Electric assist bicycle

Abstract

Provided is an electric assist bicycle provided with a so-called single-axle motor drive unit capable of maintaining high torque detection performance. On an outer periphery of a crank shaft (7a), there are disposed a cylindrical human power transmission member (28) formed with a torque sensor (31) for detecting human power drive force, and a combined-force member (29) that combines the human power drive force and auxiliary drive force from a motor (21). No one-way clutch is disposed in a drive force transmission route spanning the crank shaft (7a), the human power transmission member (28), and the combined-force member (28), so that the human power transmission member (28) and the combined-force member (29) are rotated at all times as the crank shaft (7a) rotates. A rotation detector (10) is also fitted to detect the rotation of the combined-force member (29).

Description

technical field [0001] The present invention relates to an electric-assisted bicycle that can travel by a human-powered driving force realized by pedaling force and an auxiliary driving force generated by an electric motor. Background technique [0002] There is known a power-assisted bicycle that includes an electric motor supplied with power from an accumulator such as a battery, detects a human driving force composed of a pedaling force applied to a pedal by a torque sensor or the like, and adds an electric motor corresponding to the human driving force. The assisted driving force (assist force) of the 1000W allows you to drive easily even when going uphill, etc. [0003] In this power-assisted bicycle, a motor drive unit having a built-in electric motor or the like is arranged at a site where the crankshaft is provided. In the power-assisted bicycle with this arrangement, the relatively heavy motor drive unit is disposed at a lower position in the center of the power-as...

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

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