CN110712474B

CN110712474B - Sprocket support body and bicycle rear hub assembly

Info

Publication number: CN110712474B
Application number: CN201910915759.5A
Authority: CN
Inventors: 冈智成
Original assignee: Shimano Inc
Current assignee: Shimano Inc
Priority date: 2017-05-30
Filing date: 2018-05-11
Publication date: 2023-08-08
Anticipated expiration: 2038-05-11
Also published as: DE202018006055U1; TW202012207A; JP2020138735A; TWI707802B; TW202124212A; JP6885915B2; CN108973524A; JP6918184B2; JP6670342B2; JP2018203243A; JP7016290B2; TWI785387B; CN108974239A; JP7232296B2; JP2018203242A; TW201900446A; CN114379280B; JP2021191678A; CN114379280A; JP2019038539A

Abstract

The bicycle rear hub assembly comprises a hub axle, a hub body and a sprocket support body. The hub axle includes an axle through hole having a minimum inner diameter equal to or greater than 13 mm. The hub body is rotatably mounted on the hub axle about a central axis of rotation of the bicycle rear hub assembly. The sprocket support body is rotatably mounted on the hub axle about the rotational center axis.

Description

Sprocket support body and bicycle rear hub assembly

Description of the division

The application is a divisional application, the application number of the original application is 201810466367.0, the application date is 2018, 05 month and 11 days, and the invention is named as a bicycle rear hub assembly.

Cross Reference to Related Applications

This application is a continuation-in-part application of U.S. patent application Ser. No. 15/712,407, filed on 22, 9, 2017. The contents of this application are incorporated herein by reference in their entirety.

Technical Field

The invention relates to a bicycle rear hub assembly.

Background

Bicycling is becoming an increasingly popular form of recreation as well as a means of transportation. In addition, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is continually improving the various components of the bicycle. One bicycle component that has been extensively redesigned is the hub assembly.

Disclosure of Invention

According to a first aspect of the present invention, a bicycle rear hub assembly includes a hub axle, a hub body and a sprocket support body. The hub axle includes an axle through-hole having a minimum inner diameter equal to or greater than 13 mm. The hub body is rotatably mounted on the hub axle about a central axis of rotation of the bicycle rear hub assembly. The sprocket support body is rotatably mounted on the hub axle about the rotational center axis.

With the bicycle rear hub assembly in accordance with the first aspect, since the wheel securing axle having a larger outer diameter can be mounted in the axle through-hole of the hub axle of the bicycle rear hub assembly, the strength of the bicycle drive train around the rear wheel can be improved.

According to a second aspect of the present invention, the bicycle rear hub assembly according to the first aspect is configured such that the minimum inner diameter of the shaft through hole is equal to or greater than 14mm.

With the bicycle rear hub assembly in accordance with the second aspect, since the wheel securing axle having a larger outer diameter can be mounted in the axle through-hole of the hub axle of the bicycle rear hub assembly, the strength of the bicycle drive train around the rear wheel can be further improved.

According to a third aspect of the present invention, the bicycle rear hub assembly according to the first or second aspect is configured such that the minimum inner diameter of the shaft through hole is equal to or smaller than 21mm.

With the bicycle rear hub assembly according to the third aspect, necessary inner spaces between the sprocket support body and the hub axle and between the hub body and the hub axle can be obtained, thereby improving the degree of freedom in designing the bicycle rear hub assembly.

According to a fourth aspect of the present invention, the bicycle rear hub assembly according to any one of the first to third aspects is configured such that the hub axle has a maximum outer diameter equal to or greater than 17 mm.

With the bicycle rear hub assembly according to the fourth aspect, the minimum inner diameter of the shaft through hole of the hub shaft can be increased, so that the strength of the bicycle transmission around the rear wheel can be improved.

According to a fifth aspect of the present invention, the bicycle rear hub assembly according to the fourth aspect is configured such that the maximum outer diameter of the hub axle is equal to or greater than 20mm.

With the bicycle rear hub assembly according to the fifth aspect, the minimum inner diameter of the shaft through hole of the hub shaft can be increased, so that the strength of the bicycle transmission around the rear wheel is improved.

According to a sixth aspect of the present invention, the bicycle rear hub assembly according to the fourth or fifth aspect is configured such that the maximum outer diameter of the hub axle is equal to or less than 23mm.

With the bicycle rear hub assembly according to the sixth aspect, necessary inner spaces between the sprocket support body and the hub axle and between the hub body and the hub axle can be obtained, thereby improving the degree of freedom in designing the bicycle rear hub assembly.

According to a seventh aspect of the present invention, the bicycle rear hub assembly according to any one of the first to sixth aspects is configured such that the sprocket support body includes at least ten external spline teeth configured to engage with the bicycle rear sprocket assembly, each of the at least ten external spline teeth having an external spline drive surface and an external spline non-drive surface.

With the bicycle rear hub assembly according to the seventh aspect, at least ten external spline teeth reduce the rotational force applied to each of the at least ten external spline teeth as compared to a sprocket support body that includes nine or fewer external spline teeth. This improves the durability of the sprocket support body and/or improves the freedom of choice of materials for the sprocket support body without reducing the durability of the sprocket support body.

According to an eighth aspect of the present invention, the bicycle rear hub assembly according to the seventh aspect is configured such that the total number of the at least ten external spline teeth is equal to or greater than 20.

With the bicycle rear hub assembly according to the eighth aspect, the durability of the sprocket support body and/or the freedom of material selection of the sprocket support body can be further improved without reducing the durability of the sprocket support body.

According to a ninth aspect of the present invention, the bicycle rear hub assembly according to the seventh aspect is configured such that the total number of the at least ten external spline teeth is equal to or greater than 25.

With the bicycle rear hub assembly according to the ninth aspect, the durability of the sprocket support body and/or the freedom of material selection of the sprocket support body can be further improved without reducing the durability of the sprocket support body.

According to a tenth aspect of the present invention, the bicycle rear hub assembly according to the seventh aspect is configured such that the total number of the at least ten external spline teeth is equal to or greater than 28.

With the bicycle rear hub assembly according to the tenth aspect, the durability of the sprocket support body and/or the freedom of material selection of the sprocket support body can be further improved without reducing the durability of the sprocket support body.

According to an eleventh aspect of the present invention, the bicycle rear hub assembly according to any one of the seventh to tenth aspects is configured such that at least one of the at least ten external spline teeth has an axial spline tooth length equal to or less than 27 mm.

With the bicycle rear hub assembly according to the eleventh aspect, the weight of the bicycle rear hub assembly can be reduced.

According to a twelfth aspect of the present invention, the bicycle rear hub assembly according to the eleventh aspect is configured such that the axial spline tooth length is equal to or greater than 22mm.

With the bicycle rear hub assembly according to the twelfth aspect, the speed stage of the bicycle rear sprocket assembly can be increased.

According to a thirteenth aspect of the present invention, the bicycle rear hub assembly according to any one of the seventh to twelfth aspects is configured such that the at least ten external spline teeth have a first external pitch angle and a second external pitch angle different from the first external pitch angle.

With the bicycle rear hub assembly according to the thirteenth aspect, the bicycle rear sprocket assembly can be easily attached to the bicycle rear hub assembly in the correct circumferential position.

According to a fourteenth aspect of the present invention, the bicycle rear hub assembly according to any one of the seventh to thirteenth aspects is configured such that at least two of the at least ten external spline teeth are circumferentially arranged at a first external tooth pitch angle with respect to the rotational center axis. The first external tooth pitch angle ranges from 5 degrees to 36 degrees.

With the bicycle rear hub assembly according to the fourteenth aspect, the durability of the sprocket support body and/or the freedom of material selection of the sprocket support body can be further improved without reducing the durability of the sprocket support body.

According to a fifteenth aspect of the present invention, the bicycle rear hub assembly according to the fourteenth aspect is configured such that the first external tooth pitch angle ranges from 10 degrees to 20 degrees.

With the bicycle rear hub assembly according to the fifteenth aspect, the durability of the sprocket support body and/or the freedom of material selection of the sprocket support body can be further improved without reducing the durability of the sprocket support body.

According to a sixteenth aspect of the present invention, the bicycle rear hub assembly according to the fifteenth aspect is configured such that the first external tooth pitch angle is equal to or less than 15 degrees.

With the bicycle rear hub assembly according to the sixteenth aspect, the durability of the sprocket support body and/or the freedom of material selection of the sprocket support body can be further improved without reducing the durability of the sprocket support body.

According to a seventeenth aspect of the present invention, the bicycle rear hub assembly according to any one of the first to sixteenth aspects is configured such that the sprocket support body includes at least one external spline tooth configured to engage with the bicycle rear sprocket assembly. The at least one external spline tooth has an external spline tip diameter equal to or less than 34 mm.

With the bicycle rear hub assembly according to the seventeenth aspect, the weight of the bicycle rear hub assembly can be reduced.

According to an eighteenth aspect of the present invention, the bicycle rear hub assembly according to the seventeenth aspect is configured such that the external spline top diameter is 33mm or less.

With the bicycle rear hub assembly according to the eighteenth aspect, the weight of the bicycle rear hub assembly can be further reduced.

According to a nineteenth aspect of the present invention, the bicycle rear hub assembly according to the seventeenth aspect is configured such that the external spline top diameter is equal to or greater than 29mm.

With the bicycle rear hub assembly according to the nineteenth aspect, the strength of the sprocket support body can be ensured.

According to a twentieth aspect of the present invention, the bicycle rear hub assembly according to any one of the first to nineteenth aspects is configured such that the sprocket support body includes at least one external spline tooth configured to engage with the bicycle rear sprocket assembly. The at least one external spline tooth has an external spline bottom diameter equal to or less than 32 mm.

With the bicycle rear hub assembly according to the twentieth aspect, the external spline bottom diameter can be increased by a radial length of the driving surface of the at least one external spline tooth. This improves the strength of the sprocket support body.

According to a twenty-first aspect of the present invention, the bicycle rear hub assembly according to the twentieth aspect is configured such that the external spline bottom diameter is equal to or smaller than 31mm.

With the bicycle rear hub assembly according to the twenty-first aspect, the external spline bottom diameter can be increased by a radial length of the driving surface of the at least one external spline tooth. This improves the strength of the sprocket support body.

According to a twenty-second aspect of the present invention, the bicycle rear hub assembly according to the twentieth or twenty-first aspect is configured such that the external spline bottom diameter is equal to or greater than 28mm.

With the bicycle rear hub assembly according to the twenty-second aspect, the strength of the sprocket support body can be ensured.

According to a thirteenth aspect of the present invention, the bicycle rear hub assembly according to any one of the first to twenty-second aspects is configured such that the sprocket support body comprises at least one external spline tooth configured to engage with the bicycle rear sprocket assembly. The at least one external spline tooth includes a plurality of external spline teeth including a plurality of external spline drive surfaces to receive a driving rotational force from the bicycle rear sprocket assembly during pedaling. The plurality of external spline drive surfaces each include a radially outermost edge, a radially innermost edge, and a radial length defined from the radially outermost edge to the radially innermost edge. The sum of the radial lengths of the plurality of external spline drive surfaces is equal to or greater than 7mm.

With the bicycle rear hub assembly according to the thirteenth aspect, the radial length of the plurality of external spline driving surfaces can be increased. This improves the strength of the sprocket support body.

According to a twenty-fourth aspect of the present invention, the bicycle rear hub assembly according to the twenty-third aspect is configured such that the sum of the radial lengths is equal to or greater than 10mm.

With the bicycle rear hub assembly according to the twenty-fourth aspect, the radial length of the plurality of external spline driving surfaces can be further increased. This improves the strength of the sprocket support body.

According to a twenty-fifth aspect of the present invention, the bicycle rear hub assembly according to the twenty-third aspect is configured such that the sum of the radial lengths is equal to or greater than 15mm.

With the bicycle rear hub assembly according to the twenty-fifth aspect, the radial length of the plurality of external spline driving surfaces can be further increased. This improves the strength of the sprocket support body.

According to a twenty-sixth aspect of the present invention, the bicycle rear hub assembly according to any one of the twenty-third to twenty-fifth aspects is configured such that the sum of the radial lengths is equal to or less than 36mm.

With the bicycle rear hub assembly in accordance with the twenty-sixth aspect, the productivity of the sprocket support body can be improved.

According to a twenty-seventh aspect of the present invention, the bicycle rear hub assembly according to any one of the first to twenty-sixth aspects is configured such that the hub body includes a first spoke mounting portion having a first axially outermost portion, a second spoke mounting portion having a second axially outermost portion, and a first axial length defined between the first axially outermost portion of the first spoke mounting portion and the second axially outermost portion of the second spoke mounting portion in an axial direction with respect to a rotational center axis of the bicycle rear hub assembly. The first axial length is equal to or greater than 55mm.

With the bicycle rear hub assembly according to the twenty-seventh aspect, the first axial length improves the strength of the wheel including the bicycle rear hub assembly.

According to a twenty-eighth aspect of the present invention, the bicycle rear hub assembly according to the twenty-seventh aspect is configured such that the first axial length is equal to or greater than 60mm.

With the bicycle rear hub assembly according to the twenty-eighth aspect, the first axial length further improves the strength of the wheel comprising the bicycle rear hub assembly.

According to a twenty-ninth aspect of the present invention, the bicycle rear hub assembly according to the twenty-seventh aspect is configured such that the first axial length is equal to or greater than 65mm.

With the bicycle rear hub assembly according to the twenty-ninth aspect, the first axial length further improves the strength of the wheel including the bicycle rear hub assembly.

According to a thirty-fifth aspect of the present invention, the bicycle rear hub assembly according to any one of the first to twenty-fourth aspects is configured such that the hub axle includes a first axial frame abutment surface, a second axial frame abutment surface and a second axial length. The first axial frame abutment surface is configured to abut against a first portion of the bicycle frame in an axial direction with respect to a rotational center axis of the bicycle rear hub assembly in a state in which the bicycle rear hub assembly is mounted to the bicycle frame. The second axial frame abutment surface is configured to abut against a second portion of the bicycle frame in the axial direction in a state in which the bicycle rear hub assembly is mounted to the bicycle frame. The second axial length is defined between the first axial frame abutment surface and the second axial frame abutment surface in the axial direction. The second axial length is equal to or greater than 140mm.

With the bicycle rear hub assembly according to the thirty-first aspect, the second axial length allows the bicycle rear hub assembly to be attached to multiple types of bicycle frames and achieves the effect of the first aspect.

According to a thirty-first aspect of the present invention, the bicycle rear hub assembly according to the thirty-first aspect is configured such that the second axial length is 145mm or greater.

With the bicycle rear hub assembly according to the thirty-first aspect, the second axial length increases the freedom of selecting the first axial length and/or a wider range of bicycle rear sprocket assemblies is achieved.

According to a thirty-second aspect of the present invention, the bicycle rear hub assembly according to the thirty-second aspect is configured such that the second axial length is equal to or greater than 147mm.

With the bicycle rear hub assembly according to the thirty-second aspect, the second axial length increases the freedom of selecting the first axial length and/or a wider range of bicycle rear sprocket assemblies is achieved.

According to a thirteenth aspect of the present invention, the bicycle rear hub assembly according to any one of the first to thirty-second aspects further comprises a freewheel structure. The flywheel structure includes a first ratchet member including at least one first ratchet tooth; and a second ratchet member comprising at least one second ratchet tooth configured to be torque-transmitting engaged with the at least one first ratchet tooth. The first ratchet member is configured to be torque-transmitting engaged with one of the hub body and the sprocket support body. The second ratchet member is configured to be torque-transmitting engaged with the other of the hub body and the sprocket support body. At least one of the first ratchet member and the second ratchet member is movable relative to the hub axle in an axial direction about the rotational central axis.

With the bicycle rear hub assembly according to the thirteenth aspect, the driving efficiency of the bicycle rear hub assembly can be improved, and the weight of the flywheel structure can be reduced.

According to a thirty-fourth aspect of the present invention, the bicycle rear hub assembly according to the thirty-third aspect is configured such that the at least one first ratchet tooth is disposed on an axially facing surface of the first ratchet member. The at least one second ratchet tooth is disposed on an axially facing surface of the second ratchet member. The axially facing surface of the second ratchet member faces the axially facing surface of the first ratchet member.

With the bicycle rear hub assembly according to the thirty-fourth aspect, it is possible to further improve the driving efficiency of the bicycle rear hub assembly and reduce the weight of the flywheel structure.

According to a thirty-fifth aspect of the present invention, the bicycle rear hub assembly according to the thirteenth or thirty-fourth aspect is configured such that the sprocket support body has an outer peripheral surface having a first helical spline. The first ratchet member is configured to be torque transmitting engaged with the sprocket support body and includes a second helical spline that mates with the first helical spline.

With the bicycle rear hub assembly in accordance with the thirty-fifth aspect, engagement and/or disengagement between the first ratchet member and the second ratchet member can be smoothed.

According to a thirty-sixth aspect of the present invention, the bicycle rear hub assembly according to the thirty-fifth aspect is configured such that the outer peripheral surface of the sprocket support body has a guide portion configured to guide the first ratchet member toward the hub body during coasting.

With the bicycle rear hub assembly in accordance with the thirty-sixth aspect, noise generated in the freewheel structure during coasting can be reduced.

According to a thirty-seventh aspect of the present invention, the bicycle rear hub assembly according to the thirty-sixth aspect is configured such that during coasting, the guide guides the first ratchet member toward the hub body to release the meshing engagement between the at least one first ratchet tooth and the at least one second ratchet tooth.

With the bicycle rear hub assembly in accordance with the thirty-seventh aspect, noise generated in the flywheel structure during coasting can be further reduced.

According to a thirty-eighth aspect of the present invention, the bicycle rear hub assembly according to the thirty-sixteenth or thirty-seventh aspect is configured such that the guide portion extends at least in a circumferential direction with respect to the sprocket support body.

With the bicycle rear hub assembly according to the thirty-eighth aspect, noise generated in the flywheel structure during coasting can be further reduced.

According to a thirty-ninth aspect of the present invention, the bicycle rear hub assembly according to any one of the thirty-sixth to thirty-eighth aspects is configured such that the guide portion is arranged to define an obtuse angle with the first helical spline.

With the bicycle rear hub assembly in accordance with the thirty-ninth aspect, noise generated in the freewheel structure during coasting can be further reduced.

According to a fortieth aspect of the present invention, the bicycle rear hub assembly according to any one of the thirty-third to thirty-ninth aspects is configured such that each of the first and second ratchet members has an annular shape.

With the bicycle rear hub assembly according to the fortieth aspect, it is possible to further improve the driving efficiency of the bicycle rear hub assembly and reduce the weight of the flywheel structure.

According to a twenty-fourth aspect of the present invention, the bicycle rear hub assembly according to any one of the first to twenty-first aspects further comprises a brake rotor supporting body comprising at least one additional external spline tooth configured to engage with a bicycle brake rotor. The at least one additional external spline tooth has an additional external spline tip diameter that is greater than the external spline tip diameter.

With the bicycle rear hub assembly according to the eleventh aspect, the brake rotor supporting body improves braking performance and widens the range of gears of the bicycle rear sprocket assembly mounted to the bicycle rear hub assembly, and the effect of the first aspect is obtained. The brake rotor support body also improves the attachment and detachment of the bicycle brake rotor.

According to a forty-second aspect of the present invention, the bicycle rear hub assembly according to any one of the seventh to sixteenth aspects is configured such that at least one of the at least ten external spline teeth is circumferentially symmetrical about a reference line extending from the rotational center axis to a circumferential center point of a radially outermost end of the at least one of the at least ten external spline teeth in a radial direction with respect to the rotational center axis.

With the bicycle rear hub assembly according to the forty-second aspect, the productivity of the sprocket support body can be improved.

According to a thirteenth aspect of the present invention, the bicycle rear hub assembly according to the fortieth aspect is configured such that at least one of the plurality of external spline driving surfaces has a first external spline surface angle defined between the external spline driving surface and a first radial line extending from a rotational central axis of the bicycle rear hub assembly to a radially outermost edge of the external spline driving surface. The first external spline surface angle is equal to or less than 6 degrees.

With the bicycle rear hub assembly according to the thirteenth aspect, the strength of the external spline driving surface can be improved.

According to a forty-fourth aspect of the present invention, the bicycle rear hub assembly according to the forty-fourth or thirteenth aspect is configured such that at least one of the externally splined non-driving surfaces has a second externally splined surface angle defined between the externally splined non-driving surface and a second radial line extending from a rotational central axis of the bicycle rear hub assembly to a radially outermost edge of the externally splined non-driving surface. The second external spline surface angle is equal to or less than 6 degrees.

With the bicycle rear hub assembly in accordance with the forty-fourth aspect, the productivity of the bicycle rear sprocket assembly can be improved due to the symmetrical configuration between the external spline driving surface and the external spline non-driving surface.

According to a forty-fifth aspect of the present invention, a bicycle rear hub assembly includes a hub axle, a hub body and a sprocket support body. The hub body is rotatably mounted on the hub axle about a central axis of rotation of the bicycle rear hub assembly. The sprocket support body is rotatably mounted on the hub axle about the rotational center axis. The sprocket support body includes at least ten external spline teeth configured to engage a bicycle rear sprocket assembly. Each of the at least ten external spline teeth has an external spline drive surface and an external spline non-drive surface. At least one of the at least ten external spline teeth is circumferentially symmetric about a reference line extending from the rotational central axis in a radial direction with respect to the rotational central axis to a circumferential center point of a radially outermost end of the at least one of the at least ten external spline teeth.

With the bicycle rear hub assembly according to the forty-fifth aspect, at least ten external spline teeth reduce the rotational force applied to each of the at least ten external spline teeth as compared to a sprocket support body that includes nine or fewer external spline teeth. This improves the durability of the sprocket support body and/or improves the freedom of choice of materials for the sprocket support body without reducing the durability of the sprocket support body. In addition, the symmetrical shape improves productivity of the sprocket support body. The forty-fifth aspect of the present invention may be combined with any one of the first to forty-fourth aspects.

According to a forty-sixth aspect of the present invention, the bicycle rear hub assembly according to the forty-fifth aspect is configured such that the total number of the at least ten external spline teeth is equal to or greater than 28.

With the bicycle rear hub assembly according to the forty-sixth aspect, the durability of the sprocket support body can be improved and/or the freedom of material selection of the sprocket support body can be improved without reducing the durability of the sprocket support body.

According to a forty-seventh aspect of the present invention, the bicycle rear hub assembly according to the forty-fifth or forty-sixth aspect is configured such that at least one of the plurality of external spline driving surfaces has a first external spline surface angle defined between the external spline driving surface and a first radial line extending from a rotational central axis of the bicycle rear hub assembly to a radially outermost edge of the external spline driving surface. The first external spline surface angle is equal to or less than 6 degrees.

With the bicycle rear hub assembly according to the forty-seventh aspect, the strength of the external spline driving surface can be improved.

According to a forty-eighth aspect of the present invention, the bicycle rear hub assembly according to the forty-seventh aspect is configured such that at least one of the externally splined non-driving surfaces has a second externally splined surface angle defined between the externally splined non-driving surface and a second radial line extending from a rotational central axis of the bicycle rear hub assembly to a radially outermost edge of the externally splined non-driving surface. The second external spline surface angle is equal to or less than 6 degrees.

With the bicycle rear hub assembly in accordance with the forty-eighth aspect, the productivity of the bicycle rear sprocket assembly can be improved due to the symmetrical configuration between the external spline driving surface and the external spline non-driving surface.

According to a forty-ninth aspect of the present invention, the bicycle rear hub assembly according to any one of the forty-fifth to forty-eighth aspects is configured such that at least one of the at least ten external spline teeth has an axial spline tooth length equal to or less than 27 mm.

With the bicycle rear hub assembly according to the forty-ninth aspect, the weight of the sprocket support body can be saved.

According to a fifty-fifth aspect of the present invention, the bicycle rear hub assembly according to any one of the seventh to tenth aspects is configured such that at least one of the at least ten external spline teeth has an axial spline tooth length equal to or less than 27 mm.

With the bicycle rear hub assembly in accordance with the fifty-th aspect, the weight of the sprocket support body can be saved.

According to a twenty-first aspect of the present invention, the bicycle rear hub assembly according to the twenty-first aspect is configured such that the total number of the at least ten external spline teeth ranges from 22 to 24.

With the bicycle rear hub assembly according to the twenty-first aspect, the total number of at least ten external spline teeth improves the durability of the sprocket support body and improves the productivity of the bicycle rear hub assembly.

According to a fifty-second aspect of the present invention, the bicycle rear hub assembly according to the thirteenth aspect is configured such that the first external tooth pitch angle ranges from 13 degrees to 17 degrees. The second external tooth pitch angle ranges from 28 degrees to 32 degrees.

With the bicycle rear hub assembly according to the fifty-second aspect, it is possible to easily attach the bicycle rear sprocket assembly to the bicycle rear hub assembly in the correct circumferential position and to improve the durability of the sprocket support body and the productivity of the bicycle rear hub assembly.

According to a thirteenth aspect of the present invention, the bicycle rear hub assembly according to the thirteenth aspect is configured such that the first external tooth pitch angle is half of the second external tooth pitch angle.

According to a seventeenth aspect of the present invention, the bicycle rear hub assembly according to the thirteenth aspect is configured such that the first external tooth pitch angle ranges from 13 degrees to 17 degrees.

With the bicycle rear hub assembly in accordance with the fifty-fourth aspect, the first external tooth pitch angle improves the durability of the sprocket support body and improves the productivity of the bicycle rear hub assembly.

According to a fifty-fifth aspect of the present invention, the bicycle rear hub assembly according to the fortieth aspect is configured such that the total number of the at least ten external spline teeth ranges from 22 to 24.

With the bicycle rear hub assembly in accordance with the fifty-fifth aspect, the total number of at least ten external spline teeth improves the durability of the sprocket support body and improves the productivity of the bicycle rear hub assembly.

According to a fifty-sixth aspect of the present invention, the bicycle rear hub assembly according to the twenty-third aspect is configured such that the sum of the radial lengths of the plurality of external spline driving surfaces ranges from 11mm to 14mm.

With the bicycle rear hub assembly according to the fifty-sixth aspect, the sum of the radial lengths increases the strength of the sprocket support body within the range of increased productivity of the bicycle rear hub assembly.

Drawings

A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings.

FIG. 1 is a schematic diagram of a bicycle drive train in accordance with one embodiment.

FIG. 2 is an exploded perspective view of the bicycle drive train illustrated in FIG. 1.

FIG. 3 is a cross-sectional view of the bicycle drive train taken along line III-III of FIG. 2.

FIG. 4 is a perspective view of the bicycle rear hub assembly of the bicycle drive train illustrated in FIG. 2 with the locking member of the bicycle rear sprocket assembly.

FIG. 5 is a side elevational view of the bicycle rear sprocket assembly of the bicycle drive train illustrated in FIG. 1.

FIG. 6 is an enlarged cross-sectional view of the bicycle drive train illustrated in FIG. 4.

FIG. 7 is a side elevational view of the sprocket of the bicycle rear sprocket assembly illustrated in FIG. 5.

FIG. 8 is a side elevational view of the sprocket of the bicycle rear sprocket assembly illustrated in FIG. 5.

FIG. 9 is a side elevational view of the sprocket of the bicycle rear sprocket assembly illustrated in FIG. 5.

FIG. 10 is a side elevational view of the first sprocket of the bicycle rear sprocket assembly illustrated in FIG. 5.

FIG. 11 is a side elevational view of the sprocket of the bicycle rear sprocket assembly illustrated in FIG. 5.

FIG. 12 is a side elevational view of the sprocket of the bicycle rear sprocket assembly illustrated in FIG. 5.

FIG. 13 is a side elevational view of the sprocket of the bicycle rear sprocket assembly illustrated in FIG. 5.

FIG. 14 is a side elevational view of the sprocket of the bicycle rear sprocket assembly illustrated in FIG. 5.

FIG. 15 is a side elevational view of the sprocket of the bicycle rear sprocket assembly illustrated in FIG. 5.

FIG. 16 is a side elevational view of the sprocket of the bicycle rear sprocket assembly illustrated in FIG. 5.

FIG. 17 is a side elevational view of the sprocket of the bicycle rear sprocket assembly illustrated in FIG. 5.

FIG. 18 is a side elevational view of the sprocket of the bicycle rear sprocket assembly illustrated in FIG. 5.

FIG. 19 is an exploded perspective view of the bicycle rear sprocket assembly illustrated in FIG. 5.

FIG. 20 is a perspective view of the sprocket support body of the bicycle rear hub assembly illustrated in FIG. 4.

FIG. 21 is another perspective view of the sprocket support body of the bicycle rear hub assembly illustrated in FIG. 4.

FIG. 22 is a rear elevational view of the sprocket support body of the bicycle rear hub assembly illustrated in FIG. 4.

FIG. 23 is a side elevational view of the sprocket support body of the bicycle rear hub assembly illustrated in FIG. 4.

FIG. 24 is a side elevational view of a sprocket support body of the bicycle rear hub assembly in accordance with one variation.

Fig. 25 is an enlarged cross-sectional view of the sprocket support body illustrated in fig. 23.

Fig. 26 is a cross-sectional view of the sprocket support body illustrated in fig. 23.

FIG. 27 is a perspective view of the bicycle rear hub assembly illustrated in FIG. 4.

FIG. 28 is a side elevational view of the bicycle rear hub assembly illustrated in FIG. 4.

FIG. 29 is a rear elevational view of the bicycle rear hub assembly illustrated in FIG. 4.

FIG. 30 is an exploded perspective view of the sprocket support body and the plurality of spacers of the bicycle rear hub assembly illustrated in FIG. 4.

FIG. 31 is an enlarged partial cross-sectional view of the bicycle drive train illustrated in FIG. 4.

FIG. 32 is another side elevational view of the sprocket illustrated in FIG. 8.

FIG. 33 is a side elevational view of the sprocket illustrated in FIG. 9.

FIG. 34 is a side elevational view of the sprocket illustrated in FIG. 9 according to one variation.

Fig. 35 is an enlarged cross-sectional view of the sprocket illustrated in fig. 29.

FIG. 36 is another cross-sectional view of the sprocket illustrated in FIG. 29.

FIG. 37 is another cross-sectional view of the bicycle drive train illustrated in FIG. 2.

Fig. 38 is an exploded perspective view of the sprocket illustrated in fig. 7 and 8.

Fig. 39 is another exploded perspective view of the sprocket illustrated in fig. 7 and 8.

FIG. 40 is an exploded perspective view of a portion of the bicycle rear hub assembly illustrated in FIG. 4.

FIG. 41 is an exploded perspective view of a portion of the bicycle rear hub assembly illustrated in FIG. 40.

FIG. 42 is an exploded perspective view of a portion of the bicycle rear hub assembly illustrated in FIG. 40.

FIG. 43 is an exploded perspective view of a portion of the bicycle rear hub assembly illustrated in FIG. 40.

FIG. 44 is a partial cross-sectional view of the bicycle rear hub assembly illustrated in FIG. 40.

FIG. 45 is a cross-sectional view of the bicycle rear hub assembly taken along the line XLV-XLV of FIG. 44.

FIG. 46 is a perspective view of the spacer of the bicycle rear hub assembly illustrated in FIG. 40.

FIG. 47 is another perspective view of the spacer of the bicycle rear hub assembly illustrated in FIG. 40.

FIG. 48 is a schematic view showing the action (pedaling) of the first ratchet member and the sprocket support body of the bicycle rear hub assembly illustrated in FIG. 40.

FIG. 49 is a schematic view showing the action (coasting) of the first ratchet member and the sprocket support body of the bicycle rear hub assembly illustrated in FIG. 40.

FIG. 50 is an enlarged cross-sectional view of a sprocket support body according to one variation.

FIG. 51 is an enlarged cross-sectional view of a sprocket according to one variation.

FIG. 52 is a side elevational view of the sprocket support body of the bicycle rear hub assembly in accordance with one variation.

Fig. 53 is an enlarged cross-sectional view of the sprocket support body illustrated in fig. 52.

FIG. 54 is an exploded perspective view of a sprocket of the bicycle rear sprocket assembly in accordance with one variation.

FIG. 55 is another exploded perspective view of the sprocket of the bicycle rear sprocket assembly in accordance with this variation.

FIG. 56 is a side elevational view of a sprocket of the bicycle rear sprocket assembly in accordance with this variation.

FIG. 57 is a side elevational view of a sprocket of the bicycle rear sprocket assembly in accordance with this variation.

FIG. 58 is a side elevational view of a sprocket of the bicycle rear sprocket assembly in accordance with this variation.

FIG. 59 is a side elevational view of the sprocket illustrated in FIG. 57.

Fig. 60 is an enlarged cross-sectional view of the sprocket illustrated in fig. 57.

FIG. 61 is a partial side elevational view of the sprocket support member of the bicycle rear sprocket assembly in accordance with this variation.

FIG. 62 is a cross-sectional view of a bicycle drive train in accordance with one variation.

Detailed Description

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

Referring initially to FIG. 1, a bicycle drive train 10 includes a bicycle rear hub assembly 12 and a bicycle rear sprocket assembly 14 in accordance with one embodiment. The bicycle rear hub assembly 12 is fixed to a bicycle frame BF. The bicycle rear sprocket assembly 14 is mounted to the bicycle rear hub assembly 12. The bicycle brake rotor 16 is mounted to the bicycle rear hub assembly 12.

The bicycle drive train 10 further includes a crank assembly 18 and a bicycle chain 20. The crank assembly 18 includes a crank axle 22, a right crank arm 24, a left crank arm 26 and a front sprocket 27. A right crank arm 24 and a left crank arm 26 are fixed to the crank axle 22. The front sprocket 27 is fixed to at least one of the crank axle 22 and the right crank arm 24. The bicycle chain 20 is engaged with the front sprocket 27 and the bicycle rear sprocket assembly 14 to transfer pedaling force from the front sprocket 27 to the bicycle rear sprocket assembly 14. In the illustrated embodiment, the crank assembly 18 includes a front sprocket 27 as a single sprocket. However, the crank assembly 18 may include a plurality of front sprockets. The bicycle rear sprocket assembly 14 is a rear sprocket assembly. However, the structure of the bicycle rear sprocket assembly 14 can be applied to the front sprockets.

In this application, the following directional terms "forward", "rearward", "forward", "left", "right", "transverse", "upward" and "downward" as well as any other similar directional terms refer to those directions as determined based on a user (e.g., a rider) sitting on a saddle (not shown) of a bicycle facing a handlebar (not shown). Accordingly, these terms, as utilized to describe the bicycle drive train 10, the bicycle rear hub assembly 12 or the bicycle rear sprocket assembly 14 should be interpreted relative to a bicycle equipped with the bicycle drive train 10, the bicycle rear hub assembly 12 or the bicycle rear sprocket assembly 14 as used in an upright riding position on a horizontal surface.

As shown in FIG. 2, the bicycle rear hub assembly 12 and the bicycle rear sprocket assembly 14 have a center axis of rotation A1. The bicycle rear sprocket assembly 14 is rotatably supported by the bicycle rear hub assembly 12 about a rotational center axis A1 relative to a bicycle frame BF (fig. 1). The bicycle rear sprocket assembly 14 is configured to engage the bicycle chain 20 to transmit a driving rotational force F1 between the bicycle chain 20 and the bicycle rear sprocket assembly 14 during pedaling. During pedaling, the bicycle rear sprocket assembly 14 rotates about the rotational center axis A1 in the driving rotational direction D11. The driving rotational direction D11 is defined along a circumferential direction D1 of the bicycle rear hub assembly 12 or the bicycle rear sprocket assembly 14. The opposite rotation direction D12 is a direction opposite to the driving rotation direction D11 and is defined along the circumferential direction D1.

As shown in FIG. 2, the bicycle rear hub assembly 12 includes a sprocket support body 28. The bicycle rear sprocket assembly 14 is configured to be mounted to a sprocket support body 28 of the bicycle rear hub assembly 12. The bicycle rear sprocket assembly 14 is mounted on the sprocket support body 28 to transmit a driving rotational force F1 between the sprocket support body 28 and the bicycle rear sprocket assembly 14. The bicycle rear hub assembly 12 includes a hub axle 30. The sprocket support body 28 is rotatably mounted on the hub axle 30 about the rotational center axis A1. The bicycle rear sprocket assembly 14 further includes a locking member 32. The locking member 32 is fixed to the sprocket support body 28 to hold the bicycle rear sprocket assembly 14 relative to the sprocket support body 28 in the axial direction D2 about the rotational center axis A1.

As shown in fig. 3, the bicycle rear hub assembly 12 is fixed to the bicycle frame BF by a wheel securing structure WS. The hub axle 30 includes an axle through hole 30A. The fixing rod WS1 of the wheel fixing structure WS extends through the shaft through hole 30A of the hub shaft 30. The hub axle 30 includes a first axle end 30B and a second axle end 30C. The hub axle 30 extends along a rotational central axis A1 between a first axle end 30B and a second axle end 30C. The first shaft end 30B is disposed in a first recess BF11 of the first frame BF1 of the bicycle frame BF. The second shaft end 30C is disposed in the second recess BF21 of the second frame BF2 of the bicycle frame BF. The hub axle 30 is held between the first frame BF1 and the second frame BF2 by the wheel securing structure WS. The wheel securing structure WS includes a structure known in the bicycle art. Therefore, for the sake of brevity, the detailed description will not be provided herein.

In this embodiment, the shaft through hole 30A has a minimum inner diameter BD1 equal to or greater than 13 mm. The minimum inner diameter BD1 of the shaft through hole 30A is preferably equal to or greater than 14mm. The minimum inner diameter BD1 of the shaft through hole 30A is preferably equal to or less than 21mm. In this embodiment, the minimum inner diameter BD1 of the shaft through hole 30A is 15mm. However, the minimum inner diameter BD1 is not limited to this embodiment and the above-described range.

The hub axle 30 has a maximum outer diameter BD2 equal to or greater than 17mm. The maximum outer diameter BD2 of the hub axle 30 is preferably equal to or greater than 20mm. The maximum outer diameter BD2 of the hub axle 30 is preferably equal to or less than 23mm. In this embodiment, the maximum outer diameter BD2 of the hub axle 30 is 21mm. However, the maximum outer diameter BD2 of the hub axle 30 is not limited to this embodiment and the above-described range. The hub axle 30 has a minimum outer diameter BD3 equal to or greater than 15 mm. The minimum outer diameter BD3 is preferably equal to or greater than 17mm. The minimum outer diameter BD3 is preferably equal to or smaller than 19mm. In this embodiment, the minimum outer diameter BD3 of the hub axle 30 is 17.6mm. However, the minimum outer diameter BD3 is not limited to this embodiment and the above-described range.

The hub axle 30 includes an axle tube 30X, a first axle portion 30Y, and a second axle portion 30Z. The shaft tube 30X has a tubular shape and extends along the rotation center axis A1. The first shaft portion 30Y is fixed to a first end of the shaft tube 30X. The second shaft portion 30Z is fixed to the second end of the shaft tube 30X. At least one of the first shaft portion 30Y and the second shaft portion 30Z may be integrally provided with the shaft tube 30X.

As shown in fig. 3 and 4, the bicycle rear hub assembly 12 further includes a brake rotor supporting body 34. The brake rotor support body 34 is rotatably mounted on the hub axle 30 about the rotational center axis A1. The brake rotor support body 34 is coupled to the bicycle brake rotor 16 (FIG. 1) to transfer brake rotational force from the bicycle brake rotor 16 to the brake rotor support body 34.

As shown in FIG. 4, the bicycle rear hub assembly 12 includes a hub body 36. The hub body 36 is rotatably mounted on the hub axle 30 about a central axis of rotation A1 of the bicycle rear hub assembly 12. In this embodiment, the sprocket support body 28 is a separate member from the hub body 36. The brake rotor support body 34 is integrally provided with the hub body 36 as a one-piece, unitary member. However, the sprocket support body 28 may be integrally provided with the hub body 36. The brake rotor support body 34 may be a separate component from the hub body 36. For example, the hub body 36 is made of a metal material including aluminum.

As shown in FIG. 5, the bicycle rear sprocket assembly 14 includes a plurality of bicycle sprockets. The plurality of bicycle sprockets includes a first sprocket and a second sprocket. In this embodiment, the plurality of bicycle sprockets includes a plurality of first sprockets SP1 and SP2 that are configured as first sprockets. The plurality of bicycle sprockets also includes a plurality of second sprockets SP3 and SP4 that are configured as second sprockets. The plurality of bicycle sprockets includes an additional sprocket. In this embodiment, the plurality of bicycle sprockets includes a plurality of additional sprockets SP5 to SP12. However, the total number of first sprockets is not limited to this embodiment. The total number of second sprockets is not limited to this embodiment. The total number of additional sprockets is not limited to this embodiment. Further, although the first sprocket SP1 is a sprocket separate from the first sprocket SP2 in this embodiment, the first sprockets SP1 and SP2 may be integrally formed as a one-piece, unitary member. In a similar manner, although the second sprocket SP3 is a sprocket separate from the second sprocket SP4 in this embodiment, the second sprockets SP3 and SP4 may be integrally formed as a one-piece, unitary member.

For example, the total number of the plurality of bicycle sprockets is equal to or greater than 10. The total number of the plurality of bicycle sprockets can be equal to or greater than 11. The total number of the plurality of bicycle sprockets can be equal to or greater than 12. In this embodiment, the total number of the plurality of bicycle sprockets is 12. However, the total number of the plurality of bicycle sprockets is not limited to this embodiment. For example, the total number of the plurality of bicycle sprockets can be 13, 14 or can be equal to or greater than 15.

In this embodiment, the first sprocket SP1 is the smallest sprocket in the bicycle rear sprocket assembly 14. The additional sprocket SP12 is the largest sprocket in the bicycle rear sprocket assembly 14. The first sprocket SP2 corresponds to a high gear in the bicycle rear sprocket assembly 14. The additional sprocket SP12 corresponds to a low gear in the bicycle rear sprocket assembly 14.

As shown in fig. 5, the first sprocket SP1 has a pitch circle diameter PCD1. The first sprocket SP2 has a pitch diameter PCD2. The second sprocket SP3 has a pitch diameter PCD3. The second sprocket SP4 has a pitch diameter PCD4. The additional sprocket SP5 has a pitch diameter PCD5. The additional sprocket SP6 has a pitch diameter PCD6. The additional sprocket SP7 has a pitch diameter PCD7. The additional sprocket SP8 has a pitch diameter PCD8. The additional sprocket SP9 has a pitch diameter PCD9. The additional sprocket SP10 has a pitch diameter PCD10. The additional sprocket SP11 has a pitch diameter PCD11. The additional sprocket SP12 has a pitch diameter PCD12.

The first sprocket SP1 has a pitch circle PC1, and the pitch circle PC1 has a pitch circle diameter PCD1. The first sprocket SP2 has a pitch circle PC2, the pitch circle PC2 having a pitch circle diameter PCD2. The second sprocket SP3 has a pitch circle PC3, the pitch circle PC3 having a pitch circle diameter PCD3. The second sprocket SP4 has a pitch circle PC4, the pitch circle PC4 having a pitch circle diameter PCD4. The additional sprocket SP5 has a pitch circle PC5, the pitch circle PC5 having a pitch circle diameter PCD5. The additional sprocket SP6 has a pitch circle PC6, the pitch circle PC6 having a pitch circle diameter PCD6. The additional sprocket SP7 has a pitch circle PC7, the pitch circle PC7 having a pitch circle diameter PCD7. The additional sprocket SP8 has a pitch circle PC8, the pitch circle PC8 having a pitch circle diameter PCD8. The additional sprocket SP9 has a pitch circle PC9, the pitch circle PC9 having a pitch circle diameter PCD9. The additional sprocket SP10 has a pitch circle PC10, the pitch circle PC10 having a pitch circle diameter PCD10. The additional sprocket SP11 has a pitch circle PC11, the pitch circle PC11 having a pitch circle diameter PCD11. The additional sprocket SP12 has a pitch circle PC12, the pitch circle PC12 having a pitch circle diameter PCD12.

The pitch circle PC1 of the first sprocket SP1 is defined by the center axis of the pin of the bicycle chain 20 (FIG. 2) that is engaged with the first sprocket SP 1. The pitch circles PC2 to PC12 are defined similarly to the pitch circle PC 1. Therefore, for the sake of brevity, this will not be described in detail herein.

In this embodiment, the pitch diameter PCD1 is smaller than the pitch diameter PCD2. The pitch diameter PCD2 is smaller than the pitch diameter PCD3. The pitch diameter PCD3 is smaller than the pitch diameter PCD4. The pitch diameter PCD4 is smaller than the pitch diameter PCD5. The pitch diameter PCD5 is smaller than the pitch diameter PCD6. The pitch diameter PCD6 is smaller than the pitch diameter PCD7. The pitch diameter PCD7 is smaller than the pitch diameter PCD8. The pitch diameter PCD8 is smaller than the pitch diameter PCD9. The pitch diameter PCD9 is smaller than the pitch diameter PCD10. The pitch diameter PCD10 is smaller than the pitch diameter PCD11. The pitch diameter PCD11 is smaller than the pitch diameter PCD12.

The pitch diameter PCD1 is the minimum pitch diameter in the bicycle rear sprocket assembly 14. The pitch diameter PCD12 is the largest pitch diameter in the bicycle rear sprocket assembly 14. The first sprocket SP1 corresponds to a high gear of the bicycle rear sprocket assembly 14. The additional sprocket SP12 corresponds to a low gear in the bicycle rear sprocket assembly 14. However, the first sprocket SP1 may correspond to another gear in the bicycle rear sprocket assembly 14. The additional sprocket SP12 may correspond to another gear in the bicycle rear sprocket assembly 14.

As shown in fig. 6, the first sprocket SP2 is adjacent to the first sprocket SP1 in the axial direction D2 with respect to the rotational center axis A1 of the bicycle rear sprocket assembly 14 without an additional sprocket between the first sprocket SP1 and the first sprocket SP 2. The second sprocket SP3 is adjacent to the first sprocket SP2 in the axial direction D2 with respect to the rotational center axis A1 of the bicycle rear sprocket assembly 14 without an additional sprocket between the first sprocket SP2 and the second sprocket SP 3. The second sprocket SP4 is adjacent to the second sprocket SP3 in the axial direction D2 with respect to the rotational center axis A1 of the bicycle rear sprocket assembly 14 without an additional sprocket between the second sprocket SP3 and the second sprocket SP 4. The first sprockets SP1 and SP2, the second sprocket SP3, the second sprocket SP4, and the additional sprockets SP5 to SP12 are arranged in this order in the axial direction D2.

As shown in fig. 7, the first sprocket SP1 includes a sprocket body SP1A and a plurality of sprocket teeth SP1B. A plurality of sprocket teeth SP1B extend radially outwardly from the sprocket body SP1A relative to a rotational center axis A1 of the bicycle rear sprocket assembly 14. The total number of teeth of the first sprocket SP1 (the total number of at least one sprocket teeth SP 1B) is equal to or less than 10. In this embodiment, the total number of at least one sprocket tooth SP1B of the first sprocket SP1 is 10. However, the total number of the plurality of sprocket teeth SP1B of the first sprocket SP1 is not limited to this embodiment and the above-described range.

As shown in fig. 8, the first sprocket SP2 includes a sprocket body SP2A and a plurality of sprocket teeth SP2B. A plurality of sprocket teeth SP2B extend radially outwardly from the sprocket body SP2A relative to a rotational center axis A1 of the bicycle rear sprocket assembly 14. In this embodiment, the total number of at least one sprocket tooth SP2B is 12. However, the total number of the plurality of sprocket teeth SP2B of the first sprocket SP2 is not limited to this embodiment.

The first sprocket SP2 includes at least one first shift promoting region SP2F1 to promote a first shift operation of the bicycle chain 20 from the first sprocket SP2 to the first sprocket SP 1. The first sprocket SP2 includes at least one second shift promoting region SP2F2 to promote a second shifting operation of the bicycle chain 20 from the first sprocket SP1 to the first sprocket SP 2. In this embodiment, the first sprocket SP2 includes a plurality of first shift promoting regions SP2F1 to promote the first shift operation. The first sprocket SP2 includes a second shift promoting region SP2F2 to promote a second shift operation. However, the total number of the first shift facilitating regions SP2F1 is not limited to this embodiment. The total number of the second shift facilitating regions SP2F2 is not limited to this embodiment. The term "shift facilitating region" as used herein is intended to be a region in which a shift operation of a bicycle chain from one sprocket to another axially adjacent sprocket is intentionally designed to be facilitated.

In this embodiment, the first sprocket SP2 includes a plurality of first shift promoting recesses SP2R1 to promote the first shift operation. The first sprocket SP2 includes a plurality of second shift promoting recesses SP2R2 to promote a second shift operation. The first shift facilitating recess SP2R1 is provided in the first shift facilitating region SP2F 1. However, the first shift facilitating region SP2F1 may include another structure instead of the first shift facilitating recess SP2R1 or in addition to the first shift facilitating recess SP2R 1. The second shift facilitating region SP2F2 may include another structure instead of or in addition to the second shift facilitating recess SP2R 2.

As shown in fig. 9, the second sprocket SP3 includes a sprocket body SP3A and a plurality of sprocket teeth SP3B. A plurality of sprocket teeth SP3B extend radially outwardly from the sprocket body SP3A relative to a rotational center axis A1 of the bicycle rear sprocket assembly 14. In this embodiment, the total number of at least one sprocket tooth SP3B is 14. However, the total number of the plurality of sprocket teeth SP3B of the second sprocket SP3 is not limited to this embodiment.

The second sprocket SP3 includes at least one first shift facilitating region SP3F1 to facilitate a first shift operation of the bicycle chain 20 from the second sprocket SP3 to the first sprocket SP2 (fig. 6). The second sprocket SP3 includes at least one second shift promoting region SP3F2 to promote a second shifting operation of the bicycle chain 20 from the first sprocket SP2 (fig. 6) to the second sprocket SP 3. In this embodiment, the second sprocket SP3 includes a plurality of first shift promoting regions SP3F1 to promote the first shift operation. The second sprocket SP3 includes a second shift promoting region SP3F2 to promote a second shift operation. However, the total number of the first shift facilitating regions SP3F1 is not limited to this embodiment. The total number of the second shift facilitating regions SP3F2 is not limited to this embodiment.

In this embodiment, the second sprocket SP3 includes a plurality of first shift facilitating recesses SP3R1 to facilitate the first shift operation. The second sprocket SP3 includes a plurality of second shift promoting recesses SP3R2 to promote a second shift operation. The first shift facilitating recess SP3R1 is provided in the first shift facilitating region SP3F 1. However, the first shift facilitating region SP3F1 may include another structure instead of the first shift facilitating recess SP3R1 or in addition to the first shift facilitating recess SP3R 1. The second shift facilitating region SP3F2 may include another structure instead of or in addition to the second shift facilitating recess SP3R 2.

As shown in fig. 10, the second sprocket SP4 includes a sprocket body SP4A and a plurality of sprocket teeth SP4B. A plurality of sprocket teeth SP4B extend radially outwardly from the sprocket body SP4A relative to a rotational center axis A1 of the bicycle rear sprocket assembly 14. In this embodiment, the total number of the at least one sprocket teeth SP4B is 16. However, the total number of the plurality of sprocket teeth SP4B of the second sprocket SP4 is not limited to this embodiment.

The second sprocket SP4 includes at least one first shift promoting region SP4F1 to promote a first shift operation of the bicycle chain 20 from the second sprocket SP4 to the second sprocket SP 3. The second sprocket SP4 includes at least one second shift promoting region SP4F2 to promote a second shift operation of the bicycle chain 20 from the second sprocket SP3 to the second sprocket SP 4. In this embodiment, the second sprocket SP4 includes a plurality of first shift promoting regions SP4F1 to promote the first shift operation. The second sprocket SP4 includes a second shift promoting region SP4F2 to promote a second shift operation. However, the total number of the first shift facilitating regions SP4F1 is not limited to this embodiment. The total number of the second shift facilitating regions SP4F2 is not limited to this embodiment.

In this embodiment, the second sprocket SP4 includes a plurality of first shift facilitating recesses SP4R1 to facilitate the first shift operation. The second sprocket SP4 includes a plurality of second shift promoting recesses SP4R2 to promote a second shift operation. The first shift facilitating recess SP4R1 is provided in the first shift facilitating region SP4F 1. However, the first shift facilitating region SP4F1 may include another structure instead of the first shift facilitating recess SP4R1 or in addition to the first shift facilitating recess SP4R 1. The second shift facilitating region SP4F2 may include another structure instead of or in addition to the second shift facilitating recess SP4R 2.

As shown in fig. 11, the additional sprocket SP5 includes a sprocket body SP5A and a plurality of sprocket teeth SP5B. A plurality of sprocket teeth SP5B extend radially outwardly from the sprocket body SP5A relative to a rotational center axis A1 of the bicycle rear sprocket assembly 14. In this embodiment, the total number of at least one sprocket tooth SP5B is 18. However, the total number of the plurality of sprocket teeth SP5B of the additional sprocket SP5 is not limited to this embodiment.

The additional sprocket SP5 includes at least one first shift facilitating region SP5F1 to facilitate a first shift operation of the bicycle chain 20 from the additional sprocket SP5 to an adjacent smaller sprocket SP 4. The additional sprocket SP5 includes at least one second shift promoting region SP5F2 to promote a second shifting operation of the bicycle chain 20 from an adjacent smaller sprocket SP4 to the additional sprocket SP 5. The adjacent smaller sprocket SP4 is adjacent to the additional sprocket SP5 in the axial direction D2 with respect to the rotational center axis A1 of the bicycle rear sprocket assembly 14 without an additional sprocket between the additional sprocket SP5 and the adjacent smaller sprocket SP 4. In this embodiment, the additional sprocket SP5 includes a plurality of first shift promoting regions SP5F1 to promote the first shift operation. The additional sprocket SP5 includes a plurality of second shift facilitating regions SP5F2 to facilitate the second shift operation. However, the total number of the first shift facilitating regions SP5F1 is not limited to this embodiment. The total number of the second shift facilitating regions SP5F2 is not limited to this embodiment.

In this embodiment, the additional sprocket SP5 includes a plurality of first shift facilitating recesses SP5R1 to facilitate the first shift operation. The additional sprocket SP5 includes a plurality of second shift facilitating recesses SP5R2 to facilitate the second shift operation. The first shift facilitating recess SP5R1 is provided in the first shift facilitating region SP5F 1. The second shift facilitating recess SP5R2 is provided in the second shift facilitating region SP5F 2. However, the first shift facilitating region SP5F1 may include another structure instead of the first shift facilitating recess SP5R1 or in addition to the first shift facilitating recess SP5R 1. The second shift facilitating region SP5F2 may include another structure instead of or in addition to the second shift facilitating recess SP5R 2.

As shown in fig. 12, the additional sprocket SP6 includes a sprocket body SP6A and a plurality of sprocket teeth SP6B. A plurality of sprocket teeth SP6B extend radially outwardly from the sprocket body SP6A relative to a rotational center axis A1 of the bicycle rear sprocket assembly 14. In this embodiment, the total number of the at least one sprocket teeth SP6B is 21. However, the total number of the plurality of sprocket teeth SP6B of the additional sprocket SP6 is not limited to this embodiment.

The additional sprocket SP6 includes at least one first shift facilitating region SP6F1 to facilitate a first shift operation of the bicycle chain 20 from the additional sprocket SP6 to an adjacent smaller sprocket SP 5. The additional sprocket SP6 includes at least one second shift facilitating region SP6F2 to facilitate a second shifting operation of the bicycle chain 20 from an adjacent smaller sprocket SP5 to the additional sprocket SP 6. The adjacent smaller sprocket SP5 is adjacent to the additional sprocket SP6 in the axial direction D2 with respect to the rotational center axis A1 of the bicycle rear sprocket assembly 14 without an additional sprocket between the additional sprocket SP6 and the adjacent smaller sprocket SP 5. In this embodiment, the additional sprocket SP6 includes a plurality of first shift facilitating regions SP6F1 to facilitate the first shift operation. The additional sprocket SP6 includes a plurality of second shift facilitating regions SP6F2 to facilitate the second shift operation. However, the total number of the first shift facilitating regions SP6F1 is not limited to this embodiment. The total number of the second shift facilitating regions SP6F2 is not limited to this embodiment.

In this embodiment, the additional sprocket SP6 includes a plurality of first shift facilitating recesses SP6R1 to facilitate the first shift operation. The additional sprocket SP6 includes a plurality of second shift facilitating recesses SP6R2 to facilitate the second shift operation. The first shift facilitating recess SP6R1 is provided in the first shift facilitating region SP6F 1. The second shift facilitating recess SP6R2 is provided in the second shift facilitating region SP6F 2. However, the first shift facilitating region SP6F1 may include another structure instead of the first shift facilitating recess SP6R1 or in addition to the first shift facilitating recess SP6R 1. The second shift facilitating region SP6F2 may include another structure instead of or in addition to the second shift facilitating recess SP6R 2.

As shown in fig. 13, the additional sprocket SP7 includes a sprocket body SP7A and a plurality of sprocket teeth SP7B. A plurality of sprocket teeth SP7B extend radially outwardly from the sprocket body SP7A relative to a rotational center axis A1 of the bicycle rear sprocket assembly 14. In this embodiment, the total number of at least one sprocket tooth SP7B is 24. However, the total number of the plurality of sprocket teeth SP7B of the additional sprocket SP7 is not limited to this embodiment.

The additional sprocket SP7 includes at least one first shift facilitating region SP7F1 to facilitate a first shift operation of the bicycle chain 20 from the additional sprocket SP7 to an adjacent smaller sprocket SP 6. The additional sprocket SP7 includes at least one second shift facilitating region SP7F2 to facilitate a second shifting operation of the bicycle chain 20 from an adjacent smaller sprocket SP6 to the additional sprocket SP 7. The adjacent smaller sprocket SP6 is adjacent to the additional sprocket SP7 in the axial direction D2 with respect to the rotational center axis A1 of the bicycle rear sprocket assembly 14 without an additional sprocket between the additional sprocket SP7 and the adjacent smaller sprocket SP 6. In this embodiment, the additional sprocket SP7 includes a plurality of first shift facilitating regions SP7F1 to facilitate the first shift operation. The additional sprocket SP7 includes a plurality of second shift facilitating regions SP7F2 to facilitate the second shift operation. However, the total number of the first shift facilitating regions SP7F1 is not limited to this embodiment. The total number of the second shift facilitating regions SP7F2 is not limited to this embodiment.

In this embodiment, the additional sprocket SP7 includes a plurality of first shift facilitating recesses SP7R1 to facilitate the first shift operation. The additional sprocket SP7 includes a plurality of second shift facilitating recesses SP7R2 to facilitate the second shift operation. The first shift facilitating recess SP7R1 is provided in the first shift facilitating region SP7F 1. The second shift facilitating recess SP7R2 is provided in the second shift facilitating region SP7F 2. However, the first shift facilitating region SP7F1 may include another structure instead of the first shift facilitating recess SP7R1 or in addition to the first shift facilitating recess SP7R 1. The second shift facilitating region SP7F2 may include another structure instead of or in addition to the second shift facilitating recess SP7R 2.

As shown in fig. 14, the additional sprocket SP8 includes a sprocket body SP8A and a plurality of sprocket teeth SP8B. A plurality of sprocket teeth SP8B extend radially outwardly from the sprocket body SP8A relative to a rotational center axis A1 of the bicycle rear sprocket assembly 14. In this embodiment, the total number of at least one sprocket tooth SP8B is 28. However, the total number of the plurality of sprocket teeth SP8B of the additional sprocket SP8 is not limited to this embodiment.

The additional sprocket SP8 includes at least one first shift facilitating region SP8F1 to facilitate a first shift operation of the bicycle chain 20 from the additional sprocket SP8 to an adjacent smaller sprocket SP 7. The additional sprocket SP8 includes at least one second shift facilitating region SP8F2 to facilitate a second shifting operation of the bicycle chain 20 from an adjacent smaller sprocket SP7 to the additional sprocket SP 8. The adjacent smaller sprocket SP7 is adjacent to the additional sprocket SP8 in the axial direction D2 with respect to the rotational center axis A1 of the bicycle rear sprocket assembly 14 without an additional sprocket between the additional sprocket SP8 and the adjacent smaller sprocket SP 7. In this embodiment, the additional sprocket SP8 includes a plurality of first shift facilitating regions SP8F1 to facilitate the first shift operation. The additional sprocket SP8 includes a plurality of second shift facilitating regions SP8F2 to facilitate the second shift operation. However, the total number of the first shift facilitating regions SP8F1 is not limited to this embodiment. The total number of the second shift facilitating regions SP8F2 is not limited to this embodiment.

In this embodiment, the additional sprocket SP8 includes a plurality of first shift facilitating recesses SP8R1 to facilitate the first shift operation. The additional sprocket SP8 includes a plurality of second shift facilitating recesses SP8R2 to facilitate the second shift operation. The first shift facilitating recess SP8R1 is provided in the first shift facilitating region SP8F 1. The second shift facilitating recess SP8R2 is provided in the second shift facilitating region SP8F 2. However, the first shift facilitating region SP8F1 may include another structure instead of the first shift facilitating recess SP8R1 or in addition to the first shift facilitating recess SP8R 1. The second shift facilitating region SP8F2 may include another structure instead of or in addition to the second shift facilitating recess SP8R 2.

As shown in fig. 15, the additional sprocket SP9 includes a sprocket body SP9A and a plurality of sprocket teeth SP9B. A plurality of sprocket teeth SP9B extend radially outwardly from the sprocket body SP9A relative to a rotational center axis A1 of the bicycle rear sprocket assembly 14. In this embodiment, the total number of the at least one sprocket teeth SP9B is 33. However, the total number of the plurality of sprocket teeth SP9B of the additional sprocket SP9 is not limited to this embodiment.

The additional sprocket SP9 includes at least one first shift facilitating region SP9F1 to facilitate a first shift operation of the bicycle chain 20 from the additional sprocket SP9 to an adjacent smaller sprocket SP 8. The additional sprocket SP9 includes at least one second shift facilitating region SP9F2 to facilitate a second shifting operation of the bicycle chain 20 from an adjacent smaller sprocket SP8 to the additional sprocket SP 9. The adjacent smaller sprocket SP8 is adjacent to the additional sprocket SP9 in the axial direction D2 with respect to the rotational center axis A1 of the bicycle rear sprocket assembly 14 without an additional sprocket between the additional sprocket SP9 and the adjacent smaller sprocket SP 8. In this embodiment, the additional sprocket SP9 includes a plurality of first shift facilitating regions SP9F1 to facilitate the first shift operation. The additional sprocket SP9 includes a plurality of second shift facilitating regions SP9F2 to facilitate the second shift operation. However, the total number of the first shift facilitating regions SP9F1 is not limited to this embodiment. The total number of the second shift facilitating regions SP9F2 is not limited to this embodiment.

In this embodiment, the additional sprocket SP9 includes a plurality of first shift facilitating recesses SP9R1 to facilitate the first shift operation. The additional sprocket SP9 includes a plurality of second shift facilitating recesses SP9R2 to facilitate the second shift operation. The first shift facilitating recess SP9R1 is provided in the first shift facilitating region SP9F 1. The second shift facilitating recess SP9R2 is provided in the second shift facilitating region SP9F 2. However, the first shift facilitating region SP9F1 may include another structure instead of the first shift facilitating recess SP9R1 or in addition to the first shift facilitating recess SP9R 1. The second shift facilitating region SP9F2 may include another structure instead of or in addition to the second shift facilitating recess SP9R 2.

As shown in fig. 16, the additional sprocket SP10 includes a sprocket body SP10A and a plurality of sprocket teeth SP10B. A plurality of sprocket teeth SP10B extend radially outwardly from the sprocket body SP10A relative to a rotational center axis A1 of the bicycle rear sprocket assembly 14. In this embodiment, the total number of at least one sprocket tooth SP10B is 39. However, the total number of the plurality of sprocket teeth SP10B of the additional sprocket SP10 is not limited to this embodiment.

The additional sprocket SP10 includes at least one first shift promoting region SP10F1 to promote a first shift operation of the bicycle chain 20 from the additional sprocket SP10 to an adjacent smaller sprocket SP 9. The additional sprocket SP10 includes at least one second shift promoting region SP10F2 to promote a second shifting operation of the bicycle chain 20 from an adjacent smaller sprocket SP9 to the additional sprocket SP 10. The adjacent smaller sprocket SP9 is adjacent to the additional sprocket SP10 in the axial direction D2 with respect to the rotational center axis A1 of the bicycle rear sprocket assembly 14 without an additional sprocket between the additional sprocket SP10 and the adjacent smaller sprocket SP 9. In this embodiment, the additional sprocket SP10 includes a plurality of first shift promoting regions SP10F1 to promote the first shift operation. The additional sprocket SP10 includes a plurality of second shift promoting regions SP10F2 to promote the second shift operation. However, the total number of the first shift facilitating regions SP10F1 is not limited to this embodiment. The total number of the second shift facilitating regions SP10F2 is not limited to this embodiment.

In this embodiment, the additional sprocket SP10 includes a plurality of first shift facilitating recesses SP10R1 to facilitate the first shift operation. The additional sprocket SP10 includes a plurality of second shift facilitating recesses SP10R2 to facilitate the second shift operation. The first shift facilitating recess SP10R1 is provided in the first shift facilitating region SP10F 1. The second shift facilitating recess SP10R2 is provided in the second shift facilitating region SP10F 2. However, the first shift facilitating region SP10F1 may include another structure instead of the first shift facilitating recess SP10R1 or in addition to the first shift facilitating recess SP10R 1. The second shift facilitating region SP10F2 may include another structure instead of or in addition to the second shift facilitating recess SP10R 2.

As shown in fig. 17, the additional sprocket SP11 includes a sprocket body SP11A and a plurality of sprocket teeth SP11B. A plurality of sprocket teeth SP11B extend radially outwardly from the sprocket body SP11A relative to a rotational center axis A1 of the bicycle rear sprocket assembly 14. In this embodiment, the total number of at least one sprocket tooth SP11B is 45. However, the total number of the plurality of sprocket teeth SP11B of the additional sprocket SP11 is not limited to this embodiment.

The additional sprocket SP11 includes at least one first shift promoting region SP11F1 to promote a first shift operation of the bicycle chain 20 from the additional sprocket SP11 to an adjacent smaller sprocket SP 10. The additional sprocket SP11 includes at least one second shift promoting region SP11F2 to promote a second shifting operation of the bicycle chain 20 from the adjacent smaller sprocket SP10 to the additional sprocket SP 11. The adjacent smaller sprocket SP10 is adjacent to the additional sprocket SP11 in the axial direction D2 with respect to the rotational center axis A1 of the bicycle rear sprocket assembly 14 without an additional sprocket between the additional sprocket SP11 and the adjacent smaller sprocket SP 10. In this embodiment, the additional sprocket SP11 includes a plurality of first shift promoting regions SP11F1 to promote the first shift operation. The additional sprocket SP11 includes a plurality of second shift promoting regions SP11F2 to promote the second shift operation. However, the total number of the first shift facilitating regions SP11F1 is not limited to this embodiment. The total number of the second shift facilitating regions SP11F2 is not limited to this embodiment.

In this embodiment, the additional sprocket SP11 includes a plurality of first shift facilitating recesses SP11R1 to facilitate the first shift operation. The additional sprocket SP11 includes a plurality of second shift facilitating recesses SP11R2 to facilitate the second shift operation. The first shift facilitating recess SP11R1 is provided in the first shift facilitating region SP11F 1. The second shift facilitating recess SP11R2 is provided in the second shift facilitating region SP11F 2. However, the first shift facilitating region SP11F1 may include another structure instead of the first shift facilitating recess SP11R1 or in addition to the first shift facilitating recess SP11R 1. The second shift facilitating region SP11F2 may include another structure instead of or in addition to the second shift facilitating recess SP11R 2.

As shown in fig. 18, the additional sprocket SP12 includes a sprocket body SP12A and a plurality of sprocket teeth SP12B. A plurality of sprocket teeth SP12B extend radially outwardly from the sprocket body SP12A relative to a rotational center axis A1 of the bicycle rear sprocket assembly 14. The total number of teeth of the additional sprocket SP12 is equal to or greater than 46. The total number of teeth of the additional sprocket SP12 may be equal to or greater than 50. In this embodiment, the total number of teeth of the additional sprocket SP12 is 51. However, the total number of the at least one sprocket tooth SP12B of the additional sprocket SP12 is not limited to this embodiment and the above-described range.

The additional sprocket SP12 includes at least one first shift facilitating region SP12F1 to facilitate a first shift operation of the bicycle chain 20 from the additional sprocket SP12 to an adjacent smaller sprocket SP 11. The additional sprocket SP12 includes at least one second shift promoting region SP12F2 to promote a second shifting operation of the bicycle chain 20 from an adjacent smaller sprocket SP11 to the additional sprocket SP 12. The adjacent smaller sprocket SP11 is adjacent to the additional sprocket SP12 in the axial direction D2 with respect to the rotational center axis A1 of the bicycle rear sprocket assembly 14 without an additional sprocket between the additional sprocket SP12 and the adjacent smaller sprocket SP 11. In this embodiment, the additional sprocket SP12 includes a plurality of first shift facilitating regions SP12F1 to facilitate the first shift operation. The additional sprocket SP12 includes a plurality of second shift facilitating regions SP12F2 to facilitate the second shift operation. However, the total number of the first shift facilitating regions SP12F1 is not limited to this embodiment. The total number of the second shift facilitating regions SP12F2 is not limited to this embodiment.

In this embodiment, the additional sprocket SP12 includes a plurality of first shift facilitating recesses SP12R1 to facilitate the first shift operation. The additional sprocket SP12 includes a plurality of second shift facilitating recesses SP12R2 to facilitate the second shift operation. The first shift facilitating recess SP12R1 is provided in the first shift facilitating region SP12F 1. The second shift facilitating recess SP12R2 is provided in the second shift facilitating region SP12F 2. However, the first shift facilitating region SP12F1 may include another structure instead of the first shift facilitating recess SP12R1 or in addition to the first shift facilitating recess SP12R 1. The second shift facilitating region SP12F2 may include another structure instead of or in addition to the second shift facilitating recess SP12R 2.

As shown in fig. 19, the sprockets SP1 to SP12 are members separated from each other. However, at least one of the sprockets SP1 to SP12 can be at least partially integrally provided with another one of the sprockets SP1 to SP 12. All of the sprockets SP1 to SP12 can be integrally formed with each other as a one-piece, unitary unit. In this case, at least one of the sprockets SP3 to SP12 can include at least ten internal spline teeth.

The bicycle rear sprocket assembly 14 further includes a sprocket support member 37, a plurality of spacers 38, a first ring 39A and a second ring 39B. The first ring 39A is disposed between the second sprocket SP3 and the second sprocket SP4 in the axial direction D2. The second ring 39B is disposed between the second sprocket SP4 and the additional sprocket SP5 in the axial direction D2. The additional sprocket is configured to be attached to the sprocket support member 37. In this embodiment, the additional sprockets SP5 to SP12 are configured to be attached to the sprocket support member 37.

As shown in fig. 6, for example, the additional sprocket is attached to the sprocket support member 37 by an adhesive 37A. In this embodiment, the additional sprockets SP5 to SP12 are attached to the sprocket support member 37 by an adhesive 37A. Accordingly, the weight of the bicycle rear sprocket assembly 14 can be reduced by reducing or eliminating metal fasteners. However, at least one of the additional sprockets SP5 to SP12 can be attached to the sprocket support member 37 using another structure (including metal fasteners) other than the adhesive 37A. At least one of the additional sprockets SP5 to SP12 can be engaged with the sprocket support body 28 without the sprocket support member 37. The sprocket support member 37 can be omitted from the bicycle rear sprocket assembly 14. Further, at least one of the second sprockets SP3 and SP4 can be attached to the sprocket support member 37.

As shown in fig. 4, the locking member 32 includes a tubular body 32A, a male threaded portion 32B, and a radial protrusion 32C. The tubular body 32A includes a first axial end 32D and a second axial end 32E. The second axial end 32E is opposite the first axial end 32D in an axial direction D2 about the rotational center axis A1 of the bicycle rear sprocket assembly 14. As shown in fig. 6, in a state in which the bicycle rear sprocket assembly 14 is mounted to the bicycle rear drum assembly 12, the first axial end portion 32D is positioned closer to the axial center plane CPL of the bicycle rear drum assembly 12 than the second axial end portion 32E. The axial center plane CPL is perpendicular to the rotational center axis A1. As shown in fig. 3, the axial center plane CPL is defined to bisect the axial length of the bicycle rear hub assembly 12 in the axial direction D2.

As seen in fig. 6, the male threaded portion 32B is provided to the first axial end portion 32D to engage the female threaded portion 28A of the sprocket support body 28 of the bicycle rear drum assembly 12 in a state in which the bicycle rear sprocket assembly 14 is mounted to the bicycle rear drum assembly 12. The radial projections 32C extend radially outwardly from the second axial end 32E with respect to the rotational center axis A1 to limit axial movement of the first sprocket SP2 with respect to the sprocket support body 28 of the bicycle rear hub assembly 12 in a state in which the bicycle rear sprocket assembly 14 is mounted to the bicycle rear hub assembly 12.

The first sprocket SP1 includes a first inward facing side SP1G and a first outward facing side SP1H. The first outward facing side SP1H is opposite to the first inward facing side SP1G in the axial direction D2. The radial projection 32C is configured to abut against the first sprocket SP1 at the first outward facing side SP1H. The first sprockets SP1 and SP2 are disposed between the radial projections 32C and the second sprocket SP3 in the axial direction. The first sprockets SP1 and SP2, the second sprocket SP3, the second sprocket SP4, and the first ring 39A are held between the radial projections 32C and the sprocket support member 37 in the axial direction D2.

As shown in fig. 4, the lock member 32 has a tool engagement portion 32F. The tool engagement portion 32F is provided on the inner peripheral surface 32A1 of the tubular body 32A to engage with a fixing tool (not shown). In this embodiment, the tool engagement portion 32F includes a plurality of engagement grooves 32G to engage with a fixing tool when the locking member 32 is threadedly attached to the sprocket support body 28 using the male threaded portion 32B and the female threaded portion 28A.

As seen in fig. 20 and 21, the sprocket support body 28 includes at least one external spline tooth 40 configured to engage the bicycle rear sprocket assembly 14 (fig. 6). The sprocket support body 28 includes at least ten external spline teeth 40 configured to engage the bicycle rear sprocket assembly 14 (FIG. 6). That is, the at least one external spline tooth 40 includes a plurality of external spline teeth 40.

The sprocket support body 28 includes a tubular base support 41. The base support 41 extends along the rotation central axis A1. External spline teeth 40 extend radially outwardly from base support 41. The sprocket support body 28 includes a larger diameter portion 42, a flange 44 and a plurality of helical external spline teeth 46. The larger diameter portion 42 and the flange 44 extend radially outwardly from the base support 41. The larger diameter portion 42 is disposed between the plurality of external spline teeth 40 and the flange 44 in the axial direction D2. The larger diameter portion 42 and the flange 44 are disposed between the plurality of external spline teeth 40 and the plurality of helical external spline teeth 46 in the axial direction D2. As seen in fig. 6, the bicycle rear sprocket assembly 14 is held between the larger diameter portion 42 and the radial projection 32C of the locking member 32 in the axial direction D2. The larger diameter portion 42 may have an internal cavity such that a drive structure, such as a one-way clutch structure, may be received within the internal cavity. The larger diameter portion 42 may be omitted from the bicycle rear hub assembly 12 as desired.

As shown in fig. 22, at least one of the at least ten external spline teeth 40 has an axial spline tooth length SL1. Each of the external spline teeth 40 has an axial spline tooth length SL1. The axial spline tooth length SL1 is equal to or less than 27mm. The axial spline tooth length SL1 is equal to or greater than 22mm. In this embodiment, the axial spline tooth length SL1 is 24.9mm. However, the axial spline tooth length SL1 is not limited to this embodiment and the above-described range.

As shown in fig. 23, the total number of at least ten external spline teeth 40 is equal to or greater than 20. The total number of at least ten external spline teeth 40 is preferably equal to or greater than 25. The total number of at least ten external spline teeth 40 is preferably equal to or greater than 28. The total number of external spline teeth 40 is preferably equal to or less than 72. In this embodiment, the total number of external spline teeth 40 is 29. However, the total number of external spline teeth 40 is not limited to this embodiment and the above-described ranges.

At least ten external spline teeth 40 have a first external pitch angle PA11 and a second external pitch angle PA12. At least two of the at least ten external spline teeth 40 are circumferentially arranged at a first external tooth pitch angle PA11 with respect to the rotational central axis A1. In other words, at least two of the plurality of external spline teeth 40 are circumferentially arranged at a first external pitch angle PA11 with respect to the rotational central axis A1 of the bicycle rear hub assembly 12. At least two of the at least ten external spline teeth 40 are circumferentially arranged at a second external pitch angle PA12 with respect to a rotational central axis A1 of the bicycle rear hub assembly 12. In other words, at least two of the plurality of external spline teeth 40 are circumferentially arranged at a second external pitch angle PA12 with respect to the rotational central axis A1 of the bicycle rear hub assembly 12. In this embodiment, the second external pitch angle PA12 is different from the first external pitch angle PA11. However, the second external pitch angle PA12 may be substantially equal to the first external pitch angle PA11.

In this embodiment, the plurality of external spline teeth 40 are arranged at a first external tooth pitch angle PA11 in the circumferential direction D1. Two of the plurality of external spline teeth 40 are arranged at a second external pitch angle PA12 in the circumferential direction D1. However, at least two external spline teeth of the plurality of external spline teeth 40 may be arranged at an additional external tooth pitch angle in the circumferential direction D1.

The first external tooth pitch angle PA11 ranges from 5 degrees to 36 degrees. The first external tooth pitch angle PA11 preferably ranges from 10 degrees to 20 degrees. The range of the first external tooth pitch angle PA11 is preferably equal to or less than 15 degrees. In this embodiment, the first external tooth pitch angle PA11 is 12 degrees. However, the first external tooth pitch angle PA11 is not limited to this embodiment and the above-described range.

The second outside pitch angle PA12 ranges from 5 degrees to 36 degrees. In this embodiment, the second external pitch angle PA12 is 24 degrees. However, the second outside pitch angle PA12 is not limited to this embodiment and the above-described range.

At least one of the external spline teeth 40 may have a first spline shape that is different from a second spline shape of another of the external spline teeth 40. At least one of the at least ten external spline teeth 40 may have a first spline size that is different from a second spline size of another one of the at least ten external spline teeth 40. At least one of the external spline teeth 40 has a profile that is different from the profile of another of the external spline teeth 40 when viewed along the rotational central axis A1. In this embodiment, the external spline teeth 40X have a first spline shape that is different from a second spline shape of the other of the external spline teeth 40. The external spline teeth 40X have a first spline size that is different from a second spline size of another one of the external spline teeth 40. However, as shown in fig. 24, at least ten external spline teeth 40 may have the same spline shape as each other. At least ten external spline teeth 40 may have the same spline dimensions as one another. At least ten external spline teeth 40 may have the same profile as each other.

As shown in fig. 25, each of the at least ten externally splined teeth 40 has an externally splined drive surface 48 and an externally splined non-drive surface 50. The plurality of external spline teeth 40 include a plurality of external spline drive surfaces 48 to receive a driving rotational force F1 from the bicycle rear sprocket assembly 14 (FIG. 6) during pedaling. The plurality of external spline teeth 40 includes a plurality of external spline non-drive surfaces 50. The external spline drive surface 48 is contactable with the bicycle rear sprocket assembly 14 to receive a driving rotational force F1 from the bicycle rear sprocket assembly 14 (FIG. 6) during pedaling. The external spline drive surface 48 faces in the opposite rotational direction D12. The externally splined drive surface 48 faces the internally splined drive surface 66 of the bicycle rear sprocket assembly 14 in a state in which the bicycle rear sprocket assembly 14 is mounted to the bicycle rear hub assembly 12. The external spline non-drive surface 50 is disposed on an opposite side of the external spline drive surface 48 in the circumferential direction D1. The externally splined non-drive surface 50 faces the drive rotational direction D11 and does not receive a drive rotational force F1 from the bicycle rear sprocket assembly 14 during pedaling. The externally splined non-driving surface 50 faces the internally splined non-driving surface 68 of the bicycle rear sprocket assembly 14 in a state in which the bicycle rear sprocket assembly 14 is mounted to the bicycle rear hub assembly 12.

At least ten external spline teeth 40 each have a circumferential maximum width MW1. The plurality of external spline teeth 40 each have a circumferential maximum width MW1. The circumferential maximum width MW1 is defined as the maximum width that receives the thrust force F2 applied to the external spline teeth 40. The circumferential maximum width MW1 is defined as the linear distance based on the external spline drive surface 48.

The plurality of externally splined drive surfaces 48 each include a radially outermost edge 48A and a radially innermost edge 48B. The external spline drive surface 48 extends from a radially outermost edge 48A to a radially innermost edge 48B. The first reference circle RC11 is defined on the radially innermost edge 48B and is centered on the rotation center axis A1. The first reference circle RC11 intersects the externally splined non-driving surface 50 at a reference point 50R. The circumferential maximum width MW1 extends linearly in the circumferential direction D1 from the radially innermost edge 48B to the reference point 50R.

The plurality of externally splined non-driving surfaces 50 each include a radially outermost edge 50A and a radially innermost edge 50B. The externally splined non-drive surface 50 extends from a radially outermost edge 50A to a radially innermost edge 50B. In this embodiment, the reference point 50R coincides with the radially innermost edge 50B. However, the reference point 50R may be offset from the radially innermost edge 50B.

The sum of the circumferential maximum widths MW1 is equal to or greater than 55mm. The sum of the circumferential maximum widths MW1 is preferably equal to or greater than 60mm. The sum of the circumferential maximum widths MW1 is preferably equal to or less than 70mm. In this embodiment, the sum of the circumferential maximum widths MW1 is 60.1mm. However, the sum of the circumferential maximum widths MW1 is not limited to this embodiment and the above-described range.

As shown in fig. 26, at least one external spline tooth 40 has an external spline tip diameter DM11, the external spline tip diameter DM11 being equal to or less than 34mm. The external spline crest diameter DM11 is equal to or less than 33mm. The external spline crest diameter DM11 is equal to or greater than 29mm. In this embodiment, the external spline crest diameter DM11 is 32.6mm. However, the male spline crest diameter DM11 is not limited to this embodiment and the above-described range.

At least one of the external spline teeth 40 has an external spline bottom diameter DM12. At least one external spline tooth 40 has an external spline root circle RC12, the external spline root circle RC12 having an external spline bottom diameter DM12. However, the external spline root circle RC12 may have another diameter different from the external spline bottom diameter DM12. The external spline bottom diameter DM12 is equal to or less than 32mm. The external spline bottom diameter DM12 is equal to or less than 31mm. The external spline bottom diameter DM12 is equal to or greater than 28mm. In this embodiment, the external spline bottom diameter DM12 is 30.2mm. However, the external spline bottom diameter DM12 is not limited to this embodiment and the above-described range.

The larger diameter portion 42 has an outer diameter DM13 that is larger than the male spline top diameter DM 11. The outer diameter DM13 ranges from 32mm to 40mm. In this embodiment, the outer diameter DM13 is 35mm. However, the outer diameter DM13 is not limited to this embodiment.

As shown in fig. 25, the plurality of externally splined drive surfaces 48 each include a radial length RL11 defined from a radially outermost edge 48A to a radially innermost edge 48B. The sum of the radial lengths RL11 of the plurality of external spline drive surfaces 48 is equal to or greater than 7mm. The sum of the radial lengths RL11 is equal to or greater than 10mm. The sum of the radial lengths RL11 is equal to or greater than 15mm. The sum of the radial lengths RL11 is equal to or less than 36mm. In this embodiment, the sum of the radial lengths RL11 is 16.6mm. However, the sum of the radial lengths RL11 is not limited to this embodiment.

The plurality of external spline teeth 40 have an additional radial length RL12. The additional radial lengths RL12 are defined from the external spline root circles RC12 to the radially outermost ends 40A of the plurality of external spline teeth 40, respectively. The sum of the additional radial lengths RL12 is equal to or greater than 20mm. In this embodiment, the sum of the additional radial lengths RL12 is 31.2mm. However, the sum of the additional radial lengths RL12 is not limited to this embodiment.

At least one of the at least ten external spline teeth 40 is circumferentially symmetrical about reference line CL 1. The reference line CL1 extends from the rotational center axis A1 to a circumferential center point CP1 of the radially outermost end 40A of at least one of the at least ten external spline teeth 40 in a radial direction with respect to the rotational center axis A1. However, at least one of the external spline teeth 40 may have an asymmetric shape with respect to the reference line CL 1. At least one of the at least ten external spline teeth 40 includes an external spline drive surface 48 and an external spline non-drive surface 50.

At least one of the plurality of externally splined drive surfaces 48 has a first externally splined surface angle AG11. A first external spline surface angle AG11 is defined between the external spline drive surface 48 and a first radial line L11. The first radial line L11 extends from the rotational center axis A1 of the bicycle rear hub assembly 12 to a radially outermost edge 48A of the externally splined driving surface 48. The first or second external tooth pitch angle PA11 or PA12 is defined between adjacent first radial lines L11 (see, e.g., fig. 23).

At least one of the externally splined non-drive surfaces 50 has a second externally splined surface angle AG12. A second external spline surface angle AG12 is defined between the external spline non-drive surface 50 and the second radial line L12. The second radial line L12 extends from the rotational center axis A1 of the bicycle rear hub assembly 12 to the radially outermost edge 50A of the externally splined non-drive surface 50.

In this embodiment, the second external spline surface angle AG12 is equal to the first external spline surface angle AG11. However, the first external spline surface angle AG11 may be different from the second external spline surface angle AG12.

The first external spline surface angle AG11 is equal to or less than 6 degrees. The first external spline surface angle AG11 is equal to or greater than 0 degrees. The second external spline surface angle AG12 is equal to or less than 6 degrees. The second external spline surface angle AG12 is equal to or greater than 0 degrees. In this embodiment, the first external spline surface angle AG11 is 5 degrees. The second external spline surface angle AG12 is 5 degrees. However, the first external spline surface angle AG11 and the second external spline surface angle AG12 are not limited to this embodiment and the above ranges.

As seen in fig. 27 and 28, the brake rotor support body 34 includes at least one additional external spline tooth 52 configured to engage the bicycle brake rotor 16 (fig. 1). In this embodiment, the brake rotor support body 34 includes an additional base support 54 and a plurality of additional external spline teeth 52. The additional base support 54 has a tubular shape and extends from the hub body 36 along a central axis of rotation A1. Additional external spline teeth 52 extend radially outwardly from an additional base support 54. The total number of additional external spline teeth 52 is 52. However, the total number of additional external spline teeth 52 is not limited to this embodiment.

As shown in fig. 28, at least one additional external spline tooth 52 has an additional external spline crest diameter DM14. As shown in fig. 29, the additional male spline crest diameter DM14 is greater than the male spline crest diameter DM11. The additional external spline crest diameter DM14 is approximately equal to the outer diameter DM13 of the larger diameter portion 42. However, the additional external spline crest diameter DM14 may be equal to or less than the external spline crest diameter DM11. The additional external spline crest diameter DM14 may be different from the outer diameter DM13 of the larger diameter portion 42.

As shown in fig. 29, the hub body 36 includes a first spoke mounting portion 36A and a second spoke mounting portion 36B. The plurality of first spokes SK1 are coupled to the first spoke mounting portion 36A. The plurality of second spokes SK2 are coupled to the second spoke mounting portion 36B. In this embodiment, the first spoke mounting portion 36A includes a plurality of first attachment holes 36A1. The first spoke SK1 extends through the first attachment hole 36A1. The second spoke mounting portion 36B includes a plurality of second attachment holes 36B1. The second spoke SK2 extends through the second attachment hole 36B1. The term "spoke mounting portion" as used herein includes a configuration in which the spoke mounting openings have a flange-like shape such that the spoke mounting portion extends radially outwardly with respect to a center axis of rotation of the bicycle rear hub assembly as shown in FIG. 29, as well as a configuration in which the spoke mounting portion is an opening formed directly on a radially outer peripheral surface of the hub body.

The second spoke mounting portion 36B is spaced apart from the first spoke mounting portion 36A in the axial direction D2. The first spoke mounting portion 36A is disposed between the sprocket support body 28 and the second spoke mounting portion 36B in the axial direction D2. The second spoke mounting portion 36B is disposed between the first spoke mounting portion 36A and the brake rotor supporting body 34 in the axial direction D2.

The first spoke mounting portion 36A has a first axially outermost portion 36C. The second spoke mounting portion 36B has a second axially outermost portion 36D. The first axially outermost portion 36C includes a surface that faces the first frame BF1 in the axial direction D2 in a state in which the bicycle rear hub assembly 12 is mounted to the bicycle frame BF. The second axially outermost portion 36D includes a surface that faces the second frame BF2 in the axial direction D2 in a state in which the bicycle rear hub assembly 12 is mounted to the bicycle frame BF.

The hub body 36 includes a first axial length AL1. The first axial length AL1 is defined between the first axially outermost portion 36C of the first spoke mounting portion 36A and the second axially outermost portion 36D of the second spoke mounting portion 36B in an axial direction D2 about the rotational center axis A1 of the bicycle rear sprocket assembly 14. The first axial length AL1 may be equal to or greater than 55mm. The first axial length AL1 may be equal to or greater than 60mm. The first axial length AL1 may be equal to or greater than 65mm. In this embodiment, the first axial length AL1 may be 67mm. However, the first axial length AL1 is not limited to this embodiment and the above-described range. Examples of the first axial length AL1 include 55.7mm, 62.3mm, and 67mm.

As shown in fig. 29, the hub axle 30 includes a first axial frame abutment surface 30B1 and a second axial frame abutment surface 30C1. The first axial frame abutment surface 30B1 is configured to abut against the first portion BF12 of the bicycle frame BF in the axial direction D2 with respect to the rotational center axis A1 of the bicycle rear sprocket assembly 14 in a state in which the bicycle rear hub assembly 12 is mounted to the bicycle frame BF. The second axial frame abutment surface 30C1 is configured to abut against the second portion BF22 of the bicycle frame BF in the axial direction D2 in a state in which the bicycle rear hub assembly 12 is mounted to the bicycle frame BF. The first axial frame abutment surface 30B1 is positioned closer to the sprocket support body 28 in the axial direction D2 than the second axial frame abutment surface 30C1. The sprocket support body 28 is disposed between the first axial frame abutment surface 30B1 and the second axial frame abutment surface 30C1 in the axial direction D2.

The hub axle 30 includes a second axial length AL2, the second axial length AL2 being defined between the first axial frame abutment surface 30B1 and the second axial frame abutment surface 30C1 in the axial direction D2. The second axial length AL2 may be equal to or greater than 140mm. The second axial length AL2 may be equal to or greater than 145mm. The second axial length AL2 may be equal to or greater than 147mm. The second axial length AL2 may be 148mm. However, the second axial length AL2 is not limited to this embodiment and the above-described range. Examples of the second axial length AL2 include 142mm, 148mm, and 157mm.

The ratio of the first axial length AL1 to the second axial length AL2 may be equal to or greater than 0.3. The ratio of the first axial length AL1 to the second axial length AL2 may be equal to or greater than 0.4. The ratio of the first axial length AL1 to the second axial length AL2 may be equal to or less than 0.5. For example, the ratio of the first axial length AL1 (67 mm) to the second axial length AL2 (148 mm) is about 0.45. However, the ratio of the first axial length AL1 to the second axial length AL2 is not limited to this embodiment and the above-described range. Examples of ratios of the first axial length AL1 to the second axial length AL2 include about 0.42 (AL 1 is 62.3mm and AL2 is 148 mm), or about 0.39 (AL 1 is 55.7mm and AL2 is 142 mm).

As shown in fig. 6, the sprocket support body 28 includes a first axial end 28B, a second axial end 28C and an axial sprocket abutment surface 28D. The second axial end 28C is opposite the first axial end 28B in the axial direction D2. The axial center plane CPL bisects the second axial length AL2 in the axial direction D2. The axial sprocket abutment surface 28D is located closer to the axial center plane CPL of the bicycle rear hub assembly 12 than the first axial end portion 28B in the axial direction D2. The second axial end 28C is positioned closer to the axial center plane CPL of the bicycle rear hub assembly 12 than the axial sprocket abutment surface 28D in the axial direction D2. In this embodiment, the axial sprocket abutment surface 28D is provided on the larger diameter portion 42, however, the axial sprocket abutment surface 28D may be provided on other portions of the bicycle rear hub assembly 12 as desired. The axial sprocket abutment surface 28D contacts the bicycle rear sprocket assembly 14 in a state in which the bicycle rear sprocket assembly 14 is mounted on the sprocket support body 28. The axial sprocket abutment surface 28D faces the first axial end 28B in the axial direction D2.

As shown in fig. 6, the sprocket arrangement axial length AL3 is defined in the axial direction D2 between the first axial frame abutment surface 30B1 and the axial sprocket abutment surface 28D of the sprocket support body 28. In this embodiment, the sprocket arrangement axial length AL3 ranges from 35mm to 45mm. For example, the sprocket arrangement axial length AL3 is 39.64mm. For example, the sprocket arrangement axial length AL3 may also extend to 44.25mm by omitting the larger diameter portion 42. However, the sprocket arrangement axial length AL3 is not limited to this embodiment and the above-described ranges.

The larger diameter portion 42 has an axial end 42A that is furthest from the first axial frame abutment surface 30B1 in the axial direction D2. The additional axial length AL4 is defined in the axial direction D2 from the first axial frame abutment surface 30B1 to the axial end 42A. The additional axial length AL4 ranges from 38mm to 47mm. The additional axial length AL4 may range from 44mm to 45mm. The additional axial length AL4 may also range from 40mm to 41mm. In this embodiment, the additional axial length AL4 is 44.25mm. However, the additional axial length AL4 is not limited to this embodiment and the above-described ranges.

The larger diameter axial length AL5 of the larger diameter portion 42 ranges from 3mm to 6mm. In this embodiment, the larger diameter axial length AL5 is 4.61mm. However, the larger diameter axial length AL5 is not limited to this embodiment and the above-described range.

The ratio of the first axial length AL1 to the sprocket arrangement axial length AL3 ranges from 1.2 to 1.7. For example, if the first axial length AL1 is 55.7mm and the sprocket arrangement axial length AL3 is 39.64mm, the ratio of the first axial length AL1 to the sprocket arrangement axial length AL3 is 1.4. However, the ratio of the first axial length AL1 to the sprocket arrangement axial length AL3 is not limited to this embodiment and the above-described ranges. For example, if the first axial length AL1 is 62.3mm and the sprocket placement axial length AL3 is 39.64mm, the ratio of the first axial length AL1 to the sprocket placement axial length AL3 may be 1.57, or if the first axial length AL1 is 67mm and the sprocket placement axial length AL3 is 39.64mm, the ratio of the first axial length AL1 to the sprocket placement axial length AL3 may be 1.69.

As shown in fig. 30, the sprocket support member 37 includes a hub engagement portion 60 and a plurality of support arms 62. A plurality of support arms 62 extend radially outwardly from the hub interface 60. The support arm 62 includes first to eighth attachment portions 62A to 62H. The plurality of spacers 38 includes a plurality of first spacers 38A, a plurality of second spacers 38B, a plurality of third spacers 38C, a plurality of fourth spacers 38D, a plurality of fifth spacers 38E, a plurality of sixth spacers 38F, and a plurality of seventh spacers 38G.

As shown in fig. 6, the first spacer 38A is disposed between the additional sprockets SP5 and SP 6. The second spacer 38B is disposed between the additional sprockets SP6 and SP 7. The third spacer 38C is disposed between the additional sprockets SP7 and SP 8. The fourth spacer 38D is disposed between the additional sprockets SP8 and SP 9. The fifth spacer 38E is disposed between the additional sprockets SP9 and SP 10. The sixth spacer 38F is disposed between the additional sprockets SP10 and SP 11. The seventh spacer 38G is disposed between the additional sprockets SP11 and SP 12.

The additional sprocket SP6 and the first spacer 38A are attached to the first attachment portion 62A by an adhesive 37A. The additional sprocket SP7 and the second spacer 38B are attached to the second attachment portion 62B by an adhesive 37A. The additional sprocket SP8 and the third spacer 38C are attached to the third attachment portion 62C by an adhesive 37A. The additional sprocket SP9 and the fourth spacer 38D are attached to the fourth attachment portion 62D by an adhesive 37A. The additional sprocket SP10 and the fifth spacer 38E are attached to the fifth attachment portion 62E by an adhesive 37A. The additional sprocket SP11 and the sixth spacer 38F are attached to the sixth attachment portion 62F by an adhesive 37A. The additional sprocket SP12 and the seventh spacer 38G are attached to the seventh attachment portion 62G by an adhesive 37A. The additional sprocket SP5 and the second ring 38B are attached to the eighth attachment portion 62H by an adhesive 37A. The hub engaging portion 60, the sprockets SP1 to SP4, the first ring 39A and the second ring 39B are held between the larger diameter portion 42 and the radial projection 32C of the locking member 32 in the axial direction D2.

In this embodiment, each of the sprockets SP1 to SP12 is made of a metal material such as aluminum, iron or titanium. The sprocket support member 37 is made of a nonmetallic material including a resin material. Each of the first to seventh spacers 38A to 38G, the first ring 39A, and the second ring 39B is made of a nonmetallic material such as a resin material. However, at least one of the sprockets SP1 to SP12 can be at least partially made of a non-metallic material. At least one of the sprocket support member 37, the first through seventh spacers 38A through 38G, the first ring 39A and the second ring 39B may be at least partially made of a metallic material such as aluminum, iron or titanium.

As shown in fig. 7, the first sprocket SP1 includes a first opening SP1K. The first opening SP1K has a first minimum diameter MD1. As seen in fig. 31, in a state in which the bicycle rear sprocket assembly 14 is mounted to the sprocket support body 28, the tubular body 32A of the locking member 32 extends through the first opening SP1K of the first sprocket SP 1. The first opening SP1K of the first sprocket SP1 is configured such that the first axial end 32D of the tubular body 32A of the locking member 32 passes through the first opening SP1K of the first sprocket SP1 in a state in which the bicycle rear sprocket assembly 14 is mounted to the sprocket support body 28. The first axial end 28B of the sprocket support body 28 is spaced apart from the first opening SP1K of the first sprocket SP1 without extending through the first opening SP1K. The first minimum diameter MD1 is smaller than the minimum outer diameter MD28 of the sprocket support body 28 of the bicycle rear hub assembly 12. In this embodiment, the minimum outer diameter MD28 is equal to the outer spline bottom diameter DM12 (FIG. 26) of the plurality of outer spline teeth 40 of the sprocket support body 28.

As shown in fig. 31, the tubular body 32A has a first outer diameter ED1 equal to or smaller than 27 mm. The first outer diameter ED1 is equal to or greater than 26mm. The radial protrusion 32C has a second outer diameter ED2 equal to or smaller than 32 mm. The second outer diameter ED2 is equal to or greater than 30mm. In this embodiment, the first outer diameter ED1 is 26.2mm. The second outer diameter ED2 is 30.8mm. However, at least one of the first outer diameter ED1 and the second outer diameter ED2 is not limited to this embodiment and the above-described range.

The radial projection 32C has an axial width ED3 defined along the axial direction D2. For example, the axial width ED3 of the radial protrusion 32C is 2mm. However, the axial width ED3 is not limited to this embodiment.

The locking member 32 has an axial length ED4 defined in the axial direction D2 from the radial projection 32C to the first axial end 32D. The axial length ED4 of the locking member 32 is 10mm. However, the axial length ED4 is not limited to this embodiment.

As shown in fig. 8, the first sprocket SP2 includes a first opening SP2K. That is, the plurality of first sprockets SP1 and SP2 each include a first opening. The first opening SP2K has a first minimum diameter MD2. As seen in fig. 31, in a state in which the bicycle rear sprocket assembly 14 is mounted to the sprocket support body 28, the tubular body 32A of the locking member 32 extends through the first opening SP2K of the first sprocket SP 2. The first axial end 28B of the sprocket support body 28 is spaced apart from the first opening SP2K of the first sprocket SP2 without extending through the first opening SP2K. The first minimum diameter MD2 is smaller than the minimum outer diameter MD28 of the sprocket support body 28 of the bicycle rear hub assembly 12.

As shown in fig. 9, the second sprocket SP3 includes a second opening SP3K. The second opening SP3K has a second minimum diameter MD3. As seen in fig. 31, in a state in which the bicycle rear sprocket assembly 14 is mounted to the sprocket support body 28, the tubular body 32A of the locking member 32 and the sprocket support body 28 extend through the second opening SP3K of the second sprocket SP 3. The first axial end 28B of the sprocket support body 28 is disposed between the second opening SP3K and the first opening SP1K in the axial direction D2. The first axial end 28B of the sprocket support body 28 is disposed between the second opening SP3K and the first opening SP2K in the axial direction D2. The second minimum diameter MD3 is equal to or greater than the minimum outer diameter MD28 of the sprocket support body 28 of the bicycle rear hub assembly 12.

As shown in fig. 10, the second sprocket SP4 includes a second opening SP4K. That is, the plurality of second sprockets SP3 and SP4 each include a second opening. The second opening SP4K has a second minimum diameter MD4. As seen in fig. 31, in a state in which the bicycle rear sprocket assembly 14 is mounted to the sprocket support body 28, the sprocket support body 28 extends through the second opening SP4K of the second sprocket SP 4. The first axial end 28B of the sprocket support body 28 is disposed between the second opening SP4K and the first opening SP1K in the axial direction D2. The second minimum diameter MD4 is equal to or greater than the minimum outer diameter MD28 of the sprocket support body 28 of the bicycle rear hub assembly 12.

As shown in fig. 32, the first sprocket SP2 includes at least ten internal spline teeth 63 configured to engage the sprocket support body 28 of the bicycle rear drum assembly 12. At least ten internal spline teeth 63 are provided to the first opening SP2K. At least ten internal spline teeth 63 are provided as a first torque transmitting structure of the first sprocket SP2, as described below.

The total number of at least ten internal spline teeth 63 of the first sprocket SP2 is equal to or greater than 20. The total number of at least ten internal spline teeth 63 of the first sprocket SP2 is equal to or greater than 28. The total number of internal spline teeth 63 is equal to or less than 72. In this embodiment, the total number of internal spline teeth 63 is 29. However, the total number of the internal spline teeth 63 is not limited to this embodiment and the above-described range.

As shown in fig. 9, the second sprocket SP3 includes at least ten internal spline teeth 64 configured to engage the sprocket support body 28 of the bicycle rear drum assembly 12. In this embodiment, at least ten of the internal spline teeth 64 of the second sprocket SP3 define the second minimum diameter MD3 as the internal spline crest diameter of at least ten of the internal spline teeth 64.

The total number of at least ten internal spline teeth 64 of the second sprocket SP3 is equal to or greater than 20. The total number of at least ten internal spline teeth 64 of the second sprocket SP3 is equal to or greater than 28. The total number of internal spline teeth 64 is equal to or less than 72. In this embodiment, the total number of internal spline teeth 64 is 29. However, the total number of internal spline teeth 64 is not limited to this embodiment and the above-described ranges.

As shown in fig. 10, the second sprocket SP4 includes at least ten internal spline teeth 65 configured to engage the sprocket support body 28 of the bicycle rear drum assembly 12. That is, the plurality of second sprockets SP3 and SP4 each include at least ten internal spline teeth configured to engage with the sprocket support body 28 of the bicycle rear hub assembly 12. In this embodiment, at least ten of the internal spline teeth 65 of the second sprocket SP4 define the second minimum diameter MD4 as the internal spline crest diameter of at least ten of the internal spline teeth 65.

The total number of at least ten internal spline teeth 65 of the second sprocket SP4 is equal to or greater than 20. The total number of at least ten internal spline teeth 65 of the second sprocket SP4 is equal to or greater than 28. The total number of internal spline teeth 65 is equal to or less than 72. In this embodiment, the total number of internal spline teeth 65 is 29. However, the total number of the internal spline teeth 65 is not limited to this embodiment and the above-described range.

As shown in fig. 33, at least ten internal spline teeth 64 of the second sprocket SP3 have a first pitch angle PA21 and a second pitch angle PA22. At least two of the at least ten internal spline teeth 64 of the second sprocket SP3 are circumferentially arranged at a first internal pitch angle PA21 with respect to the rotational center axis A1 of the bicycle rear sprocket assembly 14. At least two of the at least ten internal spline teeth 64 are adjacent to each other in the circumferential direction D1 without additional spline teeth therebetween. In other words, at least two of the plurality of internal spline teeth 64 are circumferentially arranged at a first internal pitch angle PA21 relative to the rotational center axis A1 of the bicycle rear sprocket assembly 14. At least two other of the at least ten internal spline teeth 64 of the second sprocket SP3 are circumferentially arranged at a second internal pitch angle PA22 with respect to the rotational center axis A1. At least two other of the at least ten internal spline teeth 64 of the second sprocket SP3 are adjacent to each other in the circumferential direction D1 without additional spline teeth therebetween. In other words, at least two of the plurality of internal spline teeth 64 of the second sprocket SP3 are circumferentially arranged at the second internal pitch angle PA22 with respect to the rotational center axis A1. In this embodiment, the second pitch angle PA22 is different from the first pitch angle PA21. However, the second pitch angle PA22 may be substantially equal to the first pitch angle PA21.

In this embodiment, the internal spline teeth 64 are circumferentially arranged at a first internal pitch angle PA21 in the circumferential direction D1. The two internal spline teeth of the internal spline teeth 64 are arranged at the second internal pitch angle PA22 in the circumferential direction D1. However, at least two of the internal spline teeth 64 may be arranged at another internal pitch angle in the circumferential direction D1.

The first internal pitch angle PA21 ranges from 5 degrees to 36 degrees. The first internal pitch angle PA21 ranges from 10 degrees to 20 degrees. The first internal pitch angle PA21 is equal to or smaller than 15 degrees. In this embodiment, for example, the first internal tooth pitch angle PA21 is 12 degrees. However, the first internal tooth pitch angle PA21 is not limited to this embodiment and the above-described range.

The second internal pitch angle PA22 ranges from 5 degrees to 36 degrees. In this embodiment, the second internal pitch angle PA22 is 24 degrees. However, the second internal tooth pitch angle PA22 is not limited to this embodiment and the above-described range.

At least one of the at least ten internal spline teeth 64 of the second sprocket SP3 has a first spline shape that is different from a second spline shape of another one of the at least ten internal spline teeth 64. At least one of the at least ten internal spline teeth 64 of the second sprocket SP3 has a first spline size that is different from a second spline size of another one of the at least ten internal spline teeth 64. At least one of the at least ten internal spline teeth 64 has a cross-sectional shape that is different from the cross-sectional shape of another one of the at least ten internal spline teeth 64. However, as shown in fig. 34, the internal spline teeth 64 may have the same shape as each other. At least ten internal spline teeth 64 may have the same dimensions as one another. At least ten internal spline teeth 64 may have the same cross-sectional shape as each other.

As shown in fig. 35, at least one of the at least ten internal spline teeth 64 includes an internal spline drive surface 66. At least one of the at least ten internal spline teeth 64 includes an internal spline non-drive surface 68. At least ten of the internal spline teeth 64 include a plurality of internal spline drive surfaces 66 to receive a driving rotational force F1 from the bicycle rear hub assembly 12 (FIG. 6) during pedaling. At least ten of the internally splined teeth 64 include a plurality of internally splined non-driving surfaces 68. The internally splined drive surface 66 is contactable with the sprocket support body 28 to transfer the drive rotational force F1 from the sprocket SP1 to the sprocket support body 28 during pedaling. The internally splined drive surface 66 faces the drive rotational direction D11. In a state in which the bicycle rear sprocket assembly 14 is mounted to the bicycle rear drum assembly 12, the internal spline drive surface 66 faces the external spline drive surface 48 of the bicycle rear drum assembly 12. The internally splined non-drive surface 68 is disposed on an opposite side of the circumferential direction D1 of the internally splined drive surface 66. The internally splined non-drive surface 68 faces in the opposite rotational direction D12 and the drive rotational force F1 is not transferred from the sprocket SP1 to the sprocket support body 28 during pedaling. In the state in which the bicycle rear sprocket assembly 14 is mounted to the bicycle rear drum assembly 12, the internally splined non-driving surface 68 faces the externally splined non-driving surface 50 of the bicycle rear drum assembly 12.

At least ten internal spline teeth 64 each have a circumferential maximum width MW2. The plurality of internal spline teeth 64 each have a circumferential maximum width MW2. The circumferential maximum width MW2 is defined as the maximum width that receives the thrust force F3 applied to the internal spline teeth 64. The circumferential maximum width MW2 is defined as the linear distance based on the internal spline drive surface 66.

The plurality of internally splined drive surfaces 66 each include a radially outermost edge 66A and a radially innermost edge 66B. The second reference circle RC21 is defined on the radially outermost edge 66A and is centered on the rotation center axis A1. The second reference circle RC21 intersects the internally splined non-driving surface 68 at reference point 68R. The circumferential maximum width MW2 extends linearly in the circumferential direction D1 from the radially innermost edge 66B to the reference point 68R.

The internally splined non-drive surface 68 includes a radially outermost edge 68A and a radially innermost edge 68B. The internally splined non-drive surface 68 extends from a radially outermost edge 68A to a radially innermost edge 68B. The reference point 68R is disposed between the radially outermost edge 68A and the radially innermost edge 68B.

The sum of the circumferential maximum widths MW2 is equal to or greater than 40mm. The sum of the circumferential maximum widths MW2 may be equal to or greater than 45mm. The sum of the circumferential maximum widths MW2 may be equal to or greater than 50mm. In this embodiment, the sum of the circumferential maximum widths MW2 is 50.8mm. However, the sum of the circumferential maximum widths MW2 is not limited to this embodiment.

As shown in fig. 36, at least ten of the internal spline teeth 64 of the second sprocket SP3 have an internal spline bottom diameter DM21. At least one of the internal spline teeth 64 of the second sprocket SP3 has an internal spline root circle RC22, the internal spline root circle RC22 having an internal spline bottom diameter DM21. The internal spline bottom diameter DM21 is equal to or less than 34mm. The internal spline bottom diameter DM21 of the second sprocket SP3 is equal to or less than 33mm. The internal spline bottom diameter DM21 of the second sprocket SP3 is equal to or greater than 29mm. In this embodiment, the internal spline bottom diameter DM21 of the second sprocket SP3 is 32.8mm. However, the internal spline bottom diameter DM21 of the second sprocket SP3 is not limited to this embodiment and the above-described range.

At least ten of the internal spline teeth 64 of the second sprocket SP3 have an internal spline crest diameter DM22, and the internal spline crest diameter DM22 is equal to or less than 32mm. The internal spline crest diameter DM22 is equal to or less than 31mm. The internal spline crest diameter DM22 is equal to or greater than 25mm. The internal spline crest diameter DM22 is equal to or greater than 28mm. In this embodiment, the internal spline crest diameter DM22 is 30.4mm. However, the internal spline crest diameter DM22 is not limited to this embodiment and the above-described range.

As shown in fig. 18, the additional sprocket SP12 has a maximum tooth top diameter TD12. The maximum tooth crest diameter TD12 is the maximum outer diameter defined by the plurality of sprocket teeth SP 12B. The ratio of the internal spline bottom diameter DM21 (fig. 36) to the maximum tooth top diameter TD12 ranges from 0.15 to 0.18. In this embodiment, the ratio of the internal spline bottom diameter DM21 to the maximum tooth top diameter TD12 is 0.15. However, the ratio of the internal spline bottom diameter DM21 to the maximum tooth top diameter TD12 is not limited to this embodiment and the above range.

As shown in fig. 35, the plurality of internally splined drive surfaces 66 includes a radially outermost edge 66A and a radially innermost edge 66B. The plurality of internally splined drive surfaces 66 each include a radial length RL21 defined from a radially outermost edge 66A to a radially innermost edge 66B. The sum of the radial lengths RL21 of the plurality of internal spline drive surfaces 66 is equal to or greater than 7mm. The sum of the radial lengths RL21 is equal to or greater than 10mm. The sum of the radial lengths RL21 is equal to or greater than 15mm. The sum of the radial lengths RL21 is equal to or less than 36mm. In this embodiment, the sum of the radial lengths RL21 is 16.6mm. However, the sum of the radial lengths RL21 is not limited to this embodiment and the above-described range.

The plurality of internal spline teeth 64 have an additional radial length RL22. The additional radial lengths RL22 are defined from the internal spline root circles RC22 to the radially innermost ends 64A of the plurality of internal spline teeth 64, respectively. The sum of the additional radial lengths RL22 is equal to or greater than 12mm. In this embodiment, the sum of the additional radial lengths RL22 is 34.8mm. However, the sum of the additional radial lengths RL22 is not limited to this embodiment and the above-described ranges.

At least one of the at least ten internal spline teeth 64 of the second sprocket SP3 is circumferentially symmetrical about the reference line CL 2. The reference line CL2 extends from the rotational center axis A1 to a circumferential center point CP2 of the radially innermost end 64A of at least one of the at least ten internal spline teeth 64 in a radial direction with respect to the rotational center axis A1. However, at least one of the internal spline teeth 64 may have an asymmetric shape with respect to the reference line CL 2. At least one of the internally splined teeth 64 includes an internally splined drive surface 66 and an internally splined non-drive surface 68.

The internally splined drive surface 66 has a first internally splined surface angle AG21. A first internal spline surface angle AG21 is defined between the internal spline drive surface 66 and the first radial line L21. The first radial line L21 extends from the rotational center axis A1 of the bicycle rear sprocket assembly 14 to the radially outermost edge 66A of the inner spline drive surface 66. The first or second pitch angle PA21 or PA22 is defined between adjacent first radial lines L21 (see, for example, fig. 33).

The internally splined non-drive surface 68 has a second internally splined surface angle AG22. A second internal spline surface angle AG22 is defined between the internal spline non-drive surface 68 and the second radial line L22. The second radial line L22 extends from the rotational center axis A1 of the bicycle rear sprocket assembly 14 to a radially outermost edge 68A of the inner spline non-drive surface 68.

In this embodiment, the second internal spline surface angle AG22 is equal to the first internal spline surface angle AG21. However, the first internal spline surface angle AG21 may be different from the second internal spline surface angle AG22.

The first internal spline surface angle AG21 ranges from 0 degrees to 6 degrees. The second internal spline surface angle AG22 ranges from 0 degrees to 6 degrees. In this embodiment, the first internal spline surface angle AG21 is 5 degrees. The second internal spline surface angle AG22 is 5 degrees. However, the first internal spline surface angle AG21 and the second internal spline surface angle AG22 are not limited to this embodiment and the above ranges.

As shown in fig. 37, the internal spline teeth 64 mesh with the external spline teeth 40 to transmit the driving rotational force F1 from the second sprocket SP3 to the sprocket support body 28. The internally splined drive surface 66 is contactable with the externally splined drive surface 48 to transfer the driving rotational force F1 from the second sprocket SP3 to the sprocket support body 28. The internally splined non-driving surface 68 is spaced from the externally splined non-driving surface 50 in a state where the internally splined driving surface 66 is in contact with the externally splined driving surface 48.

The inner spline teeth 63 of the first sprocket SP2 and the inner spline teeth 65 of the second sprocket SP4 have substantially the same structure as the inner spline teeth 64 of the second sprocket SP 3. Therefore, for the sake of brevity, this will not be described in detail herein.

As shown in fig. 2, the sprocket support member 37 includes at least ten internal spline teeth 76 configured to engage the sprocket support body 28 of the bicycle rear hub assembly 12. The plurality of internal spline teeth 76 have substantially the same structure as the plurality of internal spline teeth 64. Therefore, for the sake of brevity, this will not be described in detail herein.

As shown in fig. 38, the first sprocket SP1 includes a first torque transmitting structure SP1T that is provided to the first inward facing side SP1H to directly or indirectly transmit pedaling torque to the sprocket support body 28. In this embodiment, the first torque transmitting structure SP1T includes a plurality of first torque transmitting teeth SP1T1 to indirectly transmit the pedaling torque to the sprocket support body 28. The first torque transmitting structure SP1T includes at least ten first torque transmitting teeth SP1T1. Preferably, the total of at least ten first torque transmitting teeth SP1T1 is equal to or greater than 20. More preferably, the total of at least ten first torque transmitting teeth SP1T1 is equal to or greater than 28. In this embodiment, the total number of at least ten first torque transmitting teeth SP1T1 is 29. However, the total number of at least ten first torque transmitting teeth SP1T1 is not limited to this embodiment and the above-described ranges.

As shown in fig. 38 and 39, the first sprocket SP2 includes a first inward facing side SP2H and a first outward facing side SP2G. The first outward facing side SP2G is opposite the first inward facing side SP2H in an axial direction D2 with respect to the rotational center axis A1 of the bicycle rear sprocket assembly 14. The first sprocket SP2 includes a first torque transmitting structure SP2M that is provided to the first inward facing side SP2H to directly or indirectly transmit the pedaling torque to the sprocket support body 28. In this embodiment, the internal spline teeth 63 of the first sprocket SP2 may also be referred to as first torque transmitting teeth 63. The first torque transmitting structure SP2M includes a plurality of first torque transmitting teeth 63 to transmit pedaling torque directly to the sprocket support body 28. The first torque transmitting structure SP2M includes at least ten first torque transmitting teeth 63. Preferably, the total number of at least ten first torque transmitting teeth 63 is equal to or greater than 20. More preferably, the total number of at least ten first torque transmitting teeth 63 is equal to or greater than 28. In this embodiment, the total number of at least ten first torque transmitting teeth 63 is 29. However, the total number of at least ten first torque transmitting teeth 63 is not limited to this embodiment and the above-described ranges. The first torque transmitting teeth 63 may also be referred to as internal spline teeth 63.

As shown in fig. 39, the first sprocket SP2 includes a second torque transmitting structure SP2T to receive the pedaling torque from the first sprocket SP 1. The second torque transmitting structure SP2T is disposed on a first outward facing side SP 2G. In this embodiment, the second torque transmitting structure SP2T includes a plurality of second torque transmitting teeth SP2T1. Preferably, the total number of second torque transmitting teeth SP2T1 is equal to or greater than 20. More preferably, the total number of second torque transmitting teeth SP2T1 is equal to or greater than 28. In this embodiment, the total number of second torque transmitting teeth SP2T1 is 29. However, the total number of the second torque transmitting teeth SP2T1 is not limited to this embodiment and the above-described range. The first torque transmitting structure SP1T is engaged with the second torque transmitting structure SP 2T. The plurality of first torque transmitting teeth SP1T1 mesh with the plurality of second torque transmitting teeth SP2T1 to transmit the driving rotational force F1.

As shown in fig. 23 and 24, the sprocket support body 28 includes a hub indicator 28I provided at an axial end of the base support 41. The hub indicator 28I is disposed in the region of the second outside pitch angle PA12 when viewed along the rotational center axis A1. In this embodiment, the hub indicator 28I includes a dot. However, the hub indicator 28I may include other shapes such as triangles and lines. Further, the hub indicator 28I may be a separate member attached to the sprocket support body 28, for example, by a bonding structure such as an adhesive. The position of the drum indicator 28I is not limited to this embodiment.

As shown in fig. 7, the first sprocket SP1 includes a sprocket indicator SP1I provided at an axial end of the sprocket body SP 1A. In this embodiment, the sprocket indicator SP1I includes a dot. However, the sprocket indicator SP1I may include other shapes such as triangles and lines. Further, the sprocket indicator SP1I may be a separate member attached to the sprocket SP1, for example, by a bonding structure such as an adhesive. The position of the sprocket indicator SP1I is not limited to this embodiment. The sprocket indicator SP1I may be provided to any one of the other sprockets SP2 to SP 12. The sprocket indicator SP1I may also be provided to the sprocket support member 37.

As shown in FIG. 6, the bicycle rear hub assembly 12 further includes a freewheel structure 78. Sprocket support body 28 is operatively coupled to hub body 36 by freewheel structure 78. The freewheel structure 78 is configured to couple the sprocket support body 28 to the hub body 36 to rotate the sprocket support body 28 with the hub body 36 in a drive rotational direction D11 (fig. 5) during pedaling. The freewheel structure 78 is configured to allow the sprocket support body 28 to rotate in an opposite rotational direction D12 (fig. 5) relative to the hub body 36 during coasting. Thus, the flywheel structure 78 may be interpreted as a one-way clutch structure 78. The flywheel structure 78 will be described in detail below.

The bicycle rear hub assembly 12 includes a first bearing 79A and a second bearing 79B. The first bearing 79A and the second bearing 79B are provided between the sprocket support body 28 and the hub axle 30 to rotatably support the sprocket support body 28 about the rotational center axis A1 with respect to the hub axle 30.

In this embodiment, each of the sprocket support body 28, the brake rotor support body 34 and the hub body 36 is made of a metallic material such as aluminum, iron or titanium. However, at least one of the sprocket support body 28, the brake rotor support body 34 and the hub body 36 may be made of a non-metallic material.

As shown in fig. 40, the flywheel structure 78 includes a first ratchet member 80 and a second ratchet member 82. The first ratchet member 80 is configured to be torque transmitting engaged with one of the hub body 36 and the sprocket support body 28. The second ratchet member 82 is configured to be torque transmitting engaged with the other of the hub body 36 and the sprocket support body 28. In this embodiment, the first ratchet member 80 is in torque transmitting engagement with the sprocket support body 28. The second ratchet member 82 is in torque transmitting engagement with the hub body 36. However, the first ratchet member 80 may be configured to engage the hub body 36 in a torque-transmitting manner. The second ratchet member 82 may be configured to engage the sprocket support body 28 in a torque transmitting manner.

The first ratchet member 80 is mounted to the sprocket support body 28 for rotation with the sprocket support body 28 about the central axis of rotation A1 with respect to the hub body 36. The second ratchet member 82 is mounted to the hub body 36 for rotation with the hub body 36 about the central axis of rotation A1 relative to the sprocket support body 28. Each of the first ratchet member 80 and the second ratchet member 82 has an annular shape.

At least one of the first ratchet member 80 and the second ratchet member 82 is movable relative to the hub axle 30 in an axial direction D2 about the rotational central axis A1. In this embodiment, each of the first ratchet member 80 and the second ratchet member 82 is movable in the axial direction D2 relative to the hub axle 30. The second ratchet member 82 is movable in the axial direction D2 relative to the hub body 36. The first ratchet member 80 is movable in the axial direction D2 relative to the sprocket support body 28.

The hub body 36 includes a flywheel housing 36H having an annular shape. The flywheel housing 36H extends in the axial direction D2. The first ratchet member 80 and the second ratchet member 82 are disposed in the flywheel housing 36H in an assembled state.

As shown in fig. 41, the first ratchet member 80 includes at least one first ratchet tooth 80A. In this embodiment, the at least one first ratchet tooth 80A includes a plurality of first ratchet teeth 80A. The plurality of first ratchet teeth 80A are arranged in the circumferential direction D1 to provide serrations.

As shown in fig. 42, the second ratchet member 82 includes at least one second ratchet tooth 82A configured to engage in torque transmitting manner with at least one first ratchet tooth 80A. The at least one second ratchet tooth 82A engages the at least one first ratchet tooth 80A to transfer the rotational force F1 from the sprocket support body 28 to the hub body 36 (fig. 40). In this embodiment, the at least one second ratchet tooth 82A includes a plurality of second ratchet teeth 82A configured to engage the plurality of first ratchet teeth 80A in a torque transmitting manner. The plurality of second ratchet teeth 82A are arranged in the circumferential direction D1 to provide serrations. The second plurality of ratchet teeth 82A are engageable with the first plurality of ratchet teeth 80A. In a state where the second ratchet teeth 82A are engaged with the first ratchet teeth 80A, the first ratchet member 80 and the second ratchet member 82 rotate together.

As shown in fig. 41 and 42, the sprocket support body 28 has an outer peripheral surface 28P, and the outer peripheral surface 28P has a first helical spline 28H. The first ratchet member 80 is configured to be torque-transmitting engaged with the sprocket support body 28 and includes a second helical spline 80H that mates with the first helical spline 28H. During driving by the first thrust force applied from the sprocket support body 28, the first ratchet member 80 is movably mounted relative to the sprocket support body 28 in the axial direction D2 via the cooperation of the second helical spline 80H with the first helical spline 28H. In this embodiment, the first helical spline 28H includes a plurality of helical external spline teeth 46. The second helical spline 80H includes a plurality of helical internal spline teeth 80H1 that mate with the plurality of helical external spline teeth 46.

As shown in fig. 43, the hub body 36 includes an inner peripheral surface 36S and at least one first tooth 36T. At least one first tooth 36T is provided on the inner peripheral surface 36S. In this embodiment, the flywheel housing 36H includes an inner peripheral surface 36S. The hub body 36 includes a plurality of first teeth 36T. The plurality of first teeth 36T are provided on the inner peripheral surface 36S, and extend radially inward from the inner peripheral surface 36S with respect to the rotation center axis A1. The first teeth 36T are arranged in the circumferential direction D1 to define a plurality of recesses 36R between adjacent two of the first teeth 36T.

The second ratchet member 82 includes a drum body engagement portion 82E, with the drum body engagement portion 82E being torsionally engaged with the drum body 36 to transmit the rotational force F1 from the first ratchet member 80 to the drum body 36 via the drum body engagement portion 82E. One of the hub body engagement portion 82E and the hub body 36 includes at least one radially extending projection. The other of the hub body engagement portion 82E and the hub body 36 includes at least one recess that engages with at least one projection. In this embodiment, the hub body engagement portion 82E includes at least one projection 82T extending radially as at least one projection. The hub body 36 includes at least one recess 36R that engages with at least one projection 82T. In this embodiment, the hub body engagement portion 82E includes a plurality of projections 82T. The plurality of projections 82T engage with the plurality of recesses 36R.

As shown in fig. 42, the outer peripheral surface 28P of the sprocket support body 28 has a guide portion 28G configured to guide the first ratchet member 80 toward the hub body 36 during coasting. The pilot portion 28G is arranged to define an obtuse angle AG28 (fig. 48) with the first helical spline 28H. The sprocket support body 28 includes a plurality of guide portions 28G. The guide portion 28G is configured to guide the first ratchet member 80 toward the hub body 36 during coasting or freewheeling. During coasting, guide portion 28G guides first ratchet member 80 toward hub body 36 to release the meshing engagement between at least one first ratchet tooth 80A (fig. 41) and at least one second ratchet tooth 82A. The guide portion 28G is configured to move the first ratchet member 80 away from the second ratchet member 82 in the axial direction D2. The guide portion 28G extends at least in the circumferential direction D1 with respect to the sprocket support body 28. The guide portion 28G extends from one of the plurality of helical external spline teeth 46 at least in the circumferential direction D1. Although the guide portion 28G is integrally provided with the helical external spline teeth 46 as a one-piece, unitary member in this embodiment, the guide portion 28G may be a separate member from the plurality of helical external spline teeth 46. During coasting, the first and second ratchet members 80, 82 smoothly disengage from one another due to the guide portion 28G, particularly if the guide portion 28G is arranged to define an obtuse angle AG28 relative to the first helical spline 28H. This also results in reduced noise during taxiing as the at least one first ratchet tooth 80A and the at least one second ratchet tooth 82A are smoothly separated from each other during taxiing.

As shown in FIG. 40, the bicycle rear hub assembly 12 further includes a biasing member 84. A biasing member 84 is disposed between the hub body 36 and the first ratchet member 80 to bias the first ratchet member 80 toward the second ratchet member 82 in the axial direction D2. In this embodiment, for example, the biasing member 84 is a compression spring.

As shown in fig. 44, the biasing member 84 is compressed between the hub body 36 and the first ratchet member 80 in the axial direction D2. The biasing member 84 biases the first ratchet member 80 toward the second ratchet member 82 to maintain the engaged state in which the first ratchet member 80 and the second ratchet member 82 are engaged with each other via the first ratchet teeth 80A and the second ratchet teeth 82A.

Preferably, the biasing member 84 engages the hub body 36 for rotation with the hub body 36. The biasing member 84 is mounted to the hub body 36 for rotation with the hub body 36 about the central axis of rotation A1 (fig. 40). The biasing member 84 includes a coiled body 84A and a connecting end 84B. The hub body 36 includes a connection hole 36F. The connection end 84B is disposed in the connection hole 36F such that the biasing member 84 rotates together with the hub body 36 about the rotation center axis A1 (fig. 40).

As shown in fig. 44, the outer peripheral surface 28P of the sprocket support body 28 supports a first ratchet member 80 and a second ratchet member 82. The first ratchet member 80 includes an axially facing surface 80S facing in the axial direction D2. At least one first ratchet tooth 80A is provided on an axially facing surface 80S of the first ratchet member 80. In this embodiment, a plurality of first ratchet teeth 80A are provided on an axially facing surface 80S of the first ratchet member 80. The axially facing surface 80S is substantially perpendicular to the axial direction D2. However, the axially facing surface 80S may not be perpendicular to the axial direction D2.

The second ratchet member 82 includes an axial facing surface 82S facing in the axial direction D2. At least one second ratchet tooth 82A is provided on an axially facing surface 82S of the second ratchet member 82. The axially facing surface 82S of the second ratchet member 82 faces the axially facing surface 80S of the first ratchet member 80. In this embodiment, a plurality of second ratchet teeth 82A are provided on an axially facing surface 82S of the second ratchet member 82. The axially facing surface 82S is substantially perpendicular to the axial direction D2. However, the axially facing surface 82S may not be perpendicular to the axial direction D2.

As shown in FIG. 40, the bicycle rear hub assembly 12 includes a spacer 86, a support member 88, a sliding member 90, an additional biasing member 92 and a receiving member 94. However, at least one of the spacer 86, the support member 88, the sliding member 90, the additional biasing member 92 and the receiving member 94 can be omitted from the bicycle rear hub assembly 12.

As shown in fig. 44 and 45, the spacer 86 is at least partially disposed between the at least one first tooth 36T and the at least one protrusion 82T in the circumferential direction D1 defined about the rotational center axis A1. In this embodiment, the spacer 86 is partially disposed between the first tooth 36T and the projection 82T in the circumferential direction D1. However, the spacers 86 may be disposed entirely between the first teeth 36T and the projections 82T in the circumferential direction D1.

As shown in fig. 45-47, the spacer 86 includes at least one intermediate portion 86A disposed between the at least one first tooth 36T and the at least one projection 82T. At least one intermediate portion 86A is disposed between at least one first tooth 36T and at least one protrusion 82T in the circumferential direction D1. In this embodiment, the spacer 86 includes a plurality of intermediate portions 86A disposed between the first teeth 36T and the projections 82T, respectively, in the circumferential direction D1. Although the spacer 86 includes a plurality of intermediate portions 86A in this embodiment, the spacer 86 may include one intermediate portion 86A.

As shown in fig. 46 and 47, the spacer 86 includes a connecting portion 86B. The plurality of intermediate portions 86A extend from the connecting portion 86B in the axial direction D2 parallel to the rotation center axis A1. Although the spacer 86 includes the connection portion 86B in this embodiment, the spacer 86 may omit the connection portion 86B.

The spacer 86 comprises a non-metallic material. In this embodiment, the nonmetallic material includes a resin material. Examples of the resin material include synthetic resins. The nonmetallic material may include materials other than the resin material instead of or in addition to the resin material. Although in this embodiment, the intermediate portion 86A and the connecting portion 86B are integrally provided with each other as a one-piece, unitary member, at least one of the intermediate portions 86A may be a separate portion from the connecting portion 86B.

As shown in fig. 44 and 45, a plurality of intermediate portions 86A are provided between the inner peripheral surface 36S of the hub body 36 and the outer peripheral surface 82P of the second ratchet member 82 in the radial direction.

As shown in fig. 44, the support member 88 is disposed between the hub body 36 and the second ratchet member 82 in the axial direction D2. The support member 88 is attached to the second ratchet member 82. The support member 88 is disposed radially outward of the first ratchet member 80. The support member 88 is contactable with the first ratchet member 80. The support member 88 preferably comprises a non-metallic material. The support member 88, which is made of a non-metallic material, reduces noise during operation of the bicycle rear hub assembly 12. In this embodiment, the nonmetallic material includes a resin material. The nonmetallic material may include materials other than the resin material instead of or in addition to the resin material.

The sliding member 90 is disposed between the sprocket support body 28 and the second ratchet member 82 in an axial direction D2 parallel to the rotational center axis A1. The second ratchet member 82 is disposed between the first ratchet member 80 and the sliding member 90 in the axial direction D2. The sliding member 90 preferably comprises a non-metallic material. The sliding member 90, being made of a non-metallic material, reduces noise during operation of the bicycle rear hub assembly 12. In this embodiment, the nonmetallic material includes a resin material. The nonmetallic material may include materials other than the resin material instead of or in addition to the resin material.

The sprocket support body 28 includes an abutment 28E to abut the second ratchet member 82 to limit axial movement of the second ratchet member 82 away from the hub body 36. In this embodiment, the abutment 28E can indirectly abut the second ratchet member 82 via the sliding member 90. Alternatively, the abutment 28E may directly abut the second ratchet member 82. The first ratchet member 80 is disposed on an axial side of the second ratchet member 82 opposite the abutment 28E of the sprocket support body 28 in the axial direction D2. The sliding member 90 is disposed between the abutment 28E of the sprocket support body 28 and the second ratchet member 82 in the axial direction D2.

As shown in fig. 44, an additional biasing member 92 is disposed between the hub body 36 and the second ratchet member 82 in the axial direction D2 to bias the second ratchet member 82 toward the sprocket support body 28. In this embodiment, the additional biasing member 92 biases the second ratchet member 82 in the axial direction D2 via the support member 88. An additional biasing member 92 is disposed radially outward of the biasing member 84. In this embodiment, an additional biasing member 92 is disposed radially outward of the plurality of second ratchet teeth 82A.

The receiving member 94 comprises a non-metallic material. The receiving member 94 made of a non-metallic material prevents the biasing member 84 from being over twisted during operation of the bicycle rear hub assembly 12. In this embodiment, the nonmetallic material includes a resin material. The nonmetallic material may include materials other than the resin material instead of or in addition to the resin material. The receiving member 94 includes an axial receiving portion 96 and a radial receiving portion 98. The axial receiver 96 is disposed between the first ratchet member 80 and the biasing member 84 in the axial direction D2. The radial receiving portion 98 extends from the axial receiving portion 96 in the axial direction D2. The radial receiving portion 98 is disposed radially inward of the biasing member 84. The axial receiving portion 96 and the radial receiving portion 98 are integrally provided with each other as a one-piece, unitary member. However, the axial receiving portion 96 may be a separate member from the radial receiving portion 98.

As shown in fig. 44, the bicycle rear hub assembly 12 includes a sealing structure 100. A seal structure 100 is disposed between the sprocket support body 28 and the hub body 36. Hub body 36 includes an interior space 102. Each of the sprocket support body 28, the biasing member 84, the first ratchet member 80 and the second ratchet member 82 is at least partially disposed in the interior space 102 of the hub body 36. The interior space 102 is sealed by the sealing structure 100. In this embodiment, no lubricant is disposed in the interior space 102. However, the bicycle rear hub assembly 12 can include a lubricant disposed in the interior space 102. Each gap between the components disposed in the interior space 102 may be reduced if no lubricant is provided, as compared to the case where the bicycle rear hub assembly 12 may include a lubricant disposed in the interior space 102.

The operation of the bicycle rear hub assembly 12 will be described in detail below with reference to fig. 44, 48 and 49.

As shown in fig. 44, the axial direction D2 includes a first axial direction D21 and a second axial direction D22 opposite to the first axial direction D21. The biasing force F5 is applied from the biasing member 84 to the receiving member 94 in the first axial direction D21. The biasing force F5 of the biasing member 84 biases the receiving member 94, the first ratchet member 80, the second ratchet member 82 and the sliding member 90 in the first axial direction D21 toward the sprocket support body 28. This causes the first ratchet tooth 80A to engage the second ratchet tooth 82A.

Further, as shown in fig. 48, when the pedaling torque T1 is input to the sprocket support body 28 in the driving rotation direction D11, the helical inner spline teeth 80H1 are guided by the helical outer spline teeth 46 in the first axial direction D21 with respect to the sprocket support body 28. This firmly engages the first ratchet tooth 80A with the second ratchet tooth 82A. In this state, the pedaling torque T1 is transmitted from the sprocket support body 28 to the hub body 36 (fig. 44) via the first ratchet member 80 and the second ratchet member 82 (fig. 44).

As shown in fig. 48, during coasting, the first ratchet member 80 contacts the guide portion 28G to disengage from the second ratchet member 82 and create a rotational friction force F6 between the biasing member 84 (fig. 44) and the first ratchet member 80. As shown in fig. 49, during coasting, a coasting torque T2 is applied to the hub body 36 in the drive rotation direction D11. The slip torque T2 is transferred from the hub body 36 (fig. 44) to the first ratchet member 80 via the second ratchet member 82 (fig. 44). At this time, the helical inner spline teeth 80H1 are guided in the second axial direction D22 by the helical outer spline teeth 46 with respect to the sprocket support body 28. This causes the first ratchet member 80 to move in the second axial direction D22 relative to the sprocket support body 28 against the biasing force F5. Thus, the first ratchet member 80 moves away from the second ratchet member 82 in the second axial direction D22, resulting in a weakened engagement between the first ratchet teeth 80A and the second ratchet teeth 82A. This allows the second ratchet member 82 to rotate in the driving rotational direction D11 relative to the first ratchet member 80, preventing the sliding torque T2 from being transmitted from the hub body 36 to the sprocket support body 28 via the first ratchet member 80 and the second ratchet member 82. At this time, the first ratchet teeth 80A and the second ratchet teeth 82A slide in the circumferential direction D1.

Variants

As shown in fig. 50, in the above-described embodiment and other variations, the external spline teeth 40 may include grooves 40G disposed between the external spline drive surface 48 and the external spline non-drive surface 50 in the circumferential direction D1. The slot 40G reduces the weight of the bicycle rear drum assembly 12.

As shown in fig. 51, in the above-described embodiment and other variations, the internal spline teeth 64 may include a groove 64G disposed between the internal spline drive surface 66 and the internal spline non-drive surface 68 in the circumferential direction D1. The slots 64G reduce the weight of the bicycle rear sprocket assembly 14.

In the present application, although at least ten internal spline teeth are provided directly to the second opening of each of the second sprockets SP3 and SP4 in the above embodiment, at least ten internal spline teeth may be provided indirectly to the second opening of the second sprocket. For example, instead of providing at least ten internally splined teeth directly to the second openings of the second sprocket SP3 and/or the second sprocket SP4, at least one of the second sprockets SP3 and SP4 can be attached to a sprocket support member that includes at least ten internally splined teeth. Alternatively, instead of providing at least ten internal spline teeth directly to the second opening of the second sprocket, at least one second sprocket may be integrally formed as a one-piece, unitary member with at least one additional sprocket comprising at least ten internal spline teeth. Since such a second sprocket indirectly comprises at least ten internal spline teeth via the sprocket support member and/or the additional sprocket, this also means that the second sprocket comprises at least ten internal spline teeth configured to engage with the sprocket support body of the bicycle rear hub assembly.

Although the bicycle rear sprocket assembly 14 includes two first sprockets SP1 and SP2 in the above-described embodiment, the bicycle rear sprocket assembly 14 can include only one first sprocket or more than two first sprockets.

Although the bicycle rear sprocket assembly 14 includes two second sprockets SP3 and SP4 in the above-described embodiment, the bicycle rear sprocket assembly 14 can include only one second sprocket or more than two second sprockets.

As shown in fig. 52, the total number of at least ten external spline teeth 40 in the sprocket support body 28 can range from 22 to 24. For example, the total number of at least ten external spline teeth 40 may be 23. The first external tooth pitch angle PA11 may range from 13 degrees to 17 degrees. For example, the first external tooth pitch angle PA11 may be 15 degrees. The second outside pitch angle PA12 may range from 28 degrees to 32 degrees. For example, the second outside pitch angle PA12 may be 30 degrees. The first external tooth pitch angle PA11 is half the second external tooth pitch angle PA 12. However, the first external tooth pitch angle PA11 may be different from half of the second external tooth pitch angle PA 12. The total number of at least ten external spline teeth 40 is not limited to the above-described modifications and scope. The first external tooth pitch angle PA11 is not limited to the above-described modifications and ranges. The second outside pitch angle PA12 is not limited to the above-described modifications and ranges.

As shown in fig. 53, in the sprocket support body 28, the sum of the radial lengths RL11 of the plurality of external spline driving surfaces 48 may range from 11mm to 14mm. The sum of the radial lengths RL11 of the plurality of external spline drive surfaces 48 may be 12.5mm. The sum of the additional radial lengths RL12 may range from 26mm to 30mm. For example, the sum of the additional radial lengths RL12 may be 28.2mm. However, the sum of the additional radial lengths RL12 is not limited to the above-described modifications and scope.

As shown in fig. 54, in the first torque transmitting structure SP1T of the first sprocket SP1, the total number of at least ten first torque transmitting teeth SP1T1 may range from 22 to 24. For example, the total number of at least ten first torque transmitting teeth SP1T1 may be 23. However, the total number of at least ten first torque transmitting teeth SP1T1 is not limited to the above-described modifications and ranges.

As shown in fig. 55, in the second torque transmitting structure SP2T of the first sprocket SP2, the total number of at least ten second torque transmitting teeth SP2T1 may range from 22 to 24. For example, the total number of at least ten second torque transmitting teeth SP2T1 may be 23. However, the total number of at least ten second torque transmitting teeth SP2T1 is not limited to the above-described modifications and ranges.

As shown in fig. 56, in the first sprocket SP2, the total number of at least ten internal spline teeth 63 of the first sprocket SP2 may range from 22 to 24. For example, the total number of at least ten internal spline teeth 63 of the first sprocket SP2 may be 23. However, the total number of at least ten internal spline teeth 63 is not limited to the above-described modifications and scope.

As shown in fig. 57, in the second sprocket SP3, the total number of at least ten internal spline teeth 64 of the second sprocket SP3 may range from 22 to 24. For example, the total number of at least ten internal spline teeth 64 of the second sprocket SP3 may be 23. However, the total number of at least ten internal spline teeth 64 is not limited to the above-described modifications and scope.

As shown in fig. 58, in the second sprocket SP4, the total number of at least ten internal spline teeth 65 of the second sprocket SP4 may range from 22 to 24. For example, the total number of at least ten internal spline teeth 65 of the second sprocket SP4 may be 23. However, the total number of at least ten internal spline teeth 65 is not limited to the above-described modifications and scope.

As shown in fig. 59, among at least ten internal spline teeth 64 of the second sprocket SP3, the first internal spline angle PA21 may range from 13 degrees to 17 degrees. For example, the first internal tooth pitch angle PA21 may be 15 degrees. The second internal pitch angle PA22 may range from 28 degrees to 32 degrees. For example, the second internal tooth pitch angle PA22 may be 30 degrees. The first pitch angle PA21 may be half of the second pitch angle PA 22. However, the first pitch angle PA21 may be different from half of the second pitch angle PA 22. The first internal tooth pitch angle PA21 is not limited to the above-described modifications and ranges. The second internal pitch angle PA22 is not limited to the above-described modifications and ranges.

As shown in fig. 60, in the inner spline teeth 64 of the second sprocket SP3, the sum of the radial lengths RL21 of the plurality of inner spline driving surfaces 66 may range from 11mm to 14mm. For example, the sum of the radial lengths RL21 of the plurality of internally-splined drive surfaces 66 may be 12.5mm. However, the sum of the radial lengths RL21 is not limited to the above-described modifications and ranges. The sum of the additional radial lengths RL22 may range from 26mm to 29mm. For example, the sum of the additional radial lengths RL22 is 27.6mm. However, the sum of the additional radial lengths RL22 is not limited to this embodiment and the above-described ranges. The inner spline teeth 63 of the first sprocket SP2 and the inner spline teeth 65 of the second sprocket SP4 have the same structure as the inner spline teeth 64 of the second sprocket SP 3.

As shown in fig. 61, the internal spline teeth 76 of the sprocket support member 37 may have the same structure as that of the internal spline teeth 64 of the second sprocket SP3 illustrated in fig. 57, 59 and 60. The total number of at least ten internal spline teeth 76 of the sprocket support member 37 can range from 22 to 24. For example, the total number of at least ten internal spline teeth 76 of the sprocket support member 37 can be 23. However, the total number of at least ten internal spline teeth 76 is not limited to the above-described modifications and scope. The configuration of the internal spline teeth 64 illustrated in fig. 60 can be applied to the internal spline teeth 76 of the sprocket support member 37.

As shown in FIG. 62, the bicycle rear sprocket assembly 14 can include an additional sprocket SP13. The additional sprocket SP13 is coupled to the additional sprocket SP12 by a plurality of coupling members SP 13R. The additional sprocket SP13 includes a sprocket body SP13A and at least one sprocket tooth SP13B. The sprocket body SP13A of the additional sprocket SP13 is coupled to the sprocket body SP12A of the additional sprocket SP12 by a plurality of coupling members SP 13R. At least one sprocket tooth SP13B extends radially outwardly from the sprocket body SP 13A. The total number of the at least one sprocket SP13B is greater than the total number of the at least one sprocket SP 12B. Preferably, the total number of teeth of at least one sprocket SP13B is equal to or greater than 46. More preferably, the total number of teeth of at least one sprocket SP13B is equal to or greater than 50. For example, the total number of teeth of at least one sprocket SP13B is 54.

The tooth profiles of the sprocket teeth SP1B to SP13B of the sprockets SP1 to SP13 can have conventional gear profiles and/or narrow-wide tooth profiles. Specifically, for a narrow-wide tooth profile, the sprocket teeth SP 1B-SP 13B of the sprockets SP1 to SP13 can further include at least one first tooth each having a first axial maximum chain engagement width and at least one second tooth each having a second axial maximum chain engagement width that is less than the first axial maximum chain engagement width. The first and second axial maximum chain engagement widths are measured along the axial direction D2. The first axial maximum chain engagement width is greater than an axial inner chain distance defined by a pair of inner link plates of the bicycle chain 20 and less than an axial outer chain distance defined by a pair of outer link plates of the bicycle chain 20 that face each other in the axial direction D2 when the bicycle chain 20 is engaged with one of the sprockets SP1 to SP13. The second axial maximum chain engagement width is smaller than the axial inner chain distance defined by the pair of inner link plates of the bicycle chain 20. Thus, the at least one first tooth is configured to engage a pair of outer link plates of the bicycle chain 20 that face each other in the axial direction D2 when the bicycle chain 20 is engaged with one of the sprockets SP1 to SP13, and the at least one second tooth is configured to engage a pair of inner link plates of the bicycle chain 20 that face each other in the axial direction D2. Preferably, at least one first tooth and at least one second tooth are alternately disposed on the outer circumference of at least one of the sprockets SP1 to SP13. Preferably, the sprocket teeth SP1B to SP13B of the sprockets SP1 to SP13 include a plurality of first teeth each having the above-described first axial maximum chain engagement width and a plurality of second teeth each having the above-described second axial maximum chain engagement width. Preferably, a plurality of first teeth and a plurality of second teeth are alternately disposed on the outer circumference of at least one of the sprockets SP1 to SP13. Preferably, the sprocket teeth of the largest sprocket may have such a narrow-wide tooth profile. Therefore, it is preferable that the sprocket tooth SP12B of the sprocket SP12 in fig. 6 or the sprocket tooth SP13B of the sprocket SP13 in fig. 62 include at least one first tooth each having the above-described first axial maximum chain engagement width and at least one second tooth each having the above-described second axial maximum chain engagement width.

The term "comprises/comprising" and its derivatives, as used herein, are intended to be open ended terms that specify the presence of the 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 words of similar meaning, for example, the terms "have," "include," and their derivatives.

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

Ordinal numbers such as "first" and "second" recited in this application are merely designations, but do not have other meanings, e.g., a particular order, etc. Further, for example, the term "first element" does not itself connote the presence of "second element," and the term "second element" does not itself connote the presence of "first element.

The term "a pair" as used herein may include configurations in which a pair of elements have different shapes or structures from each other, except for configurations in which the pair of elements have the same shape or structure as each other.

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

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

Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.

Claims

1. A sprocket support body rotatably mounted on a hub axle of a bicycle rear hub assembly, the sprocket support body comprising:

at least ten external spline teeth configured to engage with a bicycle rear sprocket assembly, each of the at least ten external spline teeth having an external spline drive surface and an external spline non-drive surface;

each of the at least ten external spline teeth includes the external spline drive surface to receive a driving rotational force from the bicycle rear sprocket assembly during pedaling,

The external spline drive surface comprises

The radially outermost edge of the sleeve is provided with a radially outer edge,

radially innermost edge, and

a radial length defined from the radially outermost edge to the radially innermost edge, an

The sum of the radial lengths of the external spline drive surfaces of the at least ten external spline teeth is equal to or greater than 7mm,

the external spline drive surface has a first external spline surface angle defined between the external spline drive surface and a first radial line extending from a rotational central axis of the bicycle rear hub assembly to a radially outermost edge of the external spline drive surface, and

the first external spline surface angle is equal to or less than 6 degrees.

2. The sprocket support body of claim 1, wherein

The outer spline non-driving surface has a second outer spline surface angle defined between the outer spline non-driving surface and a second radial line extending from a rotational central axis of the bicycle rear hub assembly to a radially outermost edge of the outer spline non-driving surface, and

the second external spline surface angle is equal to or less than 6 degrees.

3. The sprocket support body of claim 1, wherein

At least one of the at least ten external spline teeth has an axial spline tooth length equal to or less than 27 mm.

4. The sprocket support body of claim 1, wherein

The total number of the at least ten external spline teeth ranges from 22 to 24.

5. The sprocket support body of claim 1, wherein

The at least ten external spline teeth have a first external pitch angle and a second external pitch angle different from the first external pitch angle.

6. The sprocket support body of claim 5, wherein

The first external tooth angle ranges from 13 degrees to 17 degrees, and

the second external tooth pitch angle ranges from 28 degrees to 32 degrees.

7. The sprocket support body of claim 5, wherein

The first external tooth pitch angle is half the second external tooth pitch angle.

8. The sprocket support body of claim 5, wherein

The first external tooth pitch angle ranges from 13 degrees to 17 degrees.

9. The sprocket support body of claim 1, wherein

The sum of the radial lengths of the external spline drive surfaces ranges from 11mm to 14mm.

10. The sprocket support body of claim 1, wherein

At least one of the at least ten external spline teeth is circumferentially symmetric about a reference line extending from a rotational central axis to a circumferential center point of a radially outermost end of the at least one of the at least ten external spline teeth in a radial direction with respect to the rotational central axis.

11. The sprocket support body of claim 1, wherein

The at least ten external spline teeth have an external spline tip diameter equal to or less than 34 mm.

12. The sprocket support body of claim 11, wherein

The external spline top diameter is equal to or less than 33mm.

13. The sprocket support body of claim 11, wherein

The external spline top diameter is equal to or greater than 29mm.

14. The sprocket support body of claim 1, wherein

The at least ten external spline teeth have an external spline bottom diameter equal to or less than 32 mm.

15. The sprocket support body of claim 14, wherein

The external spline bottom diameter is equal to or smaller than 31mm.

16. The sprocket support body of claim 14, wherein

The external spline bottom diameter is equal to or greater than 28mm.

17. A bicycle rear hub assembly comprising:

a hub shaft;

the hub body is rotatably mounted on the hub shaft around the rotation central axis of the bicycle rear hub assembly; and

the sprocket support body of claim 1.

18. The bicycle rear hub assembly of claim 17, further comprising

A flywheel structure, the flywheel structure comprising

A first ratchet member comprising at least one first ratchet tooth; and

a second ratchet member comprising at least one second ratchet tooth configured to be torque-transmitting engaged with the at least one first ratchet tooth, wherein

The first ratchet member is configured to be torque-transmitting engaged with one of the hub body and the sprocket support body,

the second ratchet member is configured to be engaged with the other of the hub body and the sprocket support body in a torque transmitting manner, and

at least one of the first ratchet member and the second ratchet member is movable relative to the hub axle in an axial direction about the rotational central axis.