electric assist bike

Abstract

An electric assist bicycle is provided with a so-called single-shaft motor drive unit that can satisfactorily keep torque detection capability. The outer periphery of a crank shaft 7a has a cylindrical human power transmission member 28 having a torque sensor 31 for detecting a human driving force and a combined-force member 29 that combines a human driving force and an auxiliary driving force from a motor 21. A one-way clutch is not provided on a driving force transmission path including the crank shaft 7a, the human power transmission member 28, and the combined-force member 28. The human power transmission member 28 and the combined-force member 29 are always rotated in response to a rotation of the crank shaft 7a. Moreover, a rotation detector 10 is provided to detect a rotation of the combined-force member 29.

Description

technical field [0001] The present invention relates to a motor-assisted bicycle that can be driven by a human driving force realized by pedaling force and an auxiliary driving force generated by an electric motor. Background technique [0002] There is known a motor-assisted bicycle that has a motor powered from an accumulator such as a storage battery, detects a human-powered driving force composed of a pedaling force applied to the pedals with a torque sensor, etc., and adds a motor that corresponds to the human-powered driving force. The auxiliary driving force (assist force) can easily drive even when going uphill. [0003] In this electrically assisted bicycle, there is a structure in which a motor drive unit incorporating a motor and the like is arranged at a portion where a crankshaft is provided. In the power-assisted bicycle with such an arrangement structure, the relatively heavy motor drive unit is arranged at a lower position in the center (that is, between the...

AI Technical Summary

Problems solved by technology

Therefore, the vibration during the switching operation of these one-way clutches 206, 252, 258 or the vibration during the meshing operation of the cam portion and the overriding operation are directly transmitted to the human force transmission body 203 provided with the torque sensor 209 or the resultant force of the torque sensor 260. body 255, therefore, it becomes noise during torque detection, and the torque detection capability may decrease

[0024] In addition, in order to maintain a good assembled state after the one-way clutches 206, 252, 258 are installed on the human power transmission body 203 or the combined force body 255, it is preferable to use a material with excellent wear resistance as the human power transmission body 203 or the combined force body 255, or Carry out heat treatment, but must form the magnetostrictive generation part of torque sensor 209,260 on the surface of manpower transmission body 203 or resultant force body 255, therefore, the material of manpower transmission body 203 or resultant force body 255 is extremely limited, depending on the situation, Sometimes have to use materials with low detection ability of torque

[0025] In addition, since the one-way clutches 206, 252, and 258 are installed on the human power transmission body 203 or the combined force body 255, even if the reverse wheel brake is to be provided on the hub of the rear wheel, the pedal is rotated in the opposite direction to that of the forward running. , the rotation of the pedals cannot be transmitted to the drive sprockets 102, 201, 257 or the chains 105, 208, 256, and cannot correspond to

Images