To provide an assist drive device which is for a power-assisted bicycle and equipped with a motor and reduction gear internally, whereby the desired gear ratio is obtained while a large size construction and heavy weight of the device are suppressed.
Multistage rollers 16 and 17 are configured so that a bunch of rollers arranged at a constant spacing in the circumferential direction are installed in steps in the radial direction between the peripheral surface of an input shaft 13 and the inside surface 14 of an outer ring 15 arranged concentrically with the input shaft 13 in such a condition that the input shaft 13, each stage rollers 16 and 17, and outer ring 15 are in frictional contact with one another, and the rotational power of an assist drive source fed to the input shaft 13 is decelerated by the rollers 16 and 17 and transmitted to the output member. Among the rollers 16 and 17, at least ones 16 positioned at either step have peripheral surfaces having two rotational radii R1S and R1L.
| WO/2021/107902 | EQUIPPING A BICYCLE WITH A PLURALITY OF GENERATORS |
| WO/2023/108917 | DRIVE PART, POWER ASSEMBLY, AND ELECTRIC BICYCLE |
| JPH0733067 | MOTOR-ASSISTED BICYCLE |
MAKINO TOMOAKI
UTSUNOMIYA SATOSHI
