| 摘要 |
<p>In an electric starter motor, a planetary reduction assembly includes: a sun gear engraved in an outer circumferential portion on a front side of a motor output shaft formed integrally with the armature; a ring formed into a cylindrical shape with a rotation stop projecting on an outer circumferential wall surface thereof and coupled to a front bracket while its movement in the circumferential direction is restricted by the rotation stop; an internal gear formed into a bottomed cylindrical shape with a center hole formed in a central portion of a bottom thereof and an inner circumferential gear portion engraved in an inner circumferential wall surface thereof, the internal gear being fitted in the ring so as to open on a rear side; a discoid flange portion formed integrally with an end portion on the rear side of the starter output shaft, supported rotatably to the bottom of the internal gear through a bearing and rotatably supporting an end portion on the front side of the motor output shaft through a bearing; and a plurality of planetary gears rotatably supported to a plurality of pins implanted concentrically at an equiangular pitch on an end face on the rear side of the flange portion, respectively, and engaging with the inner circumferential gear portion and the sun gear, and wherein the internal gear is fitted in the ring so as to slidingly rotate relative to the ring when a rotational torque to be applied to the starter output shaft exceeds a predetermined transmission rotational torque.</p> |
