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US 9,866,093 B2Granted
Brushless DC motor with permanent magnet rotor
AssigneeTaco, Inc.
InventorsDi Wu, Vladislav Milchev Stakev, Robert F. Birkenstock, Jr.
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AssigneeTaco, Inc.
InventorsDi Wu, Vladislav Milchev Stakev, Robert F. Birkenstock, Jr.
Estimating the term…
The brushless DC motor of the present invention comprises a permanent magnet rotor rotating coaxially with and inside of the stator containing the electric windings, separated by a radial, axially extending gap. The rotor can be formed of four or more permanent, e.g., ferrite ceramic magnets, spaced substantially equidistantly circumferentially around the rotor and extending radially along the axial length of the rotor. The preferred ferrite magnets are substantially corrosion resistant, and thus durable in the wet rotor environment, in which it may be used, sufficient to withstand the effects of even hot salt water. Preferably, four of the permanent magnets are bar magnets, i.e., rectangular in cross-section, extending radially and perpendicularly to the adjacent magnets. Most preferably, the bar magnets are separated by generally wedge-shaped, or quadrant-shaped, sections of magnetic material. The permanent magnets are polarized so that the north-south flux lines extend transversely to each adjacent magnet, most preferably forming a so-called Halbach Array. This brushless DC motor is especially useful for driving wet rotor pumps, wherein the particular combination of elements forming the rotor results in a highly efficient, effective and durable motor.
A method of manufacturing the rotor for a brushless DC motor, the rotor comprising a plurality of permanent magnets surrounding a central axis, the permanent magnets being formed of anisotropic magnetic material aligned transversely to adjacent magnetic material;
A method of manufacturing the rotor for a brushless DC motor, the rotor comprising a plurality of permanent magnets surrounding a central axis, the permanent magnets being formed of anisotropic magnetic material aligned transversely to adjacent magnetic material, comprising assembling the plurality of weakly magnetized such anisotropic in the proper order to form the shape of the rotor, such that each magnet is polarized in a direction transverse to the adjacent magnets, based upon the anisotropic alignment of the crystals;
Dependencies are inferred from the claim text.