Low-noise electric motor assembly for automotive blower

摘要

An electric motor assembly for driving an air blower is disclosed. The assembly comprises a casing of metal, the casing having opposed open ends closed by respective covers of metal; a rotation shaft rotatably disposed in the casing, the rotation shaft having one end exposed to the outside through an opening formed in one of the covers, the one end being adapted to connect to a fan of the air blower; a plurality of magnets installed in the casing and circumferentially surrounding the rotation axis; an armature mounted to the rotation shaft to rotate therewith; a commutator mounted to the rotation shaft and electrically connected with the armature; brushes operatively contacting with the commutator and supported by the casing; and an electric power feeding device for feeding the brushes with an electric power. A pulse width modulating device is further employed which is electrically connected with the power feeding device for modulating the electric power by means of a pulse width modulation method. The pulse width modulating device is installed in the casing for radio noise suppression.