| 摘要 |
<p>A multi-speed hub for a bicycle that includes a hub shell, a hub shaft nonrotatably mounted to the bicycle, a driver, a planetary gearing system for providing a plurality of gear ratios and a control device for selecting the desired gear ratio. The planetary gearing system includes first, second and third planetary gear mechanism. The first planetary gear mechanism includes a first sun gear, a first planet carrier and a first ring gear, The first ring gear also functions as the planet carrier for the second planetary gear mechanism. A second sun gear of the second planetary gear mechanism is connected to the first planet carrier. The second planetary mechanism includes a second ring gear that substantially surrounds the planetary gearing system. A pawl carrier including a plurality of pawls that connect the driver to the planetary gearing system to provide different gear ratios. A stepped planet gear functions as the second and third planet gears. The stepped planet gear alternately engages the second and third sun gears via control pawls.
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