Mehrgang-Getriebenabe für Fahrräder

摘要

The invention relates to a multispeed gear system for bicycles. The gear system contains an axle (1) which is rotationally fixed on a bicycle frame, a drive mechanism (7) which is rotationally mounted on the axle (1), a sleeve (12) which is rotationally mounted on the axle (1) and a switch gear mounted in the sleeve (12) and fitted with a first and a second planetary gear train (15, 16) to provide several transmission ratios between the drive mechanism (7) and the sleeve (12). Both planetary gear trains (15, 16) have at least two sun gears (19, 20 or 22, 23) which are coaxial to the axle (1) and which can be selectably connected to the axle (1) in order to choose the transmission ratios by means of a shifting device. According to the invention, the shifting device also has means (31, 32) enabling selective connection of the ring gear (24, 25) or the sun wheel (17, 21) of the first and/or second planetary gear train (15, 16) to a sun gear (19, 22) of the same planetary gear train (15, 16).