Rear sprocket assembly

Abstract

The rear sprocket assembly includes a sprocket bracket, a first sprocket, and a second sprocket. The sprocket bracket includes at least one sprocket mounting portion having a first radial portion and a second radial portion. The first radial portion has a first maximum axial length relative to the axial direction. The second radial portion has a second maximum axial length relative to the axial direction. The second maximum axial length is greater than the first maximum axial length. The at least one second mounting portion of the second sprocket is configured to axially contact the first radial portion and the second radial portion of the at least one sprocket mounting portion of the sprocket carrier with respect to the axial direction.

Description

Technical Field

[0001] The present invention relates to a rear sprocket assembly. Background Art

[0002] A human-powered vehicle includes a sprocket assembly configured to engage with a chain. The sprocket assembly includes a plurality of sprockets. One of the purposes of the present disclosure is to maintain the necessary rigidity of the sprockets and sprocket carriers of the sprocket assembly while selecting a sprocket of a lighter material. Summary of the invention

[0003] According to a first aspect of the present invention, a rear sprocket assembly for a human-powered vehicle has a rotation center axis. The rotation 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, the axially inward facing carrier surface being arranged on the opposite side of the axially outward facing carrier surface in the axial direction. The axially inward facing carrier surface is configured to face the axial center plane of the human-powered vehicle in the axial direction when the rear sprocket assembly is mounted to the human-powered vehicle. The sprocket carrier includes at least one sprocket mounting portion, the at least one sprocket mounting portion having a first radial portion and a second radial portion positioned radially inward from the first radial portion in the radial direction. The first radial portion has a first maximum axial length relative to the axial direction. The second radial portion has a second maximum axial length relative 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, the plurality of first sprocket teeth extending radially outward from the first sprocket body in the radial direction. A plurality of first sprocket teeth are arranged on the first sprocket body in a 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, which is arranged on the opposite side of the first axially outward facing surface in the axial direction. The first axially inward facing surface is configured to face the axial center plane of the human-powered vehicle in the axial direction in the installed state. The first sprocket body has at least one first mounting portion, which is configured to be mounted to the axially inward facing bracket surface of at least one sprocket mounting portion of the sprocket carrier. The at least one first mounting portion is configured to axially contact the first radial portion of at least one sprocket mounting portion of the sprocket carrier relative to the axial direction. The second sprocket includes a second sprocket body and a plurality of second sprocket teeth, which extend radially outward from the second sprocket body in a radial direction. The plurality of second sprocket teeth are arranged on the second sprocket body in a 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, which is arranged on the opposite side of the second axially outward facing surface in the axial direction. The second total number of teeth is less than the first total number of teeth 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 mounting portion, and the at least one second mounting portion is configured to be mounted to the axially outward facing bracket surface of at least one sprocket mounting portion of the sprocket carrier. The at least one second mounting portion is configured to axially contact a first radial portion and a second radial portion of at least one sprocket mounting portion of the sprocket carrier relative to the axial direction. The second sprocket is adjacent to the first sprocket in the axial direction, and there is no other sprocket between the first sprocket and the second sprocket.

[0004] With the rear sprocket assembly according to the first aspect, since at least one second mounting portion is configured to axially contact the first radial portion and the second radial portion relative to the axial direction, the at least one second mounting portion can improve the rigidity of at least one sprocket mounting portion of the sprocket carrier. As a result, the axial length of the first radial portion of at least one sprocket mounting portion of the sprocket carrier can be reduced, so that the axial thickness of the first sprocket and the axial thickness of the second sprocket are larger. Therefore, the necessary rigidity of the first sprocket and the necessary rigidity of the second sprocket can be maintained while selecting a first sprocket of a lighter material.

[0005] 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 that is equal to or greater than 2 mm.

[0006] With the rear sprocket assembly according to the second aspect, it is possible to reliably maintain the necessary rigidity of the first sprocket while selecting a first sprocket of a lighter material.

[0007] 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.

[0008] With the rear sprocket assembly according to the third aspect, the rigidity of the first radial portion and the second radial portion of the at least one sprocket mounting portion of the sprocket carrier can be ensured while maintaining the necessary rigidity of the first sprocket.

[0009] 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 that is equal to or greater than 1.5 mm.

[0010] With the rear sprocket assembly according to the fourth aspect, it is possible to select a lighter material for the second sprocket while maintaining the necessary rigidity of the second sprocket.

[0011] 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.

[0012] With the rear sprocket assembly according to the fifth aspect, the rigidity of the first radial portion and the second radial portion of the at least one sprocket mounting portion of the sprocket carrier can be ensured while maintaining the necessary rigidity of the second sprocket.

[0013] 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.

[0014] With the rear sprocket assembly according to the sixth aspect, the rigidity of the first radial portion of at least one sprocket mounting portion of the sprocket carrier can be ensured.

[0015] 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.

[0016] With the rear sprocket assembly according to the seventh aspect, the weight of the sprocket carrier can be reduced.

[0017] 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.

[0018] With the rear sprocket assembly according to the eighth aspect, it is possible to ensure the rigidity of the second radial portion of at least one sprocket mounting portion of the sprocket carrier while selecting a sprocket carrier of a lighter material.

[0019] 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.

[0020] With the rear sprocket assembly according to the ninth aspect, the weight of the sprocket carrier can be reduced.

[0021] According to 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.

[0022] With the rear sprocket assembly according to the tenth aspect, the weight of the first sprocket can be reduced.

[0023] According to 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.

[0024] With the rear sprocket assembly according to the eleventh aspect, the necessary rigidity of the second sprocket can be maintained.

[0025] According to 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.

[0026] With the rear sprocket assembly according to the twelfth aspect, the weight of the second sprocket can be reduced.

[0027] According to 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.

[0028] With the rear sprocket assembly according to the thirteenth aspect, the weight of the sprocket carrier can be reduced.

[0029] According to 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 to at least one sprocket mounting portion of the sprocket carrier by at least one common fastener.

[0030] With the rear sprocket assembly according to the fourteenth aspect, the total number of parts can be reduced, the manufacturing cost of the rear sprocket assembly can be reduced, or the productivity of the rear sprocket assembly can be improved.

[0031] According to a fifteenth aspect of the present invention, the rear sprocket assembly according to any one of the first to fourteenth aspects is constructed so that at least one first mounting portion of the first sprocket body is constructed to have no axial contact with a second radial portion of at least one sprocket mounting portion of the sprocket carrier.

[0032] With the rear sprocket assembly according to the fifteenth aspect, the axial thickness of the first sprocket can be increased, thereby making it possible to reliably maintain the necessary rigidity of the first sprocket while selecting a first sprocket of a relatively light material. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] A fuller understanding of the present invention together with many of its attendant advantages will be readily obtained by reference to the following detailed description when considered in conjunction with the accompanying drawings.

[0034] Figure 1 is a schematic diagram of a human-powered vehicle including a rear sprocket assembly according to one embodiment.

[0035] Figure 2 yes Figure 1 An exploded rear view of the rear sprocket assembly and rear hub assembly of a human powered vehicle is shown.

[0036] Figure 3 yes Figure 1 A side elevation view of the rear sprocket assembly is shown.

[0037] Figure 4 is along Figure 3 A cross-sectional view of the rear sprocket assembly taken along line IV-IV in FIG.

[0038] Figure 5 yes Figure 3 A side elevation view of a sprocket of a rear sprocket assembly is shown.

[0039] Figure 6 yes Figure 3 A side elevation view of a sprocket of a rear sprocket assembly is shown.

[0040] Figure 7 yes Figure 3A side elevation view of a sprocket of a rear sprocket assembly is shown.

[0041] Figure 8 yes Figure 3 A side elevation view of the sprocket carrier of the rear sprocket assembly is shown.

[0042] Fig. 9 is along Figure 3 A cross-sectional view of the rear sprocket assembly taken along line IX-IX in FIG.

[0043] Fig.10 yes Figure 3 A perspective view of the sprocket carrier of the rear sprocket assembly is shown.

[0044] Fig.11 yes Figure 3 Another perspective view of the sprocket carrier of the rear sprocket assembly is shown.

[0045] Fig.12 yes Figure 3 A partial perspective view of a sprocket carrier of a rear sprocket assembly is shown.

[0046] Fig.13 yes Figure 3 Another partial perspective view of the sprocket carrier of the rear sprocket assembly is shown.

[0047] Fig.14 is along Figure 3 A cross-sectional view of the rear sprocket assembly taken along line XIV-XIV in FIG.

[0048] Fig.15 is along Figure 3 A cross-sectional view of the rear sprocket assembly taken along line XV-XV in FIG.

[0049] Figures 16 to 18 is a cross-sectional view of a rear sprocket assembly according to a modified example. DETAILED DESCRIPTION

[0050] Embodiments will now be described with reference to the drawings, wherein like reference numerals designate corresponding or identical elements throughout the various drawings.

[0051] like Figure 1 As shown, the human-powered vehicle 2 includes a vehicle body 4 and a transmission system 6. The transmission system 6 includes a rear sprocket assembly 10 and a rear hub assembly 12. The rear hub assembly 12 is mounted to the vehicle body 4. 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 rotation center axis A1. The rotation center axis A1 defines an axial direction D1, a radial direction, and a circumferential direction D2 (see, for example Figure 3). The rear sprocket assembly 10 is rotatably supported by the rear hub assembly 12 about the rotation center axis A1 relative to the vehicle body 4. The human-powered vehicle 2 has an axial center plane CP. The axial center plane CP is defined at a lateral center position of the vehicle body 4 of the human-powered vehicle 2. The axial center plane CP is perpendicular to the rotation center axis A1.

[0052] The transmission system 6 includes a crank assembly 6A, a front sprocket 6B, and a transmission chain C. The crank assembly 6A is rotatably mounted to the vehicle body 4. The front sprocket 6B is mounted to the crank assembly 6A. The transmission chain C engages with the front sprocket 6B and the rear sprocket assembly 10 to transmit the pedaling force from the front sprocket 6B to the rear sprocket assembly 10. In the present embodiment, the front sprocket 6B includes a single sprocket. However, the front sprocket 6B may include a plurality of sprockets.

[0053] In the present application, the term "human-powered vehicle" includes a vehicle that travels with power including at least the human power of the user riding the vehicle. Human-powered vehicles include various bicycles, such as mountain bikes, road bikes, city bikes, cargo bikes, hand bikes and recumbent bikes. In addition, human-powered vehicles include electric bicycles known as E-bikes. Electric bicycles include electric-assisted bicycles, which are configured to assist the propulsion of the vehicle with an electric motor. However, the total number of wheels of the human-powered vehicle is not limited to two. For example, human-powered vehicles include vehicles with one wheel or three or more wheels. In particular, human-powered vehicles do not include vehicles that use only a driving source as power. Examples of driving sources include internal combustion engines and electric motors. In general, light road vehicles, including vehicles that do not require a driver's license on public roads, are considered human-powered vehicles.

[0054] In this application, the following directional terms "front", "rear", "forward", "rearward", "left", "right", "lateral", "upward", and "downward", and any other similar directional terms refer to those directions determined based on the user being in the standard user position in the human-powered vehicle 2 and facing the handlebars or steering gear. Examples of the standard user position include saddles and seats. Therefore, these terms used to describe the rear sprocket assembly 10 or other components should be interpreted relative to the human-powered vehicle 2 equipped with the rear sprocket assembly 10 or other components when used in an upright riding position on a horizontal surface.

[0055] like Figure 2 As shown, the rear sprocket assembly 10 includes a plurality of rear sprockets SP. The plurality of rear sprockets SP are configured to engage with the transmission chain C. The plurality of rear sprockets SP include a first sprocket SP1 to an eleventh sprocket SP11. That is, the rear sprocket assembly 10 includes a first sprocket SP1 and a second sprocket SP2. In the present embodiment, the total number of the plurality of sprockets SP is 11. However, the total number of the plurality of sprockets SP is not limited to 11.

[0056] The rear hub assembly 12 includes a hub axle 14, a hub body 16, and a sprocket support body 18. The hub axle 14 is configured to be mounted to the body 4 of the human-powered vehicle 2 (see, for example, Figure 1 The hub body 16 is rotatably mounted on the hub axle 14 about the rotation center axis A1. The sprocket support body 18 is rotatably mounted on the hub axle 14 about the rotation center axis A1.

[0057] The rear sprocket assembly 10 is configured to be mounted to a sprocket support body 18. The sprocket support body 18 includes a plurality of external spline teeth 18A. The rear sprocket assembly 10 is configured to engage with the plurality of external spline teeth 18A of the sprocket support body 18. The rear sprocket assembly 10 includes a locking member 19. The first sprocket SP1 to the eleventh sprocket SP11 are coupled to the sprocket support body 18 by the locking member 19.

[0058] like Figure 3 As shown, the first sprocket SP1 has a first sprocket outer diameter DM1. The second sprocket SP2 has a second sprocket outer diameter DM2 that is smaller than the first sprocket outer diameter DM1. The third sprocket SP3 has a third sprocket outer diameter DM3 that is smaller than the second sprocket outer diameter DM2. The first sprocket SP1 is the largest sprocket in the rear sprocket assembly 10. The eleventh sprocket SP11 is the smallest sprocket in the rear sprocket assembly 10. The first sprocket SP1 may also be referred to as a low-speed gear sprocket SP1. The eleventh sprocket SP11 may also be referred to as a high-speed gear sprocket SP11.

[0059] like Figure 4 As shown, for example, when the transmission chain C is shifted from the sprocket to the adjacent smaller sprocket in the upshift direction D41, an upshift occurs. When the transmission chain C is shifted from the sprocket to the adjacent larger sprocket in the downshift direction D42, a downshift occurs.

[0060] The second sprocket SP2 is adjacent to the first sprocket SP1 in the axial direction D1 without another sprocket therebetween. The third sprocket SP3 is adjacent to the second sprocket SP2 in the axial direction D1 without another sprocket therebetween.

[0061] like Figure 4 As shown, the rear sprocket assembly 10 includes a sprocket carrier 22. The rear sprocket assembly 10 includes an additional sprocket carrier 23. The first sprocket SP1 to the sixth sprocket SP6 are mounted on the sprocket carrier 22. The seventh sprocket SP7 and the eighth sprocket SP8 are mounted on the additional sprocket carrier 23.

[0062] like Figure 3 As shown, the first sprocket SP1 and the second sprocket SP2 are mounted to the sprocket carrier 22 by first fasteners 24 such as rivets. The third sprocket SP3 to the sixth sprocket SP6 are mounted to the sprocket carrier 22 by second fasteners 25 such as rivets. Figure 4 As shown, the seventh sprocket SP7 and the eighth sprocket SP8 are mounted to the additional sprocket carrier 23 by fasteners 26 such as rivets. The ninth sprocket SP9 to the eleventh sprocket SP11 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 Figure 4 The structure shown.

[0063] like Figure 3 As shown, the sprocket carrier 22 includes at least two arms 22A and a hub engaging portion 22B. The at least two arms 22A extend radially outward from the hub engaging portion 22B. The hub engaging portion 22B is configured to engage with the sprocket support body 18. The hub engaging portion 22B includes a plurality of teeth. The first sprocket SP1 and the second sprocket SP2 are mounted to each of the at least two arms 22A by a first fastener 24. The third sprocket SP3 to the sixth sprocket SP6 are mounted to each of the at least two arms 22A by a second fastener 25.

[0064] like Figure 5 As shown, the first sprocket SP1 includes a first sprocket body SP1A and a plurality of first sprocket teeth SP1B. The plurality of first sprocket teeth SP1B extend radially outward from the first sprocket body SP1A in a radial direction. The plurality of first sprocket teeth SP1B are arranged on the first sprocket body SP1A along a circumferential direction D2. The plurality of first sprocket teeth SP1B define a first sprocket outer diameter DM1.

[0065] The first sprocket SP1 has a first total number of teeth. The first total number of teeth is the total number of the first sprocket teeth SP1B. In the present embodiment, the first total number of teeth is 45. However, the first total number of teeth is not limited to the above total number of teeth.

[0066] The first sprocket body SP1A includes a first radial inner periphery SP1C. The first sprocket body SP1A includes a plurality of first fastener holes SP1D. The first fasteners 24 extend through the first fastener holes SP1D in a state where the first sprocket SP1 is fastened to the sprocket carrier 22 by the first fasteners 24 (see, for example, Figure 3 ). The first sprocket body SP1A includes a plurality of first openings SP1E.

[0067] like Figure 6 As shown, the second sprocket SP2 includes a second sprocket body SP2A and a plurality of second sprocket teeth SP2B. The plurality of second sprocket teeth SP2B extend radially outward from the second sprocket body SP2A in the radial direction. The plurality of second sprocket teeth SP2B are arranged on the second sprocket body SP2A along the circumferential direction D2. The plurality of second sprocket teeth SP2B define a second sprocket outer diameter DM2.

[0068] The second sprocket SP2 has a second total number of teeth. The second total number of teeth is the total number of the second sprocket teeth SP2B. In the present embodiment, the second total number of teeth is 39. The second total number of teeth is smaller than the first total number of teeth of the first sprocket SP1. However, the second total number of teeth is not limited to the above total number of teeth.

[0069] The second sprocket body SP2A includes a second radial inner periphery SP2C. The second sprocket body SP2A includes a plurality of second fastener holes SP2D. The first fastener 24 extends through the second fastener holes SP2D in a state where the second sprocket SP2 is fastened to the sprocket carrier 22 by the first fastener 24 (see, for example, Figure 3 ). The second sprocket body SP2A includes a plurality of second openings SP2E.

[0070] like Figure 7 As shown, the third sprocket SP3 includes a third sprocket body SP3A and a plurality of third sprocket teeth SP3B. The plurality of third sprocket teeth SP3B extend radially outward from the third sprocket body SP3A in a radial direction. The plurality of third sprocket teeth SP3B define a third sprocket outer diameter DM3.

[0071] The third sprocket SP3 has a third total number of teeth. The third total number of teeth is the total number of the third sprocket teeth SP3B. In the present embodiment, the third total number of teeth is 33. The third total number of teeth is less than the second total number of teeth of the second sprocket SP2. However, the third total number of teeth is not limited to the above total number of teeth.

[0072] The third sprocket body SP3A includes a third radial inner periphery SP3C. The third sprocket body SP3A includes a plurality of third fastener holes SP3D. The second fastener 25 extends through the third fastener holes SP3D in a state where the third sprocket SP3 is fastened to the sprocket carrier 22 by the second fastener 25 (see, for example, Figure 4 ). The third sprocket body SP3A includes a plurality of third openings SP3E.

[0073] like Figure 8 As shown, the sprocket carrier 22 includes a plurality of first holes 22C and a plurality of second holes 22D. At least one hole in the plurality of first holes 22C is arranged radially outside at least one hole in the plurality of second holes 22D. The arm 22A includes two holes in the plurality of first holes 22C and four holes in the plurality of second holes 22D.

[0074] like Fig. 9As shown, the first sprocket SP1 has a first axially outward facing surface SP1F and a first axially inward facing surface SP1G. The first axially inward facing surface SP1G is arranged on the opposite side of the first axially outward facing surface SP1F along the axial direction D1. The first axially inward facing surface SP1G is configured to face the axial center plane CP of the human-powered vehicle 2 in the axial direction D1 when the rear sprocket assembly 10 is mounted to the human-powered vehicle 2.

[0075] The second sprocket SP2 has a second axially outward facing surface SP2F and a second axially inward facing surface SP2G. The second axially inward facing surface SP2G is disposed on the opposite side of the second axially outward facing surface SP2F in the axial direction D1. The second axially inward facing surface SP2G is configured to face the first axially outward facing surface SP1F of the first sprocket SP1 in the axial direction D1.

[0076] The third sprocket SP3 has a third axially outward facing surface SP3F and a third axially inward facing surface SP3G. The third axially inward facing surface SP3G is disposed on the opposite side of the third axially outward facing surface SP3F in the axial direction D1. The third axially inward facing surface SP3G is configured to face the second axially outward facing surface SP2F of the second sprocket SP2 in the axial direction D1.

[0077] like Fig. 9 As shown, the sprocket carrier 22 includes at least one sprocket mounting portion 22K. The at least one sprocket mounting portion 22K has a first radial portion 22M and a second radial portion 22N. The second radial portion 22N is positioned radially inward from the first radial portion 22M in the radial direction. The first radial portion 22M extends radially outward from the second radial portion 22N.

[0078] In the present embodiment, the sprocket bracket 22 includes at least two sprocket mounting portions 22K. The at least two sprocket mounting portions 22K are respectively provided to at least two arms 22A. The at least two sprocket mounting portions 22K are respectively provided to at least two radially outer ends of the at least two arms 22A. The sprocket mounting portion 22K is provided to the radially outer ends of the arms 22A.

[0079] The sprocket carrier 22 has an axially outwardly facing carrier surface 22F and an axially inwardly facing carrier surface 22G. The axially inwardly facing carrier surface 22G is disposed on the opposite side of the axially outwardly facing carrier surface 22F in the axial direction D1. The axially inwardly facing carrier surface 22G is configured to face the axial center plane CP of the human-powered vehicle 2 in the axial direction D1 when the rear sprocket assembly 10 is mounted to the human-powered vehicle 2.

[0080] An axially inward facing bracket surface 22G is provided to the first radial portion 22M and the second radial portion 22N. An axially outward facing bracket surface 22F is provided to the first radial portion 22M and the second radial portion 22N.

[0081] like Fig.10 and Fig.11 As shown, the sprocket carrier 22 has at least one axially outwardly facing carrier surface 22F and at least one axially inwardly facing carrier surface 22G. The sprocket carrier 22 has at least two axially outwardly facing carrier surfaces 22F and at least two axially inwardly facing carrier surfaces 22G. The at least two axially outwardly facing carrier surfaces 22F are arranged along the circumferential direction D2. The at least two axially inwardly facing carrier surfaces 22G are arranged along the circumferential direction D2.

[0082] The at least two sprocket mounting portions 22K include at least two axially outwardly facing carrier surfaces 22F, respectively. The at least two sprocket mounting portions 22K include at least two axially inwardly facing carrier surfaces 22G, respectively. The sprocket mounting portions 22K include the axially outwardly facing carrier surfaces 22F and the axially inwardly facing carrier surfaces 22G.

[0083] The first radial portion 22M has a first maximum axial length L1 relative to the axial direction D1. The second radial portion 22N has a second maximum axial length L2 relative to the axial direction D1. The second maximum axial length L2 is greater than the first maximum axial length L1. The first maximum axial length L1 is defined in the axial direction D1. The second maximum axial length L2 is defined in the axial direction D1.

[0084] The first maximum axial length L1 is defined between the axially outwardly facing carrier surface 22F and the axially inwardly facing carrier surface 22G in the axial direction D1. The first sprocket SP1 is in contact with the axially inwardly facing carrier surface 22G in a state where the first sprocket SP1 is coupled to the sprocket carrier 22. The second sprocket SP2 is in contact with the axially outwardly facing carrier surface 22F in a state where the second sprocket SP2 is coupled to the sprocket carrier 22. That is, the first maximum axial length L1 is defined between the first sprocket SP1 and the second sprocket SP2 in the axial direction D1.

[0085] The axially inwardly facing bracket 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 D1. The additional axial surface 22P faces the axial center plane CP in the axial direction D1. The curved surface 22Q faces the axial center plane CP in the axial direction D1. The first maximum axial length L1 is defined between the axially outwardly facing bracket surface 22F and the axial surface 22R in the axial direction D1. The second maximum axial length L2 is defined between the axially outwardly facing bracket surface 22F and the additional axial surface 22P in the axial direction D1. In the present embodiment, the axial surface 22R is perpendicular to the axial direction D1. The additional axial surface 22P is not parallel to and not perpendicular to the axial direction D1. The additional axial surface 22P is inclined relative to the axial direction D1. However, if necessary or desired, the additional axial surface 22P may be perpendicular to the axial direction D1. If necessary or desired, the axial surface 22R may not be perpendicular to the axial direction D1.

[0086] like Fig.12 and Fig.13 As shown, the axial surface 22R extends in the circumferential direction D2. The curved surface 22Q extends in the circumferential direction D2. Two holes of the plurality of first holes 22C are provided on the axially outwardly facing bracket surface 22F and the axially inwardly facing bracket surface 22G. Fig.13 As shown, two holes of the plurality of first holes 22C are provided on the axial surface 22R.

[0087] like Fig. 9 As shown, the first sprocket body SP1A has at least one first mounting portion SP1M. The at least one first mounting portion SP1M is configured to be mounted to the axially inwardly facing carrier surface 22G of at least one sprocket mounting portion 22K of the sprocket carrier 22. The at least one first mounting portion SP1M is configured to axially contact the first radial portion 22M of at least one sprocket mounting portion 22K of the sprocket carrier 22 with respect to the axial direction D1. The first mounting portion SP1M is configured to axially contact the axially inwardly facing carrier surface 22G in the axial direction D1.

[0088] The at least one first mounting portion SP1M of the first sprocket body SP1A is configured to have no axial contact with the second radial portion 22N of the at least one sprocket mounting portion 22K of the sprocket carrier 22. The at least one first mounting portion SP1M is disposed radially outside the second radial portion 22N.

[0089] The second sprocket body SP2A has at least one second mounting portion SP2M. The at least one second mounting portion SP2M is configured to be mounted to the axially outwardly facing carrier surface 22F of at least one sprocket mounting portion 22K of the sprocket carrier 22. The at least one second mounting portion SP2M is configured to axially contact the first radial portion 22M and the second radial portion 22N of at least one sprocket mounting portion 22K of the sprocket carrier 22 with respect to the axial direction D1. The second mounting portion SP2M is configured to axially contact the axially outwardly facing carrier surface 22F in the axial direction D1. A first maximum axial length L1 is defined between the first mounting portion SP1M and the second mounting portion SP2M in the axial direction D1.

[0090] The first sprocket SP1 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 metal material. The second material includes a metal material. The third material includes a metal material or a non-metal material. For example, the first material is different from the second material. 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-metal material. Examples of non-metal materials include resin materials. That is, the first sprocket SP1 is made of aluminum. The second sprocket SP2 is made of iron. The sprocket carrier 22 is made of one of aluminum and a non-metal material. However, if necessary or desired, the first sprocket SP1 may be made of a material other than aluminum. If necessary or desired, the second sprocket SP2 may be made of a material other than iron. If necessary or desired, the sprocket carrier 22 may be made of a material other than aluminum and a non-metal material. For example, the second sprocket SP2 may be made of aluminum.

[0091] The first sprocket body SP1A has a first maximum axial body length L5. The first maximum axial body length L5 is defined in the axial direction D1. The second sprocket body SP2A has a second maximum axial body length L6. The second maximum axial body length L6 is defined in the axial direction D1.

[0092] In the present embodiment, the first maximum axial body length L5 is longer than the second maximum axial body length L6. The first maximum axial body length L5 is longer than the first maximum axial length L1 of the first radial portion 22M. The second maximum axial body length L6 is longer than the first maximum axial length L1 of the first radial portion 22M. The first maximum axial body length L5 is shorter than the second maximum axial length L2 of the second radial portion 22N. The second maximum axial body length L6 is shorter than the second maximum axial length L2 of the second radial portion 22N. However, if necessary or desired, the first maximum axial body length L5 may be shorter than the second maximum axial body length L6. If necessary or desired, the first maximum axial body length L5 may be shorter than the first maximum axial length L1 of the first radial portion 22M. If necessary or desired, the second maximum axial body length L6 may be shorter than the first maximum axial length L1 of the first radial portion 22M. If necessary or desired, the first maximum axial body length L5 may be longer than the second maximum axial length L2 of the second radial portion 22N. If necessary or desired, the second maximum axial body length L6 may be longer than the second maximum axial length L2 of the second radial portion 22N.

[0093] In the present embodiment, the first maximum axial body length L5 is equal to or greater than 2 mm. The first maximum axial body length L5 is equal to or less than 3.5 mm. The second maximum axial body length L6 is equal to or greater than 1.5 mm. The second maximum axial body length L6 is equal to or less than 3.5 mm. However, the first maximum axial body length L5 is not limited to the above range. The second maximum axial body length L6 is not limited to the above range. In the present embodiment, the first maximum axial body length L5 is 2.8 mm. However, the first maximum axial body length L5 is not limited to the above value.

[0094] For example, in the case where the second sprocket SP2 is made of iron, the second maximum axial body length L6 ranges from 1.5 mm to 2.5 mm. In the case where the second sprocket SP2 is made of iron, the second maximum axial body length L6 is 1.95 mm. In the case where the second sprocket SP2 is made of aluminum, the second maximum axial body length L6 ranges from 2 mm to 3.5 mm. In the case where the second sprocket SP2 is made of aluminum, the second maximum axial body length L6 is 2.8 mm. However, the second maximum axial body length L6 is not limited to the above ranges and values.

[0095] The first maximum axial length L1 of the first radial portion 22M is equal to or greater than 1.3 mm. The first maximum axial length L1 of the first radial portion 22M is equal to or less than 3 mm. The second maximum axial length L2 of the second radial portion 22N is equal to or greater than 3.5 mm. The second maximum axial length L2 of the second radial portion 22N is equal to or less than 5 mm. However, the first maximum axial length L1 is not limited to the above range. The second maximum axial length L2 is not limited to the above range. In the present embodiment, the first maximum axial length L1 is 1.8 mm. However, the first maximum axial length L1 is not limited to the above value. In the present embodiment, the second maximum axial length L2 is 4.2 mm. However, the second maximum axial length L2 is not limited to the above value.

[0096] like Fig.14 and Fig.15 As shown, the first sprocket SP1 and the second sprocket SP2 are mounted to at least one sprocket mounting portion 22K of the sprocket carrier 22 by at least one common fastener. In the present embodiment, the first sprocket SP1 and the second sprocket SP2 are mounted to the sprocket mounting portion 22K of the sprocket carrier 22 by the first fastener 24. The first sprocket SP1 and the second sprocket SP2 are coupled to the first radial portion 22M of the sprocket mounting portion 22K by the first fastener 24. The first fastener 24 extends through the first fastener hole SP1D, the second fastener hole SP2D and the first hole 22C. However, if needed or desired, the first sprocket SP1 and the second sprocket SP2 may be mounted to the at least one sprocket mounting portion 22K of the sprocket carrier 22 by separate fasteners.

[0097] like Figures 16 to 18 As shown, the first sprocket SP1, the second sprocket SP2 and the sprocket carrier 22 may have Figures 1 to 13 Shapes other than those shown.

[0098] In this application, the term "comprise" and its derivatives used herein are intended to be open terms, which specify the presence of the features, elements, components, groups, integers and / or steps, but do not exclude the presence of other unspecified features, elements, components, groups, integers and / or steps. This concept also applies to words with similar meanings, such as the terms "have", "include" and their derivatives.

[0099] The terms “member,” “section,” “portion,” “part,” “element,” “body,” and “structure” when used in the singular can have the dual meaning of a single part or a plurality of parts.

[0100] Ordinal numbers such as “first” and “second” recorded in the present application are merely identifiers and do not have any other meanings, such as a specific order, etc. In addition, 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”.

[0101] The term “a pair” as used herein may encompass a configuration in which a pair of elements have shapes or structures different from each other as well as a configuration in which the pair of elements have shapes or structures identical to each other.

[0102] The terms "a" (or "an"), "one or more" and "at least one" are used interchangeably herein.

[0103] The phrase “at least one” as used in the present disclosure means “one or more” of the desired options. For one example, if the number of its options is two, the phrase “at least one” as used in the present disclosure means “only a single option” or “both options”. For other examples, if the number of its options is equal to or greater than three, the phrase “at least one” as used in the present disclosure means “only a single option” or “any combination of equal to or greater than two options”. For example, the phrase “at least one of A and B” includes (1) A alone, (2) B alone, and (3) A and B. The phrase “at least one of A, B, and C” includes (1) A alone, (2) B alone, (3) C alone, (4) A and B, (5) B and C, (6) A and C, and (7) all of A, B, and C. In other words, the phrase “at least one of A and B” in the present disclosure does not mean “at least one of A and at least one of B”.

[0104] Finally, terms of degree such as "substantially", "about" and "approximately" as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. All numerical values ​​described in this application are to be understood to include terms such as "substantially", "about" and "approximately".

[0105] Obviously, many 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 present invention may be practiced otherwise than as specifically described herein.

Claims

1. A rear sprocket assembly for a human-powered vehicle, the rear sprocket assembly having a rotational center axis, the rotational center axis defining an axial direction, a radial direction, and a circumferential direction, the rear sprocket assembly comprising: a sprocket carrier having an axially outwardly facing carrier surface and an axially inwardly facing carrier surface, the axially inwardly facing carrier surface being disposed on an opposite side of the axially outwardly facing carrier surface in the axial direction, the axially inwardly facing carrier surface being configured to face an axial center plane of the human-powered vehicle in the axial direction when the rear sprocket assembly is mounted to the human-powered vehicle, the sprocket carrier comprising at least one sprocket mounting portion, the at least one sprocket mounting portion having a first radial portion and a second radial portion positioned radially inwardly from the first radial portion in the radial direction, the first radial portion having a first maximum axial length relative to the axial direction, the second radial portion having a second maximum axial length relative to the axial direction, the second maximum axial length being greater than the first maximum axial length; a first sprocket, the first sprocket comprising a first sprocket body and a plurality of first sprocket teeth, the plurality of first sprocket teeth extending radially outward from the first sprocket body in the radial direction, the plurality of first sprocket teeth being arranged on the first sprocket body in the circumferential direction, the first sprocket having a first total number of teeth, a first axially outward facing surface, and a first axially inward facing surface, the first axially inward facing surface being arranged on an opposite side of the first axially outward facing surface in the axial direction, the first axially inward facing surface being configured to face the axial center plane of the human-powered vehicle in the axial direction in the installed state, the first sprocket body having at least one first mounting portion, the at least one first mounting portion being configured to be mounted to the axially inward facing bracket surface of the at least one sprocket mounting portion of the sprocket carrier, the at least one first mounting portion being configured to axially contact the first radial portion of the at least one sprocket mounting portion of the sprocket carrier relative to the axial direction; as well as a second sprocket, the second sprocket comprising a second sprocket body and a plurality of second sprocket teeth, the plurality of second sprocket teeth extending radially outward from the second sprocket body in the radial direction, the plurality of second sprocket teeth being arranged on the second sprocket body in the circumferential direction, the second sprocket having a second total number of teeth, a second axially outward facing surface, and a second axially inward facing surface, the second axially inward facing surface being arranged on the opposite side of the second axially outward facing surface in the axial direction, the second total number of teeth being smaller than the first total number of teeth of the first sprocket, the second axially inward facing surface being configured to face the first axially outward facing surface of the first sprocket in the axial direction, the second sprocket body having at least one second mounting portion, the at least one second mounting portion being configured to be mounted to the axially outward facing carrier surface of the at least one sprocket mounting portion of the sprocket carrier, the at least one second mounting portion being configured to axially contact the first radial portion and the second radial portion of the at least one sprocket mounting portion of the sprocket carrier relative to the axial direction, the second sprocket being adjacent to the first sprocket in the axial direction, and no other sprocket being between the first sprocket and the second sprocket.

2. The rear sprocket assembly according to claim 1, wherein The first sprocket body has a first maximum axial body length, and the first maximum axial body length is equal to or greater than 2 mm.

3. The rear sprocket assembly according to claim 2, wherein The first maximum axial body length is equal to or less than 3.5 mm.

4. The rear sprocket assembly according to claim 1, wherein The second sprocket body has a second maximum axial body length, and the second maximum axial body length is equal to or greater than 1.5 mm.

5. The rear sprocket assembly according to claim 4, wherein The second maximum axial body length is equal to or less than 3.5 mm.

6. The rear sprocket assembly according to claim 1, wherein The first maximum axial length of the first radial portion is equal to or greater than 1.3 mm.

7. The rear sprocket assembly according to claim 6, wherein The first maximum axial length of the first radial portion is equal to or less than 3 mm.

8. The rear sprocket assembly according to claim 1, wherein The second maximum axial length of the second radial portion is equal to or greater than 3.5 mm.

9. The rear sprocket assembly according to claim 8, wherein The second maximum axial length of the second radial portion is equal to or smaller than 5 mm.

10. The rear sprocket assembly of claim 1, wherein The first sprocket is made of aluminum.

11. The rear sprocket assembly of claim 1, wherein The second sprocket is made of iron.

12. The rear sprocket assembly of claim 1, wherein The second sprocket is made of aluminum.

13. The rear sprocket assembly of claim 1, wherein The sprocket bracket is made of one of aluminum and a non-metallic material.

14. The rear sprocket assembly of claim 1, wherein The first sprocket and the second sprocket are mounted to the at least one sprocket mounting portion of the sprocket carrier by at least one common fastener.

15. The rear sprocket assembly of claim 1, wherein The at least one first mounting portion of the first sprocket body is configured to have no axial contact with the second radial portion of the at least one sprocket mounting portion of the sprocket carrier.

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