Brush-less DC motor

摘要

A brush-less DC motor includes a stator member; a stationary cylindrical member projected from the stator member and having bearings on its inner circumferential surface; a rotary shaft being rotatably supported by the bearings of the stationary cylindrical member; a rotary cylindrical member into which the stationary cylindrical member is inserted, and to which the rotary shaft is fixed; two rotary discs of magnetic material, fixed to the rotary cylindrical member and spaced from each other; a permanent magnet fixed to one of the rotary discs; a rotational-position detecting member; and a coil assembly including a plurality of coil units. The working point of the rotary shaft is nearer to the stationary cylindrical member than to the rotary cylindrical member.