WO2001094058A1

WO2001094058A1 - Composite structural body, method of manufacturing the structural body, and motor

Info

Publication number: WO2001094058A1
Application number: PCT/JP2001/004829
Authority: WO
Inventors: Hiroyuki Okuda
Original assignee: Sumitomo Special Metals Co., Ltd.
Priority date: 2000-06-09
Filing date: 2001-06-07
Publication date: 2001-12-13
Also published as: JP2001355006A; US20040052671A1

Abstract

A composite structural body, comprising a rotor, a stator, and magnetic materials such as of magnet-buried type capable of providing excellent strength and thermal resistance and preventing a metal container from being deformed by a hot hydrostatic forming, wherein a specified part is formed of a material and formed with a thickness difficult to be deformed by a pressure at the time of hot hydrostatic forming so as to form a highly strong part and formed of a material and formed with a thickness easy to be deformed by the pressure so as to set a low strength part, and powder is put in the metal container, and the container is sealed and put in a high temperature and high pressure atmosphere, whereby, because the part weak against the pressure is deformed, the deformation of the part strong against the pressure, i.e., the preset highly strong part requiring a specified accuracy and shape is reduced, the metal container and the powder filled therein are fitted to each other and formed integrally with each other, and a magnetic structural body durable, heat resistant, and complicated more than a conventional structure can be provided and, because the metal container is not deformed, the working after forming is facilitated and the productivity is improved tremendously.

Description

Description Composite structure, manufacturing method thereof, and motor

The present invention relates to a composite structure using a magnetic material, such as a structure in which a yoke, a support member and a magnet are integrated, a method of manufacturing the same, and a motor. Background art

In a motor using a magnet, the magnet and the yoke or the magnet and the parts for fixing the magnet are incorporated as a rotor or a stator.

In addition, magnets and yokes are used in motors in order to use magnetism more effectively. Recently, in order to increase the energy efficiency of motors, more complex yokes such as magnet-embedded magnet rotors are used. It has been devised.

In a magnet rotor with embedded magnets, the magnet is inserted into the yoke with a gap, and the magnet is inserted and fixed in the yoke.To cope with complicated shapes, magnet magnetic powder and resin are mixed. A method of introducing a material having fluidity and then hardening it (JP-A-11-215746) has been studied.

As a method for obtaining the strength of the structure itself, a method of obtaining an integrally joined structure by putting a sintered magnet or the like in a metal container and performing hot isostatic pressing has been proposed (W098 / 31497).

Generally, in assembling such a composite structure, an adhesive is often used for fixing the magnet to the yoke, and there were problems in reliability such as strength and heat resistance. Also, in the magnet buried type, high strength and heat resistance cannot be obtained because the adhesive and the resin are used. In addition, in the above-mentioned hot isostatic pressing, a sintered magnet is put in a metal container, so that a complicated shape cannot be obtained, or when a magnet is inserted in a metal container, a gap is generated. Therefore, when the gap disappears, there arises a problem that the metal container may be deformed. Disclosure of the invention

An object of the present invention is to obtain a composite structure using a magnetic material such as the above-described rotor, stator, and magnet embedded type, which has excellent strength and heat resistance, and deforms a metal container during hot isostatic pressing. It is an object of the present invention to provide a composite structure having a configuration, a method for manufacturing the same, and a motor.

The inventors of the present invention have conducted various studies on the structure of the container and the processing conditions for the purpose of preventing the metal container from deforming during hot isostatic pressing. As a result, when forming the metal container, the required portions were subjected to hot isostatic pressing. A high-strength part is set as a material or thickness that is not easily deformed by the pressure at the time, and a low-strength part is set as a material or thickness that is easily deformed by the pressure. By placing in a predetermined high-temperature, high-pressure atmosphere and deforming the above-mentioned pressure-sensitive portion, the deformation of the high-pressure portion, which requires high accuracy and shape, is reduced. Accordingly, the present inventors have found that the metal container and the powder loaded therein can be integrally molded with good adhesiveness and can achieve the object, and have completed the present invention.

That is, the present invention provides a metal container having a high-strength portion that is hardly deformed under a required pressure and a low-strength portion that can be deformed, A composite structure having an integrated powder compact. Further, the present invention provides a composite structure having the above structure,

A composite structure in which the high-strength part and the low-strength part of the metal container are made of different materials, or made of the same material with different thicknesses;

The powder before molding is a composite structure which is a magnetic powder containing a magnetic powder or a non-magnetic powder.

The powder before molding is a composite structure containing powder containing different melting points,

Composite in which the magnetic powder is at least one of Nd-Fe-B magnet powder, Sm-Co magnet powder, Pr-Fe-B magnet powder, exchange spring magnet powder, alnico magnet powder, and ferrite magnet powder The structure and are also proposed.

The present invention also provides a step of loading and encapsulating powder in a metal container having a high-strength portion that is hardly deformed under the required pressure of hot isostatic pressing and a deformable low-strength portion, This is a method of manufacturing a composite structure including a step of integrally molding a metal container and a powder, or a processing step of taking out a required portion from the integrally molded product by mechanical processing such as slicing.

Further, the present invention provides the method of manufacturing a composite structure having the above structure, wherein the high-strength portion and the low-strength portion of the metal container are made of different materials or the same material having different thicknesses,

The present invention also proposes a manufacturing method in which hot isostatic pressing conditions are a temperature of 600 ° C. or more and 1000 ° C. or less and a pressure of 1 MPa to 200 MPa. Description of the drawings

FIG. 1 is an explanatory view of a metal container showing a process of the present invention, FIG. 1A is a longitudinal sectional view before hot isostatic pressing, FIG. 1B is a longitudinal sectional view after hot isostatic pressing, and FIG. It is a perspective explanatory view which shows the product which carried out the processing.

FIG. 2 is an explanatory cross-sectional view of a rotor according to the present invention. FIG. 3A is a graph showing the relationship between processing temperature and powder density in one embodiment of the present invention, and FIG. 3B is a graph showing the relationship between processing pressure and powder density.

FIG. 4A is a graph showing the relationship between processing temperature and powder density in one embodiment of the present invention, and FIG. 4B is a graph showing the relationship between processing pressure and powder density. BEST MODE FOR CARRYING OUT THE INVENTION

The present invention provides a metal container with a portion that is strong against hot isostatic pressing pressure and a portion that is weak against pressure, and deforms a portion that is weak against pressure in a predetermined high-temperature high-pressure atmosphere to reduce deformation of a portion that is strong against pressure. It is characterized in that the container and the powder are integrally molded with good adhesion.

FIG. 1 is a cross-sectional view of a metal container showing a process according to the present invention. The metal container 1 shown in FIG. 1A is provided in a cylindrical container body 2 with disk lids 3 and 4 provided at upper and lower ends thereof, and is loaded into the body 2. This is a configuration that seals all powder. Here, the disk lids 3 and 4 are configured to be deformable with respect to a required pressure in hot isostatic pressing, and the container body 2 is configured to withstand the pressure.

For example, the powder 5 is loaded into the container body 2 in contact with the lower disk cover 3, and the upper disk cover 4 is placed thereon, and the inside of the metal container 1 is evacuated and sealed as shown in FIG.1A. . Next, the metal container 1 is put into a hot isostatic device, and when the temperature and pressure are increased using gas as a pressure medium, the parts weak to the pressure of the metal container 1, that is, the disk lids 3 and 4 are deformed by the gas pressure. (Crush), thereby compressing the powder inside the metal container 1, that is, the powder inside the container body 2. By further increasing the temperature, the sintering of the sample powder proceeds and at the same time, the metal container 1 and the sample powder Are integrally molded to obtain a state as shown in FIG. 1B.

Further, by slicing the upper and lower parts of the integrally molded metal container 1 shown in FIG. 1B, a composite structure 6 in which the cylindrical metal material and the powder inside thereof shown in FIG. 1C are integrally molded is formed. You. For example, when iron is used for the container body 2, different materials such as aluminum and copper can be used for the disk lids 3 and 4 in order to form a portion that can be deformed by a required pressure. When the same metal material is used, by reducing the thickness of the disk lids 3 and 4 to be smaller than the thickness of the container body 2, it is possible to deform only a required portion with respect to the pressure.

According to the present invention, the magnet and the yoke having various complicated shapes can be integrally formed by the above-described mechanism at the time of hot isostatic pressing. For example, a magnet embedded type rotor as shown in FIG. 2 of the embodiment can be manufactured. It is possible.

In the present invention, for the metal container, for example, a material having high magnetic permeability such as iron used as a yoke or permalloy can be used.

When making magnetic parts used for motors, etc., the powder to be charged into the metal container is Nd-Fe-B magnet powder, Sm-Co magnet powder, Pr-Fe-B magnet powder, replacement spring magnet powder. , Alnico magnet powder, ferrite magnet powder and the like can be used.

In addition to magnetic powders, various metal alloys (Ti, Co, Cu, Permalloy), various ceramics (PZT, barium titanate), etc., are used to achieve a combination of strength, heat conduction, corrosion resistance, and functionality. It can be used as powder to import into it.

Further, in the powder loading, the putting high powder electrical resistance with a non-magnetic, such as Si0 _{_2,} A1 ₂ 0 _3, it is possible to avoid heat generation due to eddy currents. The smaller the average particle size of these powders, the more they can be dispersed, which is advantageous for increasing electric resistance. It is preferably at most ΙΟΟμιη, more preferably at most Ιμπι.

Furthermore, in order to solidify the powder and improve the adhesion to the container, heat is added by adding a material having a different melting point from the powder, for example, a low-melting glass such as borosilicate glass and a low-melting metal such as Zn, Pb, and Sn. Since the temperature and pressure during hot isostatic pressing can be reduced, deformation of the metal container and deterioration of the inserted powder can be suppressed. In the present invention, any known structure can be adopted for the hot isostatic pressing method and apparatus, and it may be appropriately selected according to the container to be selected and the shape and application of the powder or product. The processing conditions are appropriately selected according to the shape and application of the product, but it is not preferable to raise the temperature and pressure more than necessary from the viewpoint of productivity.The temperature is 600 ° C to 900 ° C and the pressure is Is preferably 10 MPa to 100 MPa. Furthermore, when priority is given to improving magnetic properties, the temperature is preferably 500 to 900 ° C, and the pressure is preferably 10 to 100 MPa. Example

Example 1

As the metal container, use a cylindrical container made of tubular SUS304 and disc-shaped copper, and use Ne-Fe-B-based magnet powder (average particle size of 200μπι or less) as the loading powder, and place it in the metal container. The powder was vacuum-sealed at a degree of vacuum of 8 Pa. The hot isostatic pressing apparatus performed hot isostatic pressing under various conditions at a temperature of 300 ° C. to 1000 ° C. and a pressure of lMPa to 200 MPa using argon gas as a pressure medium.

The pressure was kept constant at 50 MPa, and the temperature was changed from 300 ° C to 1000 ° C to perform hot isostatic pressing. FIG. 3A shows the relationship between the processing temperature and the density of the obtained powder compact at this time. As is evident from Fig. 3A, the density increases as the processing temperature increases, but the difference is small above 700 ° C.

Similarly, at a constant pressure of 50 MPa, changing the temperature from 300 ° C to 1000 ° C, the processing temperature during hot isostatic pressing and the magnetic properties (residual magnetic flux density, Fig. 3B shows the relationship with (magnetic force). As is evident from Fig. 3B, the residual magnetic flux density increases as the processing temperature increases, but the difference is small above 700 ° C. In addition, the coercive force decreases as the temperature increases, but does not decrease until 700 ° C.

Next, the temperature was kept constant at 700 ° C., and the pressure was changed from 1 MPa to 200 MPa to perform hot isostatic pressing. The relationship between the processing pressure at this time and the density of the obtained powder compact was See Figure 4A. As is evident from Fig. 4A, the density increases as the processing pressure increases, but the difference is small at 50MPa and above. Considering productivity, it is not desirable to raise the temperature-pressure too much.

Similarly, when the temperature is kept constant at 700 ° C and the pressure is changed from lMPa to 200MPa, the processing pressure and the magnetic properties (residual magnetic flux density, Fig. 4B shows the relationship with (magnetic force). As is clear from FIG. 4B, the residual magnetic flux density increases as the processing pressure increases, but the difference is small at 50 MPa or more. Also, the coercive force hardly changes with pressure. Therefore, when giving priority to the magnetic characteristics, it is understood that the temperature is preferably 500 ° C to 900 ° C, and the pressure is preferably 10 MPa to 100 MPa.

In addition, the circumference of the composite structure obtained under the hot isostatic pressing conditions was measured to determine whether or not there was any deformation. However, no deformation was observed in the circumference of any of the composite structures.

Example 2

Using a cylindrical iron material as a metal container, a rectangular hole is pierced in parallel with the axial direction to obtain a rotor as shown in Fig. 2, and Ne-Fe-B-based magnet powder (average (Particle size: 200μπι or less) was vacuum-sealed and formed using a copper plate as a lid material at both ends. In the hot isostatic pressing apparatus, hot isostatic pressing was performed at a temperature of 800 ° C. and a pressure of 100 MPa using argon gas as a pressure medium.

It was found that the obtained rotor did not deform even at a temperature of 300 ° C. Furthermore, when this was used for a motor, it was found that it was excellent in heat resistance and strength. Industrial applicability

According to the present invention, the metal container is provided with a high-strength portion as a material or thickness that is not easily deformed by the pressure during hot isostatic pressing, and a low-strength portion that is more easily deformed. The deformation of the high strength part can be reduced by deforming the weak part, and the metal container and the powder can be integrally molded with good adhesion.

Therefore, according to the present invention, it is possible to provide a magnet element having strength, heat resistance, and a complicated shape as compared with the conventional composite structure. Furthermore, since the metal container is not deformed, processing after molding is simplified, and there is an advantage that productivity is dramatically improved.

Claims

The scope of the claims

1. A metal container having a high-strength part that is not easily deformed under the required pressure and a low-strength part that can be deformed, and the container is filled with powder and sealed in the container, and is integrated with the container by hot isostatic pressing And a powder compact.

2. The composite structure according to claim 1, wherein the high-strength portion and the low-strength portion of the metal container are made of different materials, or made of the same material but of different thicknesses.

3. The composite structure according to claim 1, wherein the powder is a magnetic powder containing a magnetic powder or a non-magnetic powder.

4. The composite structure according to claim 1, wherein the powder further contains powders having different melting points.

5. The magnetic powder is at least one of Nd-Fe-B magnet powder, Sm-Co magnet powder, Pr-Fe-B magnet powder, exchange spring magnet powder, alnico magnet powder, and ferrite magnet powder. The composite structure according to claim 3.

6. The process of loading and encapsulating the powder in a metal container having a high strength part and a deformable low strength part that is difficult to deform under the required pressure of hot isostatic pressing, by hot isostatic pressing A method for producing a composite structure, comprising a step of integrally molding a metal container and powder.

7. The process of loading and encapsulating powder in a metal container having a high-strength part that is hardly deformed by the required pressure of hot isostatic pressing and a low-strength part that can be deformed. And a powder, and a method of manufacturing a composite structure including a step of processing an integrally molded product.

8. The method for manufacturing a composite structure according to claim 6, wherein the high-strength portion and the low-strength portion of the metal container are made of different materials or materials having the same thickness but different thicknesses.

9. When the hot isostatic pressing condition is between 600 ° C and 1000 ° C

The method for producing a composite structure according to claim 6, wherein the pressure is 1 MPa to 200 MPa.

10. A motor having the composite structure according to claim 5.