Patent ID: 8091443

Claim:
A reduction-gear starter for an engine, comprising: an electric motor having an armature shaft; a set of planetary speed reducers having a different reduction ratios disposed on the armature shaft side-by-side, wherein one of the speed reducers is selected in order to reduce a revolving speed of the motor; a pair of internal gears used in the set of planetary speed reducers; an engaging part arranged coaxially on a perimeter of the pair of internal gears, wherein the engaging part is arranged unrotatably to a fixed member inside the starter and arranged movably along a direction of an axis, and engages mechanically to one of the internal gears in order to regulate the rotation of the internal gear; a 1 st teeth part formed on the perimeter of a 1 st internal gear of the pair of internal gears, the first teeth part being arranged on a side opposite the motor; a 2nd teeth part formed on the perimeter of a 2nd internal gear of the pair of internal gears, the second teeth part being arranged on a side toward the motor; a 3rd teeth part formed in an inner circumference of the engaging part and engageable with the 1st teeth part formed in the 1st internal gear; and a 4th teeth part formed in the inner circumference of the engaging part and engageable with the 2nd teeth part formed in the 2nd internal gear; wherein the reduction ratio is selected by switching the internal gears by moving the engaging part along the direction of the axis, the rotation of the 1st internal gear is regulated when the 3rd teeth part engages with the 1st teeth part of the 1st internal gear by moving the engaging part toward the motor, and the rotation of the 2nd internal gear is regulated when the 4th teeth part engages with the 2nd teeth part of the 2nd internal gear by moving the engaging part away from the motor.