Direct current brushless electric motor

Abstract

A hollow cylindrical permanent magnet having its semicircle magnetized as N pole and the remaining semicircle magnetized as S pole forms the rotor. Two stator magnetic poles which are planted radially around the outer periphery of a cylindrical stator yoke, pole shoes which are firmly mounted on the outer peripheral side of each stator magnetic pole so as to have its outer peripheral side oppose to the inner peripheral surface of aforesaid permanent magnet, and intermediary magnetic poles which are planted radially on the outer periphery of the stator yoke so as to place each of them in between each of these pole shoes, form the stator with all of these components made of magnetic materials. Around each of the stator magnetic poles windings are wound. One magnetism detector which detects the revolutional position of the permanent magnet is mounted at the position within the gap of magnetic flux which is located in a position slightly deviated toward the pole shoe side from the center line connecting the center of the peripheral gap between the end point of the pole shoe and the end point of the intermediary magnetic pole with the center of the stator yoke. A current control circuit controls the flow of current that flows through the windings of each stator winding upon receiving the output of the above-mentioned magnetism detector.