| 摘要 |
A bicycle gearbox having sixteen ratios comprises four primary planetary gear sets (see fig 2) and four secondary planetary gear sets arranged in series. Gear engagement is achieved by a selector which moves splined coupling ring 15, having a saw tooth profile on a face, into engagement with a matching saw tooth profile on ring gear 13 of one of the primary planetary gear sets. The coupling ring 15 is splined to a steel sleeve 12 which transmits rotation of shaft 10, via another coupling ring 15, to a ring gear of one of the secondary planetary gear sets that is connected to a multi-tooth drive wheel 18. Transmission to a rear wheel is completed by a rubber belt (eg a cam type belt 20, fig 4). The selector is moved by a cable operated lever which rotates a selector plate (26, fig 3) and thereby pinions so that cams are rotated. Rotation of the cams imparts an axial movement to pressure plates (28, fig 3) which drives the coupling rings 15 into engagement. |
