Yamaha Hatsudoki Kabushiki Kaisha

Izumi Yamashita

Yoshiharu Yokoyama

Takeshi Nagase

Akiyoshi Suzuki

Several embodiments of prime mover-assisted pedal-operated vehicles, such as a bicycle. In each embodiment, both the prime mover and the pedal mechanism drive the rear wheel through a common transfer shaft. The transfer shaft is disposed vertically above the pedal-operated crankshaft axis so as to improve the ground clearance and simplify the overall construction of the bicycle. The transmission arrangement is such that the prime mover transmission ratios are always in a step-down condition while the pedal-operated crankshaft drives the transfer shaft through a step-up transmission. Various embodiments of improved torque sensors are also employed so as to provide smooth transition and smooth feel to the rider.

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Iwata, Japan

Izumi Yamashita