Driving device for a bicycle

摘要

Driving device for a bicycle which achieves a high gear transmission ratio and high propulsive power even with a driving-chain sprocket having a relatively small diameter, in which bicycle a planet gear device is arranged either between the driving chain sprocket and a drive shaft or between a hub and a rear-wheel shaft, or on the drive shaft and on the rear-wheel shaft, and, as a result, high-speed driving or uphill driving on a steep road can be achieved with less propulsive power than in a conventional gear-changing device.