Sprocket wheel for a bicycle drive

Patent metadata

Field	Value
Publication number	US-10578201-B2
Application number	US-201615205180-A
Country	US
Kind code	B2
Filing date	Jul 8, 2016
Priority date	Jul 3, 2015
Publication date	Mar 3, 2020
Grant date	Mar 3, 2020

Abstract

An individual chain wheel for a bicycle front crank arrangement for engaging in a drive chain includes a plurality of teeth formed on a circumference of the chain wheel and having a first and a second group of teeth. The teeth of the second group of teeth are arranged in an alternating manner between the teeth of the first group of teeth. Each tooth has a load flank via which force is transmitted between an adjacent roller of the drive chain and the respective tooth. Each tooth of the first group may also have at least one profile with an opening in the vicinity of the flank, in which a portion of an inner link plate of the drive chain, which portion protrudes beyond the roller, engages.

First claim

The invention claimed is:

1. An individual chain wheel for a bicycle front crank arrangement for engaging in a drive chain, said individual chain wheel comprising:
a plurality of teeth formed on a circumference of the chain wheel and having a first and a second group of teeth, wherein the teeth of the second group of teeth are arranged in an alternating manner between the teeth of the first group of teeth,
wherein each tooth has a load flank via which force is transmitted between an adjacent roller of the drive chain and a respective tooth of the plurality of teeth,
wherein each tooth of the first group has at least one profile with an opening in a vicinity of the flank, the opening having an opening flank protruding from a side of the first set of teeth, and
wherein the load flank of the first set of teeth has a recess which is arranged radially outside and away from a contact point of a roller with the load flank during operation.

2. The individual chain wheel according to claim 1 , wherein the load flank of the at least one tooth of the first group of teeth has a load flank angle within a region of 110° and 125°.

3. The individual chain wheel according to claim 2 , wherein the load flank of the at least one tooth of the first group of teeth has a load flank angle within a region of 115°.

4. The individual chain wheel according to claim 1 , wherein at least one projection which engages, at least in sections, over the adjacent roller or the inner link plate is formed at least on every second tooth.

5. The individual chain wheel according to claim 4 , wherein the at least one projection is provided on a region of the respective tooth, which region lies radially on the outside with respect to a central axis of the individual chain wheel.

6. The individual chain wheel according to claim 5 , wherein the at least one projection connects the load flank and a radially outwardly facing upper side of the respective tooth.

7. The individual chain wheel according to claim 4 , wherein the at least one projection forms a hook projecting in a circumferential direction from the load flank.

8. The individual chain wheel according to claim 4 , wherein the at least one projection has, as viewed transversely with respect to a circumferential direction of the individual chain wheel, a smaller width than the load flank or is formed with a decreasing material thickness, as viewed in the circumferential direction.

9. The individual chain wheel according to claim 4 , wherein the at least one projection is provided in the at least one opening in the vicinity of the flank.

10. The individual chain wheel according to claim 9 , wherein the at least one projection is provided at one end of the at least one opening in the vicinity of the flank, wherein the at least one projection by means of a radially outer edge is adjacent to a region of the load flank.

11. The individual chain wheel according to claim 1 , wherein the first set of teeth include lateral flank edges of the load flank, and the opening flank is set back in the circumferential direction from the lateral flank edges.

12. The individual chain wheel according to claim 1 , wherein the recess has a curved contour.

13. The individual chain wheel according to claim 1 , wherein the recess extends over an entire width of the load flank.

14. The individual chain wheel according to claim 1 , wherein the load flank has a first recess free load flank portion which is adjacent to the recess radially inward with respect to a central axis of the chain wheel.

15. The individual chain wheel according to claim 14 , wherein the recess connects the first recess free load flank portion and a radially outer crest region or a radially outer side surface of the respective tooth, which side surface faces in a circumferential direction, wherein the recess by means of an end region, which lies radially on the inside with respect to the central axis of the chain wheel, is adjacent to the recess free load flank portion and by means of an end region, which lies radially on the outside with respect to the central axis of the chain wheel, is adjacent to the crest region or to the side surface which lies radially on the outside and faces in the circumferential direction.

16. The individual chain wheel according to claim 14 , wherein the load flank has a second recess free load flank portion which is adjacent to the recess radially outward with respect to the central axis of the chain wheel.

17. The individual chain wheel according to claim 16 , wherein the first and/or the second recess free load flank portion has a load flank angle within a region of 110° and 125°.

18. The individual chain wheel according to claim 17 , wherein the first and/or the second recess free load flank portion has a load flank angle within a region of 115°.

19. The individual chain wheel according to claim 1 , wherein each tooth has a counterload flank which is arranged opposite the load flank and is spaced apart therefrom, wherein the counterload flank is formed substantially symmetrically with respect to the load flank.

20. The individual chain wheel according to claim 1 , wherein, in a region of the profile, the opening in the vicinity of the flank is set back only in sections in relation to the load flank by a greater distance than the distance over which a portion of an inner link plate of the drive chain, which portion runs ahead during operation, protrudes over the roller.

21. The individual chain wheel according to claim 20 , wherein the opening in the vicinity of the flank has, in a region of a tooth crest, a projection pointing toward the load flank.

22. The individual chain wheel according to claim 1 , wherein the teeth of the second group of teeth in a radial direction of the individual chain wheel are formed with a lower height than the teeth of the first group of teeth.

23. The individual chain wheel according to claim 22 , wherein the teeth of the second group of teeth have a height of at maximum 90% of the height of the teeth of the first group of teeth.

24. The individual chain wheel according to claim 1 , wherein, between teeth of the first group of teeth and teeth of the second group of teeth on a rear side of a tooth of the second group of teeth, which rear side is opposite the load flank, or in a tooth gap adjacent to the load flank, the individual chain wheel has an outer contouring leading to local contact points or contact portions with a roller.

25. The individual chain wheel according to claim 24 , wherein the outer contouring is provided by adding at least one recess shaped as an arc of a circle, wherein a radius of the arc of the circle is smaller than the radius of the roller.

26. The individual chain wheel according to claim 1 , wherein at least one tooth of the first group of teeth and/or at least one tooth of the second group of teeth has at least one wear indicator in the form of a depression.

27. The individual chain wheel according to claim 26 , wherein the at least one wear indicator is formed in a region of the load flank of the respective tooth.

28. The individual chain wheel according to claim 26 , wherein the at least one wear indicator is formed in a region of a side surface of the respective tooth.

29. A front crank arrangement for a bicycle, the front crank arrangement comprising:
a crank arm; and
an individual chain wheel atta

Assignees

• Sram De Gmbh

Inventors

• Reiter Markus
• Hanke Joachim
• Johnson Bryn
• Vonend Andreas
• Kehrer Martin
• Braedt Henrik
• Santos Pedro Miguel Nunes Dos
• Figueiredo Luis
• Antunes Rodrigo

Classifications

• B62M9/105

  involving front sprocket chain-wheels engaged by the chain, belt or the like · CPC title

• F16H55/08

  Profiling · CPC title

• B62M9/00 Primary

  Transmissions characterised by use of an endless chain, belt, or the like (cycle chain guards B62J13/00) · CPC title

• F16H55/30 Primary

  Chain-wheels · CPC title

• F16H57/01

  Monitoring wear or stress of gearing elements, e.g. for triggering maintenance · CPC title