Patent ID: 7510497

Claim:
An internal teeth oscillating inner gearing planetary gear system comprising: a through-hole provided at a center of the gear system; an input shaft; an eccentric gear being rotated by the input shaft and having an eccentric inner circumferential surface with respect to a rotational center thereof; an internal oscillating body being guided by the inner circumferential surface of the eccentric gear and oscillatingly moved thereby, the internal oscillating body having internal teeth on an inner periphery thereof; and an external gear internally meshing with the internal oscillating body, the external gear having slightly less number of external teeth than that of the internal teeth of the internal oscillating body, and having the through-hole at the center of the gear system, wherein power is transmitted from the eccentric gear to the internal oscillating gear, and directly from the internal oscillating gear to the external gear, and wherein the through-hole is without a solid shaft which can transmit power from the gear system therein.