Sumitomo Special Metals Co., Ltd.

Neomax Co., Ltd.

Seiichi Kohara

Shinji Kidowaki

Shuhei Okumura

Akira Nakamura

Osamu Yamashita

Tsutomu Harada

Tsunekazu Saigo

Hiroshi Hashikawa

Hirokazu Kitayama

In a rare earth metal-based alloy powder supplying apparatus, a rare earth metal-based alloy powder is supplied from a feeder box having an opening in its bottom surface into a cavity by moving the feeder box to above the cavity. The apparatus includes a bar-shaped member which is moved horizontally and in parallel in the bottom of the feeder box. A plurality of the bar-shaped members may be provided horizontally at distances. The apparatus further includes a powder replenishing device for sequentially replenishing the alloy powder into the feeder box in an amount corresponding to a decrement in amount resulting from the supplying of the alloy powder from the feeder box to the cavity, an inert gas supply device for filling an inert gas into said powder feeder box, and a plate member made of a fluorine-contained resin and mounted on the bottom surface of the feeder box. Thus, an alloy powder extremely poor in fluidity and in agitatability and liable to be inflamed can be supplied into the cavity with an extremely uniform filled density without production of agglomerates and bridges and with no fear of inflammation.

Process and apparatus for supplying rare earth metal-based alloy powder

A powder pressing apparatus comprises a die having a through hole, an upper punch and a lower punch. At least one of the upper and lower punches has a punching surface having an edge portion provided with a projection. The projection has a tip chamfered by a width not greater than 0.5 mm. The punching surface has a slope having a surface roughness Ra not greater than 1.0 &mgr;m. A rare-earth alloy powder is fed into a cavity formed in the through hole of the die. The rare-earth alloy powder in the cavity is oriented by magnetic field, and pressed by using the upper and lower punches. The upper punch and the lower punch are brought closest to each other at a minimum distance not smaller than 1.7 mm during the pressing. An obtained compact is used for manufacture of a sintered body and a voice coil motor.

Punch, powder pressing apparatus and powder pressing method

A powder pressing apparatus comprises a die formed with a plurality of cavities. None of the cavities overlap with another in the direction of pushing the compacts. The magnetic field generator includes a pair of yokes sandwiching the die. The yokes and the die have their respective upper surfaces generally in a same plane. A die lubricant is applied to the die but not to a region on which the compacts are to be slid. A rare-earth alloy powder in a feeder box is supplied into each of the cavities. The powder in the cavities is oriented, pressed, and the formed compacts and the yokes are demagnetized. The compacts are pushed and slid off the die on an anti-wear layer, by a flexible pushing member provided in a front portion of the feeder box. The compacts are sintered into rare-earth magnets, which are suitable for a coreless motor.

Powder pressing apparatus and powder pressing method

A powder pressing apparatus comprises an upper punch and a lower punch for compression of a powder in a cavity formed in a through hole of a die. A gap between a side surface of the lower punch and a side surface of the through hole of the die is sealed by a sealing member. A lubricant is supplied with a gas from a nozzle in the side surface of the lower punch to the side surface of the through hole, and the lubricant applied to the side surface of the through hole is spread by an absorbing member. The cavity is filled with the powder while the cavity is under suction by a reduced pressure provided from the nozzle in the side surface of the lower punch. During the suction, a filtering member provides filtration for the lower punch not to draw the powder in.

The purpose of this invention is to present fabrication methods and equipment for granulated powders whereby, the reaction between the R--Fe--B-type or R--Co-type rare earth containing alloy powders and the binder is controlled, the residual oxygen and carbon content of the sintered products after sintering is reduced, and whereby it is possible to obtain isotropic or anisotropic granulated powders having good powder flowability and lubrication properties when molding. After stirring a slurry of rare earth containing alloy powders formed by adding a binder consisting of water and at least one of either methyl cellulose, polyacryl amide or polyvinyl alcohol, and mixing, oriented liquid droplets are formed by applying a magnetic field to the slurry to orientate the said powder particles and spraying within the chamber of a spray dryer apparatus. By instantaneously dry solidifying these anisotropic granulated powders, it is possible to fabricate spherical granulated powders with good magnetic properties and a high flowability whereby the flowability and lubrication properties of the powder at the time of compression molding are improved, as well as improving the molding cycle and the dimensional precision of the molded product.

Fabrication methods and equipment for granulated powders

The purpose of this invention is to present fabrication methods and equipment for granulated powders whereby, the reaction between the R-Fe-B-type or R-Co-type rare earth containing alloy powders and the binder is controlled, the residual oxygen and carbon content of the sintered products after sintering is reduced, and whereby it is possible to obtain isotropic or anisotropic granulated powders having good powder flowability and lubrication properties when molding. After stirring a slurry of rare earth containing alloy powders formed by adding a binder consisting of water and at least one of either methyl cellulose, polyacryl amide or polyvinyl alcohol, and mixing, oriented liquid droplets are formed by applying a magnetic field to the slurry to orientate the said powder particles and spraying within the chamber of a spray dryer apparatus. By instantaneously dry solidifying these anisotropic granulated powders, it is possible to fabricate spherical granulated powders with good magnetic properties and a high flowability whereby the flowability and lubrication properties of the powder at the time of compression molding are improved, as well as improving the molding cycle and the dimensional precision of the molded product.

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Mishima-gun, Japan

Seiichi Kohara