Bicycle sprocket assembly and bicycle sprocket

Abstract

A bicycle sprocket assembly includes a first sprocket and a second sprocket. The first sprocket includes a plurality of first sprocket teeth, an inner surface of the first sprocket, an outer surface of the first sprocket, and an axial space. The second sprocket includes a plurality of second sprocket teeth, an inner surface of the second sprocket, and an outer surface of the second sprocket. In a meshing state where one of the plurality of second sprocket teeth is located between an axially inward inner link plate and an axially outward inner link plate in the axial direction, when the outer surface of the second sprocket contacts the axially outward inner link plate, the axial space is defined to be between the outer surface of the first sprocket and the axially inward outer link plate in the axial direction. The axial space is greater than 0 mm and equal to or less than 0.15 mm.

Description

[0001] This application is a divisional application of a Chinese patent application with an application date of August 19, 2021, an application number of 2021109550420, and an invention title of "Bicycle Sprocket Assembly and Bicycle Sprocket". Technical Field

[0002] The present invention relates to a bicycle sprocket assembly and a bicycle sprocket. Background Art

[0003] Human-powered vehicles include a sprocket assembly configured to engage with a chain. For example, such a sprocket assembly is known from U.S. Patent No. 4,889,521 and U.S. Patent No. 6,340,338. Based on this prior art, an object of the present invention is to provide a bicycle sprocket assembly with smooth shifting performance. Another object of the present invention is to provide a bicycle sprocket with high rigidity. The bicycle sprocket assembly and the bicycle sprocket according to the present invention can be used for an electric-assisted bicycle that applies not only human torque but also motor torque to the bicycle sprocket. Summary of the Invention

[0004] According to a first aspect of the present invention, a bicycle sprocket assembly includes a first sprocket and a second sprocket. The first sprocket includes a first sprocket body, a plurality of first sprocket teeth, a first sprocket inner surface, and a first sprocket outer surface. The plurality of first sprocket teeth are provided on the outer peripheral edge of the first sprocket body. The plurality of first sprocket teeth define a first maximum tip diameter. The first sprocket inner surface is configured to face the axial center plane of the bicycle in an installed state where the bicycle sprocket assembly is installed on the bicycle. The first sprocket outer surface is disposed on the opposite side of the first sprocket inner surface in the axial direction with respect to the rotation center axis of the bicycle sprocket. The second sprocket is adjacent to the first sprocket in the axial direction and there is no other sprocket therebetween. The second sprocket includes a second sprocket body, a plurality of second sprocket teeth, a second sprocket inner surface, and a second sprocket outer surface. The plurality of second sprocket teeth are provided on the outer peripheral edge of the second sprocket body. The plurality of second sprocket teeth define a second maximum tip diameter, and the second maximum tip diameter is smaller than the first maximum tip diameter. The second sprocket inner surface is configured to face the axial center plane of the bicycle in the installed state. The second sprocket outer surface is disposed on the opposite side of the second sprocket inner surface in the axial direction. The first sprocket includes an upshift promoting section and an axial space. The upshift promoting section is configured to promote an upshift operation of the bicycle chain from the first sprocket toward the second sprocket. In a meshing state where one of the plurality of second sprocket teeth is axially located between an axially inward inner link plate and an axially outward inner link plate of a pair of opposing inner link plates, when the second sprocket outer surface of the one of the plurality of second sprocket teeth contacts the axially outward inner link plate of the pair of opposing inner link plates of the bicycle chain, the axial space is defined to be between the first sprocket outer surface of one of the plurality of first sprocket teeth and the axially inward outer link plate of a pair of opposing outer link plates of the bicycle chain in the axial direction. In an assembled state of the bicycle chain, the axially inward outer link plate and the axially outward outer link plate of the pair of opposing outer link plates are spaced apart from each other in the axial direction. In an assembled state of the bicycle chain, the axially inward inner link plate and the axially outward inner link plate of the pair of opposing inner link plates are spaced apart from each other in the axial direction. The axial space is greater than 0 mm and equal to or less than 0.15 mm.

[0005] With the bicycle sprocket assembly according to the first aspect, if the axial space is equal to or less than 0 mm, an unintentional downshift operation of the bicycle sprocket from the second sprocket toward the first sprocket may occur. Such an unintentional downshift operation may cause a greater impact. If the axial space is greater than 0.15 mm, the downshift operation is likely to fail undesirably. Therefore, compared with the first sprocket where the axial space is equal to or less than 0 mm or greater than 0.15 mm, if a bicycle rider operates a downshift operation, the impact in the downshift operation can be reduced while ensuring the downshift operation.

[0006] According to a second aspect of the present invention, the bicycle sprocket assembly according to the first aspect is configured such that the first sprocket includes a downshift promoting section, and the downshift promoting section is configured to promote a downshift operation in which the bicycle chain shifts from the second sprocket toward the first sprocket.

[0007] With the bicycle sprocket assembly according to the second aspect, compared with the first sprocket without a downshift promoting section, it is possible to effectively reduce the impact during the downshift operation and at the same time reduce an unintentional downshift operation.

[0008] According to a third aspect of the present invention, a bicycle sprocket includes a sprocket body, an inner side of the sprocket, an outer side of the sprocket, and a plurality of sprocket teeth. The inner side of the sprocket is configured to be closer to the axial center plane of the bicycle than the outer side of the sprocket in a state where the bicycle sprocket is mounted to the bicycle. The outer side of the sprocket is provided on the opposite side of the inner side of the sprocket in the axial direction with respect to the rotation center axis of the bicycle sprocket. The plurality of sprocket teeth are provided on the outer peripheral edge of the sprocket body. The plurality of sprocket teeth include at least one recessed tooth, and the recessed tooth has at least one recessed portion that recesses from the outer side of the sprocket toward the inner side of the sprocket. The at least one recessed portion has an upstream end in the circumferential direction and a downstream end in the circumferential direction that is opposite to the upstream end in the circumferential direction with respect to the rotation center axis and opposite to the driving rotation direction. The upstream end in the circumferential direction has a first axial thickness defined on the pitch circle of the bicycle sprocket. The downstream end in the circumferential direction has a second axial thickness defined on the pitch circle of the bicycle sprocket. The second axial thickness is smaller than the first axial thickness. The first axial thickness is equal to or greater than 1.3 mm. The third aspect may be combined with the first aspect or the second aspect.

[0009] With the bicycle sprocket according to the third aspect, the at least one recessed tooth suppresses an increase in the weight of the bicycle sprocket because the at least one recessed tooth has a second axial thickness smaller than the first axial thickness. In addition, since the first axial thickness is equal to or greater than 1.3 mm, the strength of the at least one recessed tooth is ensured as compared with a bicycle sprocket having a first axial thickness of less than 1.3 mm. Therefore, it is possible to ensure the strength of the at least one recessed tooth while suppressing an increase in the weight of the bicycle sprocket.

[0010] According to a fourth aspect of the present invention, the bicycle sprocket according to the third aspect of the present invention is configured such that each of the plurality of sprocket teeth is configured to enter each of an outer link space defined between a pair of opposing outer link plates of the bicycle chain and an inner link space defined between a pair of opposing inner link plates of the bicycle chain.

[0011] With the bicycle sprocket according to the fourth aspect, the total number of the plurality of sprocket teeth may be an odd number.

[0012] According to a fifth aspect of the present invention, the bicycle sprocket according to the third or fourth aspect is configured such that at least one recessed portion has an inclined surface extending between an upstream end portion and a downstream end portion in the circumferential direction.

[0013] With the bicycle sprocket according to the fifth aspect, the inclined surface can make the downshifting operation smoother and reduce noise and / or wear of the bicycle sprocket during the downshifting operation.

[0014] According to a sixth aspect of the present invention, the bicycle sprocket according to the third or fourth aspect is configured such that at least one recessed portion has at least one stepped surface provided between an upstream end portion and a downstream end portion in the circumferential direction.

[0015] With the bicycle sprocket according to the sixth aspect, the dimensional accuracy of at least one recessed portion can be improved, thereby improving the manufacturing efficiency of the bicycle sprocket.

[0016] According to a seventh aspect of the present invention, the bicycle sprocket according to the sixth aspect is configured such that at least one stepped surface of at least one recess forms at least three steps.

[0017] With the bicycle sprocket according to the seventh aspect, the dimensional accuracy of at least one recessed portion can be improved, thereby improving the manufacturing efficiency of the bicycle sprocket.

[0018] According to an eighth aspect of the present invention, the bicycle sprocket according to any one of the third to seventh aspects further includes an upshifting promotion section and a downshifting promotion section. The upshifting promotion section is configured to promote an upshifting operation of the bicycle chain from the bicycle sprocket toward a smaller sprocket, the smaller sprocket being adjacent to the bicycle sprocket in the axial direction and having no other sprocket therebetween. The downshifting promotion section is configured to promote a downshifting operation of the bicycle chain from the smaller sprocket toward the bicycle sprocket. The downshifting promotion section is provided on the upstream side of the upshifting promotion section in the circumferential direction.

[0019] With the bicycle sprocket according to the eighth aspect, the width of some of the plurality of sprocket teeth can be increased, thereby improving the strength of the bicycle sprocket.

[0020] According to a ninth aspect of the present invention, the bicycle sprocket according to the eighth aspect is configured such that the upshifting promotion section is formed by a first set of teeth among the plurality of sprocket teeth. The downshifting promotion section is formed by a second set of teeth among the plurality of sprocket teeth. The second set of teeth is completely different from the first set of teeth.

[0021] With the bicycle sprocket according to the ninth aspect, the thickness of some of the plurality of sprocket teeth can be increased, thereby improving the strength of the bicycle sprocket.

[0022] According to a tenth aspect of the present invention, a bicycle sprocket includes a sprocket body, a plurality of sprocket teeth, an upshift promotion section, and a downshift promotion section. The plurality of sprocket teeth are provided on an outer peripheral edge of the sprocket body. The upshift promotion section is configured to promote an upshift operation of a bicycle chain from the bicycle sprocket toward a smaller sprocket, the smaller sprocket being adjacent to the bicycle sprocket in an axial direction with respect to a rotation center axis of the bicycle sprocket and having no other sprocket therebetween. The upshift promotion section is formed by a first tooth group among the plurality of sprocket teeth. The downshift promotion section is configured to promote a downshift operation of the bicycle chain from the smaller sprocket toward the bicycle sprocket. The downshift promotion section is formed by a second tooth group among the plurality of sprocket teeth. The second tooth group is completely different from the first tooth group. The downshift promotion section is provided on an upstream side of the upshift promotion section in a circumferential direction with respect to the rotation center axis of the bicycle sprocket and with respect to a driving rotation direction. At least one of the plurality of sprocket teeth has an axial tooth root thickness equal to or greater than 1.7 mm. The tenth aspect may be combined with any one of the first to ninth aspects.

[0023] By using the bicycle sprocket according to the tenth aspect, it is possible to improve the durability of the bicycle sprocket while reducing an impact in at least one of an upshift operation and a downshift operation.

[0024] According to an eleventh aspect of the present invention, the bicycle sprocket according to the tenth aspect is configured such that the first tooth group of the upshift promotion section is adjacent to the second tooth group of the downshift promotion section and has no other tooth therebetween.

[0025] By using the bicycle sprocket according to the eleventh aspect, it is possible to further improve the durability of the bicycle sprocket while reducing an impact in at least one of an upshift operation and a downshift operation.

[0026] According to a twelfth aspect of the present invention, the bicycle sprocket according to the tenth or eleventh aspect of the present invention is configured such that each of the plurality of sprocket teeth is configured to enter each of an outer link space defined between a pair of opposing outer link plates of the bicycle chain and an inner link space defined between a pair of opposing inner link plates of the bicycle chain.

[0027] By using the bicycle sprocket according to the twelfth aspect, the total number of the plurality of sprocket teeth may be an odd number.

[0028] According to a thirteenth aspect of the present invention, a bicycle sprocket includes a sprocket body, an inner sprocket side, an outer sprocket side, and a plurality of sprocket teeth. The inner sprocket side is configured to be closer to the axial center plane of the bicycle than the outer sprocket side in a mounted state where the bicycle sprocket is mounted to the bicycle. The outer sprocket side is disposed on the opposite side of the inner sprocket side in the axial direction with respect to the rotation center axis of the bicycle sprocket. The plurality of sprocket teeth are provided on the outer peripheral edge of the sprocket body. At least one of the plurality of sprocket teeth has a tooth tip, a tooth root, and at least one tooth tip chamfer formed on the tooth tip in at least one of the outer sprocket side and the inner sprocket side. At least one tooth tip chamfer has a radially outermost end portion and a radially innermost end portion with respect to the rotation center axis of the bicycle sprocket. It is defined that a radial tooth tip distance from the tooth root to the tooth tip in the radial direction with respect to the rotation center axis is equal to or greater than 4.5 mm. It is defined that a radial chamfer distance from the tooth root to the radially innermost end portion of at least one tooth tip chamfer in the radial direction is equal to or greater than 3 mm. The thirteenth aspect can be combined with any one of the first to twelfth aspects.

[0029] With the bicycle sprocket according to the thirteenth aspect, the radial tooth tip distance and the radial chamfer distance maintain the thickness of at least one of the plurality of sprocket teeth, while the tooth tip chamfer ensures smooth engagement of at least one of the plurality of sprocket teeth with the bicycle chain. Therefore, the durability of the bicycle sprocket can be improved.

[0030] According to a fourteenth aspect of the present invention, the bicycle sprocket according to the thirteenth aspect is configured such that the tooth tip has a circumferentially upstream tooth tip end portion and a circumferentially downstream tooth tip end portion in the circumferential direction with respect to the rotation center axis and opposite to the circumferentially upstream tooth tip end portion with respect to the driving rotation direction. The circumferentially upstream tooth tip end portion has a convex curved portion configured to contact a chain roller of the bicycle chain during a driving operation of the bicycle.

[0031] With the bicycle sprocket according to the fourteenth aspect, the convex curved portion further reduces the wear of at least one of the plurality of sprocket teeth. Therefore, the durability of the bicycle sprocket can be reliably improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] By referring to the following detailed description in conjunction with the accompanying drawings, it can be easily obtained and the more complete intention of the present invention and many of its attendant advantages can be better understood.

[0033] Figure 1 is a schematic view of a bicycle including a bicycle sprocket assembly according to an embodiment.

[0034] Figure 2 is Figure 1 a side elevational view of the bicycle sprocket assembly of the bicycle shown in

[0035] Figure 3is taken along Figure 2 section III-III of the bicycle sprocket assembly shown in the figure.

[0036] Figures 4 to 13 is Figure 2 a side elevation view of the bicycle sprocket of the bicycle sprocket assembly shown in the figure.

[0037] Figure 14 is Figures 11 to 13 a side elevation view of the bicycle sprocket of the bicycle sprocket assembly shown in the figure.

[0038] Figure 15 is taken along Figure 14 section XV-XV of the bicycle sprocket assembly shown in the figure.

[0039] Figure 16 is Figure 11 another side elevation view of the bicycle sprocket shown in the figure.

[0040] Figure 17 is Figure 12 another side elevation view of the bicycle sprocket shown in the figure.

[0041] Figure 18 is Figure 13 another side elevation view of the bicycle sprocket shown in the figure.

[0042] Figure 19 is Figure 11 an enlarged side elevation view of the bicycle sprocket shown in the figure.

[0043] Figure 20 is taken along Figure 19 section XX-XX of the bicycle sprocket shown in the figure.

[0044] Figure 21 is a sectional view of a bicycle sprocket according to a variant.

[0045] Figure 22 is taken along Figure 11 section XXII-XXII of the bicycle sprocket shown in the figure.

[0046] Figure 23 is taken along Figure 19 section XXIII-XXIII of the bicycle sprocket shown in the figure.

[0047] Figure 24 is taken along Figure 19 section XXIV-XXIV of the bicycle sprocket shown in the figure.

[0048] Figure 25 is Figure 2Side elevation view of a bicycle sprocket of the bicycle sprocket assembly shown in the figure.

[0049] Figure 26 is a cross-sectional view of the bicycle sprocket taken along line XXVI-XXVI of Figure 25 .

[0050] Figure 27 is Figure 25 an enlarged side elevation view of the bicycle sprocket shown in

[0051] Figure 28 is Figure 25 another enlarged side elevation view of the bicycle sprocket shown in DETAILED DESCRIPTION

[0052] Embodiments will now be described with reference to the accompanying drawings, in which like reference numerals in the various drawings refer to corresponding or identical elements.

[0053] As Figure 1 shown, bicycle 2 includes bicycle drivetrain 10. Bicycle drivetrain 10 includes bicycle hub assembly 12 and bicycle sprocket assembly 14. Bicycle hub assembly 12 is fixed to bicycle frame BF. Bicycle sprocket assembly 14 is mounted on bicycle hub assembly 12. Bicycle sprocket assembly 14 is rotatably supported by bicycle hub assembly 12 about a center axis of rotation A1 relative to bicycle frame BF. Bicycle 2 has an axial center plane CP.

[0054] Bicycle drivetrain 10 further includes crank assembly 18 and bicycle chain 20. Crank assembly 18 includes crankshaft 22, right crank arm 24, left crank arm 26, and front sprocket 27. Right crank arm 24 and left crank arm 26 are fixed to crankshaft 22. Front sprocket 27 is fixed to at least one of crankshaft 22 and right crank arm 24. Bicycle chain 20 engages front sprocket 27 and bicycle sprocket assembly 14 to transmit pedaling force from front sprocket 27 to bicycle sprocket assembly 14. Crank assembly 18 includes front sprocket 27 as a single sprocket in this embodiment. However, crank assembly 18 may include multiple front sprockets. Bicycle sprocket assembly 14 is a rear sprocket assembly. However, the structure of bicycle sprocket assembly 14 may be applied to a front sprocket.

[0055] In the present application, the following directional terms "front", "rear", "forward", "backward", "left", "right", "lateral", "upward", and "downward", and any other similar directional terms refer to directions determined based on a user (e.g., a rider) sitting on the seat of the bicycle (not shown) and facing the handlebars (not shown). Thus, as used to describe bicycle sprocket assembly 14, these terms should be interpreted relative to a bicycle equipped with bicycle sprocket assembly 14 in an upright riding position on a horizontal plane.

[0056] As Figure 2 shown, the bicycle sprocket assembly 14 is configured to engage with the bicycle chain 20 to transmit a driving rotational force F1 between the bicycle chain 20 and the bicycle sprocket assembly 14 during pedaling. The bicycle sprocket assembly 14 rotates about the rotational center axis A1 in the driving rotational direction D11 during pedaling. The driving rotational direction D11 is defined as along the circumferential direction D1 of the bicycle hub assembly 12 or the bicycle sprocket assembly 14. The reverse rotational direction D12 is the opposite direction of the driving rotational direction D11 and is defined as along the circumferential direction D1.

[0057] The bicycle sprocket assembly 14 includes a plurality of bicycle sprockets SP. The plurality of bicycle sprockets SP are configured to engage with the bicycle chain 20 to transmit a driving rotational force F1 between the bicycle chain 20 and the bicycle sprocket assembly 14 during pedaling. In the present embodiment, the plurality of bicycle sprockets SP include bicycle sprockets SP1 to SP11. Each of the bicycle sprockets SP1 to SP11 is configured to engage with the bicycle chain 20 to transmit a driving rotational force F1 between the bicycle chain 20 and the bicycle sprocket assembly 14 during pedaling. However, the total number of the bicycle sprockets SP is not limited to the present embodiment.

[0058] As Figure 3 shown, the bicycle sprockets SP1 to SP11 are arranged in the axial direction D2 with respect to the rotational center axis A1. The sprockets are coupled to each other by fasteners. The bicycle sprocket assembly 14 further includes a locking member 32. The locking member 32 is fixed to the sprocket support body of the bicycle hub assembly 12 ( Figure 1 ) to hold the bicycle sprocket assembly 14 relative to the sprocket support body of the bicycle hub assembly 12 ( Figure 1 ) in the axial direction D2.

[0059] The bicycle sprocket assembly 14 includes a plurality of coupling rods 34, a plurality of coupling members 35, and a plurality of spacers 36. The plurality of coupling rods 34 are configured to couple at least two of the bicycle sprockets SP1 to SP11. In the present embodiment, the plurality of coupling rods 34 are configured to couple the sprockets SP2 to SP8. The plurality of coupling members 35 are configured to connect the sprockets SP1 and SP2. The spacers 36 are arranged in the axial direction D2 between two adjacent ones of the plurality of sprockets SP2 to SP9 to provide an appropriate axial space between the two adjacent sprockets.

[0060] In the present embodiment, the bicycle sprockets SP1 and SP2 may also be referred to as the first sprocket SP1 and the second sprocket SP2. The bicycle sprockets SP2 and SP3 may also be referred to as the first sprocket SP2 and the second sprocket SP3. The bicycle sprockets SP3 and SP4 may also be referred to as the first sprocket SP3 and the second sprocket SP4. The bicycle sprockets SP4 and SP5 may also be referred to as the first sprocket SP4 and the second sprocket SP5. The bicycle sprockets SP5 and SP6 may also be referred to as the first sprocket SP5 and the second sprocket SP6. The bicycle sprockets SP6 and SP7 may also be referred to as the first sprocket SP6 and the second sprocket SP7. The bicycle sprockets SP7 and SP8 may also be referred to as the first sprocket SP7 and the second sprocket SP8. The bicycle sprockets SP8 and SP9 may also be referred to as the first sprocket SP8 and the second sprocket SP9. The bicycle sprockets SP9 and SP10 may also be referred to as the first sprocket SP9 and the second sprocket SP10. The bicycle sprockets SP10 and SP11 may also be referred to as the first sprocket SP10 and the second sprocket SP11.

[0061] In other words, the bicycle sprocket assembly 14 includes the first sprocket SP1 and the second sprocket SP2. The bicycle sprocket assembly 14 includes the first sprocket SP2 and the second sprocket SP3. The bicycle sprocket assembly 14 includes the first sprocket SP3 and the second sprocket SP4. The bicycle sprocket assembly 14 includes the first sprocket SP4 and the second sprocket SP5. The bicycle sprocket assembly 14 includes the first sprocket SP5 and the second sprocket SP6. The bicycle sprocket assembly 14 includes the first sprocket SP6 and the second sprocket SP7. The bicycle sprocket assembly 14 includes the first sprocket SP7 and the second sprocket SP8. The bicycle sprocket assembly 14 includes the first sprocket SP8 and the second sprocket SP9. The bicycle sprocket assembly 14 includes the first sprocket SP9 and the second sprocket SP10. The bicycle sprocket assembly 14 includes the first sprocket SP10 and the second sprocket SP11.

[0062] As Figure 4 shown, the bicycle sprocket SP1 includes a sprocket body SP1A and a plurality of sprocket teeth SP1B. The plurality of sprocket teeth SP1B extend radially outward from the sprocket body SP1A. The plurality of sprocket teeth SP1B are disposed on the outer peripheral edge of the sprocket body SP1A. The plurality of sprocket teeth SP1B define a maximum addendum diameter DM1. The sprocket body SP1A may also be referred to as the first or second sprocket body SP1A. The plurality of sprocket teeth SP1B may also be referred to as a plurality of first or second sprocket teeth SP1B.

[0063] As Figure 5As shown, the bicycle sprocket SP2 includes a sprocket body SP2A and a plurality of sprocket teeth SP2B. The plurality of sprocket teeth SP2B extend radially outward from the sprocket body SP2A. The plurality of sprocket teeth SP2B are provided on the outer peripheral edge of the sprocket body SP2A. The plurality of sprocket teeth SP2B define a maximum outside diameter at the tip of teeth DM2. The sprocket body SP2A may also be referred to as the first or second sprocket body SP2A. The plurality of sprocket teeth SP2B may also be referred to as the plurality of first or second sprocket teeth SP2B.

[0064] As Figure 6 shown, the bicycle sprocket SP3 includes a sprocket body SP3A and a plurality of sprocket teeth SP3B. The plurality of sprocket teeth SP3B extend radially outward from the sprocket body SP3A. The plurality of sprocket teeth SP3B are provided on the outer peripheral edge of the sprocket body SP3A. The plurality of sprocket teeth SP3B define a maximum outside diameter at the tip of teeth DM3. The sprocket body SP3A may also be referred to as the first or second sprocket body SP3A. The plurality of sprocket teeth SP3B may also be referred to as the plurality of first or second sprocket teeth SP3B.

[0065] As Figure 7 shown, the bicycle sprocket SP4 includes a sprocket body SP4A and a plurality of sprocket teeth SP4B. The plurality of sprocket teeth SP4B extend radially outward from the sprocket body SP4A. The plurality of sprocket teeth SP4B are provided on the outer peripheral edge of the sprocket body SP4A. The plurality of sprocket teeth SP4B define a maximum outside diameter at the tip of teeth DM4. The sprocket body SP4A may also be referred to as the first or second sprocket body SP4A. The plurality of sprocket teeth SP4B may also be referred to as the plurality of first or second sprocket teeth SP4B.

[0066] As Figure 8 shown, the bicycle sprocket SP5 includes a sprocket body SP5A and a plurality of sprocket teeth SP5B. The plurality of sprocket teeth SP5B extend radially outward from the sprocket body SP5A. The plurality of sprocket teeth SP5B are provided on the outer peripheral edge of the sprocket body SP5A. The plurality of sprocket teeth SP5B define a maximum outside diameter at the tip of teeth DM5. The sprocket body SP5A may also be referred to as the first or second sprocket body SP5A. The plurality of sprocket teeth SP5B may also be referred to as the plurality of first or second sprocket teeth SP5B.

[0067] As Figure 9 shown, the bicycle sprocket SP6 includes a sprocket body SP6A and a plurality of sprocket teeth SP6B. The plurality of sprocket teeth SP6B extend radially outward from the sprocket body SP6A. The plurality of sprocket teeth SP6B are provided on the outer peripheral edge of the sprocket body SP6A. The plurality of sprocket teeth SP6B define a maximum outside diameter at the tip of teeth DM6. The sprocket body SP6A may also be referred to as the first or second sprocket body SP6A. The plurality of sprocket teeth SP6B may also be referred to as the plurality of first or second sprocket teeth SP6B.

[0068] As Figure 10As shown, the bicycle sprocket SP7 includes a sprocket body SP7A and a plurality of sprocket teeth SP7B. The plurality of sprocket teeth SP7B extend radially outward from the sprocket body SP7A. The plurality of sprocket teeth SP7B are provided on the outer peripheral edge of the sprocket body SP7A. The plurality of sprocket teeth SP7B define a maximum outside diameter of the tooth tips DM7. The sprocket body SP7A may also be referred to as the first or second sprocket body SP7A. The plurality of sprocket teeth SP7B may also be referred to as the plurality of first or second sprocket teeth SP7B.

[0069] As Figure 2 and Figures 4 to 10 shown, the maximum outside diameter of the tooth tips DM1 is greater than each of the maximum outside diameters of the tooth tips DM2 to DM7. The maximum outside diameter of the tooth tips DM2 is greater than each of the maximum outside diameters of the tooth tips DM3 to DM7. The maximum outside diameter of the tooth tips DM3 is greater than each of the maximum outside diameters of the tooth tips DM4 to DM7. The maximum outside diameter of the tooth tips DM4 is greater than each of the maximum outside diameters of the tooth tips DM5 to DM7. The maximum outside diameter of the tooth tips DM5 is greater than each of the maximum outside diameters of the tooth tips DM6 and DM7. The maximum outside diameter of the tooth tips DM6 is greater than the maximum outside diameter of the tooth tips DM7.

[0070] As Figure 11 shown, the first sprocket SP8 includes a first sprocket body SP8A and a plurality of first sprocket teeth SP8B. The plurality of first sprocket teeth SP8B extend radially outward from the first sprocket body SP8A. The plurality of first sprocket teeth SP8B are provided on the outer peripheral edge of the first sprocket body SP8A. The plurality of first sprocket teeth SP8B define a first maximum outside diameter of the tooth tips DM8. The first maximum outside diameter of the tooth tips DM8 is less than each of the maximum outside diameters of the tooth tips DM1 to DM7 (e.g., see Figures 4 to 10 ).

[0071] The first sprocket body SP8A may also be referred to as the sprocket body SP8A. The first sprocket teeth SP8B may also be referred to as the sprocket teeth SP8B. Thus, the bicycle sprocket SP8 includes a sprocket body SP8A and a plurality of sprocket teeth SP8B. The plurality of sprocket teeth SP8B extend radially outward from the sprocket body SP8A. The plurality of sprocket teeth SP8B are provided on the outer peripheral edge of the sprocket body SP8A.

[0072] The bicycle sprocket SP8 has a pitch circle PC8. When viewed along the rotational center axis A1, the pitch circle PC8 is defined by the centers of the rollers of the bicycle chain 20 that contact the plurality of sprocket teeth SP8B during pedaling. The pitch circle PC8 has a pitch circle diameter PC8D.

[0073] As Figure 12As shown, the second sprocket SP9 includes a second sprocket body SP9A and a plurality of second sprocket teeth SP9B. The plurality of second sprocket teeth SP9B extend radially outward from the second sprocket body SP9A. The plurality of second sprocket teeth SP9B are provided on the outer peripheral edge of the second sprocket body SP9A. The plurality of second sprocket teeth SP9B define a second maximum outside diameter DM9.

[0074] The second sprocket body SP9A may also be referred to as the sprocket body SP9A. The second sprocket teeth SP9B may also be referred to as the sprocket teeth SP9B. Thus, the bicycle sprocket SP9 includes a sprocket body SP9A and a plurality of sprocket teeth SP9B. The plurality of sprocket teeth SP9B extend radially outward from the sprocket body SP9A. The plurality of sprocket teeth SP9B are provided on the outer peripheral edge of the sprocket body SP9A.

[0075] The bicycle sprocket SP9 has a pitch circle PC9. When viewed along the rotational center axis A1, the pitch circle PC9 is defined by the centers of the rollers of the bicycle chain 20 that contact the plurality of sprocket teeth SP9B during pedaling. The pitch circle PC9 has a pitch circle diameter PC9D.

[0076] As Figure 12 shown, if the bicycle sprockets SP9 and SP10 are referred to as the first sprocket SP9 and the second sprocket SP10, then the first sprocket SP9 includes a first sprocket body SP9A and a plurality of first sprocket teeth SP9B. The plurality of first sprocket teeth SP9B are provided on the outer peripheral edge of the first sprocket body SP9A. The plurality of first sprocket teeth SP9B define a first maximum outside diameter DM9.

[0077] As Figure 13 shown, if the bicycle sprockets SP9 and SP10 are referred to as the first sprocket SP9 and the second sprocket SP10, then the second sprocket SP10 includes a second sprocket body SP10A and a plurality of second sprocket teeth SP10B. The plurality of second sprocket teeth SP10B extend radially outward from the second sprocket body SP10A. The plurality of second sprocket teeth SP10B are provided on the outer peripheral edge of the second sprocket body SP10A. The plurality of second sprocket teeth SP10B define a second maximum outside diameter DM10.

[0078] The second sprocket body SP10A may also be referred to as the sprocket body SP10A. The second sprocket teeth SP10B may also be referred to as the sprocket teeth SP10B. Thus, the bicycle sprocket SP10 includes a sprocket body SP10A and a plurality of sprocket teeth SP10B. The plurality of sprocket teeth SP10B extend radially outward from the sprocket body SP10A. The plurality of sprocket teeth SP10B are provided on the outer peripheral edge of the sprocket body SP10A.

[0079] The bicycle sprocket SP10 has a pitch circle PC10. When viewed along the rotational center axis A1, the pitch circle PC10 is defined by the centers of the rollers of the bicycle chain 20 that contact a plurality of sprocket teeth SP10B during pedaling. The pitch circle PC10 has a pitch circle diameter PC10D.

[0080] As Figure 14 shown, the second largest outside diameter of the tooth tip DM9 is smaller than the first largest outside diameter of the tooth tip DM8. The second largest outside diameter of the tooth tip DM10 is smaller than the first largest outside diameter of the tooth tip DM9. The total number of the sprocket teeth SP8B is 17. The total number of the sprocket teeth SP9B is 15. The total number of the sprocket teeth SP10B is 13. However, the total number of the sprocket teeth SP8B is not limited to 17. The total number of the sprocket teeth SP9B is not limited to 15. The total number of the sprocket teeth SP10B is not limited to 13.

[0081] As Figure 15 shown, the first sprocket SP8 includes a first sprocket inner surface SP8C and a first sprocket outer surface SP8D. The first sprocket inner surface SP8C is configured to face the axial center plane CP of the bicycle 2 (e.g., see Figure 1 ) in the mounted state where the bicycle sprocket assembly 14 is mounted to the bicycle 2. The first sprocket outer surface SP8D is provided on the opposite side of the first sprocket inner surface SP8C in the axial direction D2 with respect to the rotational center axis A1 of the bicycle sprocket SP8.

[0082] The bicycle sprocket SP8 includes a sprocket inner side SP8E and a sprocket outer side SP8F. The sprocket inner side SP8E is configured to be closer to the axial center plane CP of the bicycle 2 than the sprocket outer side SP8F in the mounted state where the bicycle sprocket SP8 is mounted to the bicycle 2. The sprocket outer side SP8F is provided on the opposite side of the sprocket inner side SP8E in the axial direction D2 with respect to the rotational center axis A1 of the bicycle sprocket SP8. The first sprocket inner surface SP8C is provided on the sprocket inner side SP8E. The first sprocket outer surface SP8D is provided on the sprocket outer side SP8F.

[0083] The second sprocket SP9 is adjacent to the first sprocket SP8 in the axial direction D2 and there is no other sprocket therebetween. The second sprocket SP9 includes a second sprocket inner surface SP9C and a second sprocket outer surface SP9D. The second sprocket inner surface SP9C is configured to face the axial center plane CP of the bicycle in the mounted state. The second sprocket outer surface SP9D is provided on the opposite side of the second sprocket inner surface SP9C in the axial direction D2.

[0084] The bicycle sprocket SP9 includes a sprocket inner side SP9E and a sprocket outer side SP9F. The sprocket inner side SP9E is configured to be closer to the axial center plane CP of the bicycle 2 than the sprocket outer side SP9F in the mounted state where the bicycle sprocket SP9 is mounted to the bicycle 2. The sprocket outer side SP9F is disposed on the opposite side of the sprocket inner side SP9E in the axial direction D2 with respect to the rotation center axis A1 of the bicycle sprocket SP9. The second sprocket inner surface SP9C is provided on the sprocket inner side SP9E. The second sprocket outer surface SP9D is provided on the sprocket outer side SP9F.

[0085] If the bicycle sprockets SP9 and SP10 are referred to as the first sprocket SP9 and the second sprocket SP10, then the first sprocket SP9 includes a first sprocket inner surface SP9C and a first sprocket outer surface SP9D. The first sprocket inner surface SP9C is configured to face the axial center plane CP of the bicycle 2 in the mounted state where the bicycle sprocket assembly 14 is mounted to the bicycle 2 (see Figure 1 ). The first sprocket outer surface SP9D is disposed on the opposite side of the first sprocket inner surface SP9C in the axial direction D2 with respect to the rotation center axis A1 of the bicycle sprocket SP9.

[0086] The second sprocket SP10 is adjacent to the first sprocket SP9 in the axial direction D2 and there is no other sprocket therebetween. The second sprocket SP10 includes a second sprocket inner surface SP10C and a second sprocket outer surface SP10D. The second sprocket inner surface SP10C is configured to face the axial center plane CP of the bicycle 2 in the mounted state. The second sprocket outer surface SP10D is disposed on the opposite side of the second sprocket inner surface SP10C.

[0087] The bicycle sprocket SP10 includes a sprocket inner side SP10E and a sprocket outer side SP10F. The sprocket inner side SP10E is configured to be closer to the axial center plane CP of the bicycle 2 than the sprocket outer side SP10F in the mounted state where the bicycle sprocket SP10 is mounted to the bicycle 2. The sprocket outer side SP10F is disposed on the opposite side of the sprocket inner side SP10E in the axial direction D2 with respect to the rotation center axis A1 of the bicycle sprocket SP10. The second sprocket inner surface SP10C is provided on the sprocket inner side SP10E. The second sprocket outer surface SP10D is provided on the sprocket outer side SP10F.

[0088] The bicycle chain 20 includes a pair of opposing outer link plates 20A and a pair of opposing inner link plates 20B. The pair of opposing outer link plates 20A includes an axially inward outer link plate 20C and an axially outward outer link plate 20D. The pair of opposing inner link plates 20B includes an axially inward inner link plate 20E and an axially outward inner link plate 20F. In the assembled state of the bicycle chain 20, the axially inward outer link plate 20C and the axially outward outer link plate 20D of the pair of opposing outer link plates 20A are spaced apart from each other in the axial direction D2. In the assembled state of the bicycle chain 20, the axially inward inner link plate 20E and the axially outward inner link plate 20F of the pair of opposing inner link plates 20B are spaced apart from each other in the axial direction D2.

[0089] Each of the plurality of sprocket teeth SP8B is configured to enter each of an outer link space 20G defined between a pair of opposing outer link plates 20A of the bicycle chain 20 and an inner link space 20H defined between a pair of opposing inner link plates 20B of the bicycle chain 20. Each of the plurality of sprocket teeth SP9B is configured to enter each of the outer link space 20G and the inner link space 20H. Each of the plurality of sprocket teeth SP10B is configured to enter each of the outer link space 20G and the inner link space 20H.

[0090] In the present embodiment, the axial length 20J of the inner link space 20H is equal to or greater than 2.32 mm. The bicycle chain 20 has an outer distance 20K defined between the axially outer surfaces of a pair of opposing outer link plates 20A in the axial direction D2. The outer distance 20K of the bicycle chain 20 is 5.62 mm. However, each of the axial length 20J of the inner link space 20H and the outer distance 20K is not limited to the above values.

[0091] The first sprocket SP8 includes an axial space AS8. In a meshing state where one of the plurality of second sprocket teeth SP9B is located between the axially inward inner link plate 20E and the axially outward inner link plate 20F of a pair of opposing inner link plates 20B in the axial direction D2, when the second sprocket outer surface SP9D of the one of the plurality of second sprocket teeth SP9B contacts the axially outward inner link plate 20F of the pair of opposing inner link plates 20B of the bicycle chain 20, the axial space AS8 is defined between the first sprocket outer surface SP8D of one of the plurality of first sprocket teeth SP8B and the axially inward outer link plate 20C of the pair of opposing outer link plates 20A of the bicycle chain 20 in the axial direction D2. In the present embodiment, the axial space AS8 is greater than 0 mm and equal to or less than 0.15 mm. In the present embodiment, the axial space AS8 is 0.08 mm. However, the axial space AS8 is not limited to the present embodiment and the above range. The value and range of the axial space AS8 can be applied to other first sprockets and second sprockets among the plurality of bicycle sprockets SP.

[0092] The first sprocket SP9 includes an axial space AS9. In a meshing state where one of the plurality of second sprocket teeth SP10B is axially located between the axially inward inner link plate 20E and the axially outward inner link plate 20F of a pair of opposing inner link plates 20B in the axial direction D2, when the second sprocket outer surface SP10D of the one of the plurality of second sprocket teeth SP10B contacts the axially outward inner link plate 20F of the pair of opposing inner link plates 20B of the bicycle chain 20, the axial space AS9 is defined as being in the axial direction D2 between the first sprocket outer surface SP9D of one of the plurality of first sprocket teeth SP9B and the axially inward outer link plate 20C of a pair of opposing outer link plates 20A of the bicycle chain 20. In the present embodiment, the axial space AS9 is greater than 0 mm and equal to or less than 0.15 mm. In the present embodiment, the axial space AS9 is 0.08 mm. However, the axial space AS9 is not limited to the above value and the above range. The value and range of the axial space AS9 can be applied to other first sprockets and second sprockets in the plurality of bicycle sprockets SP.

[0093] The axial distance AD8 is defined as being in the axial direction D2 between the sprocket outer surface SP8D of the bicycle sprocket SP8 and the sprocket inner surface SP9C of the bicycle sprocket SP9. The axial distance AD9 is defined as being in the axial direction D2 between the sprocket outer surface SP9D of the bicycle sprocket SP9 and the sprocket inner surface SP10C of the bicycle sprocket SP10. The additional axial distance AD89 is defined as being in the axial direction D2 between the sprocket outer surface SP8D of the bicycle sprocket SP8 and the sprocket inner surface SP10C of the bicycle sprocket SP10. The axial sprocket pitch PT8 is defined as being in the axial direction D2 between the axial center plane AP8 of the bicycle sprocket SP8 and the axial center plane AP9 of the bicycle sprocket SP9. The axial sprocket pitch PT9 is defined as being in the axial direction D2 between the axial center plane AP9 of the bicycle sprocket SP9 and the axial center plane AP10 of the bicycle sprocket SP10.

[0094] The axial center plane AP8 of the bicycle sprocket SP8 is defined as bisecting the axial width of the sprocket body SP8A of the bicycle sprocket SP8 in the axial direction D2 and being perpendicular to the axial direction D2. The axial center plane AP9 of the bicycle sprocket SP9 is defined as bisecting the axial width of the sprocket body SP9A of the bicycle sprocket SP9 in the axial direction D2 and being perpendicular to the axial direction D2. The axial center plane AP10 of the bicycle sprocket SP10 is defined as bisecting the axial width of the sprocket body SP10A of the bicycle sprocket SP10 in the axial direction D2 and being perpendicular to the axial direction D2.

[0095] In the present embodiment, the axial distance AD8 is 2.1 mm. The axial distance AD9 is 2.1 mm. The additional axial distance AD89 is 6.15 mm. The axial sprocket pitch PT8 is 4.05 mm. The difference between the additional axial distance AD89 and the outer distance 20K of the bicycle chain 20 is 0.53 mm. However, the axial distance AD8, the axial distance AD9, the axial sprocket pitch PT8, and the difference between the additional axial distance AD89 and the outer distance 20K are not limited to the above values. The values of the axial distance AD8, the axial distance AD9, the axial sprocket pitch PT8, and the difference between the additional axial distance AD89 and the outer distance 20K can be applied to other sprockets among the plurality of bicycle sprockets SP.

[0096] As Figure 11 shown, the bicycle sprocket SP8 further includes an upshift promotion section SP8G and a downshift promotion section SP8H. The first sprocket SP8 includes the upshift promotion section SP8G. The first sprocket SP8 includes the downshift promotion section SP8H.

[0097] The upshift promotion section SP8G is configured to promote the upshift operation of the bicycle chain 20 from the first sprocket SP8 toward the second sprocket SP9 (for example, see Figure 15 ). The upshift promotion section SP8G is intentionally designed to promote the upshift operation of the bicycle chain 20 from the first sprocket SP8 toward the second sprocket SP9. The second sprocket SP9 may also be referred to as the small sprocket SP9. Therefore, the upshift promotion section SP8G is configured to promote the upshift operation of the bicycle chain 20 from the bicycle sprocket SP8 toward the small sprocket SP9 (for example, see Figure 15 ), and the small sprocket SP9 is adjacent to the bicycle sprocket SP8 in the axial direction D2 with respect to the rotation center axis A1 of the bicycle sprocket SP8 and there is no other sprocket therebetween. The upshift promotion section SP8G is intentionally designed to promote the upshift operation of the bicycle chain 20 from the bicycle sprocket SP8 toward the small sprocket SP9.

[0098] The downshift promotion section SP8H is configured to promote the downshift operation of the bicycle chain 20 from the second sprocket SP9 (for example, see Figure 15 ) toward the first sprocket SP8. The downshift promotion section SP8H is intentionally designed to promote the downshift operation of the bicycle chain 20 from the second sprocket SP9 toward the first sprocket SP8. Therefore, the downshift promotion section SP8H is configured to promote the downshift operation of the bicycle chain 20 from the small sprocket SP9 (for example, see Figure 15 ) toward the bicycle sprocket SP8. The downshift promotion section SP8H is intentionally designed to promote the downshift operation of the bicycle chain 20 from the small sprocket SP9 toward the bicycle sprocket SP8.

[0099] The downshift promotion section SP8H is provided on the upstream side of the upshift promotion section SP8G in the circumferential direction D1. The downshift promotion section SP8H is provided on the upstream side of the upshift promotion section SP8G in the circumferential direction D1 with respect to the rotation center axis A1 of the bicycle sprocket and with respect to the driving rotation direction D11. The downshift promotion section SP8H is provided on the upstream side of the upshift promotion section SP8G in the driving rotation direction D11 and there is no other shift promotion section between the upshift promotion section SP8G and the downshift promotion section SP8H.

[0100] The upshift promotion section SP8G is formed by the first tooth group TG8A among the plurality of sprocket teeth SP8B. The downshift promotion section SP8H is formed by the second tooth group TG8B among the plurality of sprocket teeth SP8B. The second tooth group TG8B is completely different from the first tooth group TG8A. The first tooth group TG8A of the upshift promotion section SP8G is adjacent to the second tooth group TG8B of the downshift promotion section SP8H and there is no other tooth therebetween.

[0101] The first tooth group TG8A includes upshift teeth SP8G1 and SP8G2 and upshift promotion teeth SP8G3 and SP8G4. The second tooth group TG8B includes downshift promotion teeth SP8H1 and SP8H2 and downshift teeth SP8H3 and SP8H4. The total number of sprocket teeth SP8B of the second tooth group TG8B is equal to the total number of sprocket teeth SP8B of the first tooth group TG8A. However, the total number of sprocket teeth SP8B of the second tooth group TG8B may be different from the total number of sprocket teeth SP8B of the first tooth group TG8A.

[0102] The total number of sprocket teeth SP8B provided from the downstream end of the downshift promotion section SP8H to the upstream end of the upshift promotion section SP8G in the reverse rotation direction D12 is greater than the total number of sprocket teeth SP8B provided from the downstream end of the downshift promotion section SP8H to the upstream end of the upshift promotion section SP8G in the driving rotation direction D11. In the present embodiment, the total number of sprocket teeth SP8B provided from the downstream end of the downshift promotion section SP8H to the upstream end of the upshift promotion section SP8G in the reverse rotation direction D12 is nine. The total number of sprocket teeth SP8B provided from the downstream end of the downshift promotion section SP8H to the upstream end of the upshift promotion section SP8G in the driving rotation direction D11 is zero. However, the positional relationship between the upshift promotion section SP8G and the downshift promotion section SP8H is not limited to the present embodiment.

[0103] The upshift tooth SP8G2 is configured to first derail the opposing inner link plates 20B of the bicycle chain 20 from the bicycle sprocket SP8 during an upshift operation in a first state where the upshift promotion tooth SP8G3 engages in the outer link space 20G of the opposing outer link plates 20A of the bicycle chain 20 (see Figure 15 ).

[0104] The upshift tooth SP8G1 includes an upshift recess SP8G1R provided on the outer side SP8F of the sprocket to facilitate the upshift operation. The upshift recess SP8G1R is configured to derail the opposite outer link plate 20A of the bicycle chain 20 during the upshift operation after the upshift tooth SP8G2 derails the opposite inner link plate 20B of the bicycle chain 20 from the bicycle sprocket SP8.

[0105] The upshift tooth SP8G2 includes an upshift recess SP8G2R provided on the outer side SP8F of the sprocket to facilitate the upshift operation. The upshift recess SP8G2R is configured to first derail the opposite inner link plate 20B of the bicycle chain 20 during the upshift operation.

[0106] As Figure 16 shown, the upshift promoting tooth SP8G3 includes an upshift promoting recess SP8G3R provided on the inner side SP8E of the sprocket to facilitate the upshift operation. The upshift promoting recess SP8G3R is configured to promote the approach of the bicycle chain 20 toward the small sprocket SP9 during the upshift operation in a state where the bicycle chain 20 is engaged with the bicycle sprocket SP8.

[0107] The upshift promoting tooth SP8G4 includes an upshift promoting recess SP8G4R provided on the inner side SP8E of the sprocket to facilitate the upshift operation. The upshift promoting recess SP8G4R is configured to promote the approach of the bicycle chain 20 toward the small sprocket SP9 during the upshift operation in a state where the bicycle chain 20 is engaged with the bicycle sprocket SP8.

[0108] As Figure 11 shown, the downshift promoting tooth SP8H1 includes a downshift promoting recess SP8H1R provided on the outer side SP8F of the sprocket to facilitate the downshift operation. The downshift promoting recess SP8H1R is configured to reduce the interference between the bicycle sprocket SP8 and the bicycle chain 20 during the downshift operation. The downshift promoting recess SP8H1R is configured to promote the approach of the bicycle chain 20 from the small sprocket SP9 toward the bicycle sprocket SP8 during the downshift operation in a state where the bicycle chain 20 is engaged with the small sprocket SP9.

[0109] The downshift promoting tooth SP8H2 includes a downshift promoting recess SP8H2R provided on the outer side SP8F of the sprocket to facilitate the downshift operation. The downshift promoting recess SP8H2R is configured to reduce the interference between the bicycle sprocket SP8 and the bicycle chain 20 during the downshift operation. The downshift promoting recess SP8H2R is configured to promote the approach from the small sprocket SP9 toward the bicycle sprocket SP8 during the downshift operation in a state where the bicycle chain 20 is engaged with the small sprocket SP9.

[0110] The downshift tooth SP8H3 includes a downshift recess SP8H3R provided on the outer side SP8F of the sprocket to facilitate the downshift operation. The downshift recess SP8H3R is configured to facilitate the engagement of the bicycle sprocket SP8 with the bicycle chain 20 during the downshift operation.

[0111] As Figure 16 shown, the downshift tooth SP8H4 is configured to capture the opposite outer link plate 20A of the bicycle chain 20 during the downshift operation if one of the opposite inner link plates 20B contacts the downshift tooth SP8H3 during the downshift operation. The downshift tooth SP8H4 includes a downshift recess SP8H4R provided on the inner side SP8E of the sprocket to facilitate the downshift operation. The downshift recess SP8H4R is configured to facilitate the capture of the opposite outer link plate 20A of the bicycle chain 20 at the downshift tooth SP8H4 during the downshift operation.

[0112] As Figure 11 shown, the bicycle sprocket SP8 further includes an additional upshift promoting section SP8P. The additional upshift promoting section SP8P is configured to facilitate the upshift operation of the bicycle chain 20 from the first sprocket SP8 towards the second sprocket SP9 (e.g., see Figure 15 ). The additional upshift promoting section SP8P is intentionally designed to facilitate the upshift operation of the bicycle chain 20 from the first sprocket SP8 towards the second sprocket SP9. The additional upshift promoting section SP8P is configured to facilitate the upshift operation of the bicycle chain 20 from the bicycle sprocket SP8 towards the smaller sprocket SP9 (e.g., see Figure 15 ), where the smaller sprocket SP9 is adjacent to the bicycle sprocket SP8 in the axial direction D2 with respect to the rotational center axis A1 of the bicycle sprocket SP8 and there is no other sprocket therebetween. The additional upshift promoting section SP8P is intentionally designed to facilitate the upshift operation of the bicycle chain 20 from the bicycle sprocket SP8 towards the smaller sprocket SP9.

[0113] The additional upshift promoting section SP8P is formed by a third tooth group TG8C among the plurality of sprocket teeth SP8B. The first tooth group TG8A is completely different from the third tooth group TG8C. The second tooth group TG8B is completely different from the third tooth group TG8C. The third tooth group TG8C of the additional upshift promoting section SP8P is adjacent to the second tooth group TG8B of the downshift promoting section SP8H and there is no other tooth therebetween.

[0114] The third tooth group TG8C includes additional upshift teeth SP8P1 to SP8P4. The total number of sprocket teeth SP8B of the first tooth group TG8A is equal to the total number of sprocket teeth SP8B of the third tooth group TG8C. The total number of sprocket teeth SP8B of the second tooth group TG8B is equal to the total number of sprocket teeth SP8B of the third tooth group TG8C. However, the total number of sprocket teeth SP8B of the first tooth group TG8A can be different from the total number of sprocket teeth SP8B of the third tooth group TG8C. The total number of sprocket teeth SP8B of the second tooth group TG8B can be different from the total number of sprocket teeth SP8B of the third tooth group TG8C.

[0115] The upshift promoting tooth SP8P3 is configured to derail the relative inner link plate 20B of the bicycle chain 20 from the bicycle sprocket SP8 during an upshift operation in a state where the upshift tooth SP8P4 is engaged in the outer link space 20G of the relative outer link plate 20A of the bicycle chain 20 (for example, see Figure 15 ).

[0116] The upshift tooth SP8P1 includes an upshift recess SP8P1R provided on the sprocket outer side SP8F to facilitate the upshift operation. The upshift recess SP8P1R is configured to derail the relative outer link plate 20A of the bicycle chain 20 during an upshift operation after the upshift promoting tooth SP8P3 derails the relative inner link plate 20B of the bicycle chain 20 from the bicycle sprocket SP8.

[0117] The upshift tooth SP8P2 includes an upshift recess SP8P2R provided on the sprocket outer side SP8F to facilitate the upshift operation. The upshift recess SP8P2R is configured to first derail the relative inner link plate 20B of the bicycle chain 20 during an upshift operation in a state where the upshift promoting tooth SP8P3 is engaged in the outer link space 20G of the relative outer link plate 20A of the bicycle chain 20.

[0118] As Figure 16 shown, the upshift promoting tooth SP8P3 includes an upshift promoting recess SP8P3R provided on the sprocket inner side SP8E to facilitate the upshift operation. The upshift promoting recess SP8P3R is configured to promote the approach of the bicycle chain 20 toward the small sprocket SP9 during an upshift operation in a state where the bicycle chain 20 is engaged with the bicycle sprocket SP8.

[0119] The upshift promoting tooth SP8P4 includes an upshift promoting recess SP8P4R provided on the sprocket inner side SP8E to facilitate the upshift operation. The upshift promoting recess SP8P4R is configured to promote the approach of the bicycle chain 20 toward the small sprocket SP9 during an upshift operation in a state where the bicycle chain 20 is engaged with the bicycle sprocket SP8.

[0120] In the present embodiment, the bicycle sprocket SP8 further includes an additional upshift promotion section SP8P. However, the additional upshift promotion section SP8P can be omitted from the bicycle sprocket SP8.

[0121] As Figure 12 shown, the bicycle sprocket SP9 further includes an upshift promotion section SP9G and a downshift promotion section SP9H. The first sprocket SP9 includes the upshift promotion section SP9G. The first sprocket SP9 includes the downshift promotion section SP9H.

[0122] The upshift promotion section SP9G is configured to promote the upshift operation of the bicycle chain 20 from the first sprocket SP9 toward the second sprocket SP10 (e.g., see Figure 15 ). The upshift promotion section SP9G is intentionally designed to promote the upshift operation of the bicycle chain 20 shifting from the first sprocket SP9 toward the second sprocket SP10. The second sprocket SP10 may also be referred to as the small sprocket SP10. Therefore, the upshift promotion section SP9G is configured to promote the upshift operation of the bicycle chain 20 shifting from the bicycle sprocket SP9 toward the small sprocket SP10 (e.g., see Figure 15 ), and the small sprocket SP10 is adjacent to the bicycle sprocket SP9 in the axial direction D2 with respect to the rotation center axis A1 of the bicycle sprocket SP9 and there is no other sprocket therebetween. The upshift promotion section SP9G is intentionally designed to promote the upshift operation of the bicycle chain 20 shifting from the bicycle sprocket SP9 toward the small sprocket SP10.

[0123] The downshift promotion section SP9H is configured to promote the downshift operation of the bicycle chain 20 shifting from the second sprocket SP10 (e.g., see Figure 15 ) toward the first sprocket SP9. The downshift promotion section SP9H is intentionally designed to promote the downshift operation of the bicycle chain 20 shifting from the second sprocket SP10 toward the first sprocket SP9. Therefore, the downshift promotion section SP9H is configured to promote the downshift operation of the bicycle chain 20 shifting from the small sprocket SP10 (e.g., see Figure 15 ) toward the bicycle sprocket SP9. The downshift promotion section SP9H is intentionally designed to promote the downshift operation of the bicycle chain 20 shifting from the small sprocket SP10 toward the bicycle sprocket SP9.

[0124] The downshift promotion section SP9H is provided on the upstream side of the upshift promotion section SP9G in the circumferential direction D1. The downshift promotion section SP9H is provided on the upstream side of the upshift promotion section SP9G in the circumferential direction D1 with respect to the rotation center axis A1 of the bicycle sprocket and with respect to the driving rotation direction D11. The downshift promotion section SP9H is provided on the upstream side of the upshift promotion section SP9G in the driving rotation direction D11 and there is no other shift promotion section between the upshift promotion section SP9G and the downshift promotion section SP9H.

[0125] The upshift promotion section SP9G is formed by a first tooth group TG9A among a plurality of sprocket teeth SP9B. The downshift promotion section SP9H is formed by a second tooth group TG9B among the plurality of sprocket teeth SP9B. The second tooth group TG9B is completely different from the first tooth group TG9A. The first tooth group TG9A of the upshift promotion section SP9G is adjacent to the second tooth group TG9B of the downshift promotion section SP9H and there is no other tooth therebetween.

[0126] The first tooth group TG9A includes upshift teeth SP9G1 and SP9G2 and upshift promotion teeth SP9G3 and SP9G4. The second tooth group TG9B includes downshift promotion teeth SP9H1 and SP9H2 and downshift teeth SP9H3 and SP9H4. The total number of the sprocket teeth SP9B of the second tooth group TG9B is equal to the total number of the sprocket teeth SP9B of the first tooth group TG9A. However, the total number of the sprocket teeth SP9B of the second tooth group TG9B may be different from the total number of the sprocket teeth SP9B of the first tooth group TG9A.

[0127] The total number of the sprocket teeth SP9B provided in the reverse rotation direction D12 from the downstream end of the downshift promotion section SP9H to the upstream end of the upshift promotion section SP9G is greater than the total number of the sprocket teeth SP9B provided in the driving rotation direction D11 from the downstream end of the downshift promotion section SP9H to the upstream end of the upshift promotion section SP9G. In the present embodiment, the total number of the sprocket teeth SP9B provided in the reverse rotation direction D12 from the downstream end of the downshift promotion section SP9H to the upstream end of the upshift promotion section SP9G is seven. The total number of the sprocket teeth SP9B provided in the driving rotation direction D11 from the downstream end of the downshift promotion section SP9H to the upstream end of the upshift promotion section SP9G is zero. However, the positional relationship between the upshift promotion section SP9G and the downshift promotion section SP9H is not limited to the present embodiment.

[0128] The upshift tooth SP9G2 is configured to first derail the opposing inner link plates 20B of the bicycle chain 20 from the bicycle sprocket SP9 during an upshift operation in a first state where the upshift promotion tooth SP9G3 meshes in the outer link space 20G of the opposing outer link plates 20A of the bicycle chain 20 (see, for example, Figure 15 ).

[0129] The upshift tooth SP9G1 includes an upshift recess SP9G1R provided on the sprocket outer side SP9F to facilitate the upshift operation. The upshift recess SP9G1R is configured to derail the opposing outer link plates 20A of the bicycle chain 20 during the upshift operation if the upshift tooth SP9G2 derails the opposing inner link plates 20B of the bicycle chain 20 from the bicycle sprocket SP9.

[0130] The upshift tooth SP9G2 includes an upshift recess SP9G2R provided on the outer side of the sprocket SP9F to facilitate the upshift operation. The upshift recess SP9G2R is configured to first derail the opposing inner link plate 20B of the bicycle chain 20 during the upshift operation.

[0131] As Figure 17 shown, the upshift promoting tooth SP9G3 includes an upshift promoting recess SP9G3R provided on the inner side of the sprocket SP9E to facilitate the upshift operation. The upshift promoting recess SP9G3R is configured to promote the approach of the bicycle chain 20 toward the small sprocket SP10 during the upshift operation while the bicycle chain 20 is engaged with the bicycle sprocket SP9.

[0132] The upshift promoting tooth SP9G4 includes an upshift promoting recess SP9G4R provided on the inner side of the sprocket SP9E to facilitate the upshift operation. The upshift promoting recess SP9G4R is configured to promote the approach of the bicycle chain 20 toward the small sprocket SP10 during the upshift operation while the bicycle chain 20 is engaged with the bicycle sprocket SP9.

[0133] As Figure 12 shown, the downshift promoting tooth SP9H1 includes a downshift promoting recess SP9H1R provided on the outer side of the sprocket SP9F to facilitate the downshift operation. The downshift promoting recess SP9H1R is configured to reduce the interference between the bicycle sprocket SP9 and the bicycle chain 20 during the downshift operation. The downshift promoting recess SP9H1R is configured to promote the approach of the bicycle chain 20 from the small sprocket SP10 toward the bicycle sprocket SP9 during the downshift operation while the bicycle chain 20 is engaged with the small sprocket SP10.

[0134] The downshift promoting tooth SP9H2 includes a downshift promoting recess SP9H2R provided on the outer side of the sprocket SP9F to facilitate the downshift operation. The downshift promoting recess SP9H2R is configured to reduce the interference between the bicycle sprocket SP9 and the bicycle chain 20 during the downshift operation. The downshift promoting recess SP9H2R is configured to promote the approach of the bicycle chain 20 from the small sprocket SP10 toward the bicycle sprocket SP9 during the downshift operation while the bicycle chain 20 is engaged with the small sprocket SP10.

[0135] The downshift tooth SP9H3 includes a downshift recess SP9H3R provided on the outer side of the sprocket SP9F to facilitate the downshift operation. The downshift recess SP9H3R is configured to promote the engagement of the bicycle sprocket SP9 with the bicycle chain 20 during the downshift operation.

[0136] As Figure 17As shown, the downshift tooth SP9H4 is configured to capture the opposing outer link plate 20A of the bicycle chain 20 if one of the opposing inner link plates 20B contacts the downshift tooth SP9H3 during a downshift operation. The downshift tooth SP9H4 includes a downshift recess SP9H4R provided in the sprocket inner side SP9E to facilitate the downshift operation. The downshift recess SP9H4R is configured to facilitate the capture of the opposing outer link plate 20A of the bicycle chain 20 at the downshift tooth SP9H4 during the downshift operation.

[0137] As Figure 13 shown, the bicycle sprocket SP10 further includes an upshift promotion section SP10G and a downshift promotion section SP10H. The first sprocket SP10 includes the upshift promotion section SP10G. The first sprocket SP10 includes the downshift promotion section SP10H.

[0138] The upshift promotion section SP10G is configured to facilitate the upshift operation of shifting the bicycle chain 20 from the first sprocket SP10 toward the second sprocket SP11 (e.g., see Figure 3 ). The upshift promotion section SP10G is intentionally designed to facilitate the upshift operation of shifting the bicycle chain 20 from the first sprocket SP10 toward the second sprocket SP11. The second sprocket SP11 may also be referred to as the small sprocket SP11. Thus, the upshift promotion section SP10G is configured to facilitate the upshift operation of shifting the bicycle chain 20 from the bicycle sprocket SP10 toward the small sprocket SP11 (e.g., see Figure 3 ), where the small sprocket SP11 is adjacent to the bicycle sprocket SP10 in the axial direction D2 with respect to the rotational center axis A1 of the bicycle sprocket SP10 and there is no other sprocket therebetween. The upshift promotion section SP10G is intentionally designed to facilitate the upshift operation of shifting the bicycle chain 20 from the bicycle sprocket SP10 toward the small sprocket SP11.

[0139] The downshift promotion section SP10H is configured to facilitate the downshift operation of shifting the bicycle chain 20 from the second sprocket SP11 (e.g., see Figure 3 ) toward the first sprocket SP10. The downshift promotion section SP10H is intentionally designed to facilitate the downshift operation of shifting the bicycle chain 20 from the second sprocket SP11 toward the first sprocket SP10. Thus, the downshift promotion section SP10H is configured to facilitate the downshift operation of shifting the bicycle chain 20 from the small sprocket SP11 (e.g., see Figure 3 ) toward the bicycle sprocket SP10. The downshift promotion section SP10H is intentionally designed to facilitate the downshift operation of shifting the bicycle chain 20 from the small sprocket SP11 to the bicycle sprocket SP10.

[0140] The downshift promotion section SP10H is provided on the upstream side of the upshift promotion section SP10G in the circumferential direction D1. The downshift promotion section SP10H is provided on the upstream side of the upshift promotion section SP10G in the circumferential direction D1 with respect to the rotational center axis A1 of the bicycle sprocket and in the driving rotational direction D11. The downshift promotion section SP10H is provided on the upstream side of the upshift promotion section SP10G in the driving rotational direction D11 and there is no other shift promotion section between the upshift promotion section SP10G and the downshift promotion section SP10H.

[0141] The upshift promotion section SP10G is formed by the first tooth group TG10A among the plurality of sprocket teeth SP10B. The downshift promotion section SP10H is formed by the second tooth group TG10B among the plurality of sprocket teeth SP10B. The second tooth group TG10B is completely different from the first tooth group TG10A. The first tooth group TG10A of the upshift promotion section SP10G is adjacent to the second tooth group TG10B of the downshift promotion section SP10H and there is no other tooth therebetween.

[0142] The first tooth group TG10A includes upshift teeth SP10G1 and SP10G2 and upshift promotion teeth SP10G3 and SP10G4. The second tooth group TG10B includes downshift promotion teeth SP10H1 and SP10H2 and downshift teeth SP10H3 and SP10H4. The total number of the sprocket teeth SP10B of the second tooth group TG10B is equal to the total number of the sprocket teeth SP10B of the first tooth group TG10A. However, the total number of the sprocket teeth SP10B of the second tooth group TG10B may be different from the total number of the sprocket teeth SP10B of the first tooth group TG10A.

[0143] The total number of the sprocket teeth SP10B provided from the downstream end of the downshift promotion section SP10H to the upstream end of the upshift promotion section SP10G in the reverse rotational direction D12 is greater than the total number of the sprocket teeth SP10B provided from the downstream end of the downshift promotion section SP10H to the upstream end of the upshift promotion section SP10G in the driving rotational direction D11. In the present embodiment, the total number of the sprocket teeth SP10B provided from the downstream end of the downshift promotion section SP10H to the upstream end of the upshift promotion section SP10G in the reverse rotational direction D12 is five. The total number of the sprocket teeth SP10B provided from the downstream end of the downshift promotion section SP10H to the upstream end of the upshift promotion section SP10G in the driving rotational direction D11 is zero. However, the positional relationship between the upshift promotion section SP10G and the downshift promotion section SP10H is not limited to the present embodiment.

[0144] The upshift tooth SP10G2 is configured such that when the upshift promotion tooth SP10G3 engages with the outer link space 20G of the opposite outer link plate 20A of the bicycle chain 20 (for example, see Figure 15) In the state of (), during an upshift operation, first derail the opposite inner link plate 20B of the bicycle chain 20 from the bicycle sprocket SP10.

[0145] The upshift tooth SP10G1 includes an upshift recess SP10G1R provided on the sprocket outer side SP10F to facilitate the upshift operation. The upshift recess SP10G1R is configured such that if the upshift tooth SP10G2 derails the opposite inner link plate 20B of the bicycle chain 20 from the bicycle sprocket SP10, then during the upshift operation, the upshift recess SP10G1R derails the opposite outer link plate 20A of the bicycle chain 20.

[0146] The upshift tooth SP10G2 includes an upshift recess SP10G2R provided on the sprocket outer side SP10F to facilitate the upshift operation. The upshift recess SP10G2R is configured to first derail the opposite inner link plate 20B of the bicycle chain 20 during the upshift operation.

[0147] As Figure 18 shown, the upshift promoting tooth SP10G3 includes an upshift promoting recess SP10G3R provided on the sprocket inner side SP10E to facilitate the upshift operation. The upshift promoting recess SP10G3R is configured to promote the bicycle chain 20 to approach the small sprocket SP11 during the upshift operation in a state where the bicycle chain 20 is engaged with the bicycle sprocket SP10.

[0148] The upshift promoting tooth SP10G4 includes an upshift promoting recess SP10G4R provided on the sprocket inner side SP10E to facilitate the upshift operation. The upshift promoting recess SP10G4R is configured to promote the bicycle chain 20 to approach the small sprocket SP11 during the upshift operation in a state where the bicycle chain 20 is engaged with the bicycle sprocket SP10.

[0149] As Figure 13 shown, the downshift promoting tooth SP10H1 includes a downshift promoting recess SP10H1R provided on the sprocket outer side SP10F to facilitate the downshift operation. The downshift promoting recess SP10H1R is configured to reduce the interference between the bicycle sprocket SP10 and the bicycle chain 20 during the downshift operation. The downshift promoting recess SP10H1R is configured to promote the bicycle chain 20 to approach the bicycle sprocket SP10 from the small sprocket SP11 during the downshift operation in a state where the bicycle chain 20 is engaged with the small sprocket SP11.

[0150] The downshift promoting tooth SP10H2 includes a downshift promoting recess SP10H2R provided on the outer side SP10F of the sprocket to promote the downshift operation. The downshift promoting recess SP10H2R is configured to reduce the interference between the bicycle sprocket SP10 and the bicycle chain 20 during the downshift operation. The downshift promoting recess SP10H2R is configured to promote the approach of the bicycle chain 20 from the small sprocket SP11 toward the bicycle sprocket SP10 during the downshift operation in a state where the bicycle chain 20 is engaged with the small sprocket SP11.

[0151] The downshift tooth SP10H3 includes a downshift recess SP10H3R provided on the outer side SP10F of the sprocket to promote the downshift operation. The downshift recess SP10H3R is configured to promote the engagement of the bicycle sprocket SP10 with the bicycle chain 20 during the downshift operation.

[0152] As Figure 18 shown, the downshift tooth SP10H4 is configured to capture the opposing outer link plate 20A of the bicycle chain 20 during the downshift operation if one of the opposing inner link plates 20B contacts the downshift tooth SP10H3 during the downshift operation. The downshift tooth SP10H4 includes a downshift recess SP10H4R provided on the inner side SP10E of the sprocket to promote the downshift operation. The downshift recess SP10H4R is configured to promote the capture of the opposing outer link plate 20A of the bicycle chain 20 at the downshift tooth SP10H4 during the downshift operation.

[0153] Figures 11 to 13 and Figures 16 to 18 The upshift promoting sections SP8G, SP9G, and SP10G and the downshift promoting sections SP8H, SP9H, and SP10H of the bicycle sprockets SP8, SP9, and SP10 shown in Figures 4 to 10 can be applied to the bicycle sprockets SP1 to SP7 shown in

[0154] As Figure 11 shown, the plurality of sprocket teeth SP8B includes at least one recessed tooth T8. In the present embodiment, the plurality of sprocket teeth SP8B includes the recessed tooth T8. One of the recessed teeth T8 corresponds to the upshift tooth SP8G1 of the first tooth group TG8A. The other of the recessed teeth T8 corresponds to the upshift tooth SP8P1 of the third tooth group TG8C. The total number of the recessed teeth T8 is not limited to the present embodiment. The recessed teeth T8 have the same structure as each other. The recessed tooth can be any one of the teeth SP8G2, SP8H1, SP8H2, SP8P2, SP9G1, SP9G2, SP9H1, SP9H2, SP10G1, SP1OG2, SP10H1, SP10H2, and the recessed teeth provided on the sprockets SP1 to SP7 and SP11.

[0155] As Figure 19As shown, at least one recessed tooth T8 has at least one recessed portion T8R. In the present embodiment, the recessed tooth T8 has a recessed portion T8R. However, if necessary and / or desirable, the recessed tooth T8 may have multiple recessed portions T8R.

[0156] At least one recessed portion T8R has a circumferentially upstream end T8A and a circumferentially downstream end T8B. The circumferentially downstream end T8B is opposite to the circumferentially upstream end T8A in the circumferential direction D1 with respect to the rotational center axis A1 and with respect to the driving rotation direction D11. The circumferentially downstream end T8B is disposed on the downstream side of the circumferentially upstream end T8A in the driving rotation direction D11.

[0157] The recessed portion T8R includes a driving surface T8E and a non-driving surface T8F. The non-driving surface T8F is disposed on the reverse side of the driving surface T8E in the circumferential direction D1. The non-driving surface T8F is disposed on the downstream side of the driving surface T8E in the driving rotation direction D11. The driving surface T8E is configured to receive a driving rotational force F1 from the bicycle chain 20 during pedaling. The driving surface T8E is disposed in the circumferentially upstream end T8A. The non-driving surface T8F is disposed in the circumferentially downstream end T8B.

[0158] As Figure 20 shown, at least one recessed portion T8R recesses from the sprocket outer side SP8F toward the sprocket inner side SP8E. The recessed portion T8R includes an upshift recess SP8G1R. At least one recessed portion T8R has an inclined surface T8S. The inclined surface T8S extends between the circumferentially upstream end T8A and the circumferentially downstream end T8B. The inclined surface T8S is inclined with respect to the rotational center axis. The inclined surface T8S is inclined with respect to the circumferential direction D1.

[0159] The circumferentially upstream end T8A has a first axial thickness AT81 defined on the pitch circle diameter PC81 of the bicycle sprocket SP8. The first axial thickness AT81 is defined in the axial direction D2. The circumferentially downstream end T8B has a second axial thickness AT82 defined on the pitch circle diameter PC81 of the bicycle sprocket SP8. The second axial thickness AT82 is defined in the axial direction D2. The second axial thickness AT82 is less than the first axial thickness AT81. The first axial thickness AT81 is equal to or greater than 1.3 mm. The first axial thickness AT81 is preferably equal to or greater than 1.4 mm. In the present embodiment, the first axial thickness AT81 is equal to 1.5 mm. The second axial thickness AT82 is equal to 0.87 mm. However, the first axial thickness AT81 and the second axial thickness AT82 are not limited to the present embodiment.

[0160] In the present embodiment, the inclined surface T8S does not have a stepped surface. However, as Figure 21As shown, at least one recessed portion T8R may have at least one stepped surface T8C disposed between a circumferentially upstream end T8A and a circumferentially downstream end T8B. At least one stepped surface T8C of at least one recessed portion T8R forms at least three steps T8D. The stepped surface T8C of at least one recessed portion T8R forms three steps T8D.

[0161] As Figure 22 shown, at least one of the plurality of sprocket teeth SP8B has an axial tooth root thickness AT83 equal to or greater than 1.7 mm. The axial tooth root thickness AT83 is defined in the axial direction D2 at the tooth root SP8T of the sprocket tooth SP8B. The axial tooth root thickness AT83 is greater than Figure 20 the first axial thickness AT81 and the second axial thickness AT82 shown in

[0162] The first sprocket body SP8A has an axial thickness AT86 defined in the axial direction D2. The axial thickness AT86 is equal to or less than 2.0 mm. The axial thickness AT86 is equal to the axial tooth root thickness AT83. Each of the axial tooth root thickness AT83 and the axial thickness AT86 ranges from 1.7 mm to 2.0 mm. In the present embodiment, each of the axial tooth root thickness AT83 and the axial thickness AT86 is 1.95 mm. However, each of the axial tooth root thickness AT83 and the axial thickness AT86 is not limited to the present embodiment and the above range.

[0163] As Figure 23 shown, the recessed tooth T8 has a first axial tooth root thickness AT84 defined at the first tooth root T8T1 of the recessed tooth T8. The first axial tooth root thickness AT84 is less than the axial tooth root thickness AT83.

[0164] As Figure 24 shown, the recessed tooth T8 has a second axial tooth root thickness AT85 defined at the second tooth root T8T2 of the recessed tooth T8. The second axial tooth root thickness AT85 is less than the axial tooth root thickness AT83.

[0165] Figures 19 to 24 The structure of the bicycle sprocket SP8 shown in Figures 4 to 10 , Figure 12 and Figure 13 is applicable to the bicycle sprockets SP1 to SP7, SP9 and SP10 shown in Figure 4 shown, the plurality of sprocket teeth SP1B includes at least one recessed tooth T1. As Figure 5 shown, the plurality of sprocket teeth SP2B includes at least one recessed tooth T2. As Figure 6 shown, the plurality of sprocket teeth SP3B includes at least one recessed tooth T3. As Figure 7As shown, a plurality of sprocket teeth SP4B include at least one recessed tooth T4. As Figure 8 shown, a plurality of sprocket teeth SP5B include at least one recessed tooth T5. As Figure 9 shown, a plurality of sprocket teeth SP6B include at least one recessed tooth T6. As Figure 10 shown, a plurality of sprocket teeth SP7B include at least one recessed tooth T7. As Figure 12 shown, a plurality of sprocket teeth SP9B include at least one recessed tooth T9. As Figure 13 shown, a plurality of sprocket teeth SP10B include at least one recessed tooth T10. The recessed teeth T1 to T7, T9, and T10 have substantially the same structure as the recessed tooth T8 of the bicycle sprocket SP8. Therefore, for the sake of brevity, they will not be described in detail here.

[0166] As Figure 25 shown, the bicycle sprocket SP11 includes a sprocket body SP11A and a plurality of sprocket teeth SP11B. The plurality of sprocket teeth SP11B extend radially outward from the sprocket body SP11A. The plurality of sprocket teeth SP11B are provided on the outer peripheral edge of the sprocket body SP11A. The plurality of sprocket teeth SP11B define a maximum tip diameter DM11. The maximum tip diameter DM11 is smaller than the maximum tip diameter DM10 of the bicycle sprocket SP10.

[0167] As Figure 26 shown, the bicycle sprocket SP11 includes a sprocket inner side SP11E and a sprocket outer side SP11F. The sprocket inner side SP11E is configured to be closer to the axial center plane CP of the bicycle 2 than the sprocket outer side SP11F in a state where the bicycle sprocket SP11 is mounted on the bicycle 2. The sprocket outer side SP11F is provided on the opposite side of the sprocket inner side SP11E in the axial direction D2 with respect to the rotation center axis A1 of the bicycle sprocket SP11.

[0168] As Figure 27 and Figure 28 shown, at least one of the plurality of sprocket teeth SP11B has a tooth tip SP11G, a tooth root SP11H, and at least one tooth tip chamfer SP11K and / or SP11L. At least one tooth tip chamfer SP11K is formed on the tooth tip SP11G in at least one of the sprocket outer side SP11F and the sprocket inner side SP11E. At least one tooth tip chamfer SP11K and / or SP11L has a radially outermost end portion SP11M and a radially innermost end portion SP11N with respect to the rotation center axis A1 of the bicycle sprocket SP11.

[0169] In the present embodiment, as Figure 25 shown, the plurality of sprocket teeth SP11B include a plurality of chamfered teeth SP11S. As Figure 27 and Figure 28As shown, each chamfered tooth SP11S has a tooth tip SP11G, a tooth root SP11H, and at least one tooth tip chamfer SP11K and / or SP11L. However, the total number of chamfered teeth SP11S is not limited to this embodiment.

[0170] As Figure 27 shown, the tooth tip chamfer SP11K is provided on the outer side SP11F of the sprocket. The tooth tip chamfer SP11K has a radially outermost end portion SP11M and a radially innermost end portion SP11N. As Figure 28 shown, the tooth tip chamfer SP11L is provided on the inner side SP11E of the sprocket. The tooth tip chamfer SP11L has a radially outermost end portion SP11M and a radially innermost end portion SP11N.

[0171] As Figure 27 and Figure 28 shown, the radial tooth tip distance RD11 is defined as from the tooth root SP11H to the tooth tip SP11G in the radial direction D4 with respect to the rotational center axis A1. The radial tooth tip distance RD11 is equal to or greater than 4.5 mm. The radial chamfer distance RD12 is defined as from the tooth root SP11H to the radially innermost end portion SP11N of at least one tooth tip chamfer SP11K in the radial direction D4. The radial chamfer distance RD12 is equal to or greater than 3 mm.

[0172] In this embodiment, the radial tooth tip distance RD11 is 4.95 mm. The radial chamfer distance RD12 of the tooth tip chamfer SP11K is 3.45 mm. The radial chamfer distance RD12 of the tooth tip chamfer SP11L is 3.45 mm. However, the radial tooth tip distance RD11, the radial chamfer distance RD12 of the tooth tip chamfer SP11K, and the radial chamfer distance RD12 of the tooth tip chamfer SP11L are not limited to this embodiment and the above ranges.

[0173] As Figure 27 shown, the tooth tip SP11G has a circumferentially upstream tooth tip portion SP11G1 and a circumferentially downstream tooth tip portion SP11G2. The circumferentially downstream tooth tip portion SP11G2 is opposite to the circumferentially upstream tooth tip portion SP11G1 in the circumferential direction D1 with respect to the rotational center axis A1 and in the driving rotation direction D11. The circumferentially downstream tooth tip portion SP11G2 is provided on the downstream side of the circumferentially upstream tooth tip portion SP11G1 in the driving rotation direction D11.

[0174] The circumferentially upstream tooth tip portion SP11G1 has a convex curved portion SP11G3, and the convex curved portion SP11G3 is configured to contact the chain roller 20R of the bicycle chain 20 during the driving operation of the bicycle 2. The convex curved portion SP11G3 is configured to contact the chain roller 20R of the bicycle chain 20 during pedaling. When viewed along the rotational center axis A1, the convex curved portion SP11G3 has a curved profile. InFigures 25 to 28 The structure of the bicycle sprocket SP11 shown in [reference] can be applied to bicycle sprockets SP1 to SP10.

[0175] As used herein, the term "comprising" and its derivatives are intended to be open-ended terms, indicating the presence of the recited features, elements, components, groups, wholes, and / or steps, but not excluding the presence of other unrecited features, elements, components, groups, wholes, and / or steps. This concept also applies to words of similar meaning, such as the terms "having", "including", and their derivatives.

[0176] The terms "member", "section", "portion", "part", "element", "body", and "structure" can have a dual meaning of a single part or multiple parts when used in the singular.

[0177] Ordinal numbers such as "first" and "second" recited in this application are only for identification and do not have other meanings, such as a specific order, etc. In addition, for example, the term "first element" does not imply the existence of a "second element" by itself, and the term "second element" does not imply the existence of a "first element" by itself.

[0178] Except for configurations where a pair of elements have the same shape or structure as each other, the term "a pair" as used herein can include configurations where a pair of elements have different shapes or structures from each other.

[0179] The terms "a" (or "an"), "one or more", and "at least one" are used interchangeably herein.

[0180] The phrase "at least one of which" used in this disclosure means the "one or more" selected as desired. For example, if the number of selections is two, the phrase "at least one of which" used in this disclosure means "only one single selection" or "both of the two selections". Additionally, for example, if the number of selections is equal to or more than three, the phrase "at least one of which" used in this disclosure means "having only one selection" or "any combination of two or more selections". For example, the phrase "at least one of A and B" covers (1) A alone, (2) B alone, and (3) both A and B. The phrase "at least one of A, B, and C" covers (1) A alone, (2) B alone, (3) C alone, (4) both A and B, (5) both B and C, (6) both A and C, and (7) all of A, B, and C. In other words, in this disclosure, the phrase "at least one of A and B" does not mean "at least one of A and at least one of B".

[0181] Finally, degree terms such as "substantially", "about", and "near" as used herein mean a reasonable deviation amount of the modified term such that the end result is not significantly changed. The numerical values described in this application can be interpreted to include terms such as "substantially", "about", and "near".

[0182] Obviously, many variations and changes can be made to the present invention in accordance with the above teachings. Therefore, it is understood that within the scope of the appended claims, the present invention can be practiced otherwise than as specifically described herein.

Claims

1. A bicycle sprocket, comprising: A sprocket body; The inner side of the sprocket; The outer side of the sprocket, wherein the inner side of the sprocket is configured to be closer to the axial center plane of the bicycle than the outer side of the sprocket in a state where the bicycle sprocket is mounted to the bicycle, and the outer side of the sprocket is disposed on the opposite side of the inner side of the sprocket in the axial direction with respect to the rotation center axis of the bicycle sprocket; And A plurality of sprocket teeth, the plurality of sprocket teeth being provided on the outer peripheral edge of the sprocket body, at least one of the plurality of sprocket teeth having a tooth tip, a tooth root, and at least one tooth tip chamfer formed on the tooth tip in at least one of the outer side and the inner side of the sprocket, the at least one tooth tip chamfer having a radially outermost end and a radially innermost end with respect to the rotation center axis of the bicycle sprocket, Defined such that a radial tooth tip distance from the tooth root to the tooth tip in the radial direction with respect to the rotation center axis is equal to or greater than 4.5 mm, and Defined such that a radial chamfer distance from the tooth root to the radially innermost end of the at least one tooth tip chamfer in the radial direction is equal to or greater than 3 mm.

2. The bicycle sprocket according to claim 1, wherein The tooth tip has a circumferentially upstream tooth tip portion and a circumferentially downstream tooth tip portion in the circumferential direction with respect to the rotation center axis and opposite to the circumferentially upstream tooth tip portion with respect to the driving rotation direction, and The circumferentially upstream tooth tip portion has a convex curved portion configured to contact a chain roller of a bicycle chain during a driving operation of the bicycle.

3. The bicycle sprocket according to claim 1, wherein The plurality of sprocket teeth includes at least one recessed tooth having at least one recessed portion recessed from the outer side of the sprocket toward the inner side of the sprocket, the at least one recessed portion having a circumferentially upstream end and a circumferentially downstream end in the circumferential direction with respect to the rotation center axis and opposite to the circumferentially upstream end with respect to the driving rotation direction, the circumferentially upstream end having a first axial thickness defined on the pitch circle of the bicycle sprocket, the circumferentially downstream end having a second axial thickness defined on the pitch circle of the bicycle sprocket, the second axial thickness being less than the first axial thickness, and the first axial thickness being equal to or greater than 1.3 mm.

4. The bicycle sprocket according to claim 1, wherein Each of the plurality of sprocket teeth is configured to enter each of an outer link space defined between a pair of opposing outer link plates of a bicycle chain and an inner link space defined between a pair of opposing inner link plates of the bicycle chain.

5. The bicycle sprocket according to claim 3, wherein The at least one recessed portion has an inclined surface extending between the circumferentially upstream end and the circumferentially downstream end.

6. The bicycle sprocket according to claim 3, wherein The at least one recessed portion has at least one stepped surface provided between the circumferentially upstream end and the circumferentially downstream end.

7. The bicycle sprocket according to claim 6, wherein The at least one stepped surface of the at least one recessed portion forms at least three steps.

8. The bicycle sprocket according to claim 1, further comprising: An upshift promoting section configured to promote an upshift operation of a bicycle chain from the bicycle sprocket toward a smaller sprocket, the smaller sprocket being adjacent to the bicycle sprocket in the axial direction and having no other sprocket therebetween; and A downshift promoting section configured to promote a downshift operation of the bicycle chain from the smaller sprocket toward the bicycle sprocket, wherein The downshift promoting section is provided on the upstream side of the upshift promoting section in a circumferential direction with respect to the rotational center axis of the bicycle sprocket and with respect to the driving rotation direction.

9. The bicycle sprocket according to claim 8, wherein The upshift promoting section is formed by a first tooth group among the plurality of sprocket teeth, The downshift promoting section is formed by a second tooth group among the plurality of sprocket teeth, and The second tooth group is completely different from the first tooth group.

10. The bicycle sprocket according to claim 1, wherein At least one of the plurality of sprocket teeth has an axial tooth root thickness equal to or greater than 1.7 mm.

11. The bicycle sprocket according to claim 9, wherein The first tooth group of the upshift promoting section is adjacent to the second tooth group of the downshift promoting section and has no other tooth therebetween.

Images