Patent ID: 8398525

Claim:
A planetary gear reduction system, comprising a sun gear having external teeth; a plurality of planet gears each having external teeth that engage with the external teeth of the sun gear; a ring gear having internal teeth that engage with the external teeth of the planet gears; and a planet carrier having a first plate that supports first ends of planet shafts supporting the planet gears, a second plate that supports second ends of the planet shafts, and a cylindrical drum connecting the first and second plates; wherein the first plate includes: first portions that support the first ends of the planet shafts; second portions that connect the first plate to the drum, the second portions being located adjacent to the first portions in a circumferential direction, and the first and second portions being provided alternately in the circumferential direction; first cutouts, each of the first cutouts defined between each of the adjacent first and second portions, the first cutouts each extending radially inwardly from a circumferential edge of the first plate to a position adjacent a circle that connects central axes of the planet shafts, wherein each of the first cutouts partially defines the shape of the adjacent first and second portions; and second cutouts, each defined radially inward of the second portion and between consecutive first portions, the second cutouts each extending radially inwardly from a first region outside the circle into a second region inside the circle.