JPS59104401A - Compression molding apparatus for radially oriented ring magnet - Google Patents

Abstract

PURPOSE:To enhance radial orientation property and uniformity, by a method wherein only one set of exciting coils is used and a radial magnetic flux forming space such that orientation magnetic flux of a magnetic circuit consisting of a die having said coil enclosed therein and a core rod movably fitted in upper and lower punches passes through the die from the core rod is filled with a magnet powder to perform compression molding. CONSTITUTION:An exciting coil 1 for orientation is housed and fixed in a die 7 comprising a magnetic body so as to have a shaft in a press direction and the interior of the hole provided to the inside thereof is utilized as a compression molding part in which upper and lower punches 8, 8' each comprising a non- magnetic body are arranged in a liftable manner. A core rod 9 comprising a magnetic body is fitted movably in the punches 8, 8' and a magnetic circuit, wherein orientation magnetic flux generated in the magnetic coil 9 is diffused radially to the die while bent from the core rod 9 and flowed around in the die 7 to be returned to the core rod 9, is formed. This radial magnetic flux forming space is filled with a magnet powder 4 to perform compression molding.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved apparatus for manufacturing radially oriented ring magnets in a powder magnet forming apparatus.

When forming anisotropic magnets in manufacturing equipment for powder-molded magnets such as ferrite magnets and rare earth magnets, parallel compression molding, right-angle compression molding, isostatic pressing, etc. are generally used depending on the orientation direction and compression direction of the magnet powder. However, as another special compression molding method, there is a production method in which powder is orientated radially from the center of a cylindrical magnet and compression molded.

Conventionally, the manufacturing equipment for this type of radially oriented cylindrical magnet is as follows:
As shown in Figures 1 and 2, in Figure 1, 2
The different poles of the excitation coils 1' of the set are opposed to each other, the convex punches 2 and the rotation bunches 3 are arranged in the vertical direction, and the magnetic powder 4 is filled between the 8 punches and the rotation punches, and the magnetic flux of the excitation coil is transferred to the 8 punches. There is a compression molding apparatus that obtains a radially oriented ring magnet by forming a magnetic path leading from the magnet powder to the rotary punch via the magnet powder portion, and press-molding the magnet powder while orienting it. In addition, in Fig. 2, the same poles of two sets of excitation coils 1'' are made to face each other, the die 5 is filled with magnet powder 4, and the oriented magnetic fluxes led from the upper and lower punches 6, 6'' are made to face each other, thereby making the outer periphery A compression molding device has also been proposed in which a radially oriented ring magnet is obtained by bending the magnetic powder in the direction of the ring and guiding it to the die 5, and pressing and molding the magnet powder while orienting it.However, these manufacturing devices require two sets of excitation coils. As a result, the device becomes larger and the coil excitation current consumption increases.As is clear from the drawing, the orientation magnetic flux bends or leaks within the magnet powder, resulting in the orientation direction of the powder not being uniform and deteriorating the magnetic properties. However, there was a drawback that some variations occurred.

The present invention takes this point into consideration and aims to provide a compression molding apparatus that is downsized and that improves the radial orientation and uniformity of magnet powder.

Next, the present invention will be explained with reference to the drawings. The present invention is an apparatus for manufacturing a radially oriented ring magnet using a compression molding apparatus using upper and lower punches, in which only one set of excitation coils is used, and a die containing the coil and a core rod loosely fitted in the upper and lower punches are connected to a magnetic circuit. A radially oriented cylindrical magnet or a ring magnet is manufactured by filling magnet powder into a radial magnetic flux forming space where the oriented magnetic flux passes from the core rod to the die and press-molding the magnetic powder.

Specifically, as shown in FIG. 3, the device according to the present invention includes an orienting excitation coil 1 enclosed and fixed in a die 7 made of a magnetic material so as to cover the shaft in the pressing direction, and inside a hole inside the die 7. It has a structure in which upper and lower punches 8.8'' made of non-magnetic material are arranged movably up and down as compression molded parts, and a core rod 9 made of magnetic material is loosely fitted within the punches 8.8°. , the oriented magnetic flux generated in the excitation coil l bends from the core rod 9, radially diverges to the die 7, flows around the die, and returns to the core rod 9, forming a magnetic flux circuit. By filling the space of the diverging oriented magnetic flux with magnet powder 4 and pressurizing it with upper and lower punches 8 and 8' while oriented in a magnetic field, a compact with good uniformity and radial orientation of the magnet powder can be obtained. Furthermore, the present invention can be made into a radially oriented magnet forming device by simply replacing the compression molding device with the upper and lower punches with a die containing an excitation coil and adding a core rod, resulting in a very compact structure. At the same time, the coil can be oriented by itself, which has the effect of reducing current consumption.

[Brief explanation of the drawing]

FIGS. 1 and 2 are schematic diagrams of a conventional compression molding apparatus. FIG. 3 is a schematic diagram of the compression molding apparatus of the present invention. 1.1゛・1゛ Excitation coil 2: 8 punch 3: Round punch 4: Magnet powder 5.7: Dice 6
・8: Upper bunch 6″ ・8゛: Lower punch 9: Core rod Patent applicant Namiki Precision Jewel Co., Ltd. Drawing Surface No. 1 Fig. 2 Fig. 3

Claims (1)

[Claims] In a manufacturing device that forms a ring magnet by oriented compression molding of magnet powder, a non-magnetic material is placed in a hole of a magnetic die containing an oriented excitation coil having an axis in the pressing direction. More than the body. A lower punch is arranged so that it can be raised and lowered, and a core rond made of a magnetic material is loosely fitted into the punch, and magnet powder is filled in the oriented magnetic flux space that curves and radially diverges from the core rond, and the magnetic powder is oriented while being oriented by a magnetic field. A compression molding device for radially oriented ring magnets characterized by pressure molding.