| 摘要 |
PURPOSE:To obtain a small-sized stepless speed change gear which performs continuous and stepless speed change by axially supporting a plurality of planetary gears onto a carrier fixed onto a driving shaft, through a unidirectional clutch, and varying the position of an eccentric pin on the planetary core of each planetary gear. CONSTITUTION:An eccentric core 8 is fitted in eccentricity onto the outer periphery of a crankshaft 5, and said eccentric core 8 is fixed onto the hanger rack 4 of the frame of a bicycle, and an eccentric shifter 10 which is turned by the traction operation of a wire which is wound onto an outer peripheral groove 10b is fitted onto the outer periphery of the eccentric core 8. A carrier 13 equipped with four pivots 14 at equal angular positions in fitted onto the crankshaft 5, suppressing the revolution, and a planetary core 15 is fitted onto each pivot 14. The swing pin 20 installed onto the inner side surface of each planetary core 15 is inserted into the circular locus 9 of the eccentric shifter 10, and a planetary gear 16 is fitted onto the outer periphery of the planetary core 15 through a ratchet mechanism having a hook 18. Then, each planetary gear 16 is engaged with a trailing gear 21 formed integrally with a chain wheel 22.
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