TW202434493A - Rear sprocket assembly - Google Patents

Abstract

A rear sprocket assembly comprises a first sprocket and a second sprocket. The first sprocket includes a first sprocket body and a plurality of first sprocket teeth. The second sprocket includes a second sprocket body and a plurality of second sprocket teeth. The first sprocket and the second sprocket are integrally formed as a unitary, one-piece member. The first sprocket has a first recess provided to a first axially outwardly facing surface of the first sprocket body so as to be dented from the first axially outwardly facing surface toward a first axially inwardly facing surface. The plurality of first sprocket teeth has a first maximum axial tooth-thickness defined at a location of one of the plurality of first sprocket teeth in the axial direction. The first sprocket body has a first maximum axial recessed-thickness is equal to or larger than the first maximum axial tooth-thickness.

Description

Rear sprocket assembly

The present invention relates to a rear sprocket assembly.

A human-powered vehicle includes a sprocket assembly configured to engage with a chain. The sprocket assembly includes a plurality of sprockets. One object of the present invention is to make the sprocket assembly easier to manufacture while ensuring the rigidity of the sprocket assembly.

According to a first aspect of the present invention, a rear sprocket assembly for a human-powered vehicle has a rotation center axis defining an axial direction, a radial direction, and a circumferential direction. The rear sprocket assembly includes a first sprocket and a second sprocket. 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 first sprocket has a first total number of teeth, a first axially outward surface, and a first axially inward surface. The first axially inward surface is disposed on an opposite surface of the first axially outward surface in the axial direction. The first axially inward surface is configured to face an axial center plane of the human-powered vehicle in the axial direction in an installed state in which the rear sprocket assembly is installed to the human-powered vehicle. The second sprocket includes a second sprocket body and a plurality of second sprocket teeth extending radially outward from the second sprocket body in the radial direction. The second sprocket has a second total number of teeth less than the first total number of teeth of the first sprocket. The second sprocket has a second axially outward surface and a second axially inward surface disposed on an opposite surface of the second axially outward surface in the axial direction. The second axially inward surface is configured to face the first axially outward surface of the first sprocket in the axial direction. The second sprocket is adjacent to the first sprocket and there is no other sprocket between the first sprocket and the second sprocket in the axial direction. The first sprocket and the second sprocket are integrally formed as an integral one-piece component. The first sprocket has a first groove. The first groove is set to the first axially outward side of the first sprocket body to be recessed from the first axially outward side toward the first axially inward side. The first groove is configured to face the second axially inward side of the plurality of second sprocket teeth. The first sprocket body of the first sprocket has a first maximum axially recessed thickness defined at a position of the first groove in the axial direction. The plurality of first sprocket teeth have a first maximum axial tooth thickness defined in the axial direction at a position of one of the plurality of first sprocket teeth. The first maximum axial recessed thickness is equal to or greater than the first maximum axial tooth thickness.

With respect to the rear sprocket assembly according to the first aspect, the first groove can increase a space provided between the first sprocket body and at least one of the plurality of second sprocket teeth in the axial direction, compared to a case where the first sprocket does not include the first groove. The larger space can make at least one of the plurality of second sprocket teeth easier to form, especially in a case where the first sprocket and the second sprocket are integrally formed as an integral one-piece member. Furthermore, since the first sprocket and the second sprocket are integrally formed as an integral one-piece member and the first maximum axial recessed thickness is equal to or greater than the first maximum axial tooth thickness, the rigidity of the rear sprocket assembly can be ensured compared to a case where the first sprocket is a member separated from the second sprocket and/or where the first maximum axial recessed thickness is less than the first maximum axial tooth thickness. Therefore, the rear sprocket assembly can be made easier to manufacture while ensuring the rigidity of the rear sprocket assembly.

According to a second aspect of the present invention, the rear sprocket assembly according to the first aspect further includes a third sprocket. The third sprocket includes a third sprocket body and a plurality of third sprocket teeth extending radially outward from the third sprocket body in the radial direction. The third sprocket has a third total number of teeth less than the second total number of teeth of the second sprocket. The third sprocket has a third axially outward face and a third axially inward face disposed on an opposite face of the third axially outward face in the axial direction. The third axially inward face is configured to face the second axially outward face of the second sprocket in the axial direction. The third sprocket is adjacent to the second sprocket and there is no other sprocket between the second sprocket and the third sprocket in the axial direction. The second sprocket and the third sprocket are integrally formed as an integral one-piece component.

As for the rear sprocket assembly according to the second aspect, since the second sprocket and the third sprocket are integrally formed as an integral one-piece member, the rigidity of the rear sprocket assembly can be ensured compared to a case where the second sprocket is a member separated from the third sprocket. Therefore, the rear sprocket assembly can be made easier to manufacture while reliably ensuring the rigidity of the rear sprocket assembly.

According to a third aspect of the present invention, the rear sprocket assembly according to the second aspect is configured so that the second sprocket has a second groove, which is arranged on the second axially outer side of the second sprocket body to be recessed from the second axially outer side toward the second axially inner side. The second groove is configured to face the third axially inner side of the plurality of third sprocket teeth.

With respect to the rear sprocket assembly according to the third aspect, the second groove can increase a space provided between the second sprocket body and at least one of the plurality of third sprocket teeth in the axial direction, compared to a case in which the second sprocket does not include the second groove. The larger space can make at least one of the plurality of third sprocket teeth easier to form. Therefore, the rear sprocket assembly can be reliably made easier to manufacture while reliably ensuring the rigidity of the rear sprocket assembly.

According to a fourth aspect of the present invention, the rear sprocket assembly according to the third aspect is configured so that the second sprocket body of the second sprocket has a second maximum axial recessed thickness defined at a position of the second groove in the axial direction. The plurality of second sprocket teeth have a second maximum axial tooth thickness defined at a position of one of the plurality of second sprocket teeth in the axial direction. The second maximum axial recessed thickness is equal to or greater than the second maximum axial tooth thickness.

With respect to the rear sprocket assembly according to the fourth aspect, since the second maximum axial recessed thickness is equal to or greater than the second maximum axial tooth thickness, the rigidity of the rear sprocket assembly can be ensured compared to a case where the second maximum axial recessed thickness is less than the second maximum axial tooth thickness. Therefore, the rear sprocket assembly can be reliably made easier to manufacture while the rigidity of the rear sprocket assembly can be more reliably ensured.

According to a fifth aspect of the present invention, the rear sprocket assembly according to the first aspect further includes a third sprocket. The third sprocket includes a third sprocket body and a plurality of third sprocket teeth extending radially outward from the third sprocket body in the radial direction. The third sprocket has a third total number of teeth less than the second total number of teeth of the second sprocket. The third sprocket is adjacent to the second sprocket and there is no other sprocket between the second sprocket and the third sprocket in the axial direction. The third sprocket is a component separated from the second sprocket.

As for the rear sprocket assembly according to the fifth aspect, since the third sprocket is a component separated from the second sprocket, the design flexibility of the rear sprocket assembly can be improved compared with a case where the second sprocket and the third sprocket are integrally formed as an integral one-piece component. Therefore, the rear sprocket assembly can be made easier to manufacture while reliably ensuring the rigidity of the rear sprocket assembly.

According to a sixth aspect of the present invention, the rear sprocket assembly according to any one of the second to fifth aspects further includes a fourth sprocket. The fourth sprocket includes a fourth sprocket body and a plurality of fourth sprocket teeth extending radially outward from the fourth sprocket body in the radial direction. The fourth sprocket has a fourth total number of teeth less than the third total number of teeth of the third sprocket. The fourth sprocket is adjacent to the third sprocket and there is no other sprocket between the third sprocket and the fourth sprocket in the axial direction. The fourth sprocket is a component separated from the third sprocket.

As for the rear sprocket assembly according to the sixth aspect, since the fourth sprocket is a component separated from the third sprocket, the design flexibility of the rear sprocket assembly can be improved compared with a case where the third sprocket and the fourth sprocket are integrally formed as an integral one-piece component. Therefore, the rear sprocket assembly can be made easier to manufacture while reliably ensuring the rigidity of the rear sprocket assembly.

According to a seventh aspect of the present invention, the rear sprocket assembly according to any one of the first to sixth aspects is configured so that a circumferential tooth length is defined from a tooth bottom of one of the plurality of second sprocket teeth to an adjacent tooth bottom of the one of the plurality of second sprocket teeth. The tooth bottom is adjacent to the adjacent tooth bottom and there is no other tooth bottom between the tooth bottom and the adjacent tooth bottom in the circumferential direction. The first groove has a first circumferential groove length greater than the circumferential tooth length of the one of the plurality of second sprocket teeth.

With respect to the rear sprocket assembly according to the seventh aspect, the first groove having the first circumferential groove length can reliably increase a space provided between the first sprocket body and at least one of the plurality of second sprocket teeth in the axial direction, compared to a case in which the first sprocket does not include the first groove. Therefore, the rear sprocket assembly can be reliably made easier to manufacture while ensuring the rigidity of the rear sprocket assembly.

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 first groove includes a first circumferential end and a first additional circumferential end. The first groove extends between the first circumferential end and the first additional circumferential end in the circumferential direction.

In the rear sprocket assembly according to the eighth aspect, the first groove can reliably increase a space provided between the first sprocket body and at least one of the plurality of second sprocket teeth in the axial direction, compared to a case where the first sprocket does not include the first groove. Therefore, the rear sprocket assembly can be reliably made easier to manufacture while ensuring the rigidity of the rear sprocket assembly.

According to a ninth aspect of the present invention, the rear sprocket assembly according to the third or fourth aspect is configured so that a circumferential tooth length is defined from a tooth bottom of one of the plurality of third sprocket teeth to an adjacent tooth bottom of the one of the plurality of third sprocket teeth. The tooth bottom is adjacent to the adjacent tooth bottom and there is no other tooth bottom between the tooth bottom and the adjacent tooth bottom in the circumferential direction. The second groove has a second circumferential groove length greater than the circumferential tooth length of the one of the plurality of third sprocket teeth.

With respect to the rear sprocket assembly according to the ninth aspect, the second groove having the second circumferential groove length can reliably increase a space provided between the second sprocket body and at least one of the plurality of third sprocket teeth in the axial direction, compared to a case in which the second sprocket does not include the second groove. Therefore, the rear sprocket assembly can be reliably made easier to manufacture while ensuring the rigidity of the rear sprocket assembly.

According to a tenth aspect of the present invention, the rear sprocket assembly according to the third or fourth aspect is configured so that the second groove includes a second circumferential end and a second additional circumferential end. The second groove extends between the second circumferential end and the second additional circumferential end in the circumferential direction.

In the rear sprocket assembly according to the tenth aspect, the second groove can reliably increase a space provided between the second sprocket body and at least one of the plurality of third sprocket teeth in the axial direction, compared to a case where the second sprocket does not include the second groove. Therefore, the rear sprocket assembly can be reliably made easier to manufacture while ensuring the rigidity of the rear sprocket assembly.

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

As seen in FIG. 1 , a 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 wheel hub assembly 12. The rear wheel hub assembly 12 is fixed to the vehicle body 4. The rear sprocket assembly 10 is configured to be mounted to the rear wheel hub assembly 12 of the human-powered vehicle 2. The rear sprocket assembly 10 of 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 (e.g., see FIG. 3 ). The rear sprocket assembly 10 is rotatably supported by the rear wheel 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 transverse center position of the body 4 of the human-powered vehicle 2. The axial center plane CP is perpendicular to the rotation center axis A1.

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 fixed 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.

In this application, the following directional terms "front", "rear", "forward", "backward", "left", "right", "lateral", "upward", and "downward", and any other similar directional terms refer to directions determined based on a user (e.g., a rider) sitting in a standard position (e.g., on a saddle or a seat) facing a handlebar or steering device on a human-powered vehicle 2. Therefore, these terms when used to describe the rear sprocket assembly 10 or other components should be interpreted relative to a human-powered vehicle 2 equipped with the rear sprocket assembly 10 or other components used in an upright riding position on a horizontal surface.

In the present application, the term "human-powered vehicle" includes a vehicle that travels with a motive force, the motive force including at least one human force of a user (i.e., a rider) riding the human-powered vehicle. Human-powered vehicles include various bicycles, such as a mountain bike, a road bike, a city bike, a cargo bike, a hand-cranked bicycle, and a recumbent bicycle. In addition, human-powered vehicles include an electric bicycle (E-bike). An electric bicycle includes an electric-assisted bicycle configured to assist in propelling a vehicle with an electric motor. However, the total number of wheels of a human-powered vehicle is not limited to two. For example, a human-powered vehicle includes a vehicle having one wheel or three or more wheels. Human-powered vehicles in particular do not include a vehicle that uses only one drive source (e.g., an internal combustion engine, an electric motor) as the motive force. Generally speaking, a light road vehicle (which includes a vehicle that does not require a public road driving license) is considered a human-powered vehicle.

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 engage with the transmission chain C. The plurality of rear sprockets SP include first to twelfth sprockets SP1 to SP12, respectively. That is, the rear sprocket assembly 10 includes a first sprocket SP1 and a second sprocket SP2. The rear sprocket assembly 10 further includes a third sprocket SP3. The rear sprocket assembly 10 further includes a fourth sprocket SP4. In this embodiment, the total number of the plurality of rear sprockets SP is 12. However, the total number of the plurality of rear sprockets SP is not limited to 12.

The rear wheel hub assembly 12 includes a wheel hub shaft 14, a wheel hub body 16, and a sprocket support body 18. The wheel hub shaft 14 is configured to be fixed to the vehicle body 4 of the human-powered vehicle 2 (see, for example, FIG. 1). The wheel hub body 16 is rotatably mounted on the wheel hub shaft 14 around a rotation center axis A1. The sprocket support body 18 is rotatably mounted on the wheel hub shaft 14 around a rotation center axis A1.

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 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 to twelfth sprockets SP1 to SP12 are coupled to the sprocket support body 18 with the locking member 19.

As shown in FIG. 3 , 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 fourth sprocket SP4 has a fourth sprocket outer diameter DM4 that is smaller than the third sprocket outer diameter DM3. The first sprocket SP1 is the largest sprocket in the rear sprocket assembly 10. The twelfth sprocket SP12 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 twelfth sprocket SP12 may also be referred to as a high-speed gear sprocket SP12.

As seen in Fig. 4, for example, an upshift occurs when the transmission chain C shifts from one sprocket to an adjacent smaller sprocket in an upshift direction D41. A downshift occurs when the transmission chain C shifts from one sprocket to an adjacent larger sprocket in a downshift direction D42.

The second sprocket SP2 is adjacent to the first sprocket SP1 and there is no other sprocket between the first sprocket SP1 and the second sprocket SP2 in the axial direction D1. The third sprocket SP3 is adjacent to the second sprocket SP2 and there is no other sprocket between the second sprocket SP2 and the third sprocket SP3 in the axial direction D1. The fourth sprocket SP4 is adjacent to the third sprocket SP3 and there is no other sprocket between the third sprocket SP3 and the fourth sprocket SP4 in the axial direction D1.

The rear sprocket assembly 10 includes a sprocket carrier 22 and an additional sprocket carrier 23. The first to seventh sprockets SP1 to SP7 are mounted on the sprocket carrier 22. The eighth and ninth sprockets SP8 to SP9 are mounted on the additional sprocket carrier 23. The first to seventh sprockets SP1 to SP7 are fixed to the sprocket carrier 22 with fasteners 24 such as rivets. The eighth and ninth sprockets SP8 to SP9 are fixed to the additional sprocket carrier 23 with fasteners 25 such as rivets. The tenth to twelfth sprockets SP10 to SP12 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 shown in FIG. 4 . As needed and/or desired, at least one of the sprocket carrier 22 and the additional sprocket carrier 23 may be omitted from the rear sprocket assembly 10. In such embodiments, at least one of the first to ninth sprockets SP1 to SP9 may be configured to directly engage with the sprocket support body 18 (e.g., see FIG. 2 ).

As shown in Fig. 5, the sprocket carrier 22 includes a plurality of arms 22A. The first to seventh sprockets SP1 to SP7 are fixed to each of the plurality of arms 22A with fasteners 24.

As shown in Fig. 6, the first sprocket SP1 includes a first sprocket body SP1A and a plurality of first sprocket gears SP1B. The plurality of first sprocket gears SP1B extend radially outward from the first sprocket body SP1A in a radial direction. The plurality of first sprocket gears SP1B define a first sprocket outer diameter DM1.

The first sprocket SP1 has a first total number of teeth. The first total number of teeth is a total number of the first sprocket gears SP1B. In this embodiment, the first total number of teeth is 51. However, the first total number of teeth is not limited to the above total number of teeth.

The second sprocket SP2 includes a second sprocket body SP2A and a plurality of second sprocket gears SP2B. The plurality of second sprocket gears SP2B radially extend outward from the second sprocket body SP2A in a radial direction. The plurality of second sprocket gears SP2B define a second sprocket outer diameter DM2.

The second sprocket SP2 has a second total number of teeth. The second total number of teeth is a total number of the second sprocket gears SP2B. The second total number of teeth is less than the first total number of teeth of the first sprocket SP1. In this embodiment, the second total number of teeth is 45. However, the second total number of teeth is not limited to the above total number of teeth.

The third sprocket SP3 includes a third sprocket body SP3A and a plurality of third sprocket gears SP3B. The plurality of third sprocket gears SP3B radially extend outward from the third sprocket body SP3A in a radial direction. The plurality of third sprocket gears SP3B define a third sprocket outer diameter DM3.

The third sprocket SP3 has a third total number of teeth. The third total number of teeth is a total number of the third sprocket gears SP3B. The third total number of teeth is less than the second total number of teeth of the second sprocket SP2. In this embodiment, the third total number of teeth is 39. However, the third total number of teeth is not limited to the above total number of teeth.

The third sprocket SP3 includes a plurality of coupling portions 25. The plurality of coupling portions 25 are coupled to the sprocket carrier 22 (see, for example, FIG. 5 ) by fasteners 24. The plurality of coupling portions 25 protrude radially inward from the third sprocket body SP3A. The plurality of coupling portions 25 are arranged at a specific pitch in the circumferential direction D2.

As shown in Fig. 7, the fourth sprocket SP4 includes a fourth sprocket body SP4A and a plurality of fourth sprocket gears SP4B. The plurality of fourth sprocket gears SP4B extend radially outward from the fourth sprocket body SP4A in a radial direction. The plurality of fourth sprocket gears SP4B define a fourth sprocket outer diameter DM4.

The fourth sprocket SP4 has a fourth total number of teeth. The fourth total number of teeth is a total number of the fourth sprocket gears SP4B. The fourth total number of teeth is less than the third total number of teeth of the third sprocket SP3. In this embodiment, the fourth total number of teeth is 33. However, the fourth total number of teeth is not limited to the above total number of teeth.

As shown in FIG. 8 , the first sprocket SP1 includes at least one connecting portion 27 extending radially inward from the first sprocket body SP1A. The first sprocket SP1 includes a plurality of connecting portions 27 extending radially inward from the first sprocket body SP1A. The connecting portion 27 extends radially inward from the first sprocket body SP1A to the second sprocket body SP2A. The connecting portion 27 connects the first sprocket body SP1A and the second sprocket body SP2A. In addition, the connecting portion 27 connects the second sprocket body SP2A and the third sprocket body SP3A. That is, the connecting portion 27 connects the first sprocket body SP1A, the second sprocket body SP2A, and the third sprocket body SP3A.

The plurality of connection parts 27 include at least one first connection part 27A and at least one second connection part 27B. In this embodiment, the plurality of connection parts 27 include a plurality of first connection parts 27A and a plurality of second connection parts 27B. The plurality of first connection parts 27A and the plurality of second connection parts 27B are alternately arranged in the circumferential direction D2.

The first connecting portion 27A extends radially inward from the first sprocket body SP1A toward the coupling portion 25. The second connecting portion 27B extends radially inward from the first sprocket body SP1A toward the coupling portion 25. The first connecting portion 27A connects the first sprocket body SP1A, the second sprocket body SP2A, and the third sprocket body SP3A. The second connecting portion 27B connects the first sprocket body SP1A, the second sprocket body SP2A, and the third sprocket body SP3A. A pair of the first connecting portion 27A and the second connecting portion 27B corresponds to the coupling portion 25. The configuration of the connecting portion 27 is not limited to the illustrated embodiment.

As seen in FIGS. 9 and 10 , the first sprocket SP1 and the second sprocket SP2 are integrally formed as an integral one-piece component. The second sprocket SP2 and the third sprocket SP3 are integrally formed as an integral one-piece component. However, as seen in FIG. 11 , the third sprocket SP3 may be a component separate from the second sprocket SP2 as needed and/or desired. In these embodiments, the second sprocket SP2 and the third sprocket SP3 are fixed to the sprocket carrier 22 with fasteners 24.

As seen in FIG. 4 , the fourth sprocket SP4 is a separate component from the third sprocket SP3. However, as needed and/or desired, the third sprocket SP3 and the fourth sprocket SP4 may be integrally formed as an integral one-piece component. As needed and/or desired, the first sprocket SP1, the second sprocket SP2, the third sprocket SP3 and the fourth sprocket SP4 may be integrally formed as an integral one-piece component.

As shown in Fig. 9 and Fig. 10, the connecting portion 27 is integrally provided with the first sprocket body SP1A as a one-piece integral member. The connecting portion 27 is integrally provided with the second sprocket body SP2A as a one-piece integral member. The connecting portion 27 is integrally provided with the third sprocket body SP3A as a one-piece integral member.

As shown in Fig. 9, the first connecting portion 27A is integrally provided with the first sprocket body SP1A as a one-piece integral member. The first connecting portion 27A is integrally provided with the second sprocket body SP2A as a one-piece integral member. The first connecting portion 27A is integrally provided with the third sprocket body SP3A as a one-piece integral member.

As shown in Fig. 10, the second connecting portion 27B is integrally provided with the first sprocket body SP1A as a one-piece integral member. The second connecting portion 27B is integrally provided with the second sprocket body SP2A as a one-piece integral member. The second connecting portion 27B is integrally provided with the third sprocket body SP3A as a one-piece integral member.

As seen in FIG12 , the first sprocket SP1 has a first axially outer surface SP1C and a first axially inner surface SP1D. The first axially inner surface SP1D is disposed on an opposite side of the first axially outer surface SP1C in the axial direction D1. The first axially inner surface SP1D is configured to face the axial center plane CP of the human-powered vehicle 2 in the axial direction D1 in an installed state in which the rear sprocket assembly 10 is installed to the human-powered vehicle 2.

The second sprocket SP2 has a second axially outer surface SP2C and a second axially inner surface SP2D. The second axially inner surface SP2D is disposed on an opposite side of the second axially outer surface SP2C in the axial direction D1. The second axially inner surface SP2D is configured to face the first axially outer surface SP1C of the first sprocket SP1 in the axial direction D1.

The third sprocket SP3 has a third axially outer surface SP3C and a third axially inner surface SP3D. The third axially inner surface SP3D is disposed on an opposite side of the third axially outer surface SP3C in the axial direction D1. The third axially inner surface SP3D is configured to face the second axially outer surface SP2C of the second sprocket SP2 in the axial direction D1.

As shown in FIGS. 9 , 10 and 12 , the first sprocket SP1 has a first groove SP1E. The first groove SP1E is provided to the first axially outer side SP1C of the first sprocket body SP1A so as to be recessed from the first axially outer side SP1C toward the first axially inner side SP1D. The first groove SP1E is configured to face the second axially inner side SP2D of the plurality of second sprocket teeth SP2B. The first groove SP1E is provided between the first axially inner side SP1D and the second axially inner side SP2D in the axial direction D1.

The second sprocket SP2 has a second groove SP2E. The second groove SP2E is provided to the second axial outer surface SP2C of the second sprocket body SP2A so as to be recessed from the second axial outer surface SP2C toward the second axial inner surface SP2D. The second groove SP2E is configured to face the third axial inner surface SP3D of the plurality of third sprocket teeth SP3B. The second groove SP2E is provided between the second axial inner surface SP2D and the third axial inner surface SP3D in the axial direction D1.

As seen in FIG. 12 , the first sprocket body SP1A of the first sprocket SP1 has a first maximum axial recessed thickness T11 defined at a position of the first groove SP1E in the axial direction D1. The plurality of first sprocket teeth SP1B have a first maximum axial tooth thickness T12 defined at a position of one of the plurality of first sprocket teeth SP1B in the axial direction D1. The first maximum axial recessed thickness T11 is equal to or greater than the first maximum axial tooth thickness T12. In the present embodiment, the first maximum axial recessed thickness T11 is greater than the first maximum axial tooth thickness T12 as a preferred embodiment. However, the first maximum axial recessed thickness T11 may be equal to the first maximum axial tooth thickness T12 as needed and/or desired.

The second sprocket body SP2A of the second sprocket SP2 has a second maximum axial recessed thickness T21 defined at a position of the second groove SP2E in the axial direction D1. The plurality of second sprocket teeth SP2B have a second maximum axial tooth thickness T22 defined at a position of one of the plurality of second sprocket teeth SP2B in the axial direction D1. The second maximum axial recessed thickness T21 is equal to or greater than the second maximum axial tooth thickness T22. In the present embodiment, the second maximum axial recessed thickness T21 is greater than the second maximum axial tooth thickness T22 as a preferred embodiment. However, as needed and/or desired, the second maximum axial recessed thickness T21 may be equal to the second maximum axial tooth thickness T22.

13 and 14, a circumferential tooth length L1B is defined from a tooth bottom B11 of one of the plurality of first sprocket gears SP1B to an adjacent tooth bottom B12 of one of the plurality of first sprocket gears SP1B. The tooth bottom B11 is adjacent to the adjacent tooth bottom B12 and there is no other tooth bottom between the tooth bottom B11 and the adjacent tooth bottom B12 in the circumferential direction D2.

The first groove SP1E has a first circumferential groove length L1E. The first circumferential groove length L1E is greater than the circumferential tooth length L1B of one of the plurality of first sprocket teeth SP1B. In the present embodiment, the first groove SP1E includes a first circumferential end SP1F and a first additional circumferential end SP1G. The first groove SP1E extends between the first circumferential end SP1F and the first additional circumferential end SP1G in the circumferential direction D2. The first circumferential groove length L1E is defined between the first circumferential end SP1F and the first additional circumferential end SP1G in the circumferential direction D2.

The first sprocket SP1 includes a plurality of first grooves SP1E. A total number of the first grooves SP1E is 3. The first grooves SP1E are arranged at specific intervals in the circumferential direction D2. However, the total number of the first grooves SP1E is not limited to 3. The first sprocket SP1 may include at least one first groove SP1E. The first groove SP1E may have a ring shape as needed and/or desired.

As shown in Figures 13 and 14, a circumferential tooth length L2B is defined from a tooth bottom B21 of one of the plurality of second sprocket gears SP2B to an adjacent tooth bottom B22 of one of the plurality of second sprocket gears SP2B. The tooth bottom B21 is adjacent to the adjacent tooth bottom B22 and there is no other tooth bottom between the tooth bottom B21 and the adjacent tooth bottom B22 in the circumferential direction D2. The first circumferential groove length L1E is greater than the circumferential tooth length L2B of one of the plurality of second sprocket gears SP2B.

The second groove SP2E has a second circumferential groove length L2E. In the present embodiment, the second groove SP2E includes a second circumferential end SP2F and a second additional circumferential end SP2G. The second groove SP2E extends between the second circumferential end SP2F and the second additional circumferential end SP2G in the circumferential direction D2. The second circumferential groove length L2E is defined between the second circumferential end SP2F and the second additional circumferential end SP2G in the circumferential direction D2.

The second sprocket SP2 includes a plurality of second grooves SP2E. The total number of the second grooves SP2E is 3. The second grooves SP2E are arranged at specific intervals in the circumferential direction D2. However, the total number of the second grooves SP2E is not limited to 3. The second sprocket SP2 may include at least one second groove SP2E. The second groove SP2E may have a ring shape as needed and/or desired.

As seen in FIGS. 13 and 14 , a circumferential tooth length L3B is defined from a tooth bottom B31 of one of the plurality of third sprocket gears SP3B to an adjacent tooth bottom B32 of one of the plurality of third sprocket gears SP3B. The tooth bottom B31 is adjacent to the adjacent tooth bottom B32 and there is no other tooth bottom B31 between the tooth bottom B31 and the adjacent tooth bottom B32 in the circumferential direction D2. The second circumferential groove length L2E is greater than the circumferential tooth length L3B of one of the plurality of third sprocket gears SP3B. However, as needed and/or desired, the second circumferential groove length L2E may be equal to or less than the circumferential tooth length L3B of one of the plurality of third sprocket gears SP3B.

The shape of the first groove SP1E is not limited to the illustrated embodiment. The shape of the second groove SP2E is not limited to the illustrated embodiment. For example, the first groove SP1E may have a shape as depicted in each of FIG. 15 and FIG. 16 as needed and/or desired. The second groove SP2E may have a shape as depicted in each of FIG. 15 and FIG. 16 as needed and/or desired. In the rear sprocket assembly 10 depicted in FIG. 16, each of the first groove SP1E and the second groove SP2E has a ring shape.

In addition, the first groove SP1E may have a shape different from a shape of the second groove SP2E. The second groove SP2E may have a shape different from a shape of the first groove SP1E. For example, the first groove SP1E depicted in FIGS. 13 and 14 may be combined with the second groove SP2E depicted in each of FIGS. 15 and 16 of the rear sprocket assembly 10. The second groove SP2E depicted in FIGS. 13 and 14 may be combined with the first groove SP1E depicted in each of FIGS. 15 and 16 of the rear sprocket assembly 10. Alternatively, the first groove SP1E may have a shape depicted in FIG. 15, and the second groove SP2E may have a shape depicted in FIG. 15.

In this application, as used herein, the term "include" and its derivatives are intended to be open-ended terms that specifically refer to the presence of stated features, elements, components, groups, integers and/or steps, but do not exclude the presence of other unstated features, elements, components, groups, integers and/or steps. This concept also applies to terms with similar meanings, such as the terms "have", "include" and their derivatives.

The terms “member,” “section,” “portion,” “component,” “element,” “body” and “structure” when used in the singular can have the dual meaning of a single member or a plurality of members.

The ordinal numbers such as "first" and "second" described in this application are merely identifiers and do not have any other meanings such as a specific order and the like. Furthermore, 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".

As used herein, the term "a pair of" encompasses not only a configuration in which a pair of elements have the same shape or structure as each other, but also a configuration in which a pair of elements have different shapes or structures from each other.

The terms "a", "one or more" and "at least one" are used interchangeably herein.

As used herein, the phrase "at least one of..." means "one or more" of a desired choice. For example, if the number of choices is two, the phrase "at least one of..." means "only a single choice" or "all two choices." For another example, if the number of choices is equal to or greater than three, the phrase "at least one of..." means "only a single choice" or "any combination of equal to or greater than two choices." For example, the phrase "at least one of A and B" covers (1) only A, (2) only B, and (3) both A and B. The phrase "at least one of A, B, and C" covers (1) only A, (2) only B, (3) only C, (4) both A and B, (5) both B and C, (6) both A and C, and (7) all of A, B, and C. In other words, in the present invention, the phrase "at least one of A and B" does not mean "at least one of A and at least one of B."

Finally, as used herein, terms of degree such as "substantially", "about" and "approximately" mean a reasonable deviation of the modified term that does not significantly change the end result. All numerical values described in this application may be interpreted as including terms such as "substantially", "about" and "approximately".

Obviously, many modifications and variations of the present invention can be made in light of the above teachings. It should therefore be understood that the present invention can be practiced in ways other than those specifically described herein within the scope of the appended claims.

2: Human-powered vehicle 4: Vehicle body 6: Drive system 6A: Crank assembly 6B: Front sprocket 10: Rear sprocket assembly 12: Rear wheel hub assembly 14: Hub shaft 16: Hub body 18: Sprocket support body 18A: External spline teeth 19: Locking member 22: Sprocket bracket 22A: Arm 23: Additional sprocket bracket 24: Fastener 25: Fastener/coupling part 27: Connecting part 27A: First connecting part 27B: Second connecting part A1: Rotation center axis B11: Gear bottom B12: Adjacent tooth bottom B21: Gear bottom B22: Adjacent tooth bottom B31: Gear bottom B32: Adjacent tooth bottom C: Drive chain CP: Axial center plane D1: Axial direction D2: Circumferential direction D41: Upshift direction D42: Downshift direction DM1: First sprocket outer diameter DM2: Second sprocket outer diameter DM3: Third sprocket outer diameter DM4: Fourth sprocket outer diameter L1B: Circumferential tooth length L1E: First circumferential groove length L2B: Circumferential tooth length L2E: Second circumferential groove length L3B: Circumferential tooth length SP: Rear sprocket SP1 to SP12: First to twelfth sprockets SP1A: First sprocket body SP1B: First sprocket tooth SP1C: First axial outward SP1D: First axial inward surface SP1E: First groove SP1F: First circumferential end SP1G: First additional circumferential end SP2A: Second sprocket body SP2B: Second sprocket tooth SP2C: Second axial outward SP2D: Second axial inward surface SP2E: Second groove SP2F: Second circumferential end SP2G: Second additional circumferential end SP3A: Third sprocket body SP3B: Third sprocket tooth SP3C: Third axial outward SP3D: Third axial inward surface SP4A: Fourth sprocket body SP4B: Fourth sprocket tooth T11: First maximum axial depression thickness T12: first maximum axial tooth thickness T21: second maximum axial depression thickness T22: second maximum axial tooth thickness

A more complete appreciation and better understanding of the present invention and its many attendant advantages will be readily obtained by reference to the following detailed description considered in conjunction with the accompanying drawings.

FIG. 1 is a schematic diagram of a human powered vehicle including a rear sprocket assembly according to one embodiment.

FIG. 2 is an exploded rear view of a rear sprocket assembly and a rear wheel hub assembly of the human-powered vehicle shown 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 another side view of the rear sprocket assembly shown in FIG. 1 .

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 perspective view of the sprocket shown in FIG. 6 .

FIG. 9 is a cross-sectional view of the rear sprocket assembly taken along line IX-IX of FIG. 5 .

FIG10 is a cross-sectional view of the rear sprocket assembly taken along line X-X of FIG5.

FIG. 11 is a cross-sectional view of the sprocket assembly according to a modified embodiment.

FIG. 12 is a cross-sectional view of the rear sprocket assembly taken along line XII-XII of FIG. 3 .

FIG. 13 is a partial side view of the sprocket of the rear sprocket assembly shown in FIG. 6 .

FIG. 14 is another partial side view of the sprocket of the rear sprocket assembly shown in FIG. 6 .

15 is a partial side view of a sprocket of a rear sprocket assembly according to a first modification.

FIG. 16 is a partial side view of a sprocket of a rear sprocket assembly according to a second modification.

22: Sprocket bracket

24: Fasteners

25: Fastener/coupling part

A1: Rotation center axis

CP: axial center plane

D1: Axial direction

SP1: First sprocket

SP1A: First sprocket body

SP1B: First sprocket gear

SP1C: First axis outward

SP1D: First axial inward surface

SP1E: First groove

SP2: Second sprocket

SP2A: Second sprocket body

SP2B: Second sprocket gear

SP2C: Second axis outward

SP2D: Second axial inward surface

SP2E: Second groove

SP3: Third sprocket

SP3A: The third sprocket body

SP3B: Third chain gear

SP3C: The third axis is outward

SP3D: The third axial inward surface

T11: First maximum axial depression thickness

T12: First maximum axial tooth thickness

T21: The second maximum axial depression thickness

T22: Second maximum axial tooth thickness

Claims (10)

A rear sprocket assembly for a human-powered vehicle, the rear sprocket assembly having a rotation center axis defining an axial direction, a radial direction, and a circumferential direction, the rear sprocket assembly comprising: a first sprocket, comprising a first sprocket body and a plurality of first sprocket teeth extending radially outward from the first sprocket body in the radial direction, the first sprocket having a first total number of teeth, a first axially outward face, and a first axially inward face disposed on an opposite face of the first axially outward face in the axial direction, the first axially inward face being configured to face an axial center plane of the human-powered vehicle in the axial direction in an installed state in which the rear sprocket assembly is installed to the human-powered vehicle; A second sprocket, comprising a second sprocket body and a plurality of second sprocket teeth extending radially outward from the second sprocket body in the radial direction, the second sprocket having a second total number of teeth less than the first total number of teeth of the first sprocket, the second sprocket having a second axially outward surface and a second axially inward surface disposed on an opposite surface of the second axially outward surface in the axial direction, the second axially inward surface being configured to face the first axially outward surface of the first sprocket in the axial direction, the second sprocket being adjacent to the first sprocket and there being no other sprocket between the first sprocket and the second sprocket in the axial direction; The first sprocket and the second sprocket are integrally formed as an integral one-piece member; The first sprocket has a first groove, which is provided to the first axially outward side of the first sprocket body to be recessed from the first axially outward side toward the first axially inward side, and the first groove is configured to face the second axially inward side of the plurality of second sprocket teeth; The first sprocket body of the first sprocket has a first maximum axial recessed thickness defined at a position of the first groove in the axial direction; The plurality of first sprocket teeth have a first maximum axial tooth thickness defined at a position of one of the plurality of first sprocket teeth in the axial direction; and The first maximum axial recessed thickness is equal to or greater than the first maximum axial tooth thickness. The rear sprocket assembly of claim 1 further comprises: a third sprocket including a third sprocket body and a plurality of third sprocket teeth extending radially outward from the third sprocket body in the radial direction, wherein the third sprocket has a third total number of teeth less than the second total number of teeth of the second sprocket, the third sprocket has a third axially outward face and a third axially inward face disposed on an opposite face of the third axially outward face in the axial direction, the third axially inward face is configured to face the second axially outward face of the second sprocket in the axial direction, the third sprocket is adjacent to the second sprocket and there is no other sprocket between the second sprocket and the third sprocket in the axial direction, and The second sprocket and the third sprocket are integrally formed as an integral one-piece component. A rear sprocket assembly as claimed in claim 2, wherein the second sprocket has a second groove disposed on the second axially outer side of the second sprocket body to be recessed from the second axially outer side toward the second axially inner side, and the second groove is configured to face the third axially inner side of the plurality of third sprocket teeth. A rear sprocket assembly as claimed in claim 3, wherein the second sprocket body of the second sprocket has a second maximum axial recessed thickness defined in the axial direction at a position of the second groove, the plurality of second sprocket teeth have a second maximum axial tooth thickness defined in the axial direction at a position of one of the plurality of second sprocket teeth, and the second maximum axial recessed thickness is equal to or greater than the second maximum axial tooth thickness. The rear sprocket assembly of claim 1 further comprises a third sprocket, which includes a third sprocket body and a plurality of third sprocket teeth extending radially outward from the third sprocket body in the radial direction, wherein the third sprocket has a third total number of teeth less than the second total number of teeth of the second sprocket, the third sprocket is adjacent to the second sprocket and there is no other sprocket between the second sprocket and the third sprocket in the axial direction, and the third sprocket is a component separated from the second sprocket. The rear sprocket assembly of any one of claims 2 to 5 further comprises a fourth sprocket, which includes a fourth sprocket body and a plurality of fourth sprocket teeth extending radially outward from the fourth sprocket body in the radial direction, wherein the fourth sprocket has a fourth total number of teeth less than the third total number of teeth of the third sprocket, the fourth sprocket is adjacent to the third sprocket and there is no other sprocket between the third sprocket and the fourth sprocket in the axial direction, and the fourth sprocket is a component separated from the third sprocket. A rear sprocket assembly as claimed in any one of claims 1 to 5, wherein a circumferential tooth length is defined from a tooth bottom of one of the plurality of second sprocket teeth to an adjacent tooth bottom of the one of the plurality of second sprocket teeth, the tooth bottom is adjacent to the adjacent tooth bottom and there is no other tooth bottom between the tooth bottom and the adjacent tooth bottom in the circumferential direction, and the first groove has a first circumferential groove length greater than the circumferential tooth length of the one of the plurality of second sprocket teeth. A rear sprocket assembly as claimed in any one of claims 1 to 5, wherein the first groove includes a first circumferential end and a first additional circumferential end, and the first groove extends between the first circumferential end and the first additional circumferential end in the circumferential direction. A rear sprocket assembly as claimed in claim 3 or 4, wherein a circumferential tooth length is defined from a tooth bottom of one of the plurality of third sprocket teeth to an adjacent tooth bottom of the one of the plurality of third sprocket teeth, the tooth bottom is adjacent to the adjacent tooth bottom and there is no other tooth bottom between the tooth bottom and the adjacent tooth bottom in the circumferential direction, and the second groove has a second circumferential groove length greater than the circumferential tooth length of the one of the plurality of third sprocket teeth. A rear sprocket assembly as claimed in claim 3 or 4, wherein the second groove includes a second circumferential end and a second additional circumferential end, and the second groove extends between the second circumferential end and the second additional circumferential end in the circumferential direction.