Multipolar rotor
First Claim
1. A magnetic object having a plurality of pole regions of small dimensions, wherein the object is adapted to be molded in a molding device by being subjected to a magnetic field and temperature changes, gravity, mechanical forces or combinations thereof, the object comprising:
- a body of given shape which includes alternating spaced north and south pole regions, leaving interspace in interpolar regions, the distance between adjacent interspace defining a pole-pitch, said pole-pitch being less than 2 mm, wherein said body comprises;
a plurality of coarse grains of a fully magnetized anisotropic permanent magnet material, said grains being produced from a permanent magnet having an intrinsic coercive force of more than 5,000 Oersted by grinding the magnet until all grains have a size which is smaller than the pole-pitch, wherein in the pole regions at least those grains having a size smaller than but of the same range of size as the pole-pitch are aligned and distributed in accordance with a multipolar field pattern of said magnetic field; and
a hardening binding agent which is mixed with said grains before being inserted in the molding device to form the magnetic object.
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Abstract
A magnetic object having a plurality of pole regions of small dimensions and adapted to be molded in a molding device. The object includes a body of a given shape, for instance a cylindrical block or a cylindrical sleeve having an outer diameter smaller than 5 mm, and including alternating north and south poles. The body is made of a mixture of grains of fully magnetized anisotropic permanent magnet material and a hardening binding agent. The grains are reduced from a permanent magnet until all grains are smaller than the smallest dimension of a pole region and in the pole regions at least those grains having a size of the same range of size as the smallest dimension of a pole region are distributed in accordance with the alternating north and south poles.
27 Citations
11 Claims
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1. A magnetic object having a plurality of pole regions of small dimensions, wherein the object is adapted to be molded in a molding device by being subjected to a magnetic field and temperature changes, gravity, mechanical forces or combinations thereof, the object comprising:
a body of given shape which includes alternating spaced north and south pole regions, leaving interspace in interpolar regions, the distance between adjacent interspace defining a pole-pitch, said pole-pitch being less than 2 mm, wherein said body comprises; a plurality of coarse grains of a fully magnetized anisotropic permanent magnet material, said grains being produced from a permanent magnet having an intrinsic coercive force of more than 5,000 Oersted by grinding the magnet until all grains have a size which is smaller than the pole-pitch, wherein in the pole regions at least those grains having a size smaller than but of the same range of size as the pole-pitch are aligned and distributed in accordance with a multipolar field pattern of said magnetic field; and a hardening binding agent which is mixed with said grains before being inserted in the molding device to form the magnetic object. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A magnetic object having a plurality of poles, wherein the object is adapted to be molded in a molding device by being subjected to magnetic forces, temperature changes, gravity, mechanical forces or combinations of these forces, the object comprising:
a body having a circular outer periphery, and wherein said body includes a plurality of adjacent alternating spaced north and south pole regions leaving interspace in interpolar regions, the distance between adjacent interspace defining a pole-pitch, said pole-pitch being less than 2 mm, said body comprising; a plurality of grains of a fully magnetized anisotropic permanently magnetic material, said grains being produced from a permanent magnet having an intrinsic coercive force of more than 5,000 Oersted by grinding the magnet into grains until all grains have a long dimension which is smaller than the pole-pitch having a filling factor of 50-80 percent and wherein in the pole regions at least those grains having to a long dimension which is smaller than but of the same range of size as the pole-pitch are located adjacent the alternating north and south pole regions; and a hardening binding agent which is mixed with said grains before the grains are inserted in the molding device to form the magnetic object.
Specification