The electric bicycle dates back to around 120 years ago. Even before the first appearance of the electric bicycle, in 1867 and 1886, two inventors invited motorized bicycle that used steam engine and internal combustion engine.
At the end of 1895, one of the first patents for electric bicycle was issued by Ogden Bolton Jr (Figure1). Mr Bolton wrote that his invention includes: “6-pole brush and commutator direct current (DC) hub motor mounted in the rear wheel. It is surprising that the hub motors invented 120 years ago are still vastly used in the electric bicycle industry and it is one of the best ways to propel the electric bicycle.
Two years later, Hosea W. Libbey invented an electric bicycle with two motor, two batteries and two wheels (Figure2). Does this sound crazy? The purpose of this crazy behavior is to realize the electric bicycle controller. One a plain road, only one battery would work and when climbing the second battery will also come into action. In the original design of Mr. Horesa, the motors used crank rods to rotate the wheels. After a short while, he changed these big clumsy rods to more efficient chain drive (Figure3).
In 1898, Mathew J. Steffens issued a patent of an electric bicycle that was operated by a belt that was placed on the periphery of the back wheel and also around the motor (Figure4). The slots on the wheel can prevent the belt from slipping away. Anyway, this kind of propulsion system is very creative.
Following the belt drive system, an idea for a friction drive came in reality. In 1899, John Schnepf introduced a bicycle which used a pulley that rest on the top surface of the rear wheel (Figure5). The pulley rotated with the help of the motor and in turn propelled the rear wheel. In 1969, A. Wood Jr was inspired by the invention of Mr Schnepf and turned it to a more complex friction system consisting of 4 different motors (Figure6). Each one of them was pushed to the front wheel.
In 1946, Jesse D. Tucker assigned a patent for a motor with internal gearing and with the ability to freewheel. Due to the creative design of Mr Tucker, the cyclist can choose whether to use pedals in combination or without combination of the electric motor.
Nowadays, with the help of other invents, such as torque sensors, power controls, new batteries and better hub motors, and advanced technology, electric bicycle has become a big industry, with the fact that there are roughly 120 million e-bikes on the roads of China, and in USA and Europe, the number of electric bicycles sold are in millions now.