JPH06116606A - Isostatic pressing machine provided with magnetic field generator - Google Patents

Abstract

PURPOSE:To provide an isostatic pressing machine provided with a magnetic field generator for compacting an isotropic magnetic material with the magnetic characteristic improved without enlarging the magnetic field generator. CONSTITUTION:A high-pressure vessel consists of a high-pressure cylinder 5 of a nonmagnetic material and the upper and lower lids 3 and 4 furnished with a magnetic pole. An anisotropic magnetic powder 7 sealed in a rubber die 6 is placed in the high-pressure vessel. The high-pressure vessel is put in a yoke 1, a high magnetic field is generated in the lids 3 and 4, and the powder is densely compacted by a pressure medium 8. Since the powder 7 is densely compacted while impressing a parallel magnetic field, the powder is compacted into an isotropic magnetic material with the magnetic characteristic improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an isotropic hydrostatic molding machine with a magnetic field generator, and more particularly to an isotropic hydrostatic molding machine with a magnetic field generator suitable for powder molding of anisotropic magnet powder. It is a thing.

[0002]

2. Description of the Related Art Conventionally, powder molding of anisotropic magnet powder has been carried out by attaching a magnetic field generator to a dry molding machine (mechanical press machine).

FIG. 5 is a sectional view of a molding portion for explaining a conventional dry molding machine.

In the figure, 50 is an upper punch, 51 is a lower punch, and 52 is a cylindrical metal mold having substantially the same diameter as the punches 50 and 51. 53 is powder, for example, anisotropic magnet powder. Arrows A and B indicate the directions of pressure exerted by the upper punch 50 and the lower punch 51 on the powder 53, respectively. Reference numeral 54 denotes a coil of the magnetic field generator, and the outer diameter of the coil 54 is set to be 2 to 3 times the diameter of the powder 53.

[0005] Using the dry molding machine, in the case of powder molding, first, the powder 53 is charged into the mold 52, pressure 1 cm ² per 0.5 to upper and lower punches 50 and 51.
The powder 53 is molded by applying a pressure of about 5 tons. At this time, the powder 53, which is anisotropic magnet powder, is directed in the same direction by the magnetic field generated from the coil 54. Therefore, the powder 53 is formed into an isotropic magnetic material.

Next, the upper and lower punches 50 and 51 are opened, and the molded powder 53 (isotropic magnetic material) is taken out.
Next, the magnetism in the mold 52 is demagnetized for the next molding.

[0007]

Conventionally, as described above, the powder molding of anisotropic magnet powder has been carried out by mounting a magnetic field generator around the mold of the dry molding machine. Therefore, the pressure can be applied only from the vertical direction, and it is difficult to produce a high-quality uniform high-density molded body.

Further, since the magnetism is applied from the outside of the mold to form the magnetic field, the magnetic field is not perfectly parallel within the plane of the powder 53, and the magnetic orientation of the material is good in some parts. There was a problem of decrease.

After the anisotropic magnet powder has been molded, the mold is demagnetized. However, demagnetization is not sufficiently carried out, and magnetism remains in the mold to some extent. Therefore, the powder adheres to the edge and the inner wall surface of the mold under the influence of the residual magnetism, and the powder cannot be sufficiently charged into the mold.

In dry molding of powder, it was difficult to increase the density of the powder because the pressing force was limited to a low pressure of 0.5 to 1.5 ton / cm ² .

In order to manufacture a large isotropic magnetic material,
A large dry molding machine equipped with a magnetic field generator that maintains a high magnetic field is required, but it is unrealistic because it is expensive. There is also a problem that the magnetic field generator becomes larger as the dry molding machine becomes larger.

An object of the present invention is to eliminate the above-mentioned problems of the prior art and to form an isotropic magnetic material having improved magnetic characteristics without increasing the size of the device, and an isotropic hydrostatic molding machine with a magnetic field generator. To provide.

[0013]

In order to achieve the above-mentioned object, the present invention is an isotropic hydrostatic molding machine with a magnetic field generator used for powder molding of anisotropic magnet powder, in which a pressure medium is injected. And a pressure vessel to be discharged, a high magnetic field generator arranged on at least one of an upper surface and a lower surface of the pressure vessel, and a yoke arranged outside the pressure vessel and forming a magnetic path between the upper surface and the lower surface. It is characterized in that it is equipped with.

[0014]

According to the present invention, the anisotropic magnet powder is isotropically hydrostatically molded in a high magnetic field, so that the apparatus can be downsized and
It is possible to mold a high quality uniform and high density isotropic magnetic material.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to FIGS.

FIG. 1 is a sectional view for explaining an isotropic hydrostatic molding machine with a magnetic generator according to a first embodiment of the present invention.

In the figure, 1 is a yoke made of a magnetic material and having a U-shaped cross section, and 2 is a non-magnetic material yoke lid which covers the open portion of the yoke 1. Reference numeral 3 is an upper lid provided with magnetic poles, and reference numeral 3a is a discharge pipe which is connected to a discharge valve (not shown) and discharges a pressure medium 8 described later. Further, 4 is a lower lid provided with magnetic poles, and 4a is an injection pipe for connecting a one-way valve (not shown) to inject a pressure medium 8 described later. The magnetic poles provided on the upper and lower lids 3 and 4 are preferably composed of electromagnets.

Further, 5 is a high-pressure cylinder made of a non-magnetic material, and 6 is, for example, a rectangular parallelepiped or cubic rubber mold. Reference numeral 7 is a powder enclosed in the rubber mold 6. Here, the powder 7 is an object to be molded such as anisotropic magnet powder and becomes an isotropic magnetic material after molding. Reference numeral 8 denotes a pressure medium (hereinafter, pressure medium) which is injected through the injection pipe 4a and applies a pressure to the bag-shaped rubber mold 6. Here, the pressure medium 8 is composed of water or lubricating oil, a liquid containing an anticorrosive agent in them, or the like. 9 is
The pressure exerted by the pressure medium 8 on the isotropic magnetic material in the rubber mold 6.

2 and 3 are cross-sectional views of a specific example of the upper and lower lids 3 and 4, respectively.

2 and 3, 31 and 41 are both magnetic poles, 32 and 42 are upper and lower lid frames made of non-magnetic material, and 3
Reference numerals 3 and 43 are coils.

The isotropic hydrostatic molding machine is known as a wet method (rubber press) for a pressure molding machine, and a description thereof will be omitted.

Next, the operation of molding the powder 7 placed in the rubber mold 6 using the isotropic hydrostatic molding machine of this embodiment will be described.

First, the lower lid 4 is attached to the lower part of the high-pressure cylinder 5, and a rubber mold 6 in which powder 7 is enclosed is put therein. At this time, one surface of the rubber mold 6 is held so as to be perpendicular to the direction of the magnetic field. Next, the upper lid 3 is mounted, and the rubber mold 6 is sealed in the central portion of the high pressure cylinder 5.

The upper and lower lids 3 and 4 and the high-pressure cylinder 5 which are integrated together constitute a pressure vessel. The pressure vessel is mounted inside the yoke 1. At this time, the yoke 1 fixes the upper and lower lids 3 and 4 and the high-pressure cylinder 5. Next, the yoke lid 2 is closed and mounted on the pressurizing device or the depressurizing device of the isotropic hydrostatic molding machine.

Next, the pressure medium 8 is injected into the high-pressure cylinder 5 through the injection pipe 4a connected to a one-way valve (not shown), and the pressure 9 is increased up to about 6 tons per cm ^2. . Isotropic pressure is applied to the rubber mold 6, and the pressure of the conventional dry molding machine (pressing force, 0.5 to 1.5 per cm ^{2) is used.}
Since a pressure 9 higher than about 10 tons) is applied, the powder 7 is uniformly and densely formed. At this time, the upper and lower coils 33, 43
Since a current is supplied from a power source (not shown), a parallel magnetic field is formed between the upper and lower magnetic poles 31 and 41 provided on the upper and lower lids 3 and 4. As a result, the powder 7 is uniformly oriented in the vertical direction and is molded into a high-density isotropic magnetic material.

When the isotropic magnetic material is molded, the pressure medium 8 is discharged from the discharge pipe 3a connected to a discharge valve (not shown), the yoke lid 2 is opened, and the pressure container is taken out from the yoke 1. Next, the rubber mold 6 was removed from the pressure vessel taken out.
Further, a molded body of the isotropic magnetic material, which is the molded powder 7, is taken out.

Thereafter, the isotropic magnetic material is subjected to a treatment such as heat sintering by an apparatus (not shown) to complete the process.

The discharge valve and the one-way valve may be attached to the upper and lower lids 3 and 4, or may be attached to the main body of the isotropic hydrostatic molding machine with the magnetic generator. Is.

The lower lid 4 may be fixed to the high-pressure cylinder 5 in advance, and only the upper lid 3 may be detachable.

Next, a second embodiment of the present invention will be described with reference to FIG.

In the figure, 20 is a product frame held inside the high-pressure cylinder 5 by a holding means (not shown). Here, the product frame 20 is, for example, a net-like basket or jig made of a non-magnetic material that can easily mount and fix a rubber mold or an object to be molded at a suitable position. The reference numerals in the figure indicate the same or equivalent parts as those in FIG.

In this embodiment, the product frame 20 held inside the high-pressure cylinder 5 to which the lower lid 4 is attached.
Then, the rubber mold 6 in which the powder 7 is enclosed is fixed. Next, the high pressure cylinder 5 is covered with the upper cover 3.

After that, the same operation as in the first embodiment is performed, and the powder 7 is high-density molded with the magnetic field evenly oriented in the vertical direction. As a result, the powder 7 is formed into an isotropic magnetic material.

In each of the above embodiments, the upper and lower magnetic poles 3
Coil 3 for generating a parallel magnetic field between 1 and 41
3 and 43 are provided, but since there is the yoke 1 made of a magnetic material, it is possible to generate a magnetic field between the magnetic poles 31 and 41 if either coil is provided. Therefore, the coil may be one of the upper lid 3 and the lower lid 4.

In each of the above embodiments, the anisotropic magnet powder was used as the powder, but other powder may be used as long as it is a magnetic material.

Although the powder 7 is enclosed in the rubber mold 6, instead of this, the powder 7 is preformed and then put into a bag such as rubber or plastic, and the air in the bag is evacuated. Of course, a sealed product may be used.

By doing so, it becomes possible to separately carry out pre-molding during the main molding, which was conventionally required for molding time and immediate waiting time, and the molding efficiency is 30.
Improve about%.

Further, in this embodiment, since the powder 7 is put into the rubber mold 6, the mold 52 of the conventional apparatus is not necessary. Therefore, the demagnetization work of the mold 52 is not necessary, and the maintenance becomes easy.

[0039]

As is apparent from the above description, according to the present invention, the following effects can be expected.

(1) Since isotropic hydrostatic molding is carried out in the state where a parallel magnetic field is applied, anisotropic magnet powder can be sufficiently oriented in the same direction and high density molding can be performed. Therefore, the magnetic properties after sintering are improved by about 10 to 20%.

(2) Since a high magnetic field can be generated without increasing the size of the magnetic field generator, it is possible to mold a larger object to be molded than before.

(3) Since the pressure vessel is provided with a holding means capable of holding the rubber mold and the object to be molded, even an inexperienced operator can hold the rubber mold and the object to be molded into the pressure vessel. It can be easily fixed in a suitable position inside.

[Brief description of drawings]

FIG. 1 is a sectional view of an isotropic hydrostatic molding machine according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of an upper lid provided with magnetic poles.

FIG. 3 is a sectional view of a lower lid provided with magnetic poles.

FIG. 4 is a sectional view of an isotropic hydrostatic molding machine according to a second embodiment.

FIG. 5 is a sectional view of a molding portion of a conventional dry molding machine.

[Explanation of symbols]

1 ... Yoke 2 ... Yoke lid 3 ... Top lid 3a ... Discharge pipe,
4 ... Lower lid, 4a ... Injection tube, 5 ... High-pressure cylinder, 6 ... Rubber mold,
7 ... Powder, 8 ... Pressure medium, 9 ... Pressure, 20 ... Product frame, 31 ...
Magnetic pole, 32 ... Upper lid frame, 33 ... Coil, 41 ... Magnetic pole, 42 ... Lower lid frame, 43 ... Coil, 50 ... Upper punch, 51 ... Lower punch, 52 ... Mold, 53 ... Powder, 54 ...
coil

Claims (3)

[Claims] 1. An isotropic hydrostatic molding machine with a magnetic field generator used for powder molding of anisotropic magnet powder, comprising: a pressure vessel into which a pressure medium is injected and discharged; and an upper surface and a lower surface of the pressure vessel. An isotropic hydrostatic pressure device with a magnetic field generator, comprising: a high magnetic field generating means arranged in at least one side; and a yoke arranged outside the pressure vessel and forming a magnetic path between the upper surface and the lower surface. Molding machine. 2. The isotropic hydrostatic molding machine with a magnetic field generator according to claim 1, wherein at least one of an upper surface and a lower surface of the pressure vessel is constituted by a lid, and the high magnetic field generation means is provided on the lid. An isotropic hydrostatic molding machine with a magnetic field generator, which is characterized in that 3. The isotropic hydrostatic molding machine with a magnetic field generator according to claim 1, further comprising: a holding means capable of holding a rubber mold or an object to be molded inside the pressure vessel. Isotropic hydrostatic molding machine with device.