Two-phase brushless motor

Claim 2

A two-phase brushless motor, comprising: a rotor having at least a pair of uniformly magnetized main regions and at least a pair of uniformly magnetized sub-regions, wherein ratios of the widths of said magnetized main regions to the widths of said magnetized sub-regions are two to one and wherein said magnetized main regions are adjacent one another and said magnetized sub-regions are adjacent one another; a stator positioned in opposed relation to said rotor and having at least two pairs of two coils connected in series for producing respective phases of magnetic fields, wherein said two coils in each of said pair of coils are spaced from each other by an electrical angle of 360° electrical; a sensor mounted in a fixed position relative to said stator and positioned opposite an outer part of said rotor; and outer magnetized regions of said rotor disposed opposite said sensor and arranged for sequential sensing by said sensor, said outer magnetized regions including oppositely magnetized regions having relative widths of a ratio of one to one, a portion of ones of said outer regions overlapping said magnetized sub-regions on said rotor.

Claim 3

A two-phase brushless motor, comprising: a stator having at least two pairs of series connected coils for producing two respective phases of a magnetic field; a rotor rotationally mounted opposite said stator to provide a torque output, said rotor having at least a pair of first magnetic poles and at least a pair of second respectively oppositely magnetized magnetic poles, a width of said first magnetic poles to a width of said second magnetic poles having a ratio of approximately two to one and said pair of first magnetic poles being adjacent and said pair of second magnetic poles being adjacent, said rotor being of a disk shape and each of said second magnetic poles having an outer part extending into said first magnetic poles along an edge of said disk shaped rotor; a magnetic position sensor disposed opposite an edge of said rotor to sense said outer part of said second magnetic poles; a current switching circuit connected to supply current to said coils of said stator, said magnetic position sensor connected in said current switching circuit to effect switching; a supplemental magnetic pole of said rotor arranged in a position surrounded circumferentially by each of said first magnetic poles, said supplemental magnetic poles being oppositely magnetized relative to said first magnetic poles.

Claim 4

A two-phase brushless motor, comprising: a stator having at least two pairs of series connected coils for producing two respective phases of a magnetic field; a rotor rotationally mounted opposite said stator to provide a torque output, said rotor having at least a pair of first magnetic poles and at least a pair of second respectively oppositely magnetized magnetic poles, a width of said first magnetic poles to a width of said second magnetic poles having a ratio of approximately two to one and said pair of first magnetic poles being adjacent and said pair of second magnetic poles being adjacent, said rotor being of a disk shape and each of said second magnetic poles having an outer part extending into said first magnetic poles along an edge of said disk shaped rotor; a magnetic position sensor disposed opposite an edge of said rotor to sense said outer part of said second magnetic poles; a current switching circuit connected to supply current to said coils of said stator, said magnetic position sensor connected in said current switching circuit to effect switching; a supplemental magnetic pole of said rotor arranged in a position surrounded circumferentially by each of said first magnetic poles, said supplemental magnetic poles being oppositely magnetized relative to said first magnetic poles.