Two-phase DC brushless motor

Claim 1

A brushless motor comprising: a cylindrical bobbin-wound coil coaxially mounted on a stator axis and energized in two-phase mode; first and second annular stator discs coaxially mounted on said stator axis with said coil therebetween; first and second sets of substantially equally spaced stator poles projecting in a plate-like form and perpendicular to said stator axis from the outer peripheral edges of said first and second stator discs, respectively, said first and second sets of stator poles having protruding ends lying in a common imaginary cylindrical surface and magnetically linked to said coil by the respective one of said first and second stator discs, said stator poles of said first set being equal in number to and angularly spaced approximately 180° electrically from said stator poles of said second set, each stator pole of said first and second sets having a notched portion formed in one of opposite corners of said protruded end thereof and oriented so as to be next to the unnotched corner of said stator pole adjacent thereto; a rotor coaxially rotatable relative to said stator axis and having permanent magnetic poles equal in number to all of said stator poles and spaced alternately north and south and circumferentially arranged on a cylindrical flange of said rotor to overlap all of said stator poles with a slight annular gap therebetween, each of said permanent magnetic poles having an angular width substantially equal to the sum of angular widths of said protruded end and said notched portion of said stator pole; and position detecting means opposed to said permanent magnetic poles with a gap left therebetween for detecting the position and polarity of said magnetic pole to thereby switch a direction of direct current charged to said coil.