BICYCLE SPROCKET

• US 20110092327A1
• Filed: 10/16/2009
• Published: 04/21/2011
• Est. Priority Date: 10/16/2009
• Status: Active Grant

• Current Assignee: Shimano Inc
• Original Assignee: Shimano Inc
• Inventors: OISHI, Toshinari
• Granted Patent: US 9,376,165 B2
• Time in Patent Office: Days
• US Class Current: 474/160
• CPC Class Codes: B62M 9/10 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

Abstract

A bicycle sprocket is provided with a sprocket body and a plurality of sprocket teeth. The sprocket teeth extend radially outward from a root circle of the sprocket body with the sprocket teeth being circumferentially spaced around the outer periphery of the sprocket body. The sprocket teeth include at least one shift assist tooth that assists in a shifting operation from the bicycle sprocket to a smaller sprocket. The shift assist tooth has a maximum radial height as measured from the root circle of the sprocket body. The maximum radial height of the shift assist tooth is larger than a maximum radial height of a majority of remaining ones of the sprocket teeth as measured from the root circle of the sprocket body. The shift assist tooth has a radially inclined surface sloping toward the smaller sprocket as the radially inclined surface approaches radially toward the center rotational axis A.

Claims

1. A bicycle sprocket comprising:

a sprocket body having a center rotational axis; and

a plurality of sprocket teeth extending radially outward from a root circle of the sprocket body with the sprocket teeth being circumferentially spaced around the outer periphery of the sprocket body,

the sprocket teeth including at least one shift assist tooth that assists in a shifting operation from the bicycle sprocket to a smaller sprocket, the at least one shift assist tooth having a maximum radial height as measured from the root circle of the sprocket body, the maximum radial height of the at least one shift assist tooth being larger than a maximum radial height of a majority of remaining ones of the sprocket teeth as measured from the root circle of the sprocket body, and the at least one shift assist tooth having a radially inclined surface sloping toward the smaller sprocket as the radially inclined surface approaches radially toward the center rotational axis.

2. The bicycle sprocket according to claim 1, wherein the at least one shift assist tooth includes two shift assist teeth.

3. The bicycle sprocket according to claim 2, wherein the two shift assist teeth are identical.

4. The bicycle sprocket according to claim 2, wherein the two shift assist teeth are consecutive teeth.

5. The bicycle sprocket according to claim 2, wherein the two shift assist teeth are non-consecutive teeth.

6. The bicycle sprocket according to claim 1, wherein

the sprocket teeth includes a first engagement tooth that is engaged when a bicycle chain is shifted from the sprocket toward a larger sprocket, the at least one shift assist tooth being located within five teeth from the first engagement tooth in an upstream direction with respect to a rotational direction of the bicycle sprocket.

7. The bicycle sprocket according to claim 6, wherein

the sprocket teeth includes a recessed portion formed in a root portion of a smaller sprocket facing side surface of the sprocket body at a tooth of the sprocket teeth adjacent the first engagement tooth in a downstream direction with respect to the rotational direction of the bicycle sprocket.

8. The bicycle sprocket according to claim 6, wherein

the sprocket teeth includes a recessed portion formed in a root portion of a larger sprocket facing side surface of the sprocket body at a tooth of the sprocket teeth that is located downstream of the at least one shift assist tooth in a downstream direction with respect to the rotational direction of the bicycle sprocket and upstream of the first engagement tooth in the upstream direction with respect to the rotational direction of the bicycle sprocket.

9. The bicycle sprocket according to claim 6, wherein

the sprocket teeth includes a recessed portion formed in a root portion of a larger sprocket facing side surface of the sprocket body at a tooth of the sprocket teeth that is within two teeth from the at least one shift assist tooth in a downstream direction with respect to the rotational direction of the bicycle sprocket.

10. The bicycle sprocket according to claim 6, wherein

the sprocket teeth includes a recessed portion formed in a root portion of a larger sprocket facing side surface of the sprocket body at a tooth of the sprocket teeth adjacent the at least one shift assist tooth in a downstream direction with respect to the rotational direction of the bicycle sprocket.

11. The bicycle sprocket according to claim 6, wherein

the sprocket teeth includes two consecutive recessed portions formed in a root portion of a larger sprocket facing side surface of the sprocket body at two consecutive teeth of the sprocket teeth, respectively, with the two consecutive teeth being located consecutively adjacent the at least one shift assist tooth in a downstream direction with respect to the rotational direction of the bicycle sprocket.