Controlling a transmission with segmented wheels by means of electronic control elements
A control device for controlling a transmission ratio between a traction means and a sprocket set rotatable about an axle may include at least two sprockets alternatively wrapped around by the traction means. At least one of the sprockets may include several independently adjustable rim segments. Adjustment of the rim segments in relation to a fixed plane may be effected by a control device in a direction substantially transverse to the plane. The control device includes at least one electrically actuatable control element, e.g., a servomotor. The at least one control element is configured to rotate with the sprockets.
1. A method for controlling a transmission ratio, the method comprising:
rotating a set of sprockets about an axle using a traction device partially wrapped around the set of sprockets in a fixed plane, wherein a first sprocket of the set of sprockets includes a plurality of independently adjustable sprocket rim segments, and wherein the set of sprockets comprises one or more electrically actuatable control elements coupled to and rotatable with the set of sprockets; and
transferring the traction device between the first sprocket and a second sprocket of the plurality of sprockets by using the one or more electrically actuatable control elements to reposition at least one of the sprocket rim segments in a direction transverse to the fixed plane, wherein repositioning comprises pivoting the at least one of the sprocket rim segments in a direction transverse to the fixed plane.
2. The method of claim 1 , wherein a respective one of the one or more electrically actuatable control elements is coupled to, and configured to corotate with, each of the sprocket rim segments.
3. The method of claim 1 , further comprising:
interrogating a presence of the traction device using a respective sensor associated with each of the one or more electrically actuatable control elements; and
actuating the associated control element in response to a negative interrogation.
4. The method of claim 1 , wherein the one or more electrically actuatable control elements comprise a servo motor.
5. The method of claim 1 , wherein repositioning at least one of the sprocket rim segments comprises rotating a threaded spindle coupled to a rotationally fast nut disposed on the at least one of the sprocket rim segments, such that a position of the sprocket rim segment is adjusted.
6. The method of claim 1 , wherein repositioning at least one of the sprocket rim segments comprises using the one or more electrically actuatable control elements to rotate a respective threaded spindle to screw a corresponding nut connected to an eccentric, such that screwing each nut effects an adjustment of the position of the sprocket rim segment.
7. The method of claim 1 , further comprising:
charging at least one energy accumulator using the one or more control elements;
exerting, using the at least one charged energy accumulator, an adjusting force on at least one of the sprocket rim segments; and
preventing adjustment of the position of the at least one sprocket rim segment until the sprocket rim segment is out of contact with the traction device.
8. The method of claim 7 , wherein each of the at least one energy accumulators comprises a spring.
9. The method of claim 7 , wherein the at least one energy accumulator includes a plurality of energy accumulators each associated with one of the sprocket rim segments, and wherein the method further comprises:
using a central co-rotating electrically actuatable control element to charge the plurality of energy accumulators.
10. The method of claim 9 , wherein using the central co-rotating electrically actuatable control element to charge the plurality of energy accumulators comprises using a cam disc having a respective cam elevation for each of the energy accumulators.
11. The method of claim 1 , further comprising:
driving a plurality of spindles, one of the spindles coupled to each sprocket rim segment, via a friction clutch using a centrally disposed control element; and
mechanically enabling adjustment of each sprocket rim segment position only when the traction device is absent from the respective sprocket rim segment.
12. The method of claim 1 , wherein the one or more electrically actuatable control elements comprise an electrically operated lifting magnet.
13. The method of claim 1 , further comprising providing power to the one or more electrically actuatable control elements from a stationary voltage supply via a slip ring.
14. The method of claim 1 , further comprising actuating the one or more electrically actuatable control elements using a corotating electronic control unit.
15. The method of claim 14 , further comprising receiving wirelessly transmitted control signals at the corotating electronic control unit.
16. The method of claim 1 , wherein the one or more electrically actuatable control elements are mounted to the second sprocket.
17. The method of claim 1 , wherein the one or more electrically actuatable control elements comprise an annular lifting magnet disposed around the axle; and
wherein repositioning the at least one of the sprocket rim segments includes using the annular lifting magnet to push a lever against the at least one sprocket rim segment.
18. The method of claim 17 , further comprising preventing repositioning of each of the sprocket rim segments when a protrusion of the associated lever is in contact with the traction device.
19. The method of claim 17 , wherein pushing the lever against the at least one sprocket rim segment includes adjusting an axial position of a wedge-shaped ring.