JP2001355006A - Composite structural body, manufacturing method thereof, and motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite structural body formed of a magnetic material such as a rotor, a stator and a magnet-embedded die in which the strength and the heat resistance are excellent, and a metal container is not deformed during the hot isostatic pressing. SOLUTION: A high strength part is formed by using a material and the thickness difficult to deform against the pressure during the hot isostatic pressing, and a low strength part is formed by using a material and the thickness easy to deform against the pressure. The powder is filled in the metal container and the container is sealed, and placed in the atmosphere of the hot temperature and the high pressure. Since a weak portion is deformed by the pressure, the deformation of a strong portion against the pressure, i.e., the part of the preset high strength requiring the accuracy and the shape is reduced. The metal container is integrated with the powder filled inside with excellent adhesion, and the magnet structural body more excellent in strength, heat resistance and complicated shape than a conventional one can be provided. In addition, the metal container is not deformed, and easily machined after the pressing, and the productivity thereof becomes considerably improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention 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.

[0002]

2. Description of the Related Art In a motor using a magnet, a magnet and a yoke or a magnet and a part for fixing the magnet are incorporated as a rotor or a stator.

[0003] The use of a magnet and a yoke in a motor is for more effective use of magnetism. Recently, in order to further increase the energy efficiency of the motor, a yoke having a complicated shape such as a magnet-embedded magnet rotor has been used. Has been devised.

[0004] In a magnet buried type magnet rotor, a gap is provided for the magnet to enter the yoke, and the magnet is inserted into the yoke and fixed by adhesion. In order to cope with a more complicated shape, magnet magnetic powder and resin are mixed. For example, a method of inserting a material having fluidity and then curing the material (JP-A-11-215746) has been studied.

As a method of obtaining the strength of such a 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 (WO98 / 2005).
31497).

[0006]

Generally, in assembling such a composite structure, an adhesive is often used for fixing the magnet and the yoke, and there is a problem in reliability such as strength and heat resistance. Also, in the magnet embedded type, high strength and heat resistance cannot be obtained because an adhesive and a resin are used.

In the above-mentioned hot isostatic pressing, since a sintered magnet is put in a metal container, a complicated shape cannot be obtained, or when a magnet is inserted into the metal container, a gap is formed.
When the gap is eliminated by hot isostatic pressing, there arises a problem that the metal container may be deformed.

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 is capable of forming a metal when hot isostatic pressing. It is an object of the present invention to provide a composite structure having a configuration in which a container is not deformed, a method of manufacturing the same, and a motor.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted various studies on the structure and processing conditions of the container for the purpose of not deforming the metal container during hot isostatic pressing. The required portion is made of a high-strength portion as a material or thickness that is not easily deformed by pressure during hot isostatic pressing, and a low-strength portion is set as a material or thickness that is easily deformed by the pressure. And sealed in a powder, placed in a predetermined high-temperature and high-pressure atmosphere, the pressure-sensitive portion is deformed, the pressure-resistant portion, that is, the high strength portion of the preset high accuracy and shape is required. The inventors have found that by reducing the deformation, the metal container and the powder loaded therein can be integrally molded with good adhesion, and the object can be achieved, and the present invention has been completed.

[0010] That is, the present invention provides a metal container having a high-strength portion that is hardly deformed by a required pressure and a low-strength portion that can be deformed; A composite structure comprising the container and an integrated powder compact.

[0011] Further, according to the present invention, there is provided 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 made of the same material but different in thickness. The powder of the composite structure is a magnetic powder or a magnetic powder containing a non-magnetic powder is added, the powder before molding is a composite structure containing a powder having a different melting point, the magnetic powder is a Nd-Fe-B system Magnet powder, Sm-Co magnet powder, Pr-Fe
-A composite structure that is at least one of B-based magnet powder, exchange spring magnet powder, alnico magnet powder, and ferrite magnet powder is also proposed.

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

[0013] Further, the present invention provides a 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 hydrostatic molding conditions are a temperature of 600 ° C. or more and 1000 ° C. or less and a pressure of 1 MPa to 200 MPa.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides a metal container with a portion which is strong against hot isostatic pressing pressure and a portion which is weak with respect to hot isostatic pressing.
In a high-pressure atmosphere, a portion that is weak to pressure is deformed, so that a portion that is strong to pressure is less deformed, and the metal container and the powder are integrally formed with good adhesion.

FIG. 1 is a cross-sectional view of a metal container showing a process according to the present invention. A metal container 1 shown in FIG. This is a configuration in which the powder loaded inside is sealed. 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.

[0016] For example, the powder 5 is loaded into the container main body 2 in contact with the lower disk lid 3, and the upper disk lid 4 is placed thereon, and the inside of the metal container 1 is evacuated as shown in FIG. 1A. After sealing.

Next, the metal container 1 is placed in a hot isostatic device,
When gas is used as a pressure medium and the temperature and pressure are increased, the portion weak to the pressure of the metal container 1, that is, the disk lids 3 and 4 are deformed (crushed) by the gas pressure, thereby the portion strong to the pressure of the metal container 1, That is, the powder is compressed in the container body 2 and the temperature is further increased, so that the sintering of the sample powder proceeds, and at the same time, the metal container 1 and the sample powder are integrally formed to be in a state as shown in FIG. 1B.

Further, an integrally molded metal container 1 shown in FIG. 1B
By slicing the upper and lower parts, a composite structure 6 in which the cylindrical metal material shown in FIG. 1C and the powder inside are integrally formed is formed.

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 at a required pressure. Further, when the same metal material is used, it is possible to deform only a required portion with respect to the pressure by making the thickness of the disk lids 3 and 4 smaller than the thickness of the container body 2.

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 is manufactured. It is possible to

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

When magnetic parts used for motors and the like are made, Nd-Fe-B magnet powder, Sm-Co magnet powder, Pr-Fe-B magnet powder, and Each powder such as a spring magnet powder, an alnico magnet powder, and a ferrite magnet powder can be used.

In addition to magnetic powders, various metal alloys (T) are used to achieve a combination of strength and heat conduction, corrosion resistance and functionality.
i, Co, Cu, permalloy), various ceramics (PZT, barium titanate) and the like can be used as a container and powder to be inserted into the container.

In addition, when non-magnetic and high electric resistance powders such as SiO ₂ and Al ₂ O ₃ are put in the powder to be charged, heat generation due to eddy current can be avoided. These powders can be dispersed when the average particle size is small, which is advantageous for increasing electric resistance. Preferably not more than 100 μm, more preferably
It is 1 μm or less.

Further, in order to solidify the powder and enhance the adhesion to the container, 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 are added. Since the temperature and pressure of 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 configuration 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. In addition, the processing conditions are appropriately selected according to the shape and use of the product, but it is not preferable to raise the temperature and pressure more than necessary from the viewpoint of productivity.
00 ° C. and the pressure are preferably 10 MPa to 100 MPa. Further, when priority is given to improvement of magnetic properties, the temperature is preferably 500 ° C. to 900 ° C., and the pressure is preferably 10 MPa to 100 MPa.

[0027]

Example 1 As a metal container, a cylindrical container in which a tubular SUS304 and a disc-shaped copper were joined was used, and a Ne-Fe-B-based magnet powder (average particle size of 200 μm or less) was used as a loading powder. The powder was vacuum-sealed in a metal container 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 1 MPa 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. FIG.
As is clear, the density increases as the processing temperature increases, but the difference is small above 700 ° C.

Similarly, the pressure is kept constant at 50 MPa,
FIG. 3B shows the relationship between the processing temperature when hot isostatic pressing is performed at a temperature changed to 00 ° C. and the magnetic properties (residual magnetic flux density, coercive force) of the obtained powder compact. As is clear from FIG. 3B,
The residual magnetic flux density increases with increasing processing temperature,
Above 0 ° C, the difference is small. Further, the coercive force decreases as the temperature increases, but does not decrease much up to 700 ° C.

Next, the temperature was kept constant at 700 ° C., and 1 MPa to 200 MPa
Hot isostatic pressing was performed while changing the pressure until a. FIG. 4A shows the relationship between the processing pressure and the density of the obtained powder compact at this time. As is clear from FIG. 4A, the density increases as the processing pressure increases, but the difference is small at 50 MPa or more. Considering the productivity, it is not preferable to raise the temperature and pressure more than necessary.

Similarly, the temperature is kept constant at 700 ° C., and 1 MPa to 200 MPa
FIG. 4B shows the relationship between the processing pressure and the magnetic properties (residual magnetic flux density, coercive force) of the obtained powder compact when hot isostatic pressing is performed with the pressure changed to MPa. 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. The coercive force hardly changes with pressure. Therefore, when giving priority to magnetic properties, the temperature is preferably 500 ° C. to 900 ° C., and the pressure is 10 MPa to 100 MPa.
It turns out that MPa is preferable.

The circumference of the composite structure obtained under the above-mentioned hot isostatic pressing conditions was measured to confirm the presence or absence of 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 was penetrated in parallel to the axial direction to obtain a rotor as shown in FIG. 2, and Ne-Fe-B System magnet powder (average particle size 200
μm or less) was vacuum-sealed and formed using a copper plate as a lid material at both ends. The hot isostatic pressing apparatus was subjected to hot isostatic pressing 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.

[0035]

According to the present invention, a high strength portion and a low strength portion which are more easily deformed than a material and thickness which are hardly deformed by the pressure during hot isostatic pressing are set in a metal container. The deformation of the high-strength portion can be reduced by deforming the portion weak to pressure during the treatment, and the metal container and the powder can be integrally formed with good adhesion.

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

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory view of a metal container showing a process of the present invention, wherein A is a longitudinal sectional view before hot isostatic pressing, B is a longitudinal sectional view after hot isostatic pressing, and C is a sliced product. FIG.

FIG. 2 is an explanatory cross-sectional view of a rotor according to the present invention.

FIG. 3A is a graph showing a relationship between a processing temperature and a powder density in one embodiment of the present invention, and B is a graph showing a relationship between a processing pressure and a powder density.

FIG. 4A is a graph showing a relationship between a processing temperature and a powder density in one embodiment of the present invention, and B is a graph showing a relationship between a processing pressure and a powder density.

[Explanation of symbols]

 1 Metal container 2 Container body 3, 4 Disk lid 5 Powder 6 Composite structure

Claims (10)

[Claims] 1. A metal container having a high-strength portion that is not easily deformed by a required pressure and a low-strength portion that can be deformed, and a container that is loaded and sealed with powder in the container and is integrated with the container by hot isostatic pressing. A composite structure having a compacted 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 materials of the same material but 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, wherein the Nd-Fe-B magnet powder, Sm-
4. The composite structure according to claim 3, which is at least one of Co-based magnet powder, Pr-Fe-B-based magnet powder, exchange spring magnet powder, alnico magnet powder, and ferrite magnet powder. 6. A step of loading and encapsulating powder in a metal container having a high-strength part that is hardly deformed under the required pressure of hot isostatic pressing and a deformable low-strength part. A method for producing a composite structure, comprising a step of integrally molding a metal container and a powder by heating. 7. A step of loading and encapsulating powder in a metal container having a high-strength part that is hardly deformed under the required pressure of hot isostatic pressing and a deformable low-strength part. A method for producing a composite structure, comprising: a step of integrally molding a metal container and a powder by a step; and a step of processing the integrally molded article. 8. 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.
8. The method for producing a composite structure according to claim 6 or 7. 9. The hot isostatic pressing condition is 600 ° C. or more and 1000 ° C.
8. The method for producing a composite structure according to claim 6, wherein the temperature is as follows and the pressure is 1 MPa to 200 MPa. 10. A motor having the composite structure according to claim 5.