Axially short permanent magnet DC motor - has commutator and brushes inside drum armature

摘要

To achieve short axial length, e.g. for driving a car radiator cooling fan, the commutator (4) and brush (95) gear (9) of a permanent magnet (12) DC motor are located inside the drum armature core (1). The core is fixed to a sheet metal spider (5) pressed on to the shaft (8). The "hammer" brush gear is mounted on one end cover plate (10) in the annular space between core and commutator. The commutator bars (41,42) are extended through radial slots (51) in the spider and are formed into hooks (43,44) round which the connections (71,72) to the armature winding (7) are looped. The hooks are closed up when the connections are welded by a pair of electrodes, one passing through the spider slot.