Patent ID: 7524453

Claim:
An apparatus for manufacturing a ring-shaped powder compact, said apparatus comprising: a ring-shaped die formed by combining a plurality of arch-shaped members; a core placed inside a curved inner surface of the die; and pressurizing parts for pressurizing both the die and magnetic powder filled into a cavity formed between the die and the core in an axial direction of the die; wherein the curved inner surface of the die is corrugated with hollows and protrusions alternately formed at regular intervals in a circumferential direction, the hollows and the protrusions formed on the corrugated curved inner surface of the die being skewed about a central axis thereof, a curved outer surface of each of the pressurizing parts is corrugated with hollows and protrusions which run along the hollows and the protrusions formed on the corrugated curved inner surface of the die, and wherein at least one of the pressurizing parts is moved along the axial direction to compress the magnetic powder during a magnetic powder compression process, during which the pressurizing parts are rotated about the central axis by as much as a skew angle of the hollows and the protrusions formed on the curved inner surface of the die in synchronism with movement of said at least one of the pressurizing parts along the axial direction.