Jockey wheel for a rear derailleur in a bicycle gear system and rear derailleur with such a jockey wheel

Patent metadata

Field	Value
Publication number	US-9316302-B2
Application number	US-201313937987-A
Country	US
Kind code	B2
Filing date	Jul 9, 2013
Priority date	Jul 9, 2012
Publication date	Apr 19, 2016
Grant date	Apr 19, 2016

Abstract

The invention relates to a guide wheel for a rear derailleur in a bicycle gear system for guiding a chain, including an annular wheel body with a central opening for rotatable bearing about a rotational axis of the guide wheel. The guide wheel includes a plurality of radially projecting teeth that are arranged on an outer circumferential surface of the wheel body. A tooth gap is arranged between each adjacent pair of teeth, individual teeth in the area of a root circle of the gear teeth having a predetermined tooth width matched to the chain. For improving the guiding properties, it is provided that the guide wheel has on at least some of the tooth gaps in the area near a tooth gap base and/or on at least some of the teeth at least one guide segment with a greater width than the tooth width of at least one of the adjacent teeth.

First claim

The invention claimed is:

1. A guide wheel for a rear derailleur in a bicycle gear system for guiding a chain, comprising:
an annular wheel body with a central opening for rotation about a rotational axis of the guide wheel;
a plurality of radially projecting gear teeth arranged on an outer circumferential surface of the wheel body, each of the gear teeth at or near a root circle of the gear teeth having a predetermined tooth width engageably receivable by the chain;
a tooth gap arranged between adjacent gear teeth; and
at least one chain guide segment with a greater width than that of at least one of the adjacent gear teeth, the at least one guide segment located on one or both of i) at least some of the tooth gaps at a tooth gap base and ii) on at least some of the gear teeth.

2. A guide wheel in accordance with claim 1 , wherein the at least one chain guide segment is offset radially inwardly relative to the tooth gap base.

3. A guide wheel in accordance with claim 1 , wherein the at least one chain guide segment is offset radially inwardly relative to the root circle of the gear teeth.

4. A guide wheel in accordance with claim 1 , wherein the at least one chain guide segment extends along at least a section of one of the gear teeth.

5. A guide wheel in accordance with claim 4 , wherein the at least one chain guide segment is set back circumferentially relative to a flank of the one of the gear teeth.

6. A guide wheel in accordance with claim 1 , wherein the at least one chain guide segment is formed by a ring segment projecting axially or by a circumferential ring.

7. A guide wheel in accordance with claim 1 , wherein the at least one chain guide segment is formed by a local projection that projects axially and is one or both of i) at the tooth gap base and ii) at or near one of the gear teeth.

8. A guide wheel in accordance with claim 1 , wherein the guide wheel includes two axial lateral surfaces and at least one chain guide segment is arranged on only one of the axial lateral surfaces.

9. A guide wheel in accordance with claim 1 , wherein the guide wheel includes two axial lateral surfaces and at least one chain guide segment is provided on both of the axial lateral surfaces.

10. A guide wheel in accordance with claim 1 , wherein each of the gear teeth includes tooth flanks and wherein the guide wheel is beveled, at least in segments, on or near the tooth flanks that face one another and the tooth gap base.

11. A guide wheel in accordance with claim 10 , wherein the at least one chain guide segment is arranged outside of the beveled area.

12. A guide wheel in accordance with claim 10 , wherein the at least one chain guide segment extends into the beveled area.

13. A guide wheel in accordance with claim 1 , wherein the at least one chain guide segment includes a projection that is polygonal when viewed in the direction of the rotational axis.

14. A guide wheel in accordance with claim 13 , wherein the projection is embodied as a parallelogram, a radially outer surface of which runs one of tangential to the root circle and parallel to a tangent of the root circle.

15. A guide wheel in accordance with claim 1 , wherein the wheel body has axial cut-outs arranged at regular angular distances.

16. A guide wheel in accordance with claim 1 , wherein the predetermined width is common to all of the gear teeth.

17. A rear derailleur for a bicycle derailleur gear system for guiding a chain that has at least one guide wheel, the guide wheel comprising:
a derailleur cage movably attached to the derailleur;
an annular wheel body supported by the derailleur cage, the wheel body having a central opening for rotation about a rotational axis of the guide wheel;
a plurality of radially projecting gear teeth arranged on an outer circumferential surface of the wheel body, each of the gear teeth at or near a root circle of the gear teeth having a predetermined tooth width engageably receivable by the chain;
a tooth gap arranged between adjacent gear teeth; and
at least one chain guide segment with a greater width than that of at least one of the adjacent gear teeth, the at least one chain guide segment located on one or both of i) at least some of the tooth gaps at a tooth gap base and ii) on at least some of the gear teeth.

18. A rear derailleur in accordance with claim 17 , wherein the at least one chain guide segment is offset radially inwardly relative to the tooth gap base.

19. A rear derailleur in accordance with claim 17 , wherein the at least one chain guide segment is offset radially inwardly relative to the root circle of the gear teeth.

20. A rear derailleur in accordance with claim 17 , wherein the at least one chain guide segment extends along at least a section of one of the gear teeth.

21. A rear derailleur in accordance with claim 20 , wherein the at least one chain guide segment is set back circumferentially relative to a flank of the one of the gear teeth.

22. A rear derailleur in accordance with claim 17 , wherein the at least one chain guide segment is formed by a ring segment projecting axially or by a circumferential ring.

23. A rear derailleur in accordance with claim 17 , wherein the at least one chain guide segment is formed by a local projection that projects axially and is one or both of i) at the tooth gap base and ii) at or near one of the gear teeth.

24. A rear derailleur in accordance with claim 17 , wherein the guide wheel includes two axial lateral surfaces and the at least one chain guide segment is arranged on only one of the axial lateral surfaces.

25. A rear derailleur in accordance with claim 17 , wherein the guide wheel includes two axial lateral surface and the at least one chain guide segment is provided on both axial lateral surfaces.

26. A rear derailleur in accordance with claim 17 , wherein each of the gear teeth include tooth flanks and wherein the guide wheel is beveled, at least in segments, on or near the tooth flanks that face one another and the tooth gap base.

27. A rear derailleur in accordance with claim 26 , wherein the at least one chain guide segment is arranged outside of the beveled area.

28. A rear derailleur in accordance with claim 26 , wherein the at least one chain guide segment extends into the beveled area.

29. A rear derailleur in accordance with claim 17 , wherein the at least one chain guide segment includes a projection that is polygonal when viewed in the direction of the rotational axis.

30. A rear derailleur in accordance with claim 29 , wherein the projection is embodied as a parallelogram, the radially outer surface of which runs one of tangential to the root circle and parallel to a tangent of the root circle.

31. A rear derailleur in accordance with claim 17 , wherein the wheel body has axial cut-outs arranged at regular angular distances.

Assignees

• Sram De Gmbh

Inventors

• Braedt Henrik
• Boehm Robert
• Hamisch Thorsten

Classifications

• B62M9/126 Primary

  Chain guides; Mounting thereof · CPC title

• F16H55/30 Primary

  Chain-wheels · CPC title