| 摘要 |
PROBLEM TO BE SOLVED: To provide a power assisted vehicle with an electric motor operated in a highly efficient region at all times independently of a travelling speed. SOLUTION: The electrically assisted bicycle power assisted vehicle) which travels using a combination of manual force input by a rider and assisting motive force by an electric motor 18, as driving force, comprises a subsidiary transmission 33 provided on the way of an assisting motive force transmission system prior to the combination of the assisting motive force and the manual force, the subsidiary transmission 33 having a variable gear ratio. Since the subsidiary transmission 33 provided on the way of the assisting motive force transmission system prior to the combination of the assisting motive force and the manual force has the variable gear ratio, the electric motor 18 can be operated in the highly efficient region at all times independently of the travelling speed of the bicycle 1, that is, the electric motor 18 can be operated in the highly efficient region at all times during normal run, wheeling walk (pushing walk) and low-speed run (upsloping) for suppressing the temperature rise of the electric motor 18.
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