Bicycle sprocket and bicycle crank assembly

Patent metadata

Field	Value
Publication number	US-9540070-B2
Application number	US-201514723405-A
Country	US
Kind code	B2
Filing date	May 27, 2015
Priority date	May 27, 2015
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

A bicycle sprocket comprises a sprocket body and a chain engagement structure. The sprocket body has a rotational center axis, a first side and a second side opposite to the first side in an axial direction parallel to the rotational center axis. The chain engagement structure includes a plurality of sprocket teeth. The plurality of sprocket teeth include a plurality of first teeth and a plurality of second teeth. The plurality of first teeth each include an outer-link supporting surface, an opposite surface, and a first radially outermost tooth-tip. The opposite surface is spaced part from the second outer link plate in a state where the chain engagement structure engages with the bicycle chain. The plurality of second teeth each include a second radially outermost tooth-tip that is offset from the first radially outermost tooth-tip of each of the plurality of first teeth in the axial direction.

First claim

What is claimed is:

1. A bicycle sprocket comprising:
a sprocket body having a rotational center axis, a first side and a second side opposite to the first side in an axial direction parallel to the rotational center axis; and
a chain engagement structure disposed on an outer periphery of the sprocket body, the chain engagement structure including a plurality of sprocket teeth extending radially outward from the outer periphery of the sprocket body, the plurality of sprocket teeth including a plurality of first teeth and a plurality of second teeth, the plurality of first teeth being configured to engage with an opposed pair of a first outer link plate and a second outer link plate of a bicycle chain, the plurality of second teeth being configured to engage with an opposed pair of a first inner link plate and a second inner link plate of the bicycle chain, the plurality of first teeth each including
an outer-link supporting surface closer to the first side than to the second side in the axial direction and configured to support the first outer link plate at the first side,
an opposite surface opposite to the outer-link supporting surface in the axial direction, the opposite surface being spaced part from the second outer link plate in a state where the chain engagement structure engages with the bicycle chain, and
a first radially outermost tooth-tip positioned between the outer-link supporting surface and the opposite surface in the axial direction,

the plurality of second teeth each including
a second radially outermost tooth-tip that is offset from the first radially outermost tooth-tip of each of the plurality of first teeth in the axial direction, and
a first inner-link supporting surface closer to the first side than to the second side in the axial direction and configured to support the first inner link plate, and

at least one of the plurality of second teeth being disposed between two of the plurality of first teeth so that the at least one of the plurality of second teeth is adjacent to each of the two of the plurality of first teeth without another tooth between the at least one of the plurality of second teeth and each of the two of the plurality of first teeth.

2. The bicycle sprocket according to claim 1 , wherein
the plurality of first teeth are each positioned to be closer to the first side than the plurality of second teeth.

3. The bicycle sprocket according to claim 1 , wherein
the plurality of first teeth has a first axial chain-engagement width, and
the plurality of second teeth has a second axial chain-engagement width that is equal to or larger than the first axial chain-engagement width.

4. The bicycle sprocket according to claim 1 , wherein
a total number of the plurality of sprocket teeth is an even number.

5. The bicycle sprocket according to claim 4 , wherein
a total number of the plurality of first teeth is equal to a total number of the plurality of second teeth.

6. The bicycle sprocket according to claim 1 , wherein
the plurality of second teeth are arranged alternatingly between the plurality of first teeth.

7. The bicycle sprocket according to claim 1 , wherein
the plurality of sprocket teeth includes at least one third tooth configured to engage with a pair of outer link plates of a bicycle chain, the at least one third tooth having a chain-engagement width that is larger than an inner link space defined between a pair of inner link plates of the bicycle chain and smaller than an outer link space defined between a pair of outer link plates of the bicycle chain.

8. The bicycle sprocket according to claim 7 , wherein
a total number of the plurality of first teeth is less than a total number of the plurality of second teeth.

9. The bicycle sprocket according to claim 1 , wherein
at least one of the plurality of first teeth has an indicator to indicate that the at least one of the plurality of first teeth engages with outer link plates of the bicycle chain.

10. The bicycle sprocket according to claim 1 , wherein
the plurality of first teeth are offset from the plurality of second teeth toward the first side in the axial direction.

11. The bicycle sprocket according to claim 1 , wherein
at least one of the plurality of first teeth has a recess to avoid an excessive contact of the at least one of the plurality of first teeth with an inner link plate of the bicycle chain.

12. The bicycle sprocket according to claim 1 , wherein
the plurality of first teeth each have a recess to avoid an excessive contact of the plurality of first teeth with an inner link plate of the bicycle chain.

13. The bicycle sprocket according to claim 1 , wherein
the outer-link supporting surface is formed by bending the plurality of first teeth.

14. The bicycle sprocket according to claim 1 , wherein
the first side is closer to a bicycle frame than the second side in the axial direction in a state where the bicycle sprocket is mounted to the bicycle frame.

15. The bicycle sprocket according to claim 1 , wherein
the second side is closer to a bicycle frame than the first side in the axial direction in a state where the bicycle sprocket is mounted to the bicycle frame.

16. The bicycle sprocket according to claim 1 , further comprising:
a crank arm attachment portion.

17. A bicycle crank assembly comprising:
the bicycle sprocket according to claim 1 .

18. The bicycle crank assembly according to claim 17 , wherein
the bicycle sprocket is a single sprocket for the bicycle crank assembly.

19. A bicycle sprocket comprising:
a sprocket body having a rotational center axis, a first side and a second side opposite to the first side in an axial direction parallel to the rotational center axis; and
a chain engagement structure disposed on an outer periphery of the sprocket body, the chain engagement structure including a plurality of sprocket teeth extending radially outward from the outer periphery of the sprocket body, the plurality of sprocket teeth including a plurality of first teeth and a plurality of second teeth, the plurality of first teeth being configured to engage with an opposed pair of a first outer link plate and a second outer link plate of a bicycle chain, the plurality of second teeth being configured to engage with an opposed pair of a first inner link plate and a second inner link plate of the bicycle chain, the plurality of first teeth each including
an outer-link supporting surface closer to the first side than to the second side in the axial direction and configured to support the first outer link plate at the first side,
an opposite surface opposite to the outer-link supporting surface in the axial direction, the opposite surface being spaced part from the second outer link plate in a state where the chain engagement structure engages with the bicycle chain, and
a first radially outermost tooth-tip positioned between the outer-link supporting surface and the opposite surface in the axial direction,

the plurality of second teeth each including a second radially outermost tooth-tip that is offset from the first radially outermost tooth-tip of each of the plurality of first teeth in the axial direction,
at least one of the plurality of second teeth being disposed between two of the plurality of first teeth so that the at least one of the plurality of second teeth is adjacent to each of the two of the plurality of first teeth without another tooth between the at least one of the plurality of second teeth and each of the two of the plurality of first teeth,
the plurality

Assignees

• Shimano Kk

Inventors

• Watarai Etsuyoshi
• Kamada Kenji

Classifications

• B62M9/10 Primary

  involving different-sized wheels, {e.g. rear sprocket chain wheels} selectively engaged by the chain, belt, or the like {(bicycle hubs rotatably arranged on axle B60B27/023)} · CPC title

• F16H55/30 Primary

  Chain-wheels · CPC title

• B62M9/02 Primary

  of unchangeable ratio · CPC title

• B62M9/00

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

• B62M2009/007

  Guides to prevent chain from slipping off the sprocket · CPC title