| 摘要 |
A front variable speed drive device 20, 120 is configured and arranged to electrically operate driving of a front derailleur by a shift cable. The front variable speed drive device 20, 120 comprises a case member 60, a motor drive mechanism 61, and a cable linking portion 62. The case member 60 is mounted on a hanger portion of a bicycle frame 102. The motor drive mechanism 61 is mounted on the case member 60, and has a revolving shaft 70. The cable linking portion 62 has a retaining portion 92 configured and arranged to retain a first end of the shift cable. The cable linking portion 92 is rotatably mounted on the revolving shaft 70, and has a hypothetical arm line AR extending in the direction perpendicular to the shift cable from the center of rotation O1 with a length of the hypothetical arm line AR changing depending on the rotation phase. Thus, motor torque required for shifting gears is reduced with a simple structure. |
