Engine starter with a planetary reduction gear.

摘要

An engine starter has a DC motor with a rotor shaft 4 drivingly connected to an output shaft 6 by a planetary reduction gear 16, the sun gear 4a of the reduction gear being formed on the outer surface of the rotor shaft and the ring gear 30b of the reduction gear being formed on the inner surface of the yoke 30 of the DC motor. The yoke has a support portion 30a integrally formed thereon which rotatably supports the end of the output shaft which is connected to the rotor shaft. Preferably, the yoke is formed by deep drawing of mild steel. A dust prevening member 31 forms a labyrinth seal around the rotor shaft and prevents dust from entering the motor from the reduction gear.