New approach for an easily detachable electric drive unit for off-the-shelf bicycles

While an increasing number of electric bicycles are sold, the majority is still conventional, i.e. pedal powered. But electric bicycles could raise the share of people using them instead of more inefficient modes of transportation. This paper proposes a new approach for an electric drive unit that can easily be attached and detached to a large majority of existing off-the-shelf bicycles to convert them into legal electric assisted bicycles (pedelecs). This is achieved with a single unit that incorporates batteries, electronics, motors and sensors. It is mounted on the seat stay tube with a simple clamp mechanism and powers the bicycle over a friction roller at the rear wheel. The legally required pedal detection is done with an integrated proximity sensor. A prototype is built to prove a simple and unspecific installation and convenient usage.