Patent ID: 8193668

Claim:
A motor with speed reduction mechanism, comprising a motor section, and a gear section decelerating rotation of the motor section, the motor section including: a bottomed cylindrical yoke; an armature shaft rotatably provided in the yoke, one end of the armature shaft being supported by a bottom portion of the yoke; a commutator mounted to an other end side of the armature shaft; a brush holder covering an opening portion of the yoke, mounted by being press-fitted into the yoke, and rotatably supporting the other end side of the armature shaft; a brush held by the brush holder and slidably contacting with the commutator; and an armature-shaft-side coupling member provided to the other end of the armature shaft so as to be rotatable together with the armature shaft, and provided with protruding portions, and the gear section including: a bottomed gear case mounted on the opening portion of the yoke; a worm shaft provided in the gear case so as to be rotatable with respect to the gear case, the other end of the worm shaft being supported by a bottom portion of the gear case, and a worm being formed on the worm shaft; a worm wheel provided in the gear case so as to be rotatable with respect to the gear case, and meshing with the worm of the worm shaft; a worm-shaft-side coupling member provided to one end of the worm shaft so as to be rotatable together with the worm shaft, and provided with protruding portions, the worm-shaft-side coupling member being coupled together rotatably to the armature-shaft-side coupling member, wherein a gap is formed between each protruding portion of the worm-shaft-side coupling member and each protruding portion of the armature-shaft-side coupling member along the circumferential direction; and a sensor magnet integrally provided around an outer circumference of an attaching ring attached to the worm-shaft-side coupling member.