| 摘要 |
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. |
| 主权项 |
1. In a brushless DC motor comprising a stator and a rotor and a central shaft, the stator comprising electrical conductor windings connectable to a source of electrical power and substantially surrounding and being coaxial with the rotor and the central shaft; the rotor being rotatably, coaxially disposed relative to the stator and separated from the stator by a radial gap along its length; the rotor comprising a plurality of permanent bar magnets, having a substantially rectangular cross-section, equally spaced circumferentially around the rotor and extending radially inwardly from the outer circumference and axially the full length of the rotor, the bar magnets having a north-south polarity transverse to the axis of the rotor; the rotor further comprising an equal number of wedge-shaped permanent magnets, each being located circumferentially intermediate and adjacent to each of the bar magnets and also circumferentially equidistantly located about the rotor and extend inwardly to the rotor shaft, and wherein the wedge-shaped permanent magnets extend longitudinally along the axis of the rotor and have a north-south polarity extending circumferentially and transverse to the north-south polarity of the ceramic bar magnets; the bar magnets and the wedge-shaped permanent magnets and central rotor shaft are locked together so as to rotate when the stator windings are energized by a source of electrical power. |
