| 摘要 |
The drive hub for a vehicle, particularly for a bicycle, includes a hub axle 1, a hub shell 9 rotatable relative thereto, and a driver or actuator 13 mounted on the hub axle 1. The driver 13 drives the hub shell 9 over a ball friction gear 17, the ball carrier plates 25 and 27 of which form with the hub axle 1 a rigid gear housing the balls 35 of which, with a guide ring 33, a drive ring 51 and a driven ring 55, enter into a frictional connection which, by the swivelling of the axle pins 37 between drive ring 51 and driven ring 55, permits different rotational speeds. The pressure forces are produced by a thread 47 between driver 13 and drive sleeve 49 proportionally to the driving torque, the pressure spring 57 ensuring a dead-travel-free response of the ball friction gear 17. The infinitely variably adjustable transmission ratio of the ball friction gear 17 is controlled through a control device 79 consisting of rotational elements, through a solid cone 29 which sets in rotation a crank wheel 91, as a result of which the spiral-shaped guide grooves 95 move the ball projections 39 of the ball axles 37 radially outwards or inwards, depending upon the direction of rotation. The ball axles thus swivelled provide for an infinitely variably adjustable transmission ratio between drive ring and driven ring.
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