Battery-powered drive system for bicycle - has DC motor coupled to tyre of rear wheels via friction roller

摘要

The drive system has a permanent magnet d.c. motor whose output power corresponds roughly to the power produced by the leg muscles of the human body. The motor torque is transferred to the rear wheel of the bicycle via a friction roller pressed against the side wall of the tyre. The friction roller can be moved clear of the tyre to allow the rider to pedal the bicycle as normal. The motor may also be used when the rider is pedalling so that twice as much power is delivered to the rear wheel. The increase in weight caused by the battery, motor and other parts is roughly 10 percent. The friction roller may be tapered to provide a continuously variable transmission ratio.