Patent ID: 8357071

Claim:
A bicycle internal hub transmission comprising: a stationary shaft; a hub shell rotatable about the stationary shaft; a driver rotatable about the stationary shaft; and a planetary gear mechanism disposed within the hub shell to selectively transmit rotary power from the driver to the hub shell, the planetary gear mechanism including: at least one stepped planetary gear having a first portion and a second portion, the first portion having a plurality of first helical gear teeth with a first outer diameter and the second portion having a plurality of second helical gear teeth with a second outer diameter that is greater than the first outer diameter, the first portion and the second portion of the stepped planetary gear being a unitary one piece element as viewed in cross-section, the stepped planetary gear further including an annular surface that begins at first axial ends of the first gear teeth and extends directly radially outward from the first axial ends of the first gear teeth to inner axial ends of the second gear teeth, the annular surface having a frustoconical shape, wherein the first helical gear teeth have a first helix angle and the second gear teeth have a second helix angle with the first and second helix angles being angled such that for a given amount of rotation of the stepped planetary gear corresponding travel points on the first and second helical gear teeth move the same axial amount with respect to the rotational axis of the stepped planetary gear.