CN117302405A

CN117302405A - Rear sprocket of manpower-driven vehicle and rear sprocket assembly of manpower-driven vehicle

Info

Publication number: CN117302405A
Application number: CN202310706069.5A
Authority: CN
Inventors: 黎辉文; 林文强
Original assignee: Shimano Inc
Current assignee: Shimano Inc
Priority date: 2022-06-28
Filing date: 2023-06-14
Publication date: 2023-12-29
Also published as: DE102023205337A1; TW202400466A; JP2024004401A

Abstract

The invention provides a rear sprocket of a human-driven vehicle, which can inhibit the weight increase of a rear sprocket assembly and improve the strength. A ninth rear sprocket (49) of a bicycle (1) is provided with a first outer ring (57), a plurality of first sprocket teeth (59), an inner ring (61), a plurality of connecting arms (63), and a plurality of first rivet holes (69). Each of the plurality of connecting arms (63) has a circumferential Centerline (CL) about the rotational center axis (X). A plurality of first rivet holes (69) are at least partially provided in the first outer annular body (57). Each of the plurality of first rivet holes (69) has a hole center Hub (HC). The total number of the plurality of connecting arms (63) is different from the total number of the plurality of first rivet holes (69). At least one of the plurality of hole center axes (HC) is offset from each of the plurality of circumferential Centerlines (CL) in a circumferential direction about the rotation center axis (X).

Description

Rear sprocket of manpower-driven vehicle and rear sprocket assembly of manpower-driven vehicle

Technical Field

The present invention relates to a rear sprocket of a manually driven vehicle and a rear sprocket assembly of a manually driven vehicle.

Background

Patent document 1 discloses a rear sprocket for a human-powered vehicle, for example, a rear sprocket for a bicycle. Referring to fig. 4 of patent document 1, it is known that a rear sprocket (12) for a bicycle includes an outer ring (50), a plurality of sprocket teeth (54), an inner ring (52), a plurality of connecting arms (62), and a plurality of fastening holes (64). The plurality of sprocket teeth are disposed on the outer annular body. The inner annular body is mounted to the hub assembly. A plurality of connecting arms (62) connect the outer annular body and the inner annular body.

The plurality of fastening holes (64) are provided in the plurality of connecting arms (62), respectively. The plurality of fastening holes (64) are provided with fastening members. The fastening member fastens the rear sprocket (12) and the adjacent rear sprocket (11). Specifically, the fastening member fastens the connecting arm (62) of the rear sprocket (12) to the inner portion (42) adjacent to the rear sprocket (11) via the fastening hole (64).

Prior art literature

Patent literature

Patent document 1: U.S. patent application publication 2012/0225745.

Disclosure of Invention

Problems to be solved by the invention

In recent years, various attempts have been made to improve the strength of rear sprockets for bicycles. For example, in the above-described prior art, the strength of the rear sprocket is improved by increasing the number of the plurality of connecting arms. However, in this case, there is a problem in that the weight of the rear sprocket increases.

Further, in this case, the number of the plurality of fastening holes increases in response to an increase in the number of the plurality of link arms. As a result, the number of inner portions adjacent to the rear sprocket increases. Causing the weight of the adjacent rear sprocket to increase. That is, the weight of the rear sprocket assembly including the rear sprocket and the adjacent rear sprocket increases. As described above, in the prior art, it is difficult to achieve both weight reduction of the rear sprocket assembly and improvement of the strength of the rear sprocket.

The invention provides a rear sprocket of a manual drive vehicle, which can restrain the weight increase of a rear sprocket assembly and improve the strength.

Means for solving the problems

With respect to the first aspect of the present invention, a rear sprocket of a human-powered vehicle is used with a human-powered vehicle having an axial center plane. The rear sprocket of a human powered vehicle has an axially outer side and an axially inner side. The axially inner side surface is provided on the opposite side of the axially outer side surface in the axial direction with respect to the rotation center axis. The axially inner surface is configured to be disposed opposite to the axially central surface in an axial direction in a mounted state in which the rear sprocket is mounted on the manually driven vehicle.

The rear sprocket of a human-powered vehicle is provided with an outer ring, a plurality of sprocket teeth, an inner ring, a plurality of connecting arms, and a plurality of fastening holes. The plurality of sprocket teeth extend radially outward from the outer annular body in a radial direction about the rotational center axis. The inner annular body is configured to be coupled to a sprocket support of the hub assembly so as to be capable of transmitting torque in an assembled state in which the rear sprocket is mounted to the hub assembly.

The plurality of connecting arms extend radially between the outer annular body and the inner annular body. Each of the plurality of link arms has a circumferential centerline about the rotational center axis. The plurality of link arms form a single integral component with the outboard ring body, the plurality of sprocket teeth, and the inboard ring body. The plurality of fastening holes are at least partially provided in the outer annular body. Each of the plurality of fastening holes is configured to receive a fastening member that fastens the adjacent rear sprocket and the rear sprocket to each other.

The adjacent rear sprocket is adjacent to the rear sprocket in such a manner that no other sprocket is disposed between the adjacent rear sprocket and the rear sprocket in the axial direction. Each of the plurality of fastening holes has a hole center axis. The total number of the plurality of connecting arms is different from the total number of the plurality of fastening holes. At least one of the plurality of hole center axes is offset from each of the plurality of circumferential center lines to a circumferential direction about the rotation center axis.

According to the rear sprocket of the human-powered vehicle of the first aspect, the strength of the rear sprocket can be improved by increasing the number of the plurality of link arms. Further, a plurality of fastening holes are provided at least partially in the outer annular body, at least one of the plurality of hole center axes being offset from each of the plurality of circumferential center lines in a circumferential direction about the rotation center axis.

According to this configuration, the above-described problem caused by the increase in the number of the plurality of connecting arms can be solved. For example, an increase in weight of the adjacent rear sprocket can be suppressed. That is, according to the rear sprocket of the human-powered vehicle of the first aspect, the strength of the rear sprocket can be improved while suppressing an increase in weight of the rear sprocket assembly.

In a second aspect of the present invention, the rear sprocket of the manually driven vehicle of the first aspect is configured such that the inner annular body has a spline portion. The spline portion is configured to engage with the sprocket support body of the hub assembly in an assembled state in which the rear sprocket is mounted to the hub assembly.

The rear sprocket of the human-powered vehicle of the second aspect can reliably transmit the driving torque to the hub assembly via the spline portion.

In a third aspect of the present invention, the rear sprocket of the manually driven vehicle according to the first or second aspect is configured such that a difference between a total number of the plurality of coupling arms and a total number of the plurality of fastening holes is 3 or less.

According to the rear sprocket of the human-powered vehicle of the third aspect, an increase in weight of the adjacent rear sprocket can be appropriately suppressed. That is, according to the rear sprocket of the human-powered vehicle of the third aspect, the strength of the rear sprocket can be improved while appropriately suppressing an increase in weight of the rear sprocket assembly.

In a fourth aspect of the present invention, the rear sprocket of the manually driven vehicle according to the third aspect is configured such that a difference between a total number of the plurality of coupling arms and a total number of the plurality of fastening holes is 1.

According to the rear sprocket of the human-powered vehicle of the fourth aspect, an increase in weight adjacent to the rear sprocket can be appropriately suppressed. That is, according to the rear sprocket of the human-powered vehicle of the fourth aspect, the strength of the rear sprocket can be improved while appropriately suppressing an increase in weight of the rear sprocket assembly.

With regard to a fifth aspect of the present invention, the rear sprocket of the manually driven vehicle of any one of the first to fourth aspects is configured such that a total number of the plurality of link arms is larger than a total number of the plurality of fastening holes.

According to the rear sprocket of the human-powered vehicle of the fifth aspect, the strength of the rear sprocket can be appropriately improved. That is, according to the rear sprocket of the human-powered vehicle of the fifth aspect, the strength of the rear sprocket can be appropriately improved while suppressing an increase in weight of the rear sprocket assembly.

With regard to a sixth aspect of the present invention, the rear sprocket of the manually driven vehicle of any one of the first to fifth aspects is configured such that the plurality of hole center axes are circumferentially offset from the plurality of circumferential center axes.

According to the rear sprocket of the human-powered vehicle of the sixth aspect, an increase in weight adjacent to the rear sprocket can be appropriately suppressed. That is, according to the rear sprocket of the human-powered vehicle of the sixth aspect, the strength of the rear sprocket can be improved while appropriately suppressing an increase in weight of the rear sprocket assembly.

In a seventh aspect of the present invention, the rear sprocket of the human-powered vehicle of the sixth aspect is configured such that each of the hole center axes is offset from each of the circumferential center lines in the circumferential direction, respectively.

According to the rear sprocket of the human-powered vehicle of the seventh aspect, an increase in weight adjacent to the rear sprocket can be appropriately suppressed. That is, according to the rear sprocket of the human-powered vehicle of the seventh aspect, the strength of the rear sprocket can be improved while appropriately suppressing an increase in weight of the rear sprocket assembly.

With regard to the eighth aspect of the present invention, the rear sprocket of the human-powered vehicle of any one of the first to seventh aspects is constituted in the following manner. The plurality of connecting arms are arranged at equal intervals in the circumferential direction about the rotation center axis. The plurality of fastening holes are arranged at equal intervals in the circumferential direction.

According to the rear sprocket of the human-powered vehicle of the eighth aspect, an increase in weight of the adjacent rear sprocket can be appropriately suppressed, and the strength of the rear sprocket can be appropriately improved. That is, according to the rear sprocket of the human-powered vehicle of the eighth aspect, the weight increase of the rear sprocket assembly can be appropriately suppressed and the strength of the rear sprocket can be appropriately improved.

With regard to the ninth aspect of the present invention, the rear sprocket of the manually driven vehicle of any one of the first to eighth aspects is constituted in the following manner.

The plurality of sprocket teeth includes a plurality of downshift promoting teeth. The plurality of downshift promoting teeth are configured to promote a downshift operation of moving the drive chain from the adjacent small rear sprocket to the rear sprocket. The plurality of downshift accelerating teeth includes downshift starting teeth and downshift concave teeth. The downshift start tooth is configured to be engaged with the drive chain first in a downshift operation.

The downshift concave teeth are disposed adjacent to the downshift start teeth on the downstream side of the downshift start teeth with respect to the drive rotation direction of the rear sprocket so that no other sprocket teeth are disposed between the downshift start teeth and the downshift concave teeth in the circumferential direction. The downshift concave tooth has a downshift concave. The downshift concave portion is provided on an axially outer side surface of the downshift concave portion tooth so as to be recessed in the axial direction from the axially outer side surface toward the axially inner side surface.

According to the rear sprocket of the human-powered vehicle of the ninth aspect, since the plurality of sprocket teeth includes the plurality of downshift accelerating teeth described above, the impact at the time of the downshift operation can be relaxed and the downshift operation can be smoothly performed.

With regard to a tenth aspect of the present invention, the rear sprocket of the manually driven vehicle of any one of the first to ninth aspects is constituted in the following manner.

The plurality of sprocket teeth includes a plurality of upshift facilitating teeth. The plurality of upshift promoting teeth are configured to promote an upshift operation of moving the drive chain from the rear sprocket to the adjacent small rear sprocket.

The plurality of upshift facilitating teeth includes upshift shifting teeth, upshift starting teeth, and upshift recessed teeth. The upshift shift tooth is configured to shift the drive chain to the adjacent small rear sprocket during an upshift operation. The upshift start tooth is configured to be disengaged from the drive chain first in an upshift operation.

The upshift starting tooth is disposed adjacent to the upshift shifting tooth on the upstream side of the upshift shifting tooth with respect to the drive rotation direction so that no other sprocket tooth is disposed between the upshift starting tooth and the upshift shifting tooth in the circumferential direction. The upshift starting tooth has an upshift first recess portion. The upshift first recess portion is provided on an axially outer side surface of the upshift start tooth so as to be recessed in an axial direction from the axially outer side surface toward the axially inner side surface.

The upshift recess tooth is disposed adjacent to the upshift start tooth on the upstream side of the upshift start tooth with respect to the drive rotation direction so that no other sprocket tooth is disposed between the upshift recess tooth and the upshift start tooth in the circumferential direction. The upshift recess tooth has an upshift second recess. The upshift second recess portion is provided on an axially outer side surface of the upshift recess portion tooth so as to be recessed in the axial direction from the axially outer side surface toward the axially inner side surface.

According to the rear sprocket of the human-powered vehicle of the tenth aspect, since the plurality of sprocket teeth include the plurality of upshift promoting teeth, the impact at the time of the upshift operation can be relaxed and the upshift operation can be smoothly performed.

With regard to the eleventh aspect of the present invention, the rear sprocket of the manually driven vehicle of any one of the first to tenth aspects is constituted in the following manner. Each of the plurality of sprocket teeth has a maximum radial length defined by a radial direction and a maximum axial length defined by an axial direction. The maximum radial length is longer than the maximum axial length.

According to the rear sprocket of the human-powered vehicle of the eleventh aspect, the rear sprocket assembly can be easily made multi-staged.

In a twelfth aspect of the present invention, a rear sprocket assembly includes the rear sprocket described above and an adjacent rear sprocket. The rear sprocket has a first pitch diameter. The adjacent rear sprocket has a second pitch diameter that is greater than the first pitch diameter. The adjacent rear sprocket is coaxially arranged with the rear sprocket in an assembled state of the rear sprocket assembly.

According to the rear sprocket assembly of the twelfth aspect, the rear sprocket is a small sprocket and the adjacent rear sprocket is a large sprocket. According to this structure, the strength of the rear sprocket assembly can be improved while suppressing an increase in the weight of the rear sprocket assembly.

With regard to the thirteenth aspect of the present invention, the rear sprocket assembly of the twelfth aspect is constructed in the following manner. The adjacent rear sprocket is provided with a sprocket body and a plurality of additional sprocket teeth. The plurality of additional sprocket teeth extend radially outward from the sprocket body. Each of the plurality of additional sprocket teeth has an additional maximum radial length defined by a radial direction and an additional maximum axial length defined by an axial direction. The additional maximum radial length is longer than the additional maximum axial length.

According to the rear sprocket assembly of the thirteenth aspect, the rear sprocket assembly can be easily made multi-staged.

With regard to the fourteenth aspect of the present invention, the rear sprocket assembly of the thirteenth aspect is constructed in the following manner. The adjacent rear sprocket further has a plurality of additional fastening holes. The plurality of additional fastening holes are at least partially provided in the sprocket body. The plurality of additional fastening holes are configured to receive fastening members that fasten the rear sprocket and the adjacent rear sprocket to each other. The total number of the plurality of fastening holes is equal to the total number of the plurality of additional fastening holes.

According to the rear sprocket of the human-powered vehicle of the fourteenth aspect, since the plurality of additional fastening holes are provided at least partially in the sprocket body, an increase in weight of the adjacent rear sprocket can be suppressed. According to this structure, the strength of the rear sprocket assembly can be improved while suppressing an increase in the weight of the rear sprocket assembly.

With respect to the fifteenth aspect of the present invention, the rear sprocket of a human-powered vehicle is for a human-powered vehicle having an axial center plane. The rear sprocket of a human powered vehicle has an axially outer side and an axially inner side. The axially inner side surface is provided on the opposite side of the axially outer side surface in the axial direction with respect to the rotation center axis. The axially inner surface is configured to be disposed opposite to the axially central surface in an axial direction in a mounted state in which the rear sprocket is mounted on the manually driven vehicle.

The plurality of connecting arms extend in a radial direction between the outer annular body and the inner annular body. Each of the plurality of link arms has a circumferential centerline about the rotational center axis. The plurality of fastening holes are at least partially provided in the outer annular body. Each of the plurality of fastening holes is configured to receive a fastening member that fastens the adjacent rear sprocket and the rear sprocket to each other.

The adjacent rear sprocket is adjacent to the rear sprocket in such a manner that no other sprocket is disposed between the adjacent rear sprocket and the rear sprocket in the axial direction. Each of the plurality of fastening holes has a hole center axis. Each of the plurality of hole center axes is offset from each of the plurality of circumferential centerlines, respectively, to a circumferential direction about the rotation center axis.

According to the rear sprocket of the human-powered vehicle of the fifteenth aspect, the strength of the rear sprocket can be improved by increasing the number of the plurality of link arms. Further, a plurality of fastening holes are provided at least partially in the outer annular body, each of the plurality of hole center axes being offset from each of the plurality of circumferential center lines in a circumferential direction about the rotation center axis, respectively.

According to this configuration, the above-described problem caused by the increase in the number of the plurality of connecting arms can be solved. For example, an increase in weight of the adjacent rear sprocket can be suppressed. That is, according to the rear sprocket of the human-powered vehicle of the fifteenth aspect, the strength of the rear sprocket can be improved while suppressing an increase in weight of the rear sprocket assembly.

Further, according to the rear sprocket of the manual drive vehicle of the fifteenth aspect, since each of the plurality of hole center axes is offset from each of the plurality of circumferential center lines in the circumferential direction about the rotation center axis, respectively, the degree of freedom in arrangement of the shift-promoting teeth can be improved.

In a sixteenth aspect of the present invention, the rear sprocket of the manually driven vehicle according to the fifteenth aspect is configured such that the total number of the plurality of connecting arms is different from the total number of the plurality of fastening holes.

According to the rear sprocket of the human-powered vehicle of the sixteenth aspect, the strength of the rear sprocket can be appropriately improved. That is, according to the rear sprocket of the human-powered vehicle of the sixteenth aspect, the strength of the rear sprocket can be appropriately improved while suppressing an increase in weight of the rear sprocket assembly.

In a seventeenth aspect of the present invention, the rear sprocket of the manually driven vehicle according to the fifteenth or sixteenth aspect is configured such that the total number of the plurality of connecting arms is larger than the total number of the plurality of fastening holes.

According to the rear sprocket of the human-powered vehicle of the seventeenth aspect, the strength of the rear sprocket can be appropriately improved. That is, according to the rear sprocket of the human-powered vehicle of the seventeenth aspect, the strength of the rear sprocket can be appropriately improved while suppressing an increase in weight of the rear sprocket assembly.

With regard to the eighteenth aspect of the present invention, the rear sprocket of the human-powered vehicle of any one of the fifteenth to seventeenth aspects is constituted in the following manner. The plurality of sprocket teeth includes a plurality of downshift promoting teeth. The plurality of downshift promoting teeth are configured to promote a downshift operation of moving the drive chain from the adjacent small rear sprocket to the rear sprocket. The plurality of downshift accelerating teeth includes downshift starting teeth and downshift concave teeth. The downshift start tooth is configured to be engaged with the drive chain first in a downshift operation.

According to the rear sprocket of the human-powered vehicle of the eighteenth aspect, since the plurality of sprocket teeth includes the plurality of downshift accelerating teeth described above, the impact at the time of the downshift operation can be relaxed and the downshift operation can be smoothly performed.

Regarding the nineteenth aspect of the present invention, the rear sprocket of the human-powered vehicle of any one of the fifteenth to eighteenth aspects is configured as follows. The plurality of sprocket teeth includes a plurality of upshift facilitating teeth. The plurality of upshift promoting teeth are configured to promote an upshift operation of moving the drive chain from the rear sprocket to the adjacent small rear sprocket.

According to the rear sprocket of the human-powered vehicle of the nineteenth aspect, since the plurality of sprocket teeth includes the plurality of upshift promoting teeth, the impact at the time of the upshift operation can be relaxed and the upshift operation can be smoothly performed.

Effects of the invention

According to the present invention, the strength of the rear sprocket of the manually driven vehicle can be improved while suppressing an increase in weight of the rear sprocket assembly of the manually driven vehicle.

Drawings

FIG. 1 is a side elevational view of a bicycle in accordance with an embodiment of the present invention;

FIG. 2 is a schematic view of the bicycle as seen from above;

FIG. 3 is a front side perspective view of the rear sprocket assembly;

FIG. 4 is a rear side perspective view of the rear sprocket assembly;

FIG. 5 is a cross-sectional view of the rear sprocket assembly;

FIG. 6A is a front view of a ninth rear sprocket;

FIG. 6B is a rear view of the ninth rear sprocket;

FIG. 6C is a cross-sectional view partially enlarged of a ninth rear sprocket and a tenth rear sprocket;

FIG. 7A is a front elevational view of a ninth sprocket for illustrating a shift action related structure;

FIG. 7B is a rear elevational view of the ninth sprocket illustrating a structure associated with a shifting action;

FIG. 8A is a front elevational view of the tenth rear sprocket;

fig. 8B is a rear view of the tenth rear sprocket.

Detailed Description

As shown in fig. 1, in the embodiment of the present invention, a bicycle 1 is used as an example of a manually driven vehicle. The bicycle 1 has a drive chain 3, a frame 5, a handlebar 7, a front wheel 9, a rear wheel 11, a shift operating device 13, a drive portion 15, and a front fork 17. The bicycle 1 also has a front derailleur 21 and a rear derailleur 23. As shown in fig. 2, the bicycle 1 has an axial center plane P.

As shown in fig. 1, the front fork 17 is rotatably mounted to the frame 5. The handlebar 7 is fixed to the front fork 17. The front wheel 9 is rotatably mounted to the front fork 17 via a front hub assembly 18. The rear wheel 11 is rotatably mounted to the rear portion of the frame 5 via a rear hub assembly 19. The front tire 9a is mounted to the front wheel 9. The rear tire 11a is mounted to the rear wheel 11.

The shift operating device 13 is mounted to the handlebar 7. The shift operating device 13 operates the front derailleur 21 and the rear derailleur 23 via cables. For example, the rear derailleur 23 is mounted to the frame 5. The rear derailleur 23 moves the drive chain 3 from one rear sprocket to the other rear sprocket by the shift operating device 13. The front derailleur 21 is mounted to the frame 5. The front derailleur 21 moves the drive chain 3 from one front sprocket to the other front sprocket by the shift operating device 13.

The driving unit 15 mainly includes a rear hub assembly 19, a rear sprocket assembly 27, and a crank assembly 29. The driving part 15 may include a driving chain 3. The rear hub assembly 19 is mounted to the frame 5.

The rear hub assembly 19 is connected to the rear wheel 11. A part of the rear hub assembly 19 rotates integrally with the rear wheel 11. That is, a part of the rear hub assembly 19 rotates relative to the frame 5. The rear hub assembly 19 is configured to rotate integrally with the rear sprocket assembly 27.

As shown in fig. 1 and 2, the rear sprocket assembly 27 has a rotation center axis X. In fig. 2, a rear sprocket assembly 27 is schematically illustrated. The rear sprocket assembly 27 rotates about the rotation center axis X. For example, the rear sprocket assembly 27 rotates together with the rear drum assembly 19 via a drum shaft, not shown. The driving force input from the rider of the bicycle 1 to the crank assembly 29 is transmitted to the rear sprocket assembly 27 and the rear drum assembly 19 via the drive chain 3.

As shown in fig. 1, the crank assembly 29 has a crank arm 31 and a front sprocket assembly 33. The crank arm 31 is rotatably supported at the lower portion of the frame 5. The front sprocket assembly 33 is mounted to the crank arm 31 so as to rotate integrally with the crank arm 31. The front sprocket assembly 33 has at least one front sprocket.

As shown in fig. 3 and 4, the rear sprocket assembly 27 includes a plurality of rear sprockets 41 to 51. In fig. 4, a plurality of rear sprockets 46 to 51 are illustrated. As shown in fig. 2, each of the plurality of rear sprockets 41 to 51 engages with the drive chain 3. The driving force transmitted from the crank assembly 29 to the driving chain 3 is transmitted to each of the plurality of rear sprockets 41 to 51.

As shown in fig. 5, each of the plurality of rear sprockets 41 to 51 is attached to the sprocket support 19a of the rear drum assembly 19 so as to rotate integrally with the sprocket support 19a of the rear drum assembly 19.

In the present embodiment, as shown in fig. 3 and 5, an example is shown in which the plurality of rear sprockets 41 to 51 includes 11 rear sprockets. The first to eleventh rear sprockets 41 to 51 are coaxially arranged about the rotation center axis X. The first to eleventh rear sprockets 41 to 51 are arranged in an axial direction about the rotation center axis X. As shown in fig. 5, the spacers 28a to 28f are arranged between 2 sprockets adjacent to each other among the third to ninth rear sprockets 43 to 49.

As shown in fig. 4 and 5, the seventh to ninth rear sprockets 47 to 49 are coupled to each other by a first rivet 53 a. The eighth rear sprocket 48 and the ninth rear sprocket 49 are coupled to each other by a second rivet 53 b. The ninth rear sprocket 49 and the tenth rear sprocket 50 are fastened to each other by third rivets 53 c. The third rivet 53c is an example of a fastening member.

The tenth rear sprocket 50 and the eleventh rear sprocket 51 are coupled to each other by a fourth rivet 53 d. The first to eleventh rear sprockets 41 to 51 and the spacers 28a to 28f are coupled to each other by a coupling member 53 e. Shims 28 a-28 f, first rivet 53a, second rivet 53b, third rivet 53c, fourth rivet 53d, and attachment member 53e can be interpreted as structures of rear sprocket assembly 27.

In the present embodiment, the ninth rear sprocket 49 and the tenth rear sprocket 50 have the characteristic configuration of the present invention. The rear sprocket assembly 27 includes a ninth rear sprocket 49 and a tenth rear sprocket 50. The ninth rear sprocket 49 is an example of a rear sprocket. The tenth rear sprocket 50 is an example of an adjacent rear sprocket. The eighth rear sprocket 48 used in the following description is an example of an adjacent small rear sprocket.

Ninth rear sprocket

As shown in fig. 6A and 6B, the ninth rear sprocket 49 has a rotation center axis X. The rotation center axis X is concentric with the rotation center axis of the rear sprocket assembly 27.

The ninth rear sprocket 49 has a first axially outer side surface 49a and a first axially inner side surface 49b. The ninth rear sprocket 49 has a first pitch diameter PD1. As shown in fig. 6A, the first axially outer side surface 49a forms an outer side surface of the ninth rear sprocket 49 in the axial direction about the rotation center axis X.

As shown in fig. 6B, the first axially inner side surface 49B forms an inner side surface of the ninth rear sprocket 49 in the axial direction about the rotation center axis X. The first axially inner side surface 49b is provided on the opposite side of the first axially outer side surface 49a in the axial direction with respect to the rotation center axis X. The first axially inner side surface 49b is configured to be disposed opposite to an axial center plane P shown in fig. 2 in an axial direction about the rotation center axis X in a mounted state in which the ninth rear sprocket 49 is mounted to the bicycle 1.

As shown in fig. 6A and 6B, the first pitch diameter PD1 is defined centering on the rotation center axis X. The first pitch diameter PD1 is the diameter of the pitch circle PC1 of the ninth rear sprocket 49. The pitch circle PC1 of the ninth rear sprocket 49 is formed by connecting the centers of the sprocket rolls in the case where the sprocket rolls of the drive chain 3 are in contact with the plurality of first sprocket teeth 59 of the ninth rear sprocket 49.

As shown in fig. 6A and 6B, the ninth rear sprocket 49 includes a first outer ring 57, a plurality of first sprocket teeth 59, an inner ring 61, a plurality of connecting arms 63, and a plurality of first rivet holes 69. In the present embodiment, the first outer annular body 57, the plurality of first sprocket teeth 59, the inner annular body 61, and the plurality of connecting arms 63 are formed as a single integral component. The first outer annular body 57, the inner annular body 61, and the plurality of connecting arms 63 may be formed separately from each other.

The plurality of first sprocket teeth 59 extend radially outward from the first outer annular body 57 in the radial direction about the rotation center axis X. Specifically, the plurality of first sprocket teeth 59 extend radially outward from the outer peripheral portion 57a of the first outer annular body 57 in the radial direction about the rotation center axis X. The outer peripheral portion 57a of the first outer ring body 57 is defined by root circles CB1 of the plurality of first sprocket teeth 59.

As shown in fig. 6C, each of the plurality of first sprocket teeth 59 has a first maximum radial length L1 and a first maximum axial length L2. The first maximum radial length L1 is defined by a radial direction with respect to the rotation center axis X. For example, the first maximum radial length L1 is a length from the outer peripheral portion 57a of the first outer annular body 57 to the tooth tips 59a of the plurality of first sprocket teeth 59 in the radial direction about the rotation center axis X.

The first maximum axial length L2 is defined by an axial direction with respect to the rotation center axis X. For example, the first maximum axial length L2 is a maximum length at a position of the outer peripheral portion 57a of the first outer annular body 57 in the axial direction about the rotation center axis X. Specifically, the first maximum axial length L2 is the maximum axial length between the first axially outer side surface 49a and the first axially inner side surface 49b at the position of the root circle CB1 of the plurality of first sprocket teeth 59. The first maximum radial length L1 is longer than the first maximum axial length L2.

As shown in fig. 5, the inner annular body 61 is configured to be coupled to the sprocket support 19a of the rear hub assembly 19 so as to be able to transmit torque in an assembled state in which the rear sprocket assembly 27 is mounted to the rear hub assembly 19.

As shown in fig. 5, 6A and 6B, the inner annular body 61 has a spline portion 61a. The spline portion 61a forms an inner peripheral surface of the inner annular body 61. As shown in fig. 5, the spline portion 61a is configured to engage with the sprocket support 19a of the rear drum assembly 19 in an assembled state in which the ninth rear sprocket 49 is attached to the rear drum assembly 19. The sprocket support 19a is formed with a spline that engages with the spline portion 61a of the rear sprocket 49.

As shown in fig. 6A and 6B, the plurality of connecting arms 63 extend in the radial direction with respect to the rotation center axis X between the first outer annular body 57 and the inner annular body 61. The plurality of coupling arms 63 are arranged at equal intervals in the circumferential direction about the rotation center axis X. The plurality of coupling arms 63 are formed as a single integral component with the first outer annular body 57, the plurality of first sprocket teeth 59, and the inner annular body 61. Each of the plurality of coupling arms 63 has a circumferential center line CL about the rotation center axis X.

Each of the plurality of first rivet holes 69 shown in fig. 6A and 6B is configured to receive a third rivet 53c shown in fig. 4 and 5. The first plurality of rivet holes 69 are at least partially disposed in the first outer annular body 57. The first rivet hole 69 is an example of a fastening hole.

In the present embodiment, each of the plurality of first rivet holes 69 is at least partially provided in the first outer annular body 57. Each of the plurality of first rivet holes 69 may be partially provided in the first outer ring 57 and partially provided in the coupling arm 63. The plurality of first rivet holes 69 are arranged at equal intervals in the circumferential direction about the rotation center axis X. The third rivet 53c shown in fig. 4 and 5 is inserted through the first rivet hole 69.

Each of the plurality of first rivet holes 69 has a hole center hub HC. At least one of the plurality of hole center axes HC is offset from each of the plurality of circumferential centerlines CL in a circumferential direction about the rotation center axis X. The plurality of hole center axes HC, i.e., at least 2 hole center axes HC, are offset from the plurality of circumferential centerlines CL in the circumferential direction about the rotation center axis X. In the present embodiment, each of the plurality of hole center axes HC is offset from each of the plurality of circumferential center lines CL in the circumferential direction about the rotation center axis X.

The total number of the plurality of coupling arms 63 is different from the total number of the plurality of first rivet holes 69. The total number of the plurality of coupling arms 63 is greater than the total number of the plurality of first rivet holes 69. For example, the difference between the total number of the plurality of connecting arms 63 and the total number of the plurality of first rivet holes 69 is 3 or less. In the present embodiment, the total number of the plurality of connecting arms 63 is 7, and the total number of the plurality of first rivet holes 69 is 6. The difference between the total number of the plurality of connecting arms 63 and the total number of the plurality of first rivet holes 69 is 1.

The ninth rear sprocket 49 is configured as follows to facilitate the downshift operation smoothly. As shown in fig. 7A, the plurality of first sprocket teeth 59 include a plurality of downshift promoting teeth 59D1, 59D2. The plurality of first sprocket teeth 59 may further include additional downshift promoting teeth 59D3. The plurality of first sprocket teeth 59 may further include downshift engagement promoting teeth 59D4, 59D5.

The plurality of downshift accelerating teeth 59D1, 59D2 are configured to accelerate a downshift operation. In the downshift operation, the drive chain 3 moves from the eighth rear sprocket 48 as a small sprocket to the ninth rear sprocket 49 as a large sprocket.

As shown in fig. 7A, the plurality of downshift accelerating teeth 59D1, 59D2 includes a downshift starting tooth 59D1 and a downshift concave tooth 59D2. The downshift start tooth 59D1 is configured to be engaged with the drive chain 3 first in the downshift operation.

For example, during a downshift operation, the outer link of the drive chain 3 is engaged with the downshift start tooth 59D1 first in a state where the outer link of the drive chain 3 is located in the additional downshift acceleration tooth 59D3 and the inner link of the drive chain 3 is located in the downshift acceleration tooth 59D2.

Among the plurality of downshift promoting teeth 59D1, 59D2 and the additional downshift promoting tooth 59D3, the downshift starting tooth 59D1 is arranged on the most upstream side in the driving rotation direction RD of the ninth rear sprocket 49.

As shown in fig. 7B, the downshift start tooth 59D1 has a first axial recess 59D1a. The first axial recess 59D1a is provided in the first axial inner side surface 49b of the downshift start tooth 59D 1. For example, the first axial recess 59D1a is provided on the first axial inner side surface 49b of the downshift start tooth 59D1 so as to be recessed from the first axial inner side surface 49b toward the first axial outer side surface 49a in the axial direction about the rotation center axis X. The first axial recess 59D1a may be a recess or an inclined portion.

As shown in fig. 7A, the downshift concave tooth 59D2 is disposed adjacent to the downshift start tooth 59D1 on the downstream side of the downshift start tooth 59D1 with respect to the drive rotation direction RD of the ninth rear sprocket 49 so that another first sprocket tooth 59 is not disposed between the downshift start tooth 59D1 and the downshift concave tooth 59D2 in the circumferential direction with respect to the rotation center axis X.

The downshift concave tooth 59D2 has downshift concave portions 59D2a, 59D2b. The downshift concave portions 59D2a, 59D2b are provided on the first axially outer side surface 49a of the downshift concave tooth 59D 2. For example, the downshift concave portions 59D2a, 59D2b are provided on the first axially outer side surface 49a of the downshift concave portion tooth 59D2 so as to be recessed from the first axially outer side surface 49a toward the first axially inner side surface 49b in the axial direction with respect to the rotation center axis X.

Specifically, the downshift concave portions 59D2a, 59D2b have a downshift first concave portion 59D2a and a downshift second concave portion 59D2b. Each of the downshift first concave portion 59D2a and the downshift second concave portion 59D2b is provided on the first axially outer side surface 49a of the downshift concave portion tooth 59D2 so as to be recessed from the first axially outer side surface 49a toward the first axially inner side surface 49b in the axial direction with respect to the rotation center axis X.

The downshift first concave portion 59D2a and the downshift second concave portion 59D2b are arranged in the circumferential direction with respect to the rotation center axis X. The first downshift concave portion 59D2a and the second downshift concave portion 59D2b are disposed adjacent to each other such that no other concave portion is disposed between the first downshift concave portion 59D2a and the second downshift concave portion 59D2b. The downshift first concave portion 59D2a and the downshift second concave portion 59D2b may be formed as a single concave portion.

As shown in fig. 7A, the additional downshift accelerating tooth 59D3 is configured to accelerate a downshift operation of moving the drive chain 3 from the eighth rear sprocket 48 to the ninth rear sprocket 49.

The additional downshift accelerating tooth 59D3 includes an additional downshift concave tooth 59D3. The additional downshift concave tooth 59D3 is disposed adjacent to the downshift concave tooth 59D2 on the downstream side of the downshift concave tooth 59D2 with respect to the driving rotation direction RD of the ninth rear sprocket 49. In the present embodiment, the downshift concave teeth 59D2 and the additional downshift concave teeth 59D3 are arranged in the drive rotation direction RD of the ninth rear sprocket 49.

The additional downshift concave tooth 59D3 has an additional downshift concave 59D3a. The additional downshift concave portion 59D3a is provided on the first axially outer side surface 49a of the additional downshift concave portion tooth 59D 3. For example, the additional downshift concave portion 59D3a is provided on the first axially outer side surface 49a of the additional downshift concave portion tooth 59D3 so as to be recessed from the first axially outer side surface 49a toward the first axially inner side surface 49b in the axial direction with respect to the rotation center axis X.

As shown in fig. 7A, the downshift engagement promoting teeth 59D4 and 59D5 are configured to promote engagement of the drive chain 3 with respect to the downshift starting tooth 59D1 during the downshift operation. The downshift engagement promoting teeth 59D4, 59D5 are disposed upstream of the downshift starting tooth 59D1 in the drive rotation direction RD with respect to the ninth rear sprocket 49.

In a state where the outer link of the drive chain 3 is engaged with the downshift start tooth 59D1 at first, the outer link of the drive chain 3 is engaged with the downshift engagement promoting tooth 59D4, and the inner link of the drive chain 3 is engaged with the downshift engagement promoting tooth 59D 5.

As shown in fig. 7B, the downshift engagement promoting teeth 59D4, 59D5 have downshift engagement recesses 59D4a, 59D5a, respectively. The downshift engagement recesses 59D4a, 59D5a are provided on the first axially inner side surfaces 49b of the downshift engagement facilitating teeth 59D4, 59D 5.

For example, the downshift engagement recesses 59D4a, 59D5a are provided on the first axially inner side surfaces 49b of the downshift engagement promoting teeth 59D4, 59D5, respectively, so as to be recessed from the first axially inner side surfaces 49b toward the first axially outer side surfaces 49a in the axial direction about the rotation center axis X. The first axial recess 59D1a may be a recess or an inclined portion.

The ninth rear sprocket 49 is configured as follows to facilitate the upshift operation smoothly. As shown in fig. 7A, the plurality of first sprocket teeth 59 include a plurality of upshift promoting teeth 59U1, 59U2, 59U3. The plurality of first sprocket teeth 59 may include additional upshift facilitating teeth 59U0.

The plurality of upshift promoting teeth 59U1, 59U2, 59U3 are configured to promote an upshift operation. The additional upshift promoting teeth 59U0 are configured to promote an upshift operation.

The upshift operation is an operation in which the drive chain 3 moves from the ninth rear sprocket 49 as a large sprocket to the eighth rear sprocket 48 as a small sprocket.

As shown in fig. 7A, the plurality of upshift promoting teeth 59U1, 59U2, 59U3 include an upshift shift tooth 59U1, an upshift start tooth 59U2, and an upshift recess tooth 59U3. The additional upshift promoting teeth 59U0 include additional upshift shift teeth 59U0.

As shown in fig. 7A, the upshift shift tooth 59U1 is configured to shift the drive chain 3 toward the eighth rear sprocket 48 during an upshift operation. The additional upshift shift tooth 59U0 is configured to shift the drive chain 3 toward the eighth rear sprocket 48 during an upshift operation.

For example, when the inner link of the drive chain 3 is located at the additional upshift shift tooth 59U0 and the outer link of the drive chain 3 is located at the upshift shift tooth 59U1 during the upshift operation, the drive chain 3 is located on the eighth rear sprocket 48 side of the additional upshift shift tooth 59U0 and the upshift shift tooth 59U 1.

As shown in fig. 7B, the upshift shift tooth 59U1 has a second axial recess 59U1a. The second axial recess 59U1a is provided in the first axial inner side surface 49b of the upshift displacement tooth 59U 1. For example, the second axial recess 59U1a is provided on the first axial inner side surface 49b of the upshift displacement tooth 59U1 so as to be recessed from the first axial inner side surface 49b toward the first axial outer side surface 49a in the axial direction about the rotation center axis X.

As shown in fig. 7A, the additional upshift displacement tooth 59U0 is disposed adjacent to the upshift displacement tooth 59U1 on the downstream side of the upshift displacement tooth 59U1 with respect to the driving rotation direction RD. The additional upshift shift tooth 59U0 may be a normal drive tooth that does not have the function of an upshift shift tooth.

As shown in fig. 7B, the additional upshift shift tooth 59U0 has a third axial recess 59U0a. The third axial recess 59U0a is provided on the first axial inner side surface 49b of the additional upshift displacement tooth 59U 0. The third axial recess 59U0a is provided on the first axial inner side surface 49b of the additional upshift shift tooth 59U0 so as to be recessed from the first axial inner side surface 49b toward the first axial outer side surface 49a in the axial direction about the rotation center axis X. The second axial recess 59U1a and the third axial recess 59U0a may be recesses or inclined portions.

As shown in fig. 7A, the upshift start tooth 59U2 is configured to be first disengaged from the drive chain 3 in the upshift operation. For example, when the inner link of the drive chain 3 is located at the upshift start tooth 59U2 during the upshift operation, the drive chain 3 starts to be disengaged from the upshift start tooth 59U 2.

The upshift start tooth 59U2 is disposed adjacent to the upshift shift tooth 59U1 on the upstream side of the upshift shift tooth 59U1 with respect to the driving rotation direction RD of the ninth rear sprocket 49.

For example, the upshift start tooth 59U2 is disposed adjacent to the upshift shift tooth 59U1 on the upstream side of the upshift shift tooth 59U1 with respect to the driving rotation direction RD so that no other first sprocket tooth 59 is disposed between the upshift start tooth 59U2 and the upshift shift tooth 59U1 in the circumferential direction with respect to the rotation center axis X.

The upshift starting tooth 59U2 has an upshift first recess portion 59U2a. The upshift first recess portion 59U2a is provided in the first axially outer side surface 49a of the upshift start tooth 59U 2. For example, the upshift first recess portion 59U2a is provided on the first axially outer side surface 49a of the upshift start tooth 59U2 so as to be recessed from the first axially outer side surface 49a toward the first axially inner side surface 49b in the axial direction about the rotation center axis X.

As shown in fig. 7A, the upshift recess tooth 59U3 is used to assist in disengaging the drive chain 3 from the ninth rear sprocket 49 in the upshift operation. For example, when the inner link of the drive chain 3 is disengaged from the upshift start tooth 59U2, the upshift recess tooth 59U3 is configured such that the outer link of the drive chain 3 does not engage with the upshift recess tooth 59U 3.

The upshift concave tooth 59U3 is disposed adjacent to the upshift start tooth 59U2 on the upstream side of the upshift start tooth 59U2 with respect to the driving rotation direction RD of the ninth rear sprocket 49.

For example, the upshift recess tooth 59U3 is disposed adjacent to the upshift start tooth 59U2 on the upstream side of the upshift start tooth 59U2 with respect to the driving rotation direction RD so that another first sprocket tooth 59 is not disposed between the upshift recess tooth 59U3 and the upshift start tooth 59U2 in the circumferential direction with respect to the rotation center axis X.

The upshift recess tooth 59U3 has an upshift second recess 59U3a. The upshift second recess portion 59U3a is provided on the first axially outer side surface 49a of the upshift recess portion tooth 59U 3. For example, the upshift second recess portion 59U3a is provided on the first axially outer side surface 49a of the upshift recess portion tooth 59U3 so as to be recessed from the first axially outer side surface 49a toward the first axially inner side surface 49b in the axial direction about the rotation center axis X.

Tenth rear sprocket

As shown in fig. 3, 4 and 5, the tenth rear sprocket 50 is arranged coaxially with the ninth rear sprocket 49 in the assembled state of the rear sprocket assembly 27. The tenth rear sprocket 50 is adjacent to the ninth rear sprocket 49 such that no other sprocket is disposed between the ninth rear sprocket 49 and the tenth rear sprocket 50 in the axial direction about the rotation center axis X.

As shown in fig. 8A and 8B, the tenth rear sprocket 50 has a rotation center axis X, a second axially outer side surface 50a, and a second axially inner side surface 50B. The tenth rear sprocket 50 has a second pitch diameter PD2.

The rotation center axis X is concentric with the rotation center axis of the rear sprocket assembly 27. As shown in fig. 8A, the second axially outer side surface 50a forms an outer side surface of the tenth rear sprocket 50 in the axial direction about the rotation center axis X.

As shown in fig. 8B, the second axially inner side surface 50B forms an inner side surface of the tenth rear sprocket 50 in the axial direction about the rotation center axis X. The second axially inner side surface 50b is provided on the opposite side of the second axially outer side surface 50a in the axial direction with respect to the rotation center axis X. The second axial inner side surface 50b is configured to be disposed opposite to the axial center plane P shown in fig. 2 in the axial direction about the rotation center axis X in the mounted state to the bicycle 1.

As shown in fig. 8A and 8B, the second pitch diameter PD2 is larger than the first pitch diameter PD1 of the ninth rear sprocket 49. The second pitch diameter PD2 is defined centering on the rotation center axis X. The second pitch diameter PD2 is the diameter of the pitch circle PC2 of the tenth rear sprocket 50. The pitch circle PC2 of the tenth rear sprocket 50 is formed by connecting the centers of the sprocket when the sprocket of the drive chain 3 is in contact with a plurality of second sprocket teeth 67 described later.

As shown in fig. 8A and 8B, the tenth rear sprocket 50 includes a sprocket main body 65 and a plurality of second sprocket teeth 67. The tenth rear sprocket 50 further has a plurality of second rivet holes 71. The plurality of second sprocket teeth 67 are examples of a plurality of additional sprocket teeth, and the plurality of second rivet holes 71 are examples of a plurality of additional fastening holes.

The sprocket body 65 has a second outer annular body 73 and a plurality of radially inner side portions 74. The second outer annular body 73 and the plurality of radially inner portions 74 are formed as a single integral component.

The second outer annular body 73 is formed in an annular shape. The plurality of radially inner portions 74 are provided on the inner peripheral portion of the second outer annular body 73. The plurality of radially inner portions 74 protrude radially inward from the inner peripheral portion of the second outer annular body 73 in the radial direction about the rotation center axis X. The total number of the plurality of radially inner sides 74 is the same as the total number of the plurality of first rivet holes 69. For example, the total number of the plurality of radially inner side portions 74 is 6.

The second plurality of rivet holes 71 are configured to receive the third rivet 53c shown in fig. 4 and 5. As described above, the third rivet 53c secures the ninth rear sprocket 49 and the tenth rear sprocket 50 to each other. The second plurality of rivet holes 71 are at least partially provided in the sprocket body 65. For example, the second rivet holes 71 are provided in the radially inner side portions 74, respectively.

The second rivet holes 71 penetrate the radially inner side portions 74. The plurality of second rivet holes 71 are arranged at equal intervals from each other in the circumferential direction. The total number of the plurality of second rivet holes 71 is equal to the total number of the plurality of first rivet holes 69.

As shown in fig. 5, the plurality of second rivet holes 71 are arranged opposite to the plurality of first rivet holes 69 in the axial direction about the rotation center axis X. For example, the plurality of second rivet holes 71 are arranged so as to face the plurality of first rivet holes 69 in the axial direction about the rotation center axis X so that the hole center axes of the plurality of second rivet holes 71 are concentric with the hole center axes HC of the plurality of first rivet holes 69. Each of the plurality of second rivet holes 71 is inserted through a third rivet 53c.

As shown in fig. 8A and 8B, the plurality of second sprocket teeth 67 extend radially outward from the sprocket body 65 in the radial direction about the rotation center axis X. For example, the plurality of second sprocket teeth 67 extend radially outward from the second outer annular body 73 in the radial direction about the rotation center axis X.

Specifically, the plurality of second sprocket teeth 67 extend radially outward from the outer peripheral portion 73a of the second outer annular body 73 in the radial direction about the rotation center axis X. The outer peripheral portion 73a of the second outer annular body 73 is defined by root circles CB2 of the plurality of second sprocket teeth 67.

As shown in fig. 6C, each of the plurality of second sprocket teeth 67 has a second maximum radial length L3 and a second maximum axial length L4. The second maximum radial length L3 is an example of the additional maximum radial length. The second maximum axial length L4 is an example of the additional maximum axial length.

The second maximum radial length L3 is defined by the radial direction with respect to the rotation center axis X. For example, the second maximum radial length L3 is a length from the outer peripheral portion 73a of the second outer annular body 73 to the tooth tips 67A of the plurality of second sprocket teeth 67 in the radial direction about the rotation center axis X.

The second maximum axial length L4 is defined by the axial direction with respect to the rotation center axis X. For example, the second maximum axial length L4 is a maximum length at a position of the outer peripheral portion 73a of the second outer annular body 73 in the axial direction about the rotation center axis X.

In detail, the second maximum axial length L4 is the maximum axial length between the second axially outer side surface 50a and the second axially inner side surface 50b at the position of the root circle CB2 of the plurality of second sprocket teeth 67. The second maximum radial length L3 is longer than the second maximum axial length L2.

Symbol description:

1. bicycle with wheel

3. Driving chain

19. Rear hub assembly

19a sprocket support

27. Rear sprocket assembly

48. Eighth rear sprocket

49. Ninth rear sprocket

49a first axial outer side

49b first axial inner side

50. Tenth rear sprocket

57. First outer annular body

59. A plurality of first sprocket teeth

59D1, 59D2 downshift promoting teeth

59D1 downshift starting tooth

59D2 downshift concave tooth

59D2a, 59D2b downshift recess

59D3 additional downshift accelerating tooth

59D4 and 59D5 downshift engagement promoting teeth

59U0 additional upshift promoting tooth

59U1, 59U2, 59U3 upshift promoting teeth

59U1 up-shift shifting tooth

59U2 upshift starting tooth

59U2a upshift first concave portion

59U3 upshift concave tooth

59U3a upshift second concave portion

61. Inner annular body

61a spline portion

63. Multiple connecting arms

65. Sprocket body

67. Second sprocket tooth

69. First rivet hole

71. Second rivet hole

CL circumferential center line

HC hole center axis

L1 first maximum radial length

L2 first maximum axial length

L3 second maximum radial length

L4 second maximum axial length

P axial center plane

PD1 first pitch diameter

PD2 second pitch diameter

RD-driven direction of rotation

X rotation center axis.

Claims

1. A rear sprocket for a manually driven vehicle, which is used for a manually driven vehicle having an axial center surface, and which has an axially outer side surface and an axially inner side surface, the axially inner side surface being configured to be provided on an opposite side of the axially outer side surface in an axial direction with respect to a rotation center axis, and to be provided opposite to the axially center surface in the axial direction in a mounted state of the manually driven vehicle,

The rear sprocket includes:

an outer annular body;

a plurality of sprocket teeth extending radially outward from the outer annular body in a radial direction with respect to the rotation center axis;

an inner annular body configured to be coupled to a sprocket support body of the hub assembly so as to be capable of transmitting torque in an assembled state in which the rear sprocket is attached to the hub assembly;

a plurality of connecting arms extending in the radial direction between the outer ring body and the inner ring body, each having a circumferential center line about the rotation center axis, and formed as a single integral member together with the outer ring body, the plurality of sprocket teeth, and the inner ring body; and

a plurality of fastening holes configured to be provided at least partially in the outer annular body and to receive fastening members for fastening adjacent rear sprockets and the rear sprockets to each other, respectively,

the adjacent rear sprocket is adjacent to the rear sprocket in such a manner that no other sprocket is arranged between the adjacent rear sprocket and the rear sprocket in the axial direction,

each of the plurality of fastening holes has a hole center axis,

the total number of the plurality of coupling arms is different from the total number of the plurality of fastening holes,

At least one of the plurality of hole center axes is offset from each of the plurality of circumferential center lines to a circumferential direction about the rotation center axis.

2. The rear sprocket of a human-powered vehicle as set forth in claim 1, wherein,

the inner annular body has a spline portion configured to be engaged with the sprocket support of the hub assembly in the assembled state.

3. The rear sprocket of a human-powered vehicle as set forth in claim 1, wherein,

the difference between the total number of the plurality of coupling arms and the total number of the plurality of fastening holes is 3 or less.

4. The rear sprocket of a human-powered vehicle as set forth in claim 3, wherein,

the difference between the total number of the plurality of coupling arms and the total number of the plurality of fastening holes is 1.

5. The rear sprocket of a human-powered vehicle as set forth in claim 1, wherein,

the total number of the plurality of coupling arms is greater than the total number of the plurality of fastening holes.

6. The rear sprocket of a human-powered vehicle as set forth in claim 1, wherein,

the plurality of hole center axes are offset from the plurality of circumferential centerlines toward the circumferential direction.

7. The rear sprocket of a human-powered vehicle as set forth in claim 6, wherein,

Each of the bore center axes is offset from each of the circumferential centerlines toward the circumference, respectively.

8. The rear sprocket of a human-powered vehicle as set forth in claim 1, wherein,

the plurality of connecting arms are arranged at equal intervals in the circumferential direction with respect to the rotation center axis,

the plurality of fastening holes are arranged at equal intervals from each other in the circumferential direction.

9. The rear sprocket of a human-powered vehicle as set forth in claim 1, wherein,

the plurality of sprocket teeth includes a plurality of downshift accelerating teeth configured to accelerate a downshift action of moving the drive chain from an adjacent small rear sprocket to the rear sprocket,

the plurality of downshift promoting teeth includes:

a downshift start tooth configured to be engaged with the drive chain at first in the downshift operation; and

the gear of the gear-down concave part,

the downshift concave teeth are configured to be,

the gear shift control device is configured such that, in the circumferential direction, no other sprocket tooth is disposed between the gear shift start tooth and the gear shift recess tooth, and is disposed adjacent to the gear shift start tooth on a downstream side of the gear shift start tooth with respect to a driving rotation direction of the rear sprocket, and

the present invention is characterized by comprising a downshift concave portion provided on the axially outer side surface of the downshift concave portion tooth so as to be recessed in the axial direction from the axially outer side surface toward the axially inner side surface.

10. The rear sprocket of a human-powered vehicle as set forth in claim 1, wherein,

the plurality of sprocket teeth includes a plurality of upshift facilitating teeth configured to facilitate an upshift action of moving the drive chain from the rear sprocket to an adjacent small rear sprocket,

the plurality of upshift facilitating teeth includes:

an upshift shift tooth configured to shift the drive chain toward the adjacent small rear sprocket during the upshift operation;

an upshift starting tooth configured to be disengaged from the drive chain at first in the upshift operation; and

the gear-up concave part teeth are arranged on the upper part of the gear-up concave part,

the upshift starting tooth is configured such that,

the gear shift teeth are disposed adjacent to the gear shift teeth on an upstream side of the gear shift teeth with respect to the driving rotation direction so that no other sprocket tooth is disposed between the gear shift start teeth and the gear shift teeth in the circumferential direction, and

an upshift first recess portion provided on the axial outer side surface of the upshift start tooth so as to be recessed in the axial direction from the axial outer side surface toward the axial inner side surface,

the upshift recess teeth are configured such that,

the gear shift control device is configured such that, in the circumferential direction, no other sprocket is disposed between the gear shift concave tooth and the gear shift start tooth, and is disposed adjacent to the gear shift start tooth on an upstream side of the gear shift start tooth with respect to the drive rotation direction, and

The gear-shifting device is provided with an upshift second concave portion which is provided on the axial outer side surface of the upshift concave portion tooth so as to be recessed in the axial direction from the axial outer side surface toward the axial inner side surface.

11. The rear sprocket of a human-powered vehicle as set forth in claim 1, wherein,

each of the plurality of sprocket teeth has a maximum radial length defined by the radial direction and a maximum axial length defined by the axial direction,

the maximum radial length is longer than the maximum axial length.

12. A rear sprocket assembly, comprising:

the rear sprocket of any one of claims 1 to 11 having a first pitch diameter; and

said adjacent rear sprocket having a second pitch diameter that is greater than said first pitch diameter,

the adjacent rear sprocket is disposed coaxially with the rear sprocket in an assembled state of the rear sprocket assembly.

13. The rear sprocket assembly as set forth in claim 12, wherein,

the adjacent rear sprocket is provided with: a sprocket body; and a plurality of additional sprocket teeth extending radially outward from the sprocket body in the radial direction,

each of the plurality of supplemental sprocket teeth having a supplemental maximum radial length defined by the radial direction and a supplemental maximum axial length defined by the axial direction,

The additional maximum radial length is longer than the additional maximum axial length.

14. The rear sprocket assembly as set forth in claim 13, wherein,

the adjacent rear sprocket further includes a plurality of additional fastening holes at least partially provided in the sprocket body,

the plurality of additional fastening holes are configured to receive the fastening members fastening the rear sprocket and the adjacent rear sprocket to each other,

the total number of the plurality of fastening holes is equal to the total number of the plurality of additional fastening holes.

15. A rear sprocket for a manually driven vehicle, which is used for a manually driven vehicle having an axial center surface, and which has an axially outer side surface and an axially inner side surface, the axially inner side surface being configured to be provided on an opposite side of the axially outer side surface in an axial direction with respect to a rotation center axis, and to be provided opposite to the axially center surface in the axial direction in a mounted state of the manually driven vehicle,

the rear sprocket includes:

an outer annular body;

A plurality of connecting arms extending in the radial direction between the outer annular body and the inner annular body, each connecting arm having a circumferential center line with respect to the rotation center axis; and

a plurality of fastening holes configured to be at least partially provided to the outer annular body and to receive fastening members for fastening adjacent rear sprockets and the rear sprockets to each other, respectively,

each of the plurality of fastening holes has a hole center axis,

each of the hole center axes is offset from each of the circumferential centerlines to a circumference with respect to the rotation center axis, respectively.

16. The rear sprocket of a human-powered vehicle as set forth in claim 15, wherein,

the total number of the plurality of coupling arms is different from the total number of the plurality of fastening holes.

17. The rear sprocket of a human-powered vehicle as set forth in claim 15, wherein,

the total number of the plurality of connecting arms is greater than the total number of the plurality of fastening holes.

18. The rear sprocket of a human-powered vehicle as set forth in claim 15, wherein,

the plurality of downshift promoting teeth includes: a downshift start tooth configured to be engaged with the drive chain at first in the downshift operation; and a gear-down recess tooth,

the downshift concave teeth are configured to be,

the present invention is characterized in that the gear teeth include a gear tooth that is provided on the axial outer side surface of the gear tooth, and a gear tooth that is provided on the gear tooth and is recessed in the axial direction from the axial outer side surface toward the axial inner side surface.

19. The rear sprocket of a human-powered vehicle as set forth in claim 15, wherein,

the plurality of upshift facilitating teeth includes:

the upshift starting tooth is configured such that,

the upshift recess teeth are configured such that,