JPS59119702A - Manufacture of sintered magnet - Google Patents

Abstract

PURPOSE:To obtain a rare-earth group cobalt magnet which has large flux density all along the circumference by a method wherein, when magnetic powder is pressed and formed with a magnetic field application, an annular compression chamber, which contains a magnetic core whose circumference is covered with a non-magnetic substance at its center, is filled with a magnetic powder and the powder is compressed and formed while a magnetic field is applied to the direction perpendicular to that of the compression. CONSTITUTION:A mold 12, in which a core 13 is placed at the center, is filled with a magnetic powder 11 such as samarium-cobalt and the powder 11 is compressed and formed by an upper punch 14 and a lower punch 15. A magnetic field, produced by coils 17 provided to both ends of a base 16 which holds the mold 12, is applied to the powder 11 to the direction perpendicular to the direction of the compression. In this constitution, the mold 12 and the punches 14 and 15 are made of a non-magnetic material and the core 13 is composed of a rod-shape magnetic material 13a placed at the center and a cylindrical non-magnetic material 13b surrounding the rod 13a. Thus, magnetic lines of force are once bent at the part of the core 13 and then returned to the original condition so that the length of magnetic lines of force is expanded and large flux density all along the circumference is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a sintered magnet formed by press-molding magnetic powder at °C in a specific magnetic field.

[Technical background of the invention and its problems]

Anisotropic magnets, which are made by press-forming magnetic powder made of crystalline anisotropic materials such as ferrite or rare earth cobalt alloys in a specific magnetic field and firing if necessary, are widely used in electrical equipment.

As this kind of anisotropic magnet, there is one having a magnetization direction M perpendicular to the length direction, such as an annular magnet I shown in FIG.

In the case of press forming in the manufacturing process of this right-angle type magnet having magnetic anisotropy, magnetic powder 4 is filled inside a mold 2 in which a core 3 is arranged as shown in FIG. While forming a magnetic field (@magnetic field) in the direction of the arrow perpendicular to the press direction, the magnetic powder 4 is pressed with a punch 6°7 to impart magnetic anisotropy to the compact.

Conventionally, the mold 2, core 3, and bunches e and y1 used in the press rectangle are all made of non-magnetic material in order to improve the continuous explosion of magnetic lines of force. As shown in FIG. 3, the lines of magnetic force of the magnetic field generated by the coil 5 all pass in parallel to the magnetic powder 4 (cross section fO of the compact) of the two circles of the mold.

However, when all the lines of magnetic force pass through the magnetic powder 4 in parallel like this, the length of the lines of magnetic force passing through the part between the center line parallel to the line of magnetic force of the powder 4 and the center line perpendicular to it is small, and therefore The degree of insult given to this part is other b
There is a problem that it is smaller than the IS portion. This phenomenon becomes a problem in rare earth cobalt magnets with particularly large BI(max).

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing a sintered magnet that produces an annular magnet that can provide a large magnetic flux density throughout the circumferential direction during press molding. It is something.

[Purpose of the invention]

In the method for manufacturing a sintered magnet of the present invention, when press-molding magnetic powder while applying a magnetic field, a core having a magnetic material is placed in the center of an annular pressurizing chamber, and a magnetic material is placed inside the pressurizing chamber. It is characterized by filling powder and press-molding it while applying a magnetic field perpendicular to the pressing direction. Preferably, a core is used in which a magnetic material is provided in the center and a non-magnetic material is provided around the magnetic material.

[Embodiments of the invention]

The present invention will be described below with reference to embodiments shown in the drawings. The magnet manufactured by the present invention is an annular magnet having a magnetic field direction perpendicular to the longitudinal diagram, as shown in FIG.

In FIG. 4, magnetic powder II such as samarium cobalt is placed in the center of the core I in the same manner as explained in the conventional example above.
The magnetic powder zz'4 is filled into the inside of the mold I2 in which the magnetic powder zz'4 is placed and press-molded by an upper punch I4 and a lower bunch I5. Coil Z7 provided at both ends of bake I6 that holds mold I2. Z7 causes the magnetic powder Z inside the mold I2 to
In the Z-press press direction, a magnetic field is applied in a direction perpendicular to the press-forming direction, and two press-forming operations are performed to form a compact.

Here, in the mold used for this press molding, mold I
2 is made of non-magnetic material, and has an upper bunch I4 and a lower bunch I5.
is also made of non-magnetic material. The core I3 is arranged in the center inside the mold I2, with the lower bunch I4 passing through L and -c. As shown in FIGS. 4 and 5, this core z3 includes a rod-shaped magnetic material 13a provided at the center and a cylindrical non-magnetic material z provided surrounding the magnetic material 13a.
It is constructed by integrally combining sb. Note that examples of non-magnetic materials include copper alloys, and examples of magnetic materials include iron alloys.

In this press molding, since the core Z3 is provided with the magnetic material 13a, the lines of magnetic force pass through the magnetic powder II inside the mold I2, as shown in FIG. That is, in the cross section C of the magnetic powder IJC molded body, in the part between the center line parallel to the magnetic force line and the center line perpendicular to the magnetic force line, the magnetic force line flows from the outside toward the magnetic body 13a of the core I3 toward the magnetic powder Z1. It enters obliquely, further passes through the magnetic body rsa of the core 13, and then diagonally passes through the magnetic powder II and exits to the outside. For this reason, the length of the magnetic lines of force passing through the central portion of the magnetic powder ZI becomes larger than in the conventional case shown in Fig. S3, and the magnetic flux density applied to this portion also becomes larger than in the conventional case. Since the lines of magnetic force pass through the magnetic powder II so as to converge on the core I3, it is possible to mold a compact having a large magnetic flux density over the entire circumferential direction by press molding. In addition, the core Z3 has a non-magnetic material Z around the magnetic material 13m.
3b is provided and the molding conditions are almost the same as in the past.

Then, the molded body is manufactured by sintering and solidifying the molded body as necessary, and then applying a magnetic field again and performing a magnetic validation.

Note that the core used during press molding in the manufacturing method of the present invention is not limited to the above-mentioned embodiments, but may be one whose entire core is made of a magnetic material.

Alternatively, it is also possible to use one in which a magnetic material is provided on the outer periphery and a non-magnetic material is provided in the center.

〔Effect of the invention〕

As explained above, the method for producing a sintered magnet of the present invention can produce a magnet having a large magnetic flux density and a magnetic anisotropy throughout the entire magnet, and is particularly effective for rare earth cobalt magnets.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an annular magnet having magnetic anisotropy, FIG. 2 is a vertical cross-sectional view showing conventional press forming of a sintered magnet, FIG. A vertical cross-sectional view showing Example 2 of press forming in a method for manufacturing a sintered magnet,
FIG. 5 is a plan view of the same. I...Magnet, 2...Mold, 3...Core, 4...
Powder, 5... Coil, 6.7... Punch, II...
・Powder, I2... Mold, I3... Core, 13a...
・Magnetic material, 13b... Non-magnetic material, I4... Upper punch % I5... Lower bunch, I6... Base, 17...
·coil. Applicant's Attorney Takehiko Suzue Figure 1 Figure 2 Figure 3 et al. Figure 4 Patent Officer Kazuo Wakasugi 1. Indication of the case Japanese Patent Application No. 57-226722 2 Name of the invention Method for manufacturing sintered magnets 3 Person making the amendment Relationship to the case Patent applicant (307) Tokyo Shibaura Electric Co., Ltd. 4 Agent 1988 3 June 29th, 2016, Amendment 7, Contents of the amendment (1) In the title of the invention column of the specification, "Method for manufacturing a sintered magnet" is corrected to "Method for manufacturing a sintered magnet" .

Claims (1)

[Claims] α) When press-molding magnetic powder while applying a magnetic field, a core having a magnetic material is placed in the center of an annular pressurizing chamber, and the magnetic powder is placed inside the pressurizing chamber. 1. A method for producing a sintered magnet, which comprises filling and press-forming the magnet while applying a magnetic field in a direction perpendicular to the Brenu pressure direction. (2) A method for manufacturing a sintered magnet according to claim 1, in which the core is provided with a magnetic material at the center and a non-magnetic material at the outer periphery. (3) Sintered magnet The method for manufacturing a sintered magnet according to claim 1, wherein is a rare earth cobalt magnet.