Powder compacting apparatus and method of producing a rare-earth magnet using the same

1. A powder compacting apparatus, comprising:

an airtight container capable of storing a rare-earth alloy powder therein;

an airtight feeder box movable between a powder-filling position and a retracted position; and

an airtight powder supply device adapted to supply the rare-earth alloy powder from said container into said feeder box without exposing the rare-earth alloy powder to an atmospheric air, said powder supply device including a flexible hollow portion that is connected to the feeder box and a non-flexible hollow portion;

wherein the container is detachably connected with the powder compacting apparatus.

2. The apparatus of claim 1 , further comprising means for supplying an inert gas into said powder supply device, whereby an oxygen concentration in each of said powder supply device and said feeder box during a pressing operation is controlled to be 50000 volume ppm or less.

3. The apparatus of claim 2 , further comprising at least one gas concentration sensor for sensing the oxygen concentration in said powder supply device.

4. The apparatus of claim 1 , further comprising at least one temperature sensor for sensing a temperature of the rare-earth alloy powder in the powder supply device.

5. The apparatus of claim 1 , further comprising at least one temperature sensor for sensing a temperature of the rare-earth alloy powder in said feeder box.

6. The apparatus of claim 5 , wherein:

open/close means is provided between said non-flexible hollow portion and said flexible hollow portion, wherein said open/close means is closed in response to an increase in the temperature of the rare-earth alloy powder.

7. The apparatus of claim 1 , wherein:

said flexible hollow portion can flexibly deform as the feeder box is moved.

8. The apparatus of claim 6 , wherein said non-flexible hollow portion comprises a screw feeder for moving the rare-earth alloy powder toward said flexible hollow portion at a controlled rate.

9. The powder compacting apparatus according to claim 7 , wherein said flexible hollow portion of said powder supply device is made of a two-layer hose.

10. The apparatus of claim 7 , further comprising a means for vibrating said flexible hollow portion of said powder supply device so as to facilitate passage of the rare-earth alloy powder therein.

11. The apparatus of claim 1 , wherein said powder supply device comprises a material receptacle for receiving the rare-earth alloy powder from said container; said apparatus further comprising:

a connection section between said container and said material receptacle, said connection section comprising a valve capable of closing said material receptacle.

12. The apparatus of claim 11 , wherein said container is detachably connected to said connection section.

13. The apparatus of claim 1 , wherein:

said feeder box comprises a level sensor for sensing an upper surface level of the rare-earth alloy powder in said feeder box; and

said powder supply device is adapted to supply the rare-earth alloy powder into said feeder box when an upper surface level of the rare-earth alloy powder in said feeder box has decreased below a predetermined level.

14. The apparatus of claim 1 , wherein:

an inside of a powder supply passageway of said powder supply device contains an inert gas atmosphere; and

an outside of said powder supply passageway is an air atmosphere.