Patent ID: 8813586

Claim:
A starter motor comprising: a hollow yoke having an open end; a magnetic field system provided on an inner periphery of the yoke; an armature surrounded by the magnetic field system with a predetermined gap between the magnetic field system and the armature, the armature having an armature shaft; an end frame that closes the open end of the yoke and has a bearing box formed therein, the bearing box being recessed inward of the yoke from a rear end face of the end frame and having an open end on the rear end face of the end frame, the bearing box also having a bearing disposed therein to rotatably support an end portion of the armature shaft; and a flexible seal plate that is located entirely outside of the bearing box and attached on the rear end face of the end frame to close the open end of the bearing box and form a hermetic seal between the seal plate and the rear end face of the end frame, thereby blocking foreign matter from entering the inside of the bearing box via the open end of the bearing box, wherein the seal plate covers the rear end face of the end frame in plan view such that the entire outer peripheral edge of the seal plate is closer in proximity to the open end of the bearing box than the outer periphery of the rear end face of the end frame.