first powder material and the second powder material contact each other before compression molding.

4 is a diagram schematically showing a cross section of an interface between the first powder material and the second powder material, which corresponds to a cross section taken along line 4-4 of FIG.

FIG. 5 is a perspective view of a die and a partition plate for explaining another example of the partition plate.

FIG. 6A is a cross-sectional view of a mold for molding a molded body sample, and FIG. 6B is a perspective view of the molded body sample.

FIG. 7 (a) is an SE of a molded body sample according to an example.
It is a M image, (b) is a figure which shows the characteristic X-ray intensity analyzed with the EDS analyzer.

FIG. 8 (a) shows the fracture stress of the molded sample as Nd.
It is a figure shown in comparison with a fracture stress of a -Fe-B system magnet and a Fe powder compact, and (b) is an SEM image near the fracture surface of the compact sample after fracture.

[Explanation of symbols]

1 Motor rotor 1'compacted powder 10 mold 11 die 12 Lower punch 13 Upper punch 15 dividers 20 First powder material 30 Second powder material 40 Molding part 41 First Forming Section 42 Second molding part

─────────────────────────────────────────────────── ─── Continued Front Page (51) Int.Cl. ⁷ Identification Code FI Theme Coat (Reference) B22F 3/035 B22F 3/035 C 5/08 5/08 7/00 7/00 Z 7/04 7 / 04 AF term (reference) 4K018 AA24 AA27 BA13 BA18 BB04 CA04 CA05 CA14 CA17 DA11 HA02 HA04 JA03 KA32

Claims (8)

[Claims] 1. A partition plate is arranged inside a die for molding a molded body to partition the inside of the die into a plurality of molding parts, and a first molding part formed on one side of the partition plate Supply the powder material, supply the second powder material to the second molding portion formed on the other side of the partition plate, remove the partition plate, and then compression-mold the first and second powder materials with a punch. To obtain a green compact, and to sinter the green compact to obtain a green body. A method for producing a green body by powder metallurgy. 2. The powder metallurgical molding according to claim 1, wherein a magnetic powder material is used as at least one of the first and second powder materials, and compression molding is performed while applying a magnetic field during compression molding by the punch. Body manufacturing method. 3. The method for producing a compact by powder metallurgy according to claim 2, wherein the magnetic powder material is an Nd—Fe—B system magnet. 4. The average particle size of one of the first and second powder materials is 0.15 times or less the average particle size of the other, and any one of claims 1 to 3 is characterized. 2. A method for producing a molded body by powder metallurgy according to Item 1. 5. A step of applying vibration to the first and second powder materials after removing the partition plate and before compression-molding the first and second powder materials with the punch. The method for producing a molded body by powder metallurgy according to claim 1, wherein 6. The partition plate has a bent cross section so that one of the first and second powder materials enters the other and one has an undercut cross section. The manufacturing method of the molded object by the powder metallurgy according to claim 5. 7. A powder molded body integrally formed by joining a first molded part formed by compression molding of a first powder material and a second molded part formed by compression molding of a second powder material, One of the first and second powder materials, one of the powder materials penetrates between particles of the other powder material to form an undercut portion, which is a joined structure for a powder compact. 8. A rotor for a motor molded using the method for manufacturing a molded body by powder metallurgy according to claim 2, wherein the first powder material is iron-based. A rotor for a motor, wherein a ring-shaped yoke is formed using metal powder, a magnetic powder material is used as the second powder material, and a magnet portion is formed around the yoke.