| 摘要 |
PROBLEM TO BE SOLVED: To provide a ring-type sintered magnet which prevents the drop of the magnetic force of a rotor and where the mechanical processing of its bore becomes easy, and its manufacturing method. SOLUTION: Ring-shaped premolded bodies 1 of double cylindrical structure each composed of a peripheral section composed of magnetic powder for a cylindrical radially-oriented permanent magnet and an internal perimeter section composed of powder higher in permeability than that of the magnetic powder for a permanent magnet arranged inside the peripheral section are stacked axially in a plurality of stages, and the ring-shaped premolded bodies 1 stacked in a plurality of stages are sintered to complete a ring-shaped sintered magnet of double cylindrical structure which has permanent magnets 1a at the external peripheral side and a sintered metal 1b at the internal peripheral side of the permanent magnet 1a. COPYRIGHT: (C)2005,JPO&NCIPI
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