Sumitomo Special Metals Co., Ltd.

Neomax Co., Ltd.

Shinji Kidowaki

Seiichi Kohara

Katsumi Okayama

Tsutomu Harada

Akihito Tsujimoto

Tadayoshi Muneto

An apparatus for subjecting a rare earth alloy block to a hydrogenation process includes a casing, gas inlet and outlet ports, a member arranged to produce a gaseous flow, and a windbreak plate. The casing defines an inner space for receiving a container. The container includes an upper opening and stores the rare earth alloy block therein. A hydrogen gas and an inert gas are introduced into the inner space through the gas inlet port, and are exhausted from the inner space through the gas outlet port. The gaseous flow is produced by a fan, for example, in the inner space. The windbreak plate is disposed upstream with respect to the gaseous flow that has been produced inside the inner space. Also, the windbreak plate reduces a flow rate of the gaseous flow that has been produced near the upper opening of the container.

Apparatus for subjecting rare earth alloy to hydrogenation process and method for producing rare earth sintered magnet using the apparatus

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.

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Osaka, Japan

Shinji Kidowaki