Bicycle sprocket and bicycle sprocket assembly

Patent metadata

Field	Value
Publication number	US-10584785-B2
Application number	US-201715595345-A
Country	US
Kind code	B2
Filing date	May 15, 2017
Priority date	Jun 27, 2016
Publication date	Mar 10, 2020
Grant date	Mar 10, 2020

Abstract

A bicycle sprocket includes a first sprocket body and a plurality of first sprocket teeth. The first sprocket teeth include a plurality of tooth tip portions and a plurality of tooth bottom portions. The tooth bottom portions include at least one first tooth bottom portion and at least one second tooth bottom portion. The at least one first tooth bottom portion has a first tooth bottom shape. The at least one second tooth bottom portion has a second tooth bottom shape. The first tooth bottom shape is different from the second tooth bottom shape.

First claim

What is claimed is:

1. A bicycle sprocket having a rotational center axis, the bicycle sprocket comprising:
a sprocket body; and
a plurality of sprocket teeth that extend outwardly in a radial direction with respect to the rotational center axis from the sprocket body, each of the plurality of sprocket teeth being separated by a gap;
the sprocket teeth including a plurality of tooth tip portions and a plurality of tooth bottom portions, each of the tooth bottom portions being defined by a gap separating each of the plurality of sprocket teeth, each of the tooth bottom portions being located between a pair of the tooth tip portions that are adjacent to each other in a circumferential direction with respect to the rotational center axis;
the tooth bottom portions including at least one tooth having a first tooth bottom portion with a first tooth bottom shape and at least one other tooth having a second tooth bottom portion with a second tooth bottom shape; and
the first tooth bottom shape being different from the second tooth bottom shape.

2. The bicycle sprocket according to claim 1 , wherein
the second tooth bottom shape is formed such that a tooth bottom diameter on an upstream side with respect to a drive rotation direction of the bicycle sprocket is smaller than a tooth bottom diameter on a downstream side with respect to the drive rotation direction.

3. The bicycle sprocket according to claim 1 , wherein
the second tooth bottom portion includes a linear portion.

4. The bicycle sprocket according to claim 1 , wherein
the first tooth bottom shape is symmetric with respect to a tooth bottom center line extending in the radial direction.

5. The bicycle sprocket according to claim 1 , wherein
the second tooth bottom shape is asymmetric with respect to a tooth bottom center line extending in the radial direction.

6. The bicycle sprocket according to claim 1 , wherein
the tooth bottom portions includes a plurality of first tooth bottom portions.

7. The bicycle sprocket according to claim 6 , wherein
at least two of the first tooth bottom portions are disposed side by side in the circumferential direction.

8. The bicycle sprocket according to claim 1 , wherein
the tooth bottom portions includes a plurality of second tooth bottom portions.

9. The bicycle sprocket according to claim 8 , wherein
at least two of the second tooth bottom portions are disposed side by side in the circumferential direction.

10. The bicycle sprocket according to claim 1 , wherein
a total number of the first tooth bottom portions and a total number of the second tooth bottom portions are different from each other.

11. The bicycle sprocket according to claim 10 , wherein
the total number of the first tooth bottom portions is greater than the total number of the second tooth bottom portions.

12. The bicycle sprocket according to claim 1 , further comprising
an upward gear shift region that facilitates displacement of a bicycle chain from a small sprocket toward the bicycle sprocket, the small sprocket having less teeth than the bicycle sprocket and being adjacent to the bicycle sprocket in an axial direction that is parallel to the rotational center axis.

13. The bicycle sprocket according to claim 12 , wherein
the upward gear shift region includes a plurality of upward gear shift regions.

14. The bicycle sprocket according to claim 13 , wherein
at least one of the upward gear shift regions is provided in a vicinity of the second tooth bottom portions.

15. The bicycle sprocket according to claim 1 , further comprising
a downward gear shift region that facilitates displacement of a bicycle chain from the bicycle sprocket toward a small sprocket having less teeth than the bicycle sprocket, the small sprocket being adjacent to the bicycle sprocket in an axial direction that is parallel to the rotational center axis.

16. The bicycle sprocket according to claim 15 , wherein
the downward gear shift region includes a plurality of downward gear shift regions.

17. The bicycle sprocket according to claim 16 , wherein
at least one of the downward gear shift regions is provided in a vicinity of the second tooth bottom portions.

18. The bicycle sprocket according to claim 8 , wherein
the second tooth bottom portions are disposed sequentially in the circumferential direction.

19. The bicycle sprocket according to claim 1 wherein
the tooth bottom portions include at least one third tooth bottom portion having a third tooth bottom shape.

20. The bicycle sprocket according to claim 1 , wherein
a total number of the sprocket teeth is equal to or less than twenty.

21. The bicycle sprocket according to claim 20 , wherein
the total number of the sprocket teeth is equal to or less than fifteen.

22. A bicycle sprocket assembly comprising the bicycle sprocket according to claim 1 , and further comprising
an additional sprocket disposed adjacent the bicycle sprocket in an axial direction that is parallel to the rotational center axis.

23. The bicycle sprocket assembly according to claim 22 , wherein
the bicycle sprocket is a rear sprocket.

24. The bicycle sprocket assembly according to claim 22 , wherein
the bicycle sprocket is a front sprocket.

Assignees

• Shimano Kk

Inventors

• Kamada Kenji

Classifications

• B62M9/04

  of changeable ratio · CPC title

• F16H55/0873 Primary

  for improving axial engagement, e.g. a chamfer at the end of the tooth flank · CPC title

• F16H55/08

  Profiling · CPC title

• B62M9/124

  Mechanisms for shifting laterally · CPC title

• B21K1/30

  with gear-teeth · CPC title