Patent ID: 7645349

Claim:
A method for producing a radially anisotropic sintered R—Fe—B permanent magnet wherein R is at least one of rare earth elements including Y, comprising the steps of (a) pulverizing a rare earth magnet material to fine powder, and recovering said fine powder directly in a mineral oil, a synthetic oil or their mixture to form a slurry, (b) injecting said slurry under pressure into a ring-shaped die cavity between a hollow cylindrical die member and a solid cylindrical core, in which said slurry is wet-molded in a radially oriented magnetic field, (c) heating the resultant ring-shaped green body under reduced pressure to remove said mineral oil, said synthetic oil or their mixture from said green body, and (d) sintering said green body, which has said mineral oil, said synthetic oil, or their mixture removed, in vacuum, wherein said slurry is injected into said ring-shaped die cavity through an aperture open at an inner surface of said hollow cylindrical die member at an angle θ of 5° to 90°, wherein θ is an angle (right or acute angle) between a center axis of said aperture and a line AO, wherein A is a point at which the center axis of said aperture intersects the inner surface of said hollow cylindrical die member, and O is a center point of said solid cylindrical core.