Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2005-06-20
2009-12-01
Le, Dang D (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S156450, C310S156470
Reexamination Certificate
active
07626300
ABSTRACT:
In a radially anisotropic sintered magnet of annular shape, the remanence in a radial direction of the annulus increases and decreases at intervals of 90° in a circumferential direction of the annulus, and the remanence in a radial direction over the entire circumference of the annulus has a maximum of 0.95-1.60 T and a minimum equal to 50-95% of the maximum. In a permanent magnet motor comprising a plurality of stator teeth, the radially anisotropic annular sintered magnet is incorporated after it is magnetized in 4n poles (wherein n is an integer of 1 to 20) so that the boundary between N and S poles is located within the range that is centered at the radial direction where the remanence exhibits the minimum and extends ±10° therefrom in a circumferential direction. The radially anisotropic annular sintered magnet undergoes neither fracture nor cracking during the sintering and aging/cooling steps even when it is shaped to a low inner/outer diameter ratio and has satisfactory magnetic properties. A permanent magnet motor comprising the radially anisotropic annular sintered magnet is inexpensive and of high performance.
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Minowa Takehisa
Sato Koji
Le Dang D
Shin-Etsu Chemical Co. , Ltd.
Westerman Hattori Daniels & Adrian LLP
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