REAR CHAINRING ASSEMBLY

Abstract

A rear sprocket assembly 10 comprises a sprocket carrier 22, a first sprocket SP1, and a second sprocket SP2. The sprocket carrier 22 includes at least one sprocket mounting section 22K, which has a first radial section 22M and a second radial section 22N. The first radial section 22M has a first maximum axial length L1 with respect to the axial direction D1. The second radial section 22N has a second maximum axial length L2 with respect to the axial direction D1. The second maximum axial length L2 is greater than the first maximum axial length L1. At least one second mounted section SP2M of the second sprocket SP2 is configured to axially contact the first radial section 22M and the second radial section 22N of the at least one sprocket mounting section 22K of the sprocket carrier 22 with respect to the axial direction D1.

Description

The present invention relates to a rear sprocket assembly.A human-powered vehicle includes a sprocket assembly configured to engage a chain. The sprocket assembly includes a plurality of sprockets. An object of the present invention is to maintain the necessary stiffness of a sprocket and sprocket carrier of the sprocket assembly while selecting a lighter material for the sprocket.According to a first aspect of the present invention, a rear sprocket assembly for a human-powered vehicle has a rotational center axis. The rotational center axis defines an axial direction, a radial direction, and a circumferential direction. The rear sprocket assembly includes a sprocket carrier, a first sprocket, and a second sprocket. The sprocket carrier has an axially outward facing carrier surface and an axially inward facing carrier surface provided on a rear side of the axially outward facing carrier surface in the axial direction. The axially inward facing support surface is configured to face, in the axial direction, an axial center plane of the human-powered vehicle in an assembled state in which the rear sprocket assembly is assembled to the human-powered vehicle. The sprocket carrier includes at least one sprocket mounting portion having a first radial portion and a second radial portion positioned radially inward of the first radial portion in the radial direction. The first radial portion has a first maximum axial length with respect to the axial direction. The second radial portion has a second maximum axial length with respect to the axial direction. The second maximum axial length is greater than the first maximum axial length. The first sprocket includes a first sprocket body and a plurality of first sprocket teeth extending radially outward from the first sprocket body in the radial direction. The plurality of first sprocket teeth are disposed on the first sprocket body in the circumferential direction. The first sprocket has a first total number of teeth, a first axially outward facing surface, and a first axially inward facing surface provided on a rear side of the first axially outward facing surface in the axial direction. The first axially inward facing surface is configured to face, in the assembled state, in the axial direction toward the axial center plane of the human-powered vehicle. The first sprocket body has at least a first assembled portion configured to be assembled to the axially inward facing support surface of the at least one sprocket assembly portion of the sprocket support. The at least one first assembled portion is configured to axially contact the first radial portion of the at least one sprocket assembly portion of the sprocket carrier with respect to the axial direction. The second sprocket includes a second sprocket body and a plurality of second sprocket teeth extending outward from the second sprocket body in the radial direction. The plurality of second sprocket teeth are disposed on the second sprocket body in the circumferential direction. The second sprocket has a second total number of teeth, a second axially outward facing surface, and a second axially inward facing surface provided on a rear side of the second axially outward facing surface in the axial direction. The second total tooth number is less than the first total tooth number of the first sprocket. The second axially inward facing surface is configured to face the first axially outward facing surface of the first sprocket in the axial direction. The second sprocket body has at least one second assembled portion configured to be assembled to the axially outward facing support surface of the at least one sprocket assembly portion of the sprocket support. The at least one second assembled portion is configured to axially contact the first radial portion and the second radial portion of the at least one sprocket assembly portion of the sprocket carrier with respect to the axial direction. The second sprocket is adjacent to the first sprocket in the axial direction without another sprocket being interposed between the first sprocket and the second sprocket.With the rear sprocket assembly according to the first aspect, the at least one second assembled portion can improve rigidity of the at least one sprocket assembled portion of the sprocket carrier because the at least one second assembled portion is configured to axially contact the first radial portion and the second radial portion with respect to the axial direction. In this way, it is possible to reduce an axial length of the first radial portion of the at least one sprocket mounting portion of the sprocket carrier, so that an axial thickness of the first sprocket and an axial thickness of the second sprocket may be greater. Accordingly, it is possible to maintain the necessary rigidity of the first sprocket and the necessary rigidity of the second sprocket while selecting a lighter material for the first sprocket.According to a second aspect of the present invention, the rear sprocket assembly according to the first aspect is configured so that the first sprocket body has a first maximum axial body length equal to or greater than 2 mm. With the rear sprocket assembly according to the second aspect, it is possible to reliably maintain the required rigidity of the first sprocket while selecting a lighter material for the first sprocket.According to a third aspect of the present invention, the rear sprocket assembly according to the second aspect is configured so that the first maximum axial body length is equal to or less than 3.5 mm. With the rear sprocket assembly according to the third aspect, it is possible to ensure the rigidity of the first radial portion and the second radial portion of the at least one sprocket mounting portion of the sprocket carrier while maintaining the required rigidity of the first sprocket.According to a fourth aspect of the present invention, the rear sprocket assembly according to any one of the first to third aspects is configured so that the second sprocket body has a second maximum axial body length equal to or greater than 1.5 mm. With the rear sprocket assembly according to the fourth aspect, it is possible to maintain the necessary rigidity of the second sprocket while selecting a lighter material for the second sprocket.According to a fifth aspect of the present invention, the rear sprocket assembly according to the fourth aspect is configured so that the second maximum axial body length is equal to or less than 3.5 mm. With the rear sprocket assembly according to the fifth aspect, it is possible to ensure the rigidity of the first radial portion and the second radial portion of the at least one sprocket mounting portion of the sprocket carrier while maintaining the required rigidity of the second sprocket.According to a sixth aspect of the present invention, the rear sprocket assembly according to any one of the first to fifth aspects is configured so that the first maximum axial length of the first radial portion is equal to or greater than 1.3 mm. With the rear sprocket assembly according to the sixth aspect, it is possible to ensure the rigidity of the first radial portion of the at least one sprocket mounting portion of the sprocket carrier.According to a seventh aspect of the present invention, the rear sprocket assembly according to the sixth aspect is configured so that the first maximum axial length of the first radial portion is equal to or less than 3 mm. With the rear sprocket assembly according to the seventh aspect, it is possible to save weight of the sprocket carrier.According to an eighth aspect of the present invention, the rear sprocket assembly according to any one of the first to seventh aspects is configured so that the second maximum axial length of the second radial portion is equal to or greater than 3.5 mm. With the rear sprocket assembly according to the eighth aspect, it is possible to ensure the rigidity of the second radial portion of the at least one sprocket mounting portion of the sprocket carrier while selecting a lighter material for the sprocket carrier.According to a ninth aspect of the present invention, the rear sprocket assembly according to the eighth aspect is configured so that the second maximum axial length of the second radial portion is equal to or less than 5 mm. With the rear sprocket assembly according to the ninth aspect, it is possible to save weight of the sprocket carrier.In accordance with a tenth aspect of the present invention, the rear sprocket assembly according to any one of the first to ninth aspects is configured so that the first sprocket is made of aluminum. With the rear sprocket assembly according to the tenth aspect, it is possible to save weight of the first sprocket.In accordance with an eleventh aspect of the present invention, the rear sprocket assembly according to any one of the first to tenth aspects is configured so that the second sprocket is made of iron. With the rear sprocket assembly according to the eleventh aspect, it is possible to maintain the necessary rigidity of the second sprocket.In accordance with a twelfth aspect of the present invention, the rear sprocket assembly according to any one of the first to eleventh aspects is configured so that the second sprocket is made of aluminum. With the rear sprocket assembly according to the twelfth aspect, it is possible to save weight of the second sprocket.In accordance with a thirteenth aspect of the present invention, the rear sprocket assembly according to any one of the first to twelfth aspects is configured so that the sprocket carrier is made of one of aluminum and a non-metallic material. With the rear sprocket assembly according to the thirteenth aspect, it is possible to save weight of the sprocket carrier.In accordance with a fourteenth aspect of the present invention, the rear sprocket assembly according to any one of the first to thirteenth aspects is configured such that the first sprocket and the second sprocket are mounted on the at least one sprocket mounting portion of the sprocket carrier through at least one common fastening member. With the rear sprocket assembly according to the fourteenth aspect, it is possible to reduce the total number of parts, whereby the manufacturing cost of the rear sprocket assembly can be decreased or the productivity of the rear sprocket assembly can be improved.In accordance with a fifteenth aspect of the present invention, the rear sprocket assembly according to any one of the first to fourteenth aspects is configured so that the at least one first assembled portion of the first sprocket body is configured to be free from axial contact with the second radial portion of the at least one sprocket assembled portion of the sprocket carrier. With the rear sprocket assembly according to the fifteenth aspect, it is possible to increase an axial thickness of the first sprocket. In this way, it is possible to reliably maintain the necessary rigidity of the first sprocket while selecting a lighter material for the first sprocket.A more complete understanding of the invention and many attendant advantages thereof will be readily apparent from a reading of the following detailed description taken in conjunction with the accompanying drawings, in which FIG. 1 is a schematic illustration of a human-powered vehicle including a rear sprocket assembly according to one of the embodiments; FIG. 2 is an exploded rear view of the rear sprocket assembly and a rear hub assembly of the human-powered vehicle illustrated in FIG. 1 ; FIG. 3 is a side view of the rear sprocket assembly shown in FIG. 1 ; FIG. 4 is a cross-sectional view of the rear sprocket assembly taken along line IV-IV of FIG. 3 ; FIG. 5 is a side view of a sprocket of the rear sprocket assembly shown in FIG. 3 ; FIG. 6 is a side view of a sprocket of the rear sprocket assembly shown in FIG. 3 ; FIG. 7 is a side view of a sprocket of the rear sprocket assembly shown in FIG. 3 ; FIG. 8 is a side view of a sprocket carrier of the rear sprocket assembly shown in FIG. 3 ; FIG. 9 is a cross-sectional view of the rear sprocket assembly taken along line IX-IX of FIG. 3 ; FIG. 10 is a perspective view of the sprocket carrier of the rear sprocket assembly shown in FIG. 3 ; FIG. 11 is another perspective view of the sprocket carrier of the rear sprocket assembly shown in FIG. 3 ; FIG. 12 is a partial perspective view of the sprocket carrier of the rear sprocket assembly shown in FIG. 3 ; FIG. 13 is another partial perspective view of the sprocket carrier of the rear sprocket assembly shown in FIG. 3 ; FIG. 14 is a cross-sectional view of the rear sprocket assembly taken along line XIV-XIV of FIG. 3 ; FIG. 15 is a cross-sectional view of the rear sprocket assembly taken along line XV-XV of FIG. 3 ; and FIGS. 16 to 18 are cross-sectional views of a rear sprocket assembly according to a modification.The embodiments of the present invention will now be described with reference to the accompanying drawings, in which like reference numerals designate corresponding or identical elements throughout the several drawings.As seen in FIG. 1, a human-powered vehicle 2 includes a vehicle body 4 and a powertrain 6. the powertrain 6 includes a rear sprocket assembly 10 and a rear hub assembly 12. The rear sprocket assembly 10 is configured to be mounted to the rear hub assembly 12 for the human-powered vehicle 2. The rear sprocket assembly 10 for the human-powered vehicle 2 has a rotational center axis A 1. The rotational center axis A 1 defines an axial direction D 1, a radial direction, and a circumferential direction D 2 (see, for example, FIG. 3 ). The rear sprocket assembly 10 is rotatably supported by the rear hub assembly 12 relative to the vehicle body 4 about the rotational center axis A 1. The human-powered vehicle 2 has an axial center plane CP. The axial center plane CP is defined in a lateral center of the vehicle body 4 of the human-powered vehicle 2. The axial center plane CP is perpendicular to the rotational center axis A 1.The powertrain 6 includes a crank assembly 6A, a front sprocket 6B, and a drive chain C. The crank assembly 6A is rotatably mounted on the vehicle body 4. The front sprocket 6B is mounted on the crank assembly 6A. The drive chain C is engaged with the front sprocket 6B and the rear sprocket assembly 10 to transmit pedaling force from the front sprocket 6B to the rear sprocket assembly 10. The front sprocket 6B includes a single sprocket in the present embodiment. However, the front sprocket 6B may include a plurality of sprockets.In the present application, the term "human-powered vehicle" includes a vehicle that travels with a driving force including at least a human force of a user who travels the vehicle. The human-powered vehicle includes various types of bicycles such as a mountain bike, a race bike, a city bike, a cargo bike, a hand bike, and a recumbent bike. Moreover, the human-powered vehicle also includes an electric bicycle, a so-called e-bike. The electric bicycle is an electrically assisted bicycle configured to assist driving of a vehicle with an electric motor. However, the total number of wheels of the human-powered vehicle is not limited to two. The human-powered vehicle includes, for example, a vehicle having one wheel or three or more wheels. In particular, the human-powered vehicle does not include a vehicle that uses only one drive source as a driving force. Examples of such a drive source include an internal combustion engine and an electric motor. Generally, a light road vehicle, i.e., a vehicle that does not require a driver's license for public road traffic, is adopted as a human-powered vehicle.In the present application, the following directional terms "front", "rear", "forward", "rearward", "left", "right", "transverse", "upward", and "downward", as well as any other similar directional terms, refer to the directions determined based on the user who is in the standard position of the user in the human-powered vehicle 2 with respect to a steering bar or steering. Examples of the standard position of the user include a saddle and a seat. Accordingly, these terms, which are used to describe the rear sprocket assembly 10 or other components, are to be understood with reference to the human-powered vehicle 2 equipped with the rear sprocket assembly 10 or other components, which is used in an upright riding position on a horizontal surface.As seen in FIG. 2, the rear sprocket assembly 10 includes a plurality of rear sprockets SP. The plurality of rear sprockets SP are configured to be engaged with the drive chain C. The plurality of rear sprockets SP include first to eleventh sprockets SP 1 to SP 11. The rear sprocket assembly 10 includes the first sprocket SP 1 and the second sprocket SP 2. The total number of rear sprockets SP is 11 in the present embodiment, but the total number of rear sprockets SP is not limited to 11.The rear hub assembly 12 includes a hub axle 14, a hub body 16, and a sprocket support body 18. The hub body 16 is rotatably mounted on the hub axle 14 about the rotational center axis A 1. The sprocket support body 18 is rotatably supported on the hub axle 14 about the rotational center axis A 1.The rear sprocket assembly 10 is configured to be mounted to the sprocket support body 18. The sprocket support body 18 includes a plurality of outer spline teeth 18A. The rear sprocket assembly 10 is configured to engage with the plurality of outer spline teeth 18A of the sprocket support body 18. The rear sprocket assembly 10 includes a locking member 19. the first to eleven sprockets SP 1 to SP 11 are coupled to the sprocket support body 18 with the locking member 19.As seen in FIG. 3, the first sprocket SP 1 has a first sprocket outer diameter DM 1. The second sprocket SP 2 has a second sprocket outer diameter DM 2 that is smaller than the first sprocket outer diameter DM 1. The third sprocket SP 3 has a third sprocket outer diameter DM 3 smaller than the second sprocket outer diameter DM 2. The first sprocket SP 1 is the largest sprocket in the rear sprocket assembly 10. the eleventh sprocket SP 11 is the smallest sprocket in the rear sprocket assembly 10. The eleventh sprocket SP 11 may also be referred to as a highest speed sprocket SP 11.As seen in FIG. 4, in upshifting, the drive chain C is shifted from one sprocket to an adjacent smaller sprocket in an upshifting direction D 41. In the downshifting, the drive chain C is shifted from one sprocket to an adjacent larger sprocket in a downshifting direction D 42.The second sprocket SP 2 is adjacent to the first sprocket SP 1 in the axial direction D 1 without another sprocket being interposed between the first sprocket SP 1 and the second sprocket SP 2. The third sprocket SP 3 is adjacent to the second sprocket SP 2 in the axial direction D 1 without another sprocket being interposed between the second sprocket SP 2 and the third sprocket SP 3.As seen in FIG. 4, the rear sprocket assembly 10 includes a sprocket carrier 22. the rear sprocket assembly 10 includes an additional sprocket carrier 23. the first to sixth sprockets SP 1 to SP 6 are mounted on the sprocket carrier 22. The seventh and eighth sprockets SP 7 and SP 8 are mounted on the additional sprocket carrier 23.As seen in FIG. 3, the first sprocket SP 1 and the second sprocket SP 2 are mounted to the sprocket carrier 22 with first fasteners 24, such as rivets. The third to sixth sprockets SP 3 to SP 6 are mounted to the sprocket carrier 22 with second fasteners 25, for example, rivets. As seen in FIG. 4, the seventh and eighth sprockets SP 7 to SP 8 are mounted to the additional sprocket carrier 23 with fasteners 26, such as rivets. The ninth to eleventh sprockets SP 9 to SP 11 are held between the additional sprocket carrier 23 and the locking member 19. However, the structure of the sprocket carrier 22 is not limited to the structure illustrated in FIG. 4.As seen in FIG. 3, the sprocket carrier 22 includes at least two arms 22A and a hub engagement portion 22B. The at least two arms 22A extend radially outward from the hub engagement portion 22B. The hub engagement portion 22B is configured to be engaged with the sprocket support body 18. The hub engagement portion 22B includes a plurality of teeth. The first sprocket SP 1 and the second sprocket SP 2 are mounted to each arm of the at least two arms 22A with the first fasteners 24. The third to sixth sprockets SP 3 to SP 6 are mounted to each arm of the at least two arms 22A with the second fasteners 25.As seen in FIG. 5, the first sprocket SP 1 includes a first sprocket body SP 1A and a plurality of first sprocket teeth SP 1B. The plurality of first sprocket teeth SP 1B extend radially outward from the first sprocket body SP 1A in the radial direction. The plurality of first sprocket teeth SP 1B are disposed on the first sprocket body SP 1A in the circumferential direction D 2. The plurality of first sprocket teeth SP 1B defines the first sprocket outer diameter DM 1.The first sprocket SP 1 has a first total number of teeth. The first total tooth number is a total number of the first sprocket teeth SP 1B. In the present embodiment, the first total teeth number is 45.The first sprocket body SP 1A includes a first radially inner periphery SP 1C. The first sprocket body SP 1A includes a plurality of first attachment holes SP 1D. The first fastening member 24 extends through the first fastening hole SP 1D in a state where the first sprocket SP 1 is fastened to the sprocket carrier 22 with the first fastening member 24 (see, for example, FIG. 3 ). The first sprocket body SP 1A includes a plurality of first openings SP 1E.As seen in FIG. 6, the second sprocket SP 2 includes a second sprocket body SP 2A and a plurality of second sprocket teeth SP 2B. The plurality of second sprocket teeth SP 2B extend radially outward from the second sprocket body SP 2A in the radial direction. The plurality of second sprocket teeth SP 2B are disposed on the second sprocket body SP 2A in the circumferential direction D 2. The plurality of second sprocket teeth SP 2B defines the second sprocket outer diameter DM 2.The second sprocket SP 2 has a second total number of teeth. The total second teeth number is a total number of the second sprocket teeth SP 2B. In the present embodiment, the second total teeth number is 39. the second total teeth number is smaller than the first total teeth number of the first sprocket SP 1. However, the second total teeth number is not limited to the above total teeth number.The second sprocket body SP 2A includes a second radially inner periphery SP 2C. The second sprocket body SP 2A includes a plurality of second attachment holes SP 2D. The first fastening member 24 extends through the second fastening hole SP 2D in a state where the second sprocket SP 2 is fastened to the sprocket carrier 22 with the first fastening member 24 (see, for example, FIG. 3 ). The second sprocket body SP 2A includes a plurality of second openings SP 2E.As seen in FIG. 7, the third sprocket SP 3 includes a third sprocket body SP 3A and a plurality of third sprocket teeth SP 3B. The plurality of third sprocket teeth SP 3B extend radially outward from the third sprocket body SP 3A in the radial direction. The plurality of third sprocket teeth SP 3B defines the third sprocket outer diameter DM 3.The third sprocket SP 3 has a third total number of teeth. The third total tooth number is a total number of the third sprocket teeth SP 3B. In the present embodiment, the third total tooth number is 33. the third total tooth number is smaller than the second total tooth number of the second sprocket SP 2. However, the third total teeth number is not limited to the above total teeth number.The third sprocket body SP 3A includes a third radially inner periphery SP 3C. The third sprocket body SP 3A includes a plurality of third attachment holes SP 3D. The second fastening member 25 extends through the third fastening hole SP 3D in a state where the third sprocket SP 3 is fastened to the sprocket carrier 22 with the second fastening member 25 (see, for example, FIG. 4 ). The third sprocket body SP 3A includes a plurality of third openings SP 3E.As seen in FIG. 8, the sprocket carrier 22 includes a plurality of first holes 22C and a plurality of second holes 22D. At least one hole of the plurality of first holes 22C is provided radially outside of at least one hole of the second holes 22D. The arm 22A includes two holes of the plurality of first holes 22C and four holes of the plurality of second holes 22D.As seen in FIG. 9, the first sprocket SP 1 has a first axially outward facing surface SP 1F and a first axially inward facing surface SP 1G. The first axially inward surface SP 1G is provided on a rear side of the first axially outward surface SP 1F in the axial direction D 1. The first axially inward facing surface SP 1G is configured to face the central axial plane CP of the human-powered vehicle 2 in the axial direction D 1 in an assembled state in which the rear sprocket assembly 10 is assembled to the human-powered vehicle 2.The second sprocket SP 2 has a second axially outward facing surface SP 2F and a second axially inward facing surface SP 2G. The second axially inward surface SP 2G is provided on a rear side of the second axially outward surface SP 2F in the axial direction D 1. The second axially inward facing surface SP 2G is formed to face the first axially outward facing surface SP 1F of the first sprocket SP 1 in the axial direction D 1.The third sprocket SP 3 has a third axially outward facing surface SP 3F and a third axially inward facing surface SP 3G. The third axially inward facing surface SP 3G is provided on a rear side of the third axially outward facing surface SP 3F in the axial direction D 1. The third axially inward facing surface SP 3G is formed to face the second axially outward facing surface SP 2F of the second sprocket SP 2 in the axial direction D 1.As seen in FIG. 9, the sprocket carrier 22 includes at least one sprocket mounting portion 22K. The at least one sprocket mounting portion 22K includes a first radial portion 22M and a second radial portion 22N. The second radial portion 22N is positioned radially inward of the first radial portion 22M in the radial direction. The first radial portion 22M extends radially outward from the second radial portion 22N.In the present embodiment, the sprocket carrier 22 includes at least two sprocket mounting portions 22K. The at least two sprocket mounting portions 22K are respectively provided on the at least two arms 22A. The at least two sprocket mounting portions 22K are respectively provided at at least two radially outer ends of the at least two arms 22A. The sprocket mounting portion 22K is provided at the radially outer end of the arm 22A.The sprocket carrier 22 has an axially outward facing carrier surface 22F and an axially inward facing carrier surface 22G. The axially inward support surface 22G is provided on a rear side of the axially outward support surface 22F in the axial direction D 1. The axially inward support surface 22G is configured to face the human-powered vehicle axial center plane CP in an assembled state in which the rear sprocket assembly 10 is assembled to the human-powered vehicle 2 in the axial direction D 1.The axially inward support surface 22G is provided at the first radial portion 22M and the second radial portion 22N. The axially outward facing support surface 22F is provided at the first radial portion 22M and the second radial portion 22N.As seen in FIGS. 10 and 11, the sprocket carrier 22 has at least one axially outward facing carrier surface 22F and at least one axially inward facing carrier surface 22G. The sprocket carrier 22 has at least two axially outward facing carrier surfaces 22F and at least two axially inward facing carrier surfaces 22G. The at least two axially outward facing support surfaces 22F are arranged in the circumferential direction D 2. The at least two axially inwardly facing support surfaces 22G are arranged in the circumferential direction D 2.The at least two sprocket mounting portions 22K respectively include the at least two axially outward facing support surfaces 22F. The at least two sprocket mounting portions 22K respectively include the at least two axially inward facing support surfaces 22G. The sprocket mounting portion 22K includes the axially outward facing support surface 22F and the axially inward facing support surface 22G.The first radial portion 22M has a first maximum axial length L 1 with respect to the axial direction D 1. The second radial portion 22N has a second maximum axial length L 2 with respect to the axial direction D 1. The second maximum axial length L 2 is greater than the first maximum axial length L 1. The first maximum axial length L 1 is defined in the axial direction D 1. The second maximum axial length L 2 is defined in the axial direction D 1.The first maximum axial length L 1 is defined between the axially outward facing support surface 22F and the axially inward facing support surface 22G in the axial direction D 1. The first sprocket SP 1 is in contact with the axially inward support surface 22G in a state where the first sprocket SP 1 is coupled to the sprocket carrier 22. The second sprocket SP 2 is in contact with the axially outward facing support surface 22F in a state where the second sprocket SP 2 is coupled to the sprocket support 22. The first maximum axial length L 1 is defined between the first sprocket SP 1 and the second sprocket SP 2 in the axial direction D 1.The axially inward support surface 22G includes an axial surface 22R, an additional axial surface 22P, and a curved surface 22Q. The axial surface 22R faces the axial center plane CP in the axial direction D 1. The additional axial surface 22P faces the axial center plane CP in the axial direction D 1. The curved surface 22Q faces the central axial plane CP in the axial direction D 1. The first maximum axial length L 1 is defined between the axially outward facing support surface 22F and the axial surface 22R in the axial direction D 1. The second maximum axial length L 2 is defined between the axially outward facing support surface 22F and the additional axial surface 22P in the axial direction D 1. In the present embodiment, the axial surface 22R is perpendicular to the axial direction D 1. The additional axial surface 22P is non-parallel and non-perpendicular to the axial direction D 1. The additional axial surface 22P is inclined relative to the axial direction D 1. However, the additional axial surface 22P may also be perpendicular to the axial direction D 1, if necessary or desired. The axial surface 22R may not be perpendicular to the axial direction D 1, if necessary or desired.As seen in FIGS. 12 and 13, the axial surface 22R extends in the circumferential direction D 2. The curved surface 22Q extends in the circumferential direction D 2. Two of the plurality of first holes 22C are provided on the axially outward facing support surface 22F and the axially inward facing support surface 22G. As seen in FIG. 13, two of the plurality of first holes 22C are provided on the axial surface 22R.As seen in FIG. 9, the first sprocket body SP 1A has at least a first mounted portion SP 1M. The at least one first assembled portion SP 1M is configured to be assembled to the axially inward facing support surface 22G of the at least one sprocket assembly portion 22K of the sprocket support 22. The at least one first assembled portion SP 1M is configured to axially contact the first radial portion 22M of the at least one sprocket assembly portion 22K of the sprocket carrier 22 with respect to the axial direction D 1. The first assembled portion SP 1M is configured to axially contact the axially inward support surface 22G in the axial direction D 1.The at least one first assembled portion SP 1M of the first sprocket body SP 1A is configured to be free from axial contact with the second radial portion 22N of the at least one sprocket assembled portion 22K of the sprocket carrier 22. The at least one first assembled portion SP 1M is provided radially outside the second radial portion 22N.The second sprocket body SP 2A has at least one second assembled portion SP 2M. The at least one second assembled portion SP 2M is configured to be assembled to the axially outward facing support surface 22F of the at least one sprocket assembly portion 22K of the sprocket support 22. The at least one second assembled portion SP 2M is configured to axially contact the first radial portion 22M and the second radial portion 22N of the at least one sprocket assembled portion 22K of the sprocket carrier 22 with respect to the axial direction D 1. The second assembled portion SP 2M is configured to axially contact the axially outward facing support surface 22F in the axial direction D 1. The first maximum axial length L 1 is defined between the first assembled portion SP 1M and the second assembled portion SP 2M in the axial direction D 1.The first sprocket SP 1 is made of a first material. The second sprocket is made of a second material. The sprocket carrier is made of a third material. The first material includes a metallic material. The second material includes a metallic material. The third material includes a metallic material or a non-metallic material. The first material is different from the second material, for example. The third material is different from at least one of the first material and the second material. The first material includes aluminum. The second material includes iron. The third material includes one of aluminum and a non-metallic material. Examples of the nonmetallic material include a resin material. The first sprocket SP 1 is made of aluminum. The second sprocket SP 2 is made of iron. The sprocket carrier 22 is made of one of aluminum and a non-metallic material. However, the first sprocket SP 1 may be made of materials other than aluminum, if necessary or desired. The second sprocket SP 2 may be made of materials other than iron, if necessary or desired. The sprocket carrier 22 may also be made of materials other than aluminum and the non-metallic material, if necessary or desired. The second sprocket SP 2 may be made of, for example, aluminum.The first sprocket body SP 1A has a first maximum axial body length L 5. The first maximum axial body length L 5 is defined in the axial direction D 1. The second sprocket body SP 2A has a second maximum axial body length L 6. The second maximum axial body length L 6 is defined in the axial direction D 1.In the present embodiment, the first maximum axial body length L 5 is longer than the second maximum axial body length L 6. The first maximum axial body length L 5 is longer than the first maximum axial length L 1 of the first radial portion 22M. The second maximum axial body length L 6 is longer than the first maximum axial length L 1 of the first radial portion 22M. The first maximum axial body length L 5 is shorter than the second maximum axial length L 2 of the second radial portion 22N. The second maximum axial body length L 6 is shorter than the second maximum axial length L 2 of the second radial portion 22N. However, the first maximum axial body length L 5 may be shorter than the second maximum axial body length L 6 if necessary or desired. The first maximum axial body length L 5 may be shorter than the first maximum axial length L 1 of the first radial portion 22M, if necessary or desired. The second maximum axial body length L 6 may be shorter than the first maximum axial length L 1 of the first radial portion 22M, if necessary or desired. The first maximum axial body length L 5 may be longer than the second maximum axial length L 2 of the second radial portion 22N, if necessary or desired. The second maximum axial body length L 6 may be longer than the second maximum axial length L 2 of the second radial portion 22N, if necessary or desired.In the present embodiment, the first maximum axial body length L 5 is equal to or greater than 2 mm. The first maximum axial body length L 5 is equal to or less than 3.5 mm. The second maximum axial body length L 6 is equal to or greater than 1.5 mm. The second maximum axial body length L 6 is equal to or less than 3.5 mm. However, the first maximum axial body length L 5 is not limited to the above range. The second maximum axial body length L 6 is not limited to the above range. The first maximum axial body length L 5 is 2.8 mm in the present embodiment. However, the first maximum axial body length L 5 is not limited to the above value.For example, the second maximum axial body length L 6 is between 1.5 mm and 2.5 mm when the second sprocket SP 2 is made of iron. The second maximum axial body length L 6 is 1.95 mm when the second sprocket SP 2 is made of iron. The second maximum axial body length L 6 is between 2 mm and 3.5 mm when the second sprocket SP 2 is made of aluminum. The second maximum axial body length L 6 is 2.8 mm when the second sprocket SP 2 is made of aluminum. However, the second maximum axial body length L 6 is not limited to the above ranges and values.The first maximum axial length L 1 of the first radial portion 22M is equal to or greater than 1.3 mm. The first maximum axial length L 1 of the first radial portion 22M is equal to or less than 3 mm. The second maximum axial length L 2 of the second radial portion 22N is equal to or greater than 3.5 mm. The second maximum axial length L 2 of the second radial portion 22N is equal to or less than 5 mm. However, the first maximum axial length L 1 is not limited to the above range. The second maximum axial length L 2 is not limited to the above range. The first maximum axial length L 1 is 1.8 mm in the present embodiment. However, the first maximum axial length L 1 is not limited to the above value. The second maximum axial length L 2 is 4.2 mm in the present embodiment. However, the second maximum axial length L 2 is not limited to the above value.As seen in FIGS. 14 and 15, the first sprocket SP 1 and the second sprocket SP 2 are mounted on the at least one sprocket mounting portion 22K of the sprocket carrier 22 with at least one common fastener. In the present embodiment, the first sprocket SP 1 and the second sprocket SP 2 are mounted with the first fastening member 24 on the sprocket mounting portion 22K of the sprocket carrier 22. The first sprocket SP 1 and the second sprocket SP 2 are coupled to the first radial portion 22M of the sprocket mounting portion 22K by the first fastener 24. The first fixing member 24 extends through the first fixing hole SP 1D, the second fixing hole SP 2D, and the first hole 22C. However, the first sprocket SP 1 and the second sprocket SP 2 may be mounted to the at least one sprocket mounting portion 22K of the sprocket carrier 22 with separate fasteners, if necessary or desired.As seen in FIGS. 16 to 18, the first sprocket SP 1, the second sprocket SP 2, and the sprocket carrier 22 may have different shapes from those illustrated in FIGS. 1 to 13.In the present application, the term "comprise" and its derivatives, as used herein, are to be understood as open ended terms that specify the presence of stated features, elements, components, groups, integers, and / or steps, but do not preclude the presence of other unspecified features, elements, components, groups, integers, and / or steps. This concept also applies to words of similar meaning, for example the terms "have", "include" and their derivatives.The terms "element", "section", "portion", "part", "body" and "structure", when used in the singular, may have the dual meaning of a single part or a plurality of parts.The ordinal numbers such as "first(r / s)" and "second(r / s)" mentioned in the present application are merely identifiers, but have no other meaning such as a certain order or the like. Moreover, for example, the term "first element" itself does not imply the existence of a "second element", and the term "second element" itself does not imply the existence of a "first element".The term "pair" as used herein may include the configuration in which the pair of elements have different shapes or structures from each other, in addition to the configuration in which the pair of elements have the same shapes or structures as each other.The terms "a" (or "an / s"), "one(r / s) or more" and "at least one(r / s)" may be used interchangeably herein.The phrase "at least one of" as used in this disclosure means "one or more" of a desired selection. For example, the phrase "at least one of" as used in this disclosure means "only a single selection" or "both of two choices" when the number of choices is two. As another example, the phrase "at least one of" as used in this disclosure means "only a single selection" or "any combination of equal to or more than two choices" when the number of choices is equal to or greater than three. For example, the phrase "at least one of A and B" includes (1) A alone, (2) B alone, and (3) both A and B. The phrase "at least one of A, B, and C" includes (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 A, B, and C. In other words, the phrase "at least one of A and B" does not mean "at least one of A and at least one of B" in this disclosure.Finally, terms such as "substantially", "about" and "approximately" as used herein mean an appropriate deviation of the modified term such that the end result is not substantially changed. All numerical values described in the present application may be understood to include terms such as "substantially", "approximately", and "approximately".Of course, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.REFERENCE NUMERALS2 Human-powered vehicle 4 Vehicle body 6 Powertrain 6A Crank assembly 6B Front sprocket 10 Rear sprocket assembly 12 Rear hub assembly 14 Hub axle 16 Hub body 18 Sprocket support body 18A External spline teeth 19 Locking member 22 Sprocket carrier 22A Arm 22B Hub engagement part 22C First hole 22D Second hole 22F Axially outward facing carrier surface 22G Axially inward facing carrier surface 22K Sprocket mounting portion 22M First radial portion 22N Second radial portion 22R Axial surface 22P Additional axial surface 22Q Curved surface 23 Additional sprocket carrier 24 First fastener / rivet 25 Second fastener / rivet 26 Second fastener / rivet A1 Rotational center axis D1 Axial direction D2 Circumferential direction C Drive chain A center axial plane DM 1 of first sprocket outer diameter DM 2 of second sprocket outer diameter DM 3 of third sprocket outer diameter D 41 of an upshifting direction D 42 of a downshifting direction L 1 of first maximum axial length L 2 of second maximum axial length L 5 of first maximum axial body length L 6 of second maximum axial body length SP of rear sprocket SP 1-SP 11 of first to eleventh rear sprockets SP 1A of first sprocket body SP 1B of first sprocket teeth SP 1C of first radially inner periphery SP 1D of first attachment hole SP 1E of first opening SP 1F of first axially outward facing surface SP 1G of first axially inward facing surface SP 1M of first mounted portion SP 2A of second sprocket body SP 2B of second sprocket Sprocket teeth SP 2C Second radially inner periphery SP 2D Second attachment hole SP 2E Second opening SP 2F Second axially outward facing surface SP 2G Second axially inward facing surface SP 2M Second mounted portion SP 3A Third sprocket body SP 3B Third sprocket teeth SP 3C Third radially inner periphery SP 3D Third attachment hole SP 3E Third opening SP 3F Third axially outward facing surface SP 3G Third axially inward facing surface teeth SP 3G

Claims

A rear sprocket assembly (10) for a human-powered vehicle (2), the rear sprocket assembly (10) having a rotational center axis (A1) defining an axial direction (D1), a radial direction, and a circumferential direction (D2), the rear sprocket assembly (10) comprising: a sprocket carrier (22) having an axially outward facing carrier surface (22F) and an axially inward facing carrier surface (22G) provided on a rear side of the axially outward facing carrier surface (22F) in the axial direction (D1), the axially inward facing carrier surface (22G) being formed in an assembled state in which the rear sprocket assembly (10) is assembled to the human-powered vehicle (2), A sprocket wheel (SP1) for use in pointing in the axial direction (D1) toward a central axial plane (CP) of the human-powered vehicle, the sprocket wheel carrier (22) including at least one sprocket mounting portion (22K) having a first radial portion (22M) and a second radial portion (22N) positioned radially inward of the first radial portion (22M) in the radial direction, the first radial portion (22M) having a first maximum axial length (L1) with respect to the axial direction (D1), the second radial portion (22N) having a second maximum axial length (L2) with respect to the axial direction (D1), the second maximum axial length (L2) being greater than the first maximum axial length (L1); a first sprocket wheel (SP1), including a first sprocket body (SP 1A) and a plurality of first sprocket teeth (SP 1B) extending radially outward from the first sprocket body (SP 1A) in the radial direction, the plurality of first sprocket teeth (SP 1B) being disposed on the first sprocket body (SP 1A) in the circumferential direction (D 2), the first sprocket (SP 1) having a first total number of teeth, a first axially outward facing surface (SP 1F), and a first axially inward facing surface (SP 1G) provided on a rear side of the first axially outward facing surface (SP 1F) in the axial direction (D 1), the first axially inward facing surface (SP 1G) being formed, Facing in the axial direction (D1) toward the axial center plane (CP) of the human-powered vehicle (2) in the assembled state, wherein the first sprocket body (SP1A) has at least one first assembled portion (SP1M) configured to be assembled to the axially inward facing support surface (22G) of the at least one sprocket assembly portion (22K) of the sprocket support (22), wherein the at least one first assembled portion (SP1M) is configured to axially contact the first radial portion (22M) of the at least one sprocket assembly portion (22K) of the sprocket support (22) with respect to the axial direction (D1); and a second sprocket (SP2), including a second sprocket body (SP 2A) and a plurality of second sprocket teeth (SP 2B) extending radially outward from the second sprocket body (SP 2A) in the radial direction, the plurality of second sprocket teeth (SP 2B) being disposed on the second sprocket body (SP 2A) in the circumferential direction (D 2), the second sprocket (SP 2) having a second total number of teeth, a second axially outward facing surface (SP 2F), and a second axially inward facing surface (SP 2G) provided on a rear side of the second axially outward facing surface (SP 2F) in the axial direction (D 1), wherein the second total tooth number is smaller than the first total tooth number of the first sprocket (SP 1), the second axially inward facing surface (SP 2G) being configured to face the first axially outward facing surface (SP 1F) of the first sprocket (SP 1) in the axial direction (D 1), the second sprocket body (SP 2A) having at least one second mounted portion (SP 2M) configured to be mounted on the axially outward facing support surface (22F) of the at least one sprocket mounting portion (22K) of the sprocket support (22), the at least one second mounted portion (SP 2M) being configured, the first radial portion (22M) and the second radial portion (22N) of the at least one sprocket mounting portion (22K) of the sprocket carrier (22) to axially contact with respect to the axial direction (D 1), wherein the second sprocket (SP 2) is adjacent to the first sprocket (SP 1) in the axial direction (D 1) without another sprocket being interposed between the first sprocket (SP 1) and the second sprocket (SP 2).The rear sprocket assembly (10) according to claim 1, wherein the first sprocket body (SP1A) has a first maximum axial body length (L5) equal to or greater than 2 mm.The rear sprocket assembly (10) according to claim 2, wherein the first maximum axial body length (L5) is equal to or less than 3.5 mm.The rear sprocket assembly (10) according to any one of the preceding claims, wherein the second sprocket body (SP2A) has a second maximum axial body length (L6) equal to or greater than 1.5 mm.The rear sprocket assembly (10) according to claim 4, wherein the second maximum axial body length (L6) is equal to or less than 3.5 mm.Rear sprocket assembly (10) according to any of the preceding claims, wherein the first maximum axial length (L1) of the first radial portion (22M) is equal to or greater than 1.3 mm.The rear sprocket assembly (10) according to claim 6, wherein the first maximum axial length (L1) of the first radial portion (22M) is equal to or less than 3 mm.The rear sprocket assembly (10) according to any one of the preceding claims, wherein the second maximum axial length (L2) of the second radial portion (22N) is equal to or greater than 3.5 mm.The rear sprocket assembly (10) according to claim 8, wherein the second maximum axial length (L2) of the second radial portion (22N) is equal to or less than 5 mm.The rear sprocket assembly (10) according to any one of the preceding claims, wherein the first sprocket (SP1) is made of aluminum.The rear sprocket assembly (10) according to any one of the preceding claims, wherein the second sprocket (SP2) is made of iron.The rear sprocket assembly (10) according to any one of the preceding claims, wherein the second sprocket (SP2) is made of aluminum.The rear sprocket assembly (10) of any preceding claim, wherein the sprocket carrier (22) is made of one of aluminum and a non-metallic material.The rear sprocket assembly (10) according to any one of the preceding claims, wherein the first sprocket (SP1) and the second sprocket (SP2) are mounted to the at least one sprocket mounting portion (22K) of the sprocket carrier (22) by at least one common fastener.The rear sprocket assembly (10) according to any one of the preceding claims, wherein the at least one first assembled portion (SP1M) of the first sprocket body (SP1A) is configured to be free of axial contact with the second radial portion (22N) of the at least one sprocket assembled portion (22K) of the sprocket carrier (22).

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