DC MOTOR

摘要

A DC motor (10) is provided with a tubular housing (12) having a polygonal cross-sectional shape, a magnet (20) mounted along the inner peripheral surface of the housing (12) and having magnetic poles at corners of the housing (12), a shaft (22) inserted through the housing (12) along the axis of the housing, armatures (24) fixed to the shaft (22) and placed so as to be opposed to the magnet (20), a commutator (26) mounted to the shaft (22) so as to be coaxial with the armatures (24), columnar carbon brushes (30) placed in the radial direction of the commutator (26) and having head end surfaces making sliding contact with the outer peripheral surface of the commutator (26), and urging members placed in the housing (12) and urging the carbon brushes (30) toward the commutator (26). The carbon brushes (30) are placed at those circumferential positions in the housing (12) at which the carbon brushes (30) can have a maximum length.