To provide an annular sintered magnet, capable of controlling the distribution of residual flux density in the axial direction and superficial flux density, by controlling the orientation of magnetic field during magnetic field formation.
The annular sintered magnet comprises a plurality of annular preforms which include radially oriented magnetic powder, and are laminated in the axial direction and bonded together by sintering. In the annular sintered magnet, when N pole and S pole are alternately formed in the rotating direction of the magnet, the deviation of influx density of the magnet surface of each annular preform in the axial direction at the center position of the rotary direction of the magnetic pole from an average value is set to be within 10%. Furthermore, the difference between maximum and minimum of the flux density of the magnet surface in the axial direction is set to be within 10% in an arbitrary annular preform.
UKAI GIICHI
NAKAHARA YUJI
| JPH11186027A | 1999-07-09 | |||
| JP2003017309A | 2003-01-17 | |||
| JP2004111944A | 2004-04-08 | |||
| JPH1055929A | 1998-02-24 |
Masuo Oiwa
Toshihide Kodama
Takenaka Ikuo
Next Patent: DRIVE CIRCUIT