| 摘要 |
PURPOSE: A speed change gear for a bicycle is provided to improve appearance, to conveniently control, to prevent noise and vibration in changing speed, and to easily extent stages of a shift. CONSTITUTION: A speed change gear of a bicycle comprises a salve sprocket(100) receiving power of a diving sprocket; a carrier(210) receiving power being mounted on the slave sprocket to install plural multi-stage planetary hears(220); sun gears(231,232) forming ratchet tooth on an inner circumference while being geared to each stage of the multi-stages planetary gear; a ring gear(240) geared to the multi-stages planetary gear; a hub shell(310) delivering power by rotating with the ring gear and the carrier; a clutch unit(320) actuating by being mounted between the ring gear and the hub shell and between the carrier and the hub shell; a hub shaft forming a pawl placing unit(411); pawls(421,422) released or fixed on the ratchet tooth; a pawl control ring(430); a groove winding a wire on a peripheral face; a ledge unit(452); and a convert disk(450). The convert disk changes position of the pawl control ring with a convert mediate unit by rotating through the wire. Then, a spring(460) restores position of the convert disk, and an interval-maintaining unit maintains interval to actively move the convert disk.
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