# US 11,028,916 B2 · Bicycle sprocket > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,028,916 B2 - Document ID: US11028916B2 - Status: Granted - Kind: B2 - Application number: 16/131,965 - Filed: 2018-09-14 - Published: 2019-04-04 - Granted: 2021-06-08 - Earliest claimed: 2017-10-03 - Assignees: Shimano Inc. - Applicants: Shimano Inc. - Inventors: Yasufumi Fukunaga; Tsuyoshi Fukumori - Web page: https://patentgrep.com/patent/US11028916B2 ## CPC - F16H 55/30: Chain-wheels - B62M 9/00: Transmissions characterised by use of an endless chain, belt, or the like (cycle chain guards B62J13/00) - B62M 9/12: the chain, belt, or the like being laterally shiftable {, e.g. using a rear derailleur} - F16H: GEARING - B62M: RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR {SINGLE-TRACK} CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES (arrangements or mounting of transmissions in vehicles in general B60K; transmission elements per se F16) ## Abstract A bicycle sprocket includes a base body, a first sprocket tooth and a shifting initiation tooth. The first sprocket tooth includes a drive surface including a drive surface side tooth tip end portion, a non-drive surface including a non-drive surface side tooth tip end portion and a tooth tip portion connecting the drive surface side tooth tip end portion and the non-drive surface side tooth tip end portion. The non-drive surface extends circumferentially with respect to the rotational center axis from the non-drive surface side tooth tip end portion toward a first surface. The tooth tip portion extends circumferentially in a first direction between the drive surface side tooth tip end portion and the non-drive surface side tooth tip end portion. The non-drive surface extends circumferentially from the non-drive surface side tooth tip end portion in a second direction that is inclined with respect to the first direction. ## Claims ### Claim 1 A bicycle sprocket comprising: a base body including a rotational center axis, a first surface and a second surface that is disposed on an opposite side of the first surface in an axial direction with respect to the rotational center axis; at least one first sprocket tooth extending radially outwardly from the base body in a radial direction with respect to the rotational center axis; and at least one shifting initiation tooth extending radially outwardly from the base body in the radial direction, the at least one shifting initiation tooth being different from the at least one first sprocket tooth, the at least one first sprocket tooth including a drive surface, a non-drive surface and a tooth tip portion, the at least one first sprocket tooth further including a boundary between the drive surface and the tooth tip portion being defined by a drive surface side tooth tip end portion, and a boundary between the non-drive surface and the tooth tip portion being defined by a non-drive surface side tooth tip end portion, the tooth tip portion connecting the drive surface side tooth tip end portion and the non-drive surface side tooth tip end portion, the non-drive surface extending circumferentially with respect to the rotational center axis from the non-drive surface side tooth tip end portion at least partially toward the first surface, the tooth tip portion extending circumferentially with respect to the rotational center axis in a first direction between the drive surface side tooth tip end portion and the non-drive surface side tooth tip end portion, and the non-drive surface extending circumferentially with respect to the rotational center axis from the non-drive surface side tooth tip end portion in a second direction that is inclined with respect to the first direction in the axial direction. ### Claim 2 (depends on 1) The bicycle sprocket according to claim 1, wherein the first surface is a center plane facing surface that faces a bicycle center plane of a bicycle in a state in which the base body is attached to the bicycle. ### Claim 3 (depends on 1) The bicycle sprocket according to claim 1, wherein the at least one first sprocket tooth includes a plurality of first sprocket teeth. ### Claim 4 (depends on 1) The bicycle sprocket according to claim 1, wherein the non-drive surface includes a non-drive surface protrusion, the non-drive surface extending circumferentially toward the first surface at least between the non-drive surface side tooth tip end portion and the non-drive surface protrusion. ### Claim 5 (depends on 4) The bicycle sprocket according to claim 4, wherein the non-drive surface protrusion is disposed radially inwardly from the non-drive surface side tooth tip end portion in the radial direction. ### Claim 6 (depends on 5) The bicycle sprocket according to claim 5, wherein the non-drive surface protrusion is disposed radially inwardly from the non-drive surface side tooth tip end portion by 1 mm or greater in the radial direction. ### Claim 7 (depends on 4) The bicycle sprocket according to claim 4, wherein the tooth tip portion is at least partially disposed on an opposite side of a sprocket center plane from the non-drive surface protrusion with respect to the axial direction, the sprocket center plane dividing the base body into halves as viewed in the radial direction toward the rotational center axis. ### Claim 8 (depends on 7) The bicycle sprocket according to claim 7, wherein at least most of the tooth tip portion is disposed on the opposite side of the sprocket center plane from the non-drive surface protrusion. ### Claim 9 (depends on 4) The bicycle sprocket according to claim 4, wherein the non-drive surface protrusion is disposed on a first surface side with respect to a sprocket center plane dividing the base body into halves as viewed in the radial direction toward the rotational center axis, and the tooth tip portion is at least partially disposed on a second surface side with respect to the sprocket center plane as viewed in the radial direction toward the rotational center axis. ### Claim 10 (depends on 9) The bicycle sprocket according to claim 9, wherein the non-drive surface protrusion is disposed on the first surface side with respect to the sprocket center plane, and most of the tooth tip portion is disposed on the second surface side with respect to the sprocket center plane. ### Claim 11 (depends on 1) The bicycle sprocket according to claim 1, wherein the drive surface side tooth tip end portion is disposed closer to the second surface than the non-drive surface side tooth tip end portion in the axial direction. ### Claim 12 (depends on 4) The bicycle sprocket according to claim 4, wherein the non-drive surface side tooth tip end portion is disposed closer to the second surface than the non-drive surface protrusion in the axial direction. ### Claim 13 (depends on 1) The bicycle sprocket according to claim 1, further comprising: at least one shifting facilitation area, the at least one first sprocket tooth and the at least one shifting initiation tooth being disposed within the at least one shifting facilitation area. ### Claim 14 (depends on 1) The bicycle sprocket according to claim 1, wherein the at least one first sprocket tooth is disposed on an adjacently downstream side of the at least one shifting initiation tooth in a drive rotational direction. ### Claim 15 (depends on 1) The bicycle sprocket according to claim 1, wherein the at least one first sprocket tooth includes a recessed portion formed from the second surface toward the first surface. ### Claim 16 (depends on 1) The bicycle sprocket according to claim 1, wherein the at least one shifting initiation tooth includes a plurality of shifting initiation teeth. ### Claim 17 (depends on 13) The bicycle sprocket according to claim 13, wherein the at least one shifting facilitation area includes a plurality of shifting facilitation areas. ### Claim 18 (depends on 1) The bicycle sprocket according to claim 1, wherein a total number of teeth is greater than or equal to 16. ### Claim 19 (depends on 1) The bicycle sprocket according to claim 1, wherein the base body further includes a bicycle hub engaging portion. ### Claim 20 (depends on 1) The bicycle sprocket according to claim 1, further comprising: at least one second sprocket tooth different from the at least one first sprocket tooth and the at least one shifting initiation tooth, the at least one first sprocket tooth having a circumferential chain engaging width greater than a circumferential chain engaging width of the at least one shifting initiation tooth or a circumferential chain engaging width of the at least one second sprocket tooth, or greater than both the circumferential chain engaging width of the at least one shifting initiation tooth and the circumferential chain engaging width of the at least one second sprocket tooth. ### Claim 21 (depends on 1) A bicycle sprocket assembly comprising the at least one bicycle sprocket according to claim 1, the bicycle sprocket assembly further comprising: a sprocket support member to which the at least one bicycle sprocket is attached. ### Claim 22 (depends on 21) The bicycle sprocket assembly according to claim 21, wherein the sprocket support member includes a bicycle hub engaging portion. ### Claim 23 A bicycle sprocket comprising: a base body including a rotational center axis, a first surface and a second surface that is disposed on an opposite side of the first surface in an axial direction with respect to the rotational center axis; at least one first sprocket tooth extending radially outwardly from the base body in a radial direction with respect to the rotational center axis; and at least one shifting initiation tooth extending radially outwardly from the base body in the radial direction, the at least one shifting initiation tooth being different from the at least one first sprocket tooth, the at least one first sprocket tooth including a drive surface, a non-drive surface and a tooth tip portion, the at least one first sprocket tooth further including a boundary between the drive surface and the tooth tip portion being defined by a drive surface side tooth tip end portion, and a boundary between the non-drive surface and the tooth tip portion being defined by a non-drive surface side tooth tip end portion, the tooth tip portion connecting the drive surface side tooth tip end portion and the non-drive surface side tooth tip end portion, the non-drive surface including a non-drive surface protrusion, the non-drive surface extending circumferentially with respect to the rotational center axis toward the first surface at least between the non-drive surface side tooth tip end portion and the non-drive surface protrusion, the non-drive surface protrusion being disposed radially inwardly from the non-drive surface side tooth tip end portion in the radial direction, and the tooth tip portion and the non-drive surface side tooth tip end portion each being at least partially disposed on an opposite side of a sprocket center plane from the non-drive surface protrusion with respect to the axial direction, the sprocket center plane dividing the base body into halves as viewed in the radial direction toward the rotational center axis. ### Claim 24 (depends on 23) The bicycle sprocket according to claim 23, wherein at least most of the tooth tip portion is disposed on the opposite side of the sprocket center plane from the non-drive surface protrusion. ### Claim 25 (depends on 23) The bicycle sprocket according to claim 23, further comprising: at least one second sprocket tooth different from the at least one first sprocket tooth, the at least one first sprocket tooth having a circumferential chain engaging width greater than a circumferential chain engaging width of the at least one shifting initiation tooth or a circumferential chain engaging width of the at least one second sprocket tooth, or greater than both the circumferential chain engaging width of the at least one shifting initiation tooth and the circumferential chain engaging width of the at least one second sprocket tooth. ### Claim 26 (depends on 23) The bicycle sprocket according to claim 23, wherein the tooth tip portion extends circumferentially with respect to the rotational center axis in a first direction between the drive surface side tooth tip end portion and the non-drive surface side tooth tip end portion, and the non-drive surface extends circumferentially with respect to the rotational center axis from the non-drive surface side tooth tip end portion in a second direction that is inclined with respect to the first direction in the axial direction. ### Claim 27 (depends on 23) The bicycle sprocket according to claim 23, wherein the first surface is a center plane facing surface that faces a bicycle center plane of a bicycle in a state in which the base body is attached to the bicycle. ### Claim 28 A bicycle sprocket comprising: a base body including a rotational center axis, a first surface and a second surface that is disposed on an opposite side of the first surface in an axial direction with respect to the rotational center axis; at least one first sprocket tooth extending radially outwardly from the base body in a radial direction with respect to the rotational center axis; and at least one shifting initiation tooth extending radially outwardly from the base body in the radial direction, the at least one shifting initiation tooth being different from the at least one first sprocket tooth, the at least one first sprocket tooth including a drive surface, a non-drive surface and a tooth tip portion, the at least one first sprocket tooth further including a boundary between the drive surface and the tooth tip portion being defined by a drive surface side tooth tip end portion, and a boundary between the non-drive surface and the tooth tip portion being defined by a non-drive surface side tooth tip end portion, the tooth tip portion connecting the drive surface side tooth tip end portion and the non-drive surface side tooth tip end portion, the non-drive surface including a non-drive surface protrusion, the non-drive surface extending circumferentially with respect to the rotational center axis toward the first surface at least between the non-drive surface side tooth tip end portion and the non-drive surface protrusion, the non-drive surface protrusion being disposed radially inwardly from the non-drive surface side tooth tip end portion in the radial direction, the tooth tip portion being at least partially disposed on an opposite side of a sprocket center plane from the non-drive surface protrusion with respect to the axial direction, the sprocket center plane dividing the base body into halves as viewed in the radial direction toward the rotational center axis, and at least most of the tooth tip portion is disposed on the opposite side of the sprocket center plane from the non-drive surface protrusion. ### Claim 29 A bicycle sprocket comprising: a base body including a rotational center axis, a first surface and a second surface that is disposed on an opposite side of the first surface in an axial direction with respect to the rotational center axis; at least one first sprocket tooth extending radially outwardly from the base body in a radial direction with respect to the rotational center axis; and at least one shifting initiation tooth extending radially outwardly from the base body in the radial direction, the at least one shifting initiation tooth being different from the at least one first sprocket tooth, the at least one first sprocket tooth including a drive surface, a non-drive surface and a tooth tip portion, the at least one first sprocket tooth further including a boundary between the drive surface and the tooth tip portion being defined by a drive surface side tooth tip end portion, and a boundary between the non-drive surface and the tooth tip portion being defined by a non-drive surface side tooth tip end portion, the tooth tip portion connecting the drive surface side tooth tip end portion and the non-drive surface side tooth tip end portion, the non-drive surface including a non-drive surface protrusion, the non-drive surface extending circumferentially with respect to the rotational center axis toward the first surface at least between the non-drive surface side tooth tip end portion and the non-drive surface protrusion, the non-drive surface protrusion being disposed radially inwardly from the non-drive surface side tooth tip end portion in the radial direction, the tooth tip portion being at least partially disposed on an opposite side of a sprocket center plane from the non-drive surface protrusion with respect to the axial direction, the sprocket center plane dividing the base body into halves as viewed in the radial direction toward the rotational center axis, the tooth tip portion extending circumferentially with respect to the rotational center axis in a first direction between the drive surface side tooth tip end portion and the non-drive surface side tooth tip end portion, and the non-drive surface extending circumferentially with respect to the rotational center axis from the non-drive surface side tooth tip end portion in a second direction that is inclined with respect to the first direction in the axial direction.