Windshield wiper motor

A wiper motor having:

• a speed reduction unit with an output shaft for driving a wiper apparatus of an automotive vehicle;
• and an electric motor for driving the speed reduction unit, the electric motor comprising:
• magnetic field generating means has:
• a magnetic yoke formed into a bottomed cylinder;
• and four magnetic poles arranged cylindrically on an inner surface of the magnetic yoke, and alternatively in north and south magnetic poles,
• an armature surrounded by the magnetic poles and accommodated in the magnetic yoke, the armature having:
• an armature shaft rotatably supported by the magnetic yoke;
• a core fixed to the armature shaft, the core being composed of eighteen teeth portions;
• a commutator fixed to the armature shaft, the commutator being composed of:
• a commutator body formed of insulating resin, and eighteen commutator bars insulated from each other and arranged on the commutator body;
• a winding composed of eighteen coil portions wound on the teeth portions in a lap-winding fashion, each of the coil portions surrounding corresponding teeth portions, each of the coil portions of the winding having two terminals connected to corresponding commutator bars adjacent to each other;
• and
• an equalizing portion composed of nine connecting conductors each of which is electrically connected to two corresponding commutator bars opposite to each other, and
• brush assemblies including a first brush, a second brush shifted from the first brush by 90 degrees, and a third brush shifted from the first and second brushes by 90 or more degrees, each brush being arranged so as to come in slidable contact with the commutator bars, the first brush being connected to a common electric potential, a current for rotating the armature at low speed is selectively supplied to the second brush, and a current for rotating the armature at high speed is selectively supplied to the third brush.

A wiper motor having:

• a speed reduction unit with an output shaft for driving a wiper apparatus of an automotive vehicle;
• and an electric motor for driving the speed reduction unit, the electric motor comprising:
• magnetic field generating means composed of:
• a magnetic yoke formed into a bottomed cylinder;
• and four magnets arranged cylindrically on an inner surface of the magnetic yoke, and alternatively in north and south magnetic poles,
• an armature surrounded by four magnetic poles and accommodated in the magnetic yoke, the armature having:
• an armature shaft rotatably supported by the magnetic yoke;
• a core fixed to the armature shaft, the core being composed of eighteen teeth portions;
• a commutator fixed to the armature shaft, the commutator being composed of:
• a commutator body formed of insulating resin, and eighteen commutator bars insulated from each other and arranged on the commutator body;
• and
• a winding consisting essentially of eighteen coil portions wound on the teeth portions in a lap-winding fashion, each of the coil portions surrounding corresponding teeth portions, each of the coil portions of the winding having two terminals connected to corresponding commutator bars adjacent to each other;
• an equalizing portion composed of nine connecting conductors each of which is electrically connected to two corresponding commutator bars opposite to each other, and
• brush assemblies including a first brush, a second brush shifted from the first brush by 90 degrees, and a third brush shifted from the first and second brushes by 90 or more degrees, each brush being arranged so as to come in slidable contact with the commutator bars, the first brush being connected to a common electric potential, a current for rotating the armature at low speed is selectively supplied to the second brush, and a current for rotating the armature at high speed is selectively supplied to the third brush.