CN117184307A

CN117184307A - Rear sprocket for human-powered vehicle and rear sprocket assembly for human-powered vehicle

Info

Publication number: CN117184307A
Application number: CN202310601408.3A
Authority: CN
Inventors: 黎辉文; 林文强
Original assignee: Shimano Inc
Current assignee: Shimano Inc
Priority date: 2022-06-08
Filing date: 2023-05-25
Publication date: 2023-12-08
Also published as: DE102023204502A1; JP2023180031A; TW202348496A

Abstract

The invention provides a rear sprocket for a manual drive vehicle and a rear sprocket assembly for a manual drive vehicle, which can ensure the speed change performance of the rear sprocket. The rear sprocket includes a sprocket body, a plurality of sprocket teeth, and a plurality of fastening holes, each of the plurality of fastening holes being configured to receive a fastening member that fastens the rear sprocket and an adjacent sprocket to each other, two first adjacent fastening holes of the plurality of fastening holes being arranged at a first pitch angle in a circumferential direction about a rotation center axis, two second adjacent fastening holes of the plurality of fastening holes being arranged at a second pitch angle in the circumferential direction, the second pitch angle being different from the first pitch angle, and two third adjacent fastening holes of the plurality of fastening holes being arranged at a third pitch angle in the circumferential direction, the third pitch angle being different from each of the first pitch angle and the second pitch angle.

Description

Rear sprocket for human-powered vehicle and rear sprocket assembly for human-powered vehicle

Technical Field

The present disclosure relates to a rear sprocket assembly for a human-powered vehicle and a human-powered vehicle.

Background

Patent document 1 discloses a rear sprocket for a human-powered vehicle. The rear sprocket of patent document 1 includes a structure for improving the shifting performance and a plurality of fastening holes.

Prior art literature

Patent literature

Patent document 1: chinese patent application publication No. 102328724.

Disclosure of Invention

Problems to be solved by the invention

If the plurality of fastening holes are arranged at positions affecting the structure for improving the shifting performance, the shifting performance of the rear sprocket for the human-powered vehicle may be suppressed from being improved.

It is an object of the present disclosure to provide a rear sprocket for a human-powered vehicle and a rear sprocket assembly for a human-powered vehicle capable of securing a shifting performance of the rear sprocket.

Means for solving the problems

The rear sprocket according to a first aspect of the present disclosure is a rear sprocket for a human-powered vehicle, wherein the rear sprocket has an axially outward facing surface and an axially inward facing surface provided on an opposite side of the axially outward facing surface in an axial direction with respect to a rotation center axis of the rear sprocket, the axially inward facing surface being configured to face an axially center surface of the human-powered vehicle in an attached state of the rear sprocket to the human-powered vehicle, the rear sprocket comprising: a sprocket body; a plurality of sprocket teeth extending radially outward from the sprocket body in a radial direction with respect to the rotational center axis; and a plurality of fastening holes provided in the sprocket body, each of the plurality of fastening holes being configured to receive a fastening member that fastens the rear sprocket and an adjacent sprocket to each other, the adjacent sprocket being adjacent in such a manner that there is no other sprocket between the adjacent sprocket and the rear sprocket in the axial direction, two first adjacent fastening holes of the plurality of fastening holes being arranged at a first pitch angle in a circumferential direction that is about the rotation center axis, the two first adjacent fastening holes being arranged at the circumferential direction such that there is no other fastening hole of the plurality of fastening holes between the two first adjacent fastening holes, two second adjacent fastening holes of the plurality of fastening holes being arranged at a second pitch angle in the circumferential direction that is different from the first pitch angle, the two second adjacent fastening holes being arranged in such a manner that there is no other fastening hole of the plurality of fastening holes between the two second adjacent fastening holes in the circumferential direction, the two second adjacent fastening holes being arranged at the third pitch angle, the two adjacent fastening holes being arranged at the third pitch angle, the three adjacent fastening holes being arranged at the third pitch angle.

According to the rear sprocket of the first aspect, since the plurality of fastening holes can be arranged at different pitch angles depending on the arrangement of the structure for improving the shifting performance, the plurality of fastening holes are not easily arranged at positions affecting the structure for improving the shifting performance. Therefore, the shifting performance of the rear sprocket can be ensured. According to the rear sprocket of the first aspect, since the plurality of fastening holes can be arranged at different pitch angles, it is beneficial to the degree of freedom in the arrangement of the structure for improving the shifting performance. According to the rear sprocket of the first aspect, since the plurality of fastening holes can be arranged at different pitch angles according to the shape of the rear sprocket, the strength of the rear sprocket can be ensured.

In the rear sprocket according to the second aspect of the present disclosure, the two first adjacent fastening holes include a first fastening hole having a first hole center axis and a second fastening hole having a second hole center axis, the two second adjacent fastening holes include a third fastening hole having a third hole center axis and a fourth fastening hole having a fourth hole center axis, the two third adjacent fastening holes include a fifth fastening hole having a fifth hole center axis and a sixth fastening hole having a sixth hole center axis, the first pitch angle is defined by a first reference line passing through the first hole center axis and the rotation center axis, and a second reference line passing through the second hole center axis and the rotation center axis, the second pitch angle is defined by a third reference line passing through the third hole center axis and the rotation center axis, and a fourth reference line passing through the fourth hole center axis and the rotation center axis, and the third pitch angle is defined by a fifth reference line passing through the fifth hole center axis and the rotation center axis, the fifth pitch angle is defined by the fifth reference line passing through the rotation center axis and the rotation center axis.

According to the rear sprocket of the second aspect, the shifting performance of the rear sprocket can be ensured, and the degree of freedom of the configuration of the structure for improving the shifting performance is facilitated.

In the rear sprocket according to the third aspect of the first or second aspect of the present disclosure, the plurality of sprocket teeth includes a plurality of downshift accelerating teeth configured to accelerate a downshift action of the drive chain moving from the adjacent small sprocket to the rear sprocket, the plurality of downshift accelerating teeth including: a downshift start tooth that is engaged with the drive chain at first in the downshift operation; and a downshift concave tooth provided on the axially outward surface of the downshift concave tooth so as to be recessed from the axially outward surface toward the axially inward surface in the axial direction, the plurality of fastening holes being arranged so as to avoid overlapping with the downshift concave, on a downstream side of the downshift start tooth with respect to a driving rotation direction of the rear sprocket, in such a manner that no other sprocket tooth of the plurality of sprocket teeth is located between the downshift start tooth and the downshift concave tooth in the circumferential direction.

According to the rear sprocket of the third aspect, since the plurality of fastening holes are arranged so as to avoid overlapping with the downshift concave portion, the shifting performance of the plurality of downshift accelerating teeth is not easily affected by the plurality of fastening holes. Therefore, a smooth downshift with a small shift shock can be achieved in the downshift operation.

In the rear sprocket according to a fourth aspect of the present disclosure, the plurality of sprocket teeth includes a plurality of upshift facilitating teeth configured to facilitate an upshift of a drive chain moving from the rear sprocket to an adjacent small sprocket, the plurality of upshift facilitating teeth including: an upshift shift tooth configured to shift a drive chain toward an adjacent small sprocket during the upshift operation; an upshift starting tooth configured to be disengaged from the drive chain at first in the upshift operation; and an upshift start tooth having a first upshift recess portion that is provided on the axially outward surface of the upshift start tooth so as to be recessed from the axially outward surface toward the axially inward surface in the axial direction, the upshift start tooth being provided on the axially outward surface of the upshift start tooth so that no other sprocket tooth of the plurality of sprocket teeth is located between the upshift start tooth and the upshift shift tooth in the circumferential direction, the upshift shift tooth being adjacent to the upshift shift tooth on an upstream side of the upshift shift tooth with respect to a driving rotation direction of the rear sprocket, the upshift recess tooth having a second upshift recess portion that is provided on the axially outward surface of the upshift recess tooth so as to be recessed from the axially outward surface toward the axially inward surface, the upshift recess tooth being located on the upstream side of the upshift start tooth with respect to the second sprocket tooth without the other sprocket tooth of the plurality of sprocket teeth being located between the upshift start tooth and the upshift shift tooth in the circumferential direction, the upshift recess tooth being located on the upstream side of the sprocket teeth with respect to the driving rotation start tooth with respect to the first sprocket tooth and the upshift start tooth being prevented from overlapping with the first upshift recess tooth and the second sprocket tooth.

According to the rear sprocket of the fourth aspect, since the plurality of fastening holes are arranged so as to avoid overlapping with the first upshift recess portion and the second upshift recess portion, the shifting performance of the plurality of upshift facilitating teeth is not easily affected by the plurality of fastening holes. Therefore, a smooth upshift with small shift shock can be achieved in the upshift operation.

In the rear sprocket according to a fifth aspect of the present disclosure, each of the plurality of sprocket teeth has a maximum radial length in the radial direction and a maximum axial length in the axial direction, the maximum radial length being greater than the maximum axial length.

According to the rear sprocket of the fifth aspect, since the maximum axial length can be shortened, the number of sprockets included in the rear sprocket assembly can be increased.

A rear sprocket assembly according to a sixth aspect of the present disclosure is a rear sprocket assembly for a human-powered vehicle, and includes: the rear sprocket being the rear sprocket of any one of the first to fifth aspects of the present disclosure and having a first pitch diameter; and the adjacent sprocket having a second pitch diameter larger than the first pitch diameter and being coaxially arranged with the rear sprocket in an assembled state of the rear sprocket assembly.

According to the rear sprocket assembly of the sixth aspect, a rear sprocket assembly that ensures shifting performance and is excellent in strength can be realized.

In the rear sprocket assembly according to a seventh aspect of the present disclosure, the adjacent sprocket includes an additional sprocket body and a plurality of additional sprocket teeth extending radially outward from the additional sprocket body in the radial direction.

According to the rear sprocket assembly of the seventh aspect, a rear sprocket assembly that ensures shifting performance and is excellent in strength can be realized.

In the rear sprocket assembly according to the eighth aspect of the present disclosure, the adjacent sprocket has an additional axially outward facing surface; and an additional axially inward surface provided on an opposite side of the additional axially outward surface in the axial direction, the additional axially inward surface being configured to face the axially center surface of the manually driven vehicle in the axial direction in the mounted state, the plurality of additional sprocket teeth including a plurality of additional downshift accelerating teeth configured to accelerate an additional downshift operation of the drive chain moving from the rear sprocket to the adjacent sprocket, the plurality of additional downshift accelerating teeth including: an additional downshift start tooth configured to be engaged with the drive chain at first in the additional downshift operation; and an additional downshift concave tooth provided adjacent to the additional downshift concave tooth on a downstream side of the additional downshift start tooth with respect to a driving rotation direction of the adjacent sprocket, the additional downshift concave tooth being provided with an additional axially outward surface of the additional downshift concave tooth so as to be recessed in the axial direction from the additional axially outward surface toward the additional axially inward surface, such that no other additional sprocket tooth of the plurality of additional sprocket teeth is provided between the additional downshift start tooth and the additional downshift concave tooth in the circumferential direction.

According to the rear sprocket assembly of the eighth aspect, the shift shock during the additional downshift operation can be reduced by the plurality of additional downshift accelerating teeth. Therefore, the adjacent sprocket can perform a smooth additional downshift operation.

In the rear sprocket assembly according to the ninth aspect of the present disclosure, at least a portion of at least one of the plurality of fastening holes is arranged between the additional downshift start tooth and the additional downshift concave tooth in the circumferential direction when viewed from the axial direction.

According to the rear sprocket assembly of the ninth aspect, the rigidity of the adjacent sprocket in the axial direction of the portion of the adjacent sprocket corresponding to the fastening member in the radial direction of the adjacent sprocket is improved by the fastening member.

In the rear sprocket assembly according to a tenth aspect of the present disclosure, the plurality of additional sprocket teeth include an abutment tooth that is adjacent to the additional downshift start tooth on an upstream side of the additional downshift start tooth with respect to a driving rotation direction of the adjacent sprocket in such a manner that no other additional sprocket tooth of the plurality of additional sprocket teeth is located between the additional downshift start tooth and the abutment tooth in the circumferential direction, and at least a part of at least one of the plurality of fastening holes is arranged between the abutment tooth and the additional downshift concave tooth in the circumferential direction as viewed from the axial direction.

According to the rear sprocket assembly of the tenth aspect, the fastening member can increase the rigidity of the adjacent sprocket in the axial direction of the portion of the adjacent sprocket corresponding to the fastening member in the radial direction of the adjacent sprocket.

In the rear sprocket assembly according to an eleventh aspect of the present disclosure, at least a portion of at least one of the plurality of fastening holes is disposed between the abutment tooth and the additional downshift start tooth in the circumferential direction when viewed from the axial direction.

According to the rear sprocket assembly of the eleventh aspect, the fastening member can increase the rigidity of the adjacent sprocket in the axial direction of the portion of the adjacent sprocket corresponding to the fastening member in the radial direction of the adjacent sprocket.

In the rear sprocket assembly according to a twelfth aspect of any one of the seventh to eleventh aspects of the present disclosure, each of the plurality of additional sprocket teeth has an additional maximum radial length in the radial direction and an additional maximum axial length in the axial direction, the additional maximum radial length being greater than the additional maximum axial length.

According to the rear sprocket assembly of the twelfth aspect, since the additional maximum axial length can be shortened, the number of sprockets included in the rear sprocket assembly can be increased.

Effects of the invention

The rear sprocket assembly for the human-powered vehicle can ensure the speed change performance of the rear sprocket and improve the configuration freedom degree of a plurality of fastening holes.

Drawings

FIG. 1 is a schematic diagram illustrating a human-powered vehicle including a human-powered vehicle rear sprocket assembly having a human-powered vehicle rear sprocket according to an embodiment;

FIG. 2 is a side view of the rear sprocket assembly for the human powered vehicle of FIG. 1;

FIG. 3 is a side view of the rear sprocket of the human powered vehicle of FIG. 2;

FIG. 4 is a cross-sectional view taken along line D4-D4 of FIG. 2;

FIG. 5 is a top view showing the plurality of downshift promoting teeth and chain of FIG. 3;

FIG. 6 is a top view showing the plurality of upshift facilitating teeth and chain of FIG. 3;

FIG. 7 is a side view of the adjacent sprocket of FIG. 2;

FIG. 8 is a first side elevational view of the rear sprocket, the adjacent sprocket and the fastener members of the human powered vehicle of FIG. 2;

FIG. 9 is a second side view of the rear sprocket, adjacent sprockets and fastening members of the human powered vehicle of FIG. 2;

FIG. 10 is a top view showing the plurality of additional downshift promoting teeth and the chain of FIG. 7;

FIG. 11 is a top view showing the plurality of additional upshift facilitating teeth and the chain of FIG. 7;

Fig. 12 is a plan view showing an example of a state in which a drive chain is to be moved from an adjacent sprocket to a rear sprocket for a manually driven vehicle by an additional upshift operation in the rear sprocket assembly for a manually driven vehicle in the embodiment.

Detailed Description

< first embodiment >, first embodiment

Referring to fig. 1 to 12, a rear sprocket 30 for a manually driven vehicle and a rear sprocket assembly 26 for a manually driven vehicle according to an embodiment will be described. The human powered vehicle 10 shown in fig. 1 is a vehicle having at least one wheel that is at least drivable by a human driving force. The human powered vehicle 10 includes various bicycles such as mountain bikes, road bikes, city bikes, freight bikes, hand bikes, and recumbent bikes. The number of wheels of the manually driven vehicle 10 is not limited. The human powered vehicle 10 includes, for example, a wheelbarrow and a vehicle having two or more wheels. The manually driven vehicle 10 is not limited to a vehicle that can be driven only by a manual driving force. The human-powered vehicle 10 includes an electric bicycle (E-bike) propelled not only by human driving force but also by driving force of an electric motor. Electric bicycles (E-bike) include electric assist bicycles that are propelled assisted by an electric motor. In the following, in each embodiment, the manually driven vehicle 10 will be described as a bicycle.

In the present specification, the following terms "front", "rear", "left", "right", "transverse", "above" and "below" that indicate directions, and terms that indicate any other similar directions, refer to those directions determined on the basis of a rider facing the handlebars at a reference position (e.g., on a saddle or seat) of the manually driven vehicle 10.

As shown in FIG. 1, for example, a human-powered vehicle 10 includes a crank 12, a front sprocket 14, a rear hub assembly 16, and a drive chain 18. The front sprocket 14 is mounted to the crank 12.

The crank 12 includes a crank axle 20 and a pair of crank arms 22. A pair of crank arms 22 are each mounted to the crank axle 20. A pedal 24 is rotatably coupled to each of the pair of crank arms 22.

For example, the human powered vehicle 10 includes a rear sprocket assembly 26. For example, rear hub assembly 16 includes a rear sprocket assembly 26 and a hub axle 28. The rear sprocket assembly 26 is rotatably mounted to the hub axle 28 relative to the frame 10F of the human-powered vehicle 10. The hub axle 28 is configured to rotate integrally with the rear sprocket assembly 26 and the rear wheels of the human-powered vehicle 10.

The rear sprocket assembly 26 includes a plurality of sprockets of different sizes. The number of the plurality of sprockets can be arbitrarily selected. For example, the rear sprocket assembly 26 shown in FIG. 2 includes 10 sprockets. The rear sprocket assembly 26 may include more than 2 and less than 10 sprockets, and may include more than 11 sprockets.

As shown in fig. 5, drive chain 18 includes a plurality of rollers 18A, a plurality of outer links 18B, and a plurality of inner links 18C. The outer links 18B are formed such that a pair of outer link plates are aligned in the axial direction AD. The inner links 18C are formed such that a pair of inner link plates are aligned in the axial direction AD. The drive chain 18 is journaled to the front sprocket 14 and the rear sprocket assembly 26. The drive chain 18 transfers the manual drive force applied to the pedals 24 from the front sprocket 14 to the rear sprocket assembly 26. The rear sprocket assembly 26 transmits the manual driving force to the rear wheels of the manually driven vehicle 10 via the hub axle 28.

For example, the human powered vehicle 10 also includes a rear derailleur. The rear derailleur performs a shifting action that moves the drive chain 18 to move the drive chain 18 engaged with one of the plurality of sprockets from one of the plurality of sprockets to the other sprocket.

As shown in fig. 2, in the present embodiment, a sprocket having a second largest diameter among the plurality of sprockets is described as a rear sprocket 30. In the present embodiment, a sprocket having the largest diameter among the plurality of sprockets is described as the adjacent sprocket 70. The abutment sprocket 70 abuts the rear sprocket 30. In the present embodiment, a sprocket having the third largest diameter among the plurality of sprockets is described as an adjacent small sprocket 26A. The adjacent small sprocket 26A is adjacent to the rear sprocket 30 and smaller than the rear sprocket 30.

As shown in fig. 2, for example, the rear sprocket assembly 26 is provided with a rear sprocket 30 and an adjacent sprocket 70. In fig. 2, the rear sprocket assembly 26 is shown in an assembled state. For example, the adjacent sprocket 70 is coaxially disposed with the rear sprocket 30 in the assembled state of the rear sprocket assembly 26. The rotation center axis of the adjacent sprocket 70 coincides with the rotation center axis X1 of the rear sprocket 30.

As shown in fig. 3, for example, the rear sprocket 30 has a first pitch diameter D1. The first pitch diameter D1 is a diameter of the first pitch circle P1 passing through the center axis of the roller 18A of the drive chain 18 in a state where the drive chain 18 is arranged on the rear sprocket 30.

As shown in fig. 9, for example, the adjacent sprocket 70 has a second pitch diameter D2. The second pitch diameter D2 is the diameter of the second pitch P2 passing through the center axis of the roller 18A of the drive chain 18 in a state where the drive chain 18 is arranged adjacent to the sprocket 70. For example, the second pitch diameter D2 is greater than the first pitch diameter D1.

As shown in fig. 1 and 4, the rear sprocket 30 has an axially outward facing surface 30A and an axially inward facing surface 30B. The axially inward surface 30B is provided on the opposite side of the axially outward surface 30A in the axial direction AD with respect to the rotation center axis X1 of the rear sprocket 30. The axially inward surface 30B is configured to face an axially center surface CS of the manually driven vehicle 10 in the axial direction AD in the mounted state. For example, the axial center plane CS of the human-powered vehicle 10 substantially coincides with the lateral center of the human-powered vehicle 10. The mounted state is a state in which the rear sprocket 30 is mounted to the manually driven vehicle 10. In the installed state, the rear sprocket assembly 26 is in an assembled state. In the mounted state, the adjacent sprocket 70 is disposed coaxially with the rear sprocket 30.

As shown in fig. 3, the rear sprocket 30 includes a sprocket body 32, a plurality of sprocket teeth 34, and a plurality of fastening holes 36. For example, the sprocket body 32 includes an outer annular portion 32A, an inner annular portion 32B, and a plurality of connecting arms 32C. The outer annular portion 32A has an inner peripheral portion 32D and an outer peripheral portion 32E. The inner peripheral portion 32D is a portion of the outer annular portion 32A that faces the hub axle 28 in the mounted state. The outer peripheral portion 32E is a portion of the outer annular portion 32A that is located on the opposite side of the inner peripheral portion 32D in the radial direction with respect to the rotation center axis X1 in the mounted state. The inner annular portion 32B has a plurality of spline teeth 32F that engage the sprocket support of the rear hub assembly 16. The plurality of connecting arms 32C are located between the outer annular portion 32A and the inner annular portion 32B in the radial direction with respect to the rotation center axis X1 of the rear sprocket 30.

As shown in fig. 4 to 6, the plurality of sprocket teeth 34 extend radially outward from the sprocket body 32 in the radial direction about the rotation center axis X1. The rear sprocket 30 engages the drive chain 18 by a plurality of sprocket teeth 34 being interposed between a pair of outer link plates of the outer link 18B and between a pair of inner link plates of the inner link 18C. For example, each sprocket 34 has a drive surface and a non-drive surface that is provided on the opposite side of the drive surface in the circumferential direction CD about the rotation center axis X1. The driving surface is a side surface located upstream of the sprocket teeth 34 in the driving rotational direction RD1 of the rear sprocket 30. When the rear sprocket 30 rotates in the driving rotation direction RD1, each sprocket tooth 34 engages with the roller 18A of the drive chain 18 on the driving surface.

As shown in fig. 4, for example, each of the plurality of sprocket teeth 34 has a maximum radial length L1 in the radial direction and a maximum axial length L2 in the axial direction AD. For example, the maximum radial length L1 is a length from the outer peripheral portion 32E of the sprocket body 32 to the tooth tip. For example, the maximum axial length L2 is the length from the axially outward facing surface 30A to the axially inward facing surface 30B. The maximum radial length L1 is greater than the maximum axial length L2.

As shown in fig. 3, a plurality of fastening holes 36 are provided in the sprocket body 32. Each of the plurality of fastening holes 36 is configured to receive a fastening member 38. The fastening members 38 fasten the rear sprocket 30 and the adjacent sprocket 70 to each other. The adjacent sprocket 70 is adjacent in the axial direction AD in such a manner that there is no other sprocket between the adjacent sprocket 70 and the rear sprocket 30. For example, each of the plurality of fastening holes 36 extends in the axial direction AD. Each of the plurality of fastening holes 36 penetrates the sprocket body 32 in the axial direction AD. For example, the fastening member 38 includes a rivet. The fastening member 38 determines the position of the adjacent sprocket 70 relative to the rear sprocket 30. The outer diameter of the portion of the fastening member 38 sandwiched between the rear sprocket 30 and the adjacent sprocket 70 is larger than the inner diameter of the fastening hole 36, for example.

The fastening hole 36 has an inner diameter greater than the maximum axial length L2 of the sprocket 34. For example, the inner diameters of the plurality of fastening holes 36 are equal to each other. At least one of the inner diameters of the plurality of fastening holes 36 may be different from the others. The dimensions of the fastening member 38 correspond to the dimensions of the fastening hole 36 that receives the fastening member 38.

Each of the plurality of fastening holes 36 has a central hub C. The center axes C of the plurality of fastening holes 36 are arranged at the same position in the radial direction with respect to the rotation center axis X1. The plurality of pitch angles are defined by angles formed by two reference lines a corresponding to the adjacent two fastening holes 36, respectively, among the plurality of reference lines a. The plurality of reference lines a pass through the rotation center axis X1 and the center axes C of the plurality of fastening holes 36. In this embodiment, the plurality of reference lines a includes 14 reference lines a and defines 14 pitch angles.

For example, the plurality of fastening holes 36 includes at least three fastening holes 36. For example, the number of the plurality of fastening holes 36 is 14. In the present embodiment, a combination of two fastening holes 36, among the plurality of fastening holes 36, that are adjacent to each other in such a manner that no other fastening hole 36 among the plurality of fastening holes 36 is present in the circumferential direction CD is defined as two adjacent fastening holes. The plurality of fastener holes 36 includes more than three sets of two adjacent fastener holes. For example, the plurality of fastening holes 36 includes two first adjacent fastening holes 40, two second adjacent fastening holes 42, and two third adjacent fastening holes 44. The plurality of fastener holes 36 may include more than four sets of two adjacent fastener holes. For example, the plurality of fastening holes 36 may also include two fourth adjacent fastening holes 46. The number of groups of two adjacent fastening holes is 3 or more and the number of the plurality of fastening holes 36 is less. In the present embodiment, the number of groups of two adjacent fastening holes is 14.

The two first adjacent fastening holes 40, the two second adjacent fastening holes 42, and the two third adjacent fastening holes 44 are arbitrarily selected from the plurality of fastening holes 36. At least one of the two first adjacent fastening holes 40, the two second adjacent fastening holes 42, and the two third adjacent fastening holes 44 themselves may include two fastening holes 36 different from the other 2 sets. One of the plurality of fastening holes 36 may be selected as one of the two first adjacent fastening holes 40 and as one of the two second adjacent fastening holes 42. One of the plurality of fastening holes 36 may be selected as one of the two first adjacent fastening holes 40 and as one of the two third adjacent fastening holes 44. One of the plurality of fastening holes 36 may be selected as one of the two second adjacent fastening holes 42 and as one of the two third adjacent fastening holes 44.

The two first adjoining fastening holes 40 adjoin each other in such a manner that there is no other fastening hole 36 among the plurality of fastening holes 36 between the two first adjoining fastening holes 40 in the circumferential direction CD. For example, the two first adjacent fastening holes 40 include a first fastening hole 40A and a second fastening hole 40B. For example, the first fastening hole 40A has a first hole center axis C1. For example, the second fastening hole 40B has a second hole center axis C2.

Two first adjacent fastening holes 40 among the plurality of fastening holes 36 are arranged at a first pitch angle B1 in the circumferential direction CD about the rotation center axis X1. For example, the first pitch angle B1 is defined by a first reference line A1 and a second reference line A2. For example, the first reference line A1 passes through the first hole center axis C1 and the rotation center axis X1. For example, the second reference line A2 passes through the second hole center axis C2 and the rotation center axis X1. The first pitch angle B1 is an angle formed by the first reference line A1 and the second reference line A2.

The two second adjoining fastening holes 42 adjoin each other in such a manner that there is no other fastening hole 36 among the plurality of fastening holes 36 between the two second adjoining fastening holes 42 in the circumferential direction CD. For example, the two second adjacent fastening holes 42 include a third fastening hole 42A and a fourth fastening hole 42B. For example, the third fastening hole 42A has a third hole center axis C3. For example, the fourth fastening hole 42B has a fourth hole center axis C4. In fig. 3, the fastening hole 36 selected as the third fastening hole 42A doubles as the second fastening hole 40B.

Two second adjacent fastening holes 42 of the plurality of fastening holes 36 are arranged at a second pitch angle B2 in the circumferential direction CD. For example, the second pitch angle B2 is defined by the third reference line A3 and the fourth reference line A4. For example, the third reference line A3 passes through the third hole center axis C3 and the rotation center axis X1. For example, the fourth reference line A4 passes through the fourth hole center axis C4 and the rotation center axis X1. The second pitch angle B2 is the angle formed by the third reference line A3 and the fourth reference line A4.

The two third adjoining fastening holes 44 adjoin each other in such a manner that there is no other fastening hole 36 among the plurality of fastening holes 36 between the two third adjoining fastening holes 44 in the circumferential direction CD. For example, the two third adjacent fastening holes 44 include a fifth fastening hole 44A and a sixth fastening hole 44B. For example, the fifth fastening hole 44A has a fifth hole center axis C5. For example, the sixth fastening hole 44B has a sixth hole center axis C6. In fig. 3, the fastening hole 36 selected as the fifth fastening hole 44A doubles as the fourth fastening hole 42B.

Two third adjacent fastening holes 44 of the plurality of fastening holes 36 are arranged at a third pitch angle B3 in the circumferential direction CD. For example, the third pitch angle B3 is defined by the fifth reference line A5 and the sixth reference line A6. For example, the fifth reference line A5 passes through the fifth hole center axis C5 and the rotation center axis X1. For example, the sixth reference line A6 passes through the sixth hole center axis C6 and the rotation center axis X1. The third pitch angle B3 is the angle formed by the fifth reference line A5 and the sixth reference line A6.

For example, the two fourth adjacent fastening holes 46 are adjacent to each other in such a manner that there is no other fastening hole 36 among the plurality of fastening holes 36 between the two fourth adjacent fastening holes 46 in the circumferential direction CD. For example, the two fourth adjacent fastening holes 46 include a seventh fastening hole 46A and an eighth fastening hole 46B. For example, the seventh fastening hole 46A has a seventh hole center axis C7. For example, the eighth fastening hole 46B has an eighth hole center axis C8. In the present embodiment, the fastening hole 36 selected as the eighth fastening hole 46B doubles as the first fastening hole 40A.

Two fourth adjacent fastening holes 46 of the plurality of fastening holes 36 are arranged at a fourth pitch angle B4 in the circumferential direction CD. For example, the fourth pitch angle B4 is defined by the seventh reference line A7 and the eighth reference line A8. For example, the seventh reference line A7 passes through the seventh hole center axis C7 and the rotation center axis X1. For example, the eighth reference line A8 passes through the eighth hole center axis C8 and the rotation center axis X1. The fourth pitch angle B4 is the angle formed by the seventh reference line A7 and the eighth reference line A8.

For example, the plurality of pitch angles includes pitch angles of 3 or more values. For example, the number of kinds of values of the plurality of pitch angles is 3 or more and the number of the plurality of pitch angles is less than or equal to the number of kinds of values of the plurality of pitch angles. In this embodiment, the plurality of pitch angles includes four values of pitch angle. The pitch angles of the four values in the present embodiment correspond to the first pitch angle B1, the second pitch angle B2, the third pitch angle B3, and the fourth pitch angle B4, respectively.

The second pitch angle B2 is different from the first pitch angle B1. In the present embodiment, the second pitch angle B2 is larger than the first pitch angle B1. The third pitch angle B3 is different from each of the first and second pitch angles B1 and B2. In fig. 3, the third pitch angle B3 is greater than either of the first and second pitch angles B1 and B2. In fig. 3, the fourth pitch angle B4 is different from each of the first pitch angle B1, the second pitch angle B2, and the third pitch angle B3. In fig. 3, the fourth pitch angle B4 is larger than any one of the first pitch angle B1, the second pitch angle B2, and the third pitch angle B3.

In fig. 3, the plurality of pitch angles includes a fifth pitch angle B5, a sixth pitch angle B6, a seventh pitch angle B7, an eighth pitch angle B8, a ninth pitch angle B9, a tenth pitch angle B10, an eleventh pitch angle B11, a twelfth pitch angle B12, a thirteenth pitch angle B13, and a fourteenth pitch angle B14, in addition to the first pitch angle B1, the second pitch angle B2, the third pitch angle B3, and the fourth pitch angle B4.

In fig. 3, the first pitch angle B1 is 13 degrees, the second pitch angle B2 is 22 degrees, the third pitch angle B3 is 34 degrees, and the fourth pitch angle B4 is 39 degrees. For example, the sixth pitch angle B6, the tenth pitch angle B10, and the fourteenth pitch angle B14 are the same angles as the first pitch angle B1. For example, the seventh pitch angle B7 and the eleventh pitch angle B11 are the same angles as the second pitch angle B2. For example, the fifth pitch angle B5, the eighth pitch angle B8, the ninth pitch angle B9, the twelfth pitch angle B12, and the thirteenth pitch angle B13 are the same angles as the third pitch angle B3.

As shown in fig. 1, 3 and 5, for example, the plurality of sprocket teeth 34 include a plurality of downshift promoting teeth 48. For example, the plurality of downshift accelerating teeth 48 are configured to accelerate a downshift operation. For example, the downshift action is an action of driving the chain 18 to move from the adjacent small sprocket to the rear sprocket 30. The adjacent small sprocket is adjacent to the axially outward facing surface 30A side of the rear sprocket 30 in the mounted state. For example, during a downshift operation, the drive chain 18 is moved from the adjacent small sprocket 26A to the rear sprocket 30 by the rear derailleur of the manually driven vehicle 10.

For example, the plurality of downshift accelerating teeth 48 includes downshift starting teeth 50 and downshift concave teeth 52. For example, the downshift start tooth 50 is configured to engage with the drive chain 18 first in the downshift operation. The tip of the downshift start tooth 50 is inclined in the axial direction AD so as to approach the axially outward surface 30A from the drive surface of the downshift start tooth 50 toward the non-drive surface of the downshift start tooth 50.

For example, the downshift concave teeth 52 are configured to be able to move the drive chain 18 in the axial direction AD from the axially outward surface 30A to the axially inward surface 30B during a downshift operation. For example, the downshift concave teeth 52 are adjacent to the downshift start teeth 50 in the circumferential direction CD so that no other sprocket 34 of the plurality of sprockets 34 is located between the downshift start teeth 50 and the downshift concave teeth 52. For example, the downshift concave tooth 52 is adjacent to the downshift start tooth 50 on the downstream side of the downshift start tooth 50 with respect to the driving rotation direction RD1 of the rear sprocket 30. The tooth tip of the downshift concave tooth 52 is inclined in the axial direction AD so as to approach the axially inward surface 30B from the drive surface toward the non-drive surface.

For example, the downshift concave teeth 52 have downshift concave portions 54. For example, the downshift concave portion 54 is provided on the axially outward surface 30A of the downshift concave portion tooth 52 so as to be recessed in the axial direction AD from the axially outward surface 30A toward the axially inward surface 30B. For example, the downshift concave portion 54 includes a first downshift concave portion 54A and a second downshift concave portion 54B. The depth of the second downshift concave portion 54B in the axial direction AD is set to be different from the depth of the first downshift concave portion 54A in the axial direction AD. For example, the depth of the second downshift concave portion 54B in the axial direction AD is larger than the depth of the first downshift concave portion 54A in the axial direction AD. The depth of the second downshift concave portion 54B in the axial direction AD may be set to be the same as the depth of the first downshift concave portion 54A in the axial direction AD. For example, the first downshift concave portion 54A and the second downshift concave portion 54B are formed by a step-type blanking process.

The plurality of downshift accelerating teeth 48 form a downshift area of the rear sprocket 30. The downshift area is formed with a downshift concave portion 54 as a structure for improving the shifting performance of the rear sprocket 30 during the downshift operation. The rear sprocket 30 is formed with a plurality of downshift areas. Each of the plurality of downshift areas is formed with a downshift start tooth 50 and a downshift concave tooth 52 of the plurality of downshift accelerating teeth 48. The rear sprocket 30 of fig. 3 is formed with three downshift areas.

The operation of the drive chain 18 during the downshift operation will be described.

In the downshift operation, the drive chain 18 engaged with the adjacent small sprocket 26A is moved toward the downshift concave tooth 52 of the rear sprocket 30 by the rear derailleur. The inner link 18C of the drive chain 18 moves to a position opposing the first downshift concave portion 54A, and the outer link 18B of the drive chain 18 moves to a position opposing the second downshift concave portion 54B. With the rear derailleur, the drive chain 18 moves toward the rear sprocket 30 and is guided radially outward of the adjacent small sprocket 26A along the downshift recess 54. The tip of the downshift start tooth 50 is inclined so as to approach the axially outward surface 30A from the drive surface of the downshift start tooth 50 toward the non-drive surface of the downshift start tooth 50, and therefore the drive chain 18 is easily fitted into the downshift start tooth 50. The drive chain 18 that has been guided to the radial outside is fitted into the tooth tip of the downshift start tooth 50, whereby the downshift start tooth 50 engages with the drive chain 18. Thereafter, as rear sprocket 30 rotates in drive rotational direction RD1, drive chain 18 disengages from adjacent small sprocket 26A. The drive chain 18, which is disengaged from the adjacent small sprocket 26A, engages with the rear sprocket 30, and the downshift operation is completed.

For example, the plurality of fastening holes 36 are configured to avoid overlapping with the downshift concave portion 54. The plurality of fastening holes 36 are arranged so as not to overlap the downshift concave sections 54 in the circumferential direction CD. For example, the plurality of reference lines a are arranged so as not to overlap the downshift concave portion 54. The plurality of fastening holes 36 are arranged so as not to overlap the downshift concave portion 54 in the radial direction.

As shown in fig. 1, 3, and 6, for example, the plurality of sprocket teeth 34 includes a plurality of upshift facilitating teeth 56. The plurality of upshift promoting teeth 56 are configured to promote an upshift operation. The upshift action is an action of driving chain 18 to move from rear sprocket 30 to an adjacent small sprocket. For example, in an upshift operation, the drive chain 18 is moved from the rear sprocket 30 to the adjacent small sprocket 26A by a rear derailleur of the human powered vehicle 10.

For example, the plurality of upshift facilitating teeth 56 includes upshift shift teeth 58, upshift start teeth 60, and upshift recess teeth 62. For example, the upshift shift teeth 58 are configured to shift the drive chain 18 toward the adjacent small sprocket during the upshift operation. The tooth tip of the upshift displacement tooth 58 is inclined in the axial direction AD so as to approach the axially inward surface 30B from the driving surface of the upshift displacement tooth 58 toward the non-driving surface of the upshift displacement tooth 58.

For example, the upshift start tooth 60 is configured to be first disengaged from the drive chain 18 in the upshift operation. For example, the upshift starting tooth 60 is adjacent to the upshift changing tooth 58 in the circumferential direction CD such that no other sprocket 34 of the plurality of sprockets 34 is located between the upshift starting tooth 60 and the upshift changing tooth 58. For example, the upshift start tooth 60 is adjacent to the upshift shift tooth 58 on the upstream side of the upshift shift tooth 58 with respect to the driving rotation direction RD1 of the rear sprocket 30.

For example, the upshift starting tooth 60 has a first upshift recess portion 60A. For example, the first upshift recess 60A is provided on the axially outward surface 30A of the upshift start tooth 60 so as to be recessed in the axial direction AD from the axially outward surface 30A toward the axially inward surface 30B. The first upshift recess 60A extends from the driving surface of the upshift start tooth 60 to the non-driving surface of the upshift start tooth 60. For example, the first upshift recess 60A is formed by a step-type blanking process.

For example, the upshift recess tooth 62 is configured not to engage with the drive chain 18 from which the upshift start tooth 60 is disengaged during the upshift operation. For example, the upshift recess tooth 62 is adjacent to the upshift start tooth 60 in the circumferential direction CD such that no other sprocket 34 of the plurality of sprockets 34 is located between the upshift recess tooth 62 and the upshift start tooth 60. For example, the upshift recess tooth 62 is adjacent to the upshift start tooth 60 on the upstream side of the upshift start tooth 60 with respect to the driving rotation direction RD1 of the rear sprocket 30.

For example, the upshift recess teeth 62 have second upshift recesses 62A. For example, the second upshift recess portion 62A is provided on the axially outward surface 30A of the upshift recess portion tooth 62 so as to be recessed in the axial direction AD from the axially outward surface 30A toward the axially inward surface 30B. The second upshift recess 62A extends from the driving surface of the upshift recess tooth 62 to the non-driving surface of the upshift recess tooth 62. For example, the second upshift recess portion 62A is formed by a step-type blanking process.

The depth of the second upshift recess portion 62A in the axial direction AD is set to be different from the depth of the first upshift recess portion 60A in the axial direction AD. For example, the depth of the second upshift recess 62A in the axial direction AD is smaller than the depth of the first upshift recess 60A in the axial direction AD. The depth of the second upshift recess portion 62A in the axial direction AD may be set to be the same as the depth of the first upshift recess portion 60A in the axial direction AD.

The plurality of upshift facilitating teeth 56 form an upshift area of the rear sprocket 30. The upshift region is formed with a first upshift recess 60A and a second upshift recess 62A as a structure for improving the shifting performance of the rear sprocket 30 during the upshift operation. The rear sprocket 30 is formed with a plurality of upshift areas. Each of the plurality of upshift regions is formed with an upshift shift tooth 58, an upshift start tooth 60, and an upshift recess tooth 62 of the plurality of upshift promoting teeth 56. The rear sprocket 30 of fig. 3 is formed with four upshift areas.

The operation of the drive chain 18 during the upshift operation will be described.

In the upshift operation, the drive chain 18 engaged with the rear sprocket 30 is moved toward the adjacent small sprocket 26A by the rear derailleur. When the drive chain 18 engages with the upshift shift teeth 58, the tooth tops of the upshift shift teeth 58 incline from the drive surface of the upshift shift teeth 58 toward the non-drive surface of the upshift shift teeth 58 toward the axially inward surface 30B, and therefore the drive chain 18 approaches the adjacent small sprocket 26A. The tooth tip of the upshift starting tooth 60 is moved closer to the axially inward surface 30B by the first upshift recess portion 60A, and therefore the drive chain 18 moved closer to the adjacent small sprocket 26A is easily disengaged from the upshift starting tooth 60. The tip of the upshift recess tooth 62 is located closer to the axially inward surface 30B than the tip of the upshift start tooth 60 by the second upshift recess 62A. Therefore, the drive chain 18 that is disengaged from the upshift start tooth 60 does not engage with the upshift recess tooth 62. Thereafter, as the rear sprocket 30 rotates in the driving rotation direction RD1, the driving chain 18 is disengaged from the rear sprocket 30. The drive chain 18, which is disengaged from the rear sprocket 30, engages with the adjacent small sprocket 26A, and the upshift operation is completed.

For example, the plurality of fastening holes 36 are arranged so as not to overlap the first upshift recess 60A and the second upshift recess 62A. For example, the plurality of fastening holes 36 are arranged so as not to overlap with any one of the first upshift recess 60A and the second upshift recess 62A. The plurality of fastening holes 36 may be configured to avoid overlapping with only a portion of the first upshift recess 60A and the second upshift recess 62A. The plurality of fastening holes 36 are arranged so as not to overlap the first upshift recess 60A and the second upshift recess 62A in the circumferential direction CD. For example, the plurality of reference lines a are arranged so as not to overlap the first upshift recess 60A and the second upshift recess 62A. The plurality of fastening holes 36 are arranged so as not to overlap the first upshift recess 60A and the second upshift recess 62A in the radial direction.

As shown in fig. 7, for example, the adjacent sprocket 70 includes an additional sprocket body 72 and a plurality of additional sprocket teeth 74. For example, the additional sprocket body 72 includes an additional outer annular portion 72A and a plurality of additional connecting arms 72B. The additional outer annular portion 72A has an additional inner peripheral portion 72C and an additional outer peripheral portion 72D. The additional inner peripheral portion 72C is a portion of the additional outer annular portion 72A that faces the hub axle 28 in the mounted state. The additional outer peripheral portion 72D is a portion of the additional outer annular portion 72A located on the opposite side of the additional inner peripheral portion 72C in the radial direction with respect to the rotation center axis X1 in the mounted state. The plurality of additional connecting arms 72B are located inside the additional outer annular portion 72A in the radial direction with respect to the rotation center axis X1.

As shown in fig. 7 and 10, for example, a plurality of additional sprocket teeth 74 extend radially outward from the additional sprocket body 72. The plurality of additional sprocket teeth 74 are engaged with the drive chain 18 by being interposed between a pair of outer link plates of the outer link 18B and between a pair of inner link plates of the inner link 18C, thereby abutting the sprocket 70. For example, each additional sprocket 74 has an additional driving surface and an additional non-driving surface, and the additional non-driving surface is provided on the opposite side of the additional driving surface in the circumferential direction CD about the rotation center axis X1. The additional driving surface is a side surface located upstream of the additional sprocket 74 in the driving rotation direction RD1 of the additional sprocket 74. When the adjacent sprocket 70 rotates in the driving rotation direction RD1, each additional sprocket tooth 74 engages with the roller 18A of the drive chain 18 at the additional driving surface.

As shown in fig. 4, for example, each of the plurality of additional sprocket teeth 74 has an additional maximum radial length L3 in the radial direction and an additional maximum axial length L4 in the axial direction AD. For example, the additional maximum radial length L3 is a length from the additional outer peripheral portion 72D of the additional sprocket body 72 to the tooth tip. For example, the additional maximum axial length L4 is a length from the additional axially outward surface 70A to the additional axially inward surface 70B. For example, the additional maximum radial length L3 is greater than the additional maximum axial length L4.

As shown in fig. 8 and 9, for example, the adjacent sprocket 70 includes a plurality of additional fastening holes 76. Each of the plurality of additional fastening holes 76 is configured to receive a fastening member 38. The plurality of additional fastening holes 76 are provided in the additional sprocket body 72 so as to correspond to the plurality of fastening holes 36 in the axial direction AD. The plurality of fastening members 38 are provided so as to penetrate the fastening holes 36 and the additional fastening holes 76, whereby the adjacent sprocket 70 is fastened to the rear sprocket 30.

For example, the number of the plurality of additional fastening holes 76 is determined based on the number of the plurality of fastening holes 36. For example, the inner diameter of the additional fastening hole 76 is equal to the inner diameter of the fastening hole 36. For example, the plurality of additional fastening holes 76 includes 14 additional fastening holes 76. For example, the inner diameters of the plurality of additional fastening holes 76 are equal to each other. At least one of the inner diameters of the plurality of additional fastening holes 76 may be different from the others.

As shown in fig. 1 and 4, for example, the adjacent sprocket 70 has an additional axially outward surface 70A and an additional axially inward surface 70B. For example, the additional axially inward surface 70B is provided on the opposite side of the additional axially outward surface 70A in the axial direction AD. For example, the additional axially inward surface 70B is configured to face the axially central surface CS of the manually driven vehicle 10 in the axial direction AD in the mounted state.

As shown in fig. 1, 7 and 10, for example, the plurality of additional sprocket teeth 74 include a plurality of additional downshift promoting teeth 78. For example, the plurality of additional downshift accelerating teeth 78 are configured to accelerate an additional downshift operation. For example, the additional downshift operation is an operation of moving the drive chain 18 from the rear sprocket 30 to the adjacent sprocket 70. For example, in the additional downshift operation, the drive chain 18 is moved from the rear sprocket 30 to the adjacent sprocket 70 by the rear derailleur of the manually driven vehicle 10.

For example, the plurality of additional downshift accelerating teeth 78 includes additional downshift starting teeth 80 and additional downshift concave teeth 82. For example, the additional downshift start tooth 80 is configured to engage with the drive chain 18 first in the additional downshift operation. The tip of the additional downshift start tooth 80 is inclined in the axial direction AD so as to approach the additional axially outward surface 70A from the additional driving surface of the additional downshift start tooth 80 toward the additional non-driving surface of the additional downshift start tooth 80.

For example, the additional downshift concave teeth 82 are configured such that the drive chain 18 can move in the axial direction AD from the additional axially outward surface 70A toward the additional axially inward surface 70B during the additional downshift operation. For example, the additional downshift concave teeth 82 are adjacent to the additional downshift start teeth 80 in the circumferential direction CD so that no additional one 74 of the plurality of additional sprockets 74 is located between the additional downshift start teeth 80 and the additional downshift concave teeth 82. For example, the additional downshift concave tooth 82 is adjacent to the additional downshift start tooth 80 on the downstream side of the additional downshift start tooth 80 with respect to the driving rotation direction RD1 of the adjacent sprocket 70.

For example, the additional downshift concave tooth 82 has an additional downshift concave 84. For example, the additional downshift concave portion 84 is provided on the additional axially outward surface 70A of the additional downshift concave portion tooth 82 so as to be recessed in the axial direction AD from the additional axially outward surface 70A toward the additional axially inward surface 70B. For example, the additional downshift concave portion 84 includes a first additional downshift concave portion 84A and a second additional downshift concave portion 84B. The depth of the second additional downshift concave portion 84B in the axial direction AD is set to be different from the depth of the first additional downshift concave portion 84A in the axial direction AD. For example, the depth of the second additional downshift concave portion 84B in the axial direction AD is greater than the depth of the first additional downshift concave portion 84A in the axial direction AD. The depth of the second additional downshift concave portion 84B in the axial direction AD may be the same as the depth of the first additional downshift concave portion 84A in the axial direction AD. For example, the first additional downshift concave portion 84A and the second additional downshift concave portion 84B are formed by a step-type blanking process.

The plurality of additional downshift accelerating teeth 78 form an additional downshift area adjacent to the sprocket 70. The additional downshift area is formed with an additional downshift concave portion 84 as a structure for improving the shifting performance of the adjacent sprocket 70 during the additional downshift operation. A plurality of additional downshift regions are formed adjacent to the sprocket 70. Each of the plurality of additional downshift areas is formed with an additional downshift start tooth 80 and an additional downshift concave tooth 82 of the plurality of additional downshift accelerating teeth 78. Three additional downshift regions are formed adjacent to the sprocket 70 of fig. 7.

The operation of the drive chain 18 in the additional downshift operation will be described.

In the additional downshift operation, the drive chain 18 engaged with the rear sprocket 30 is moved toward the additional downshift concave tooth 82 of the adjacent sprocket 70 by the rear derailleur. The inner link 18C of the drive chain 18 moves to a position facing the first additional downshift concave portion 84A, and the outer link 18B of the drive chain 18 moves to a position facing the second additional downshift concave portion 84B. With the rear derailleur, the drive chain 18 moves toward the adjacent sprocket 70 and is guided radially outward of the rear sprocket 30 along the additional downshift recess 84. Since the tooth tip of the additional downshift start tooth 80 is inclined so as to approach the additional axially outward surface 70A from the additional driving surface of the additional downshift start tooth 80 toward the additional non-driving surface of the additional downshift start tooth 80, the drive chain 18 is easily fitted into the additional downshift start tooth 80. The drive chain 18 that has been guided to the radial outside is fitted into the tooth tip of the additional downshift start tooth 80, whereby the additional downshift start tooth 80 engages with the drive chain 18. Thereafter, as the adjacent sprocket 70 rotates in the driving rotational direction RD1, the driving chain 18 is disengaged from the rear sprocket 30. The drive chain 18, which is disengaged from the rear sprocket 30, engages with the adjacent sprocket 70, and the additional downshift operation is completed.

For example, when viewed from the axial direction AD, at least a part of at least one of the plurality of fastening holes 36 is arranged between the additional downshift start tooth 80 and the additional downshift concave tooth 82 in the circumferential direction CD. For example, the plurality of fastening holes 36 includes a prescribed fastening hole 36A. At least a part of the predetermined fastening hole 36A is disposed between the first additional reference line AL1 and the second additional reference line AL2 and downstream of the first additional reference line AL1 with respect to the driving rotation direction RD 1. The first additional reference line AL1 is formed by adding the tip of the downshift starting tooth 80 and the rotation center axis X1. The second additional reference line AL2 passes through the tip of the additional downshift concave tooth 82 and the rotation center axis X1. For example, the predetermined fastening hole 36A is arranged so as to overlap the first additional reference line AL1 in the axial direction AD.

For example, the plurality of supplemental sprocket teeth 74 includes abutment teeth 86. For example, the adjacent tooth 86 is adjacent to the additional downshift start tooth 80 in the circumferential direction CD so that no additional sprocket 74 out of the plurality of additional sprockets 74 is located between the additional downshift start tooth 80 and the adjacent tooth 86. For example, the adjacent tooth 86 is adjacent to the additional downshift start tooth 80 on the upstream side of the additional downshift start tooth 80 with respect to the driving rotation direction RD1 of the adjacent sprocket 70.

For example, when viewed from the axial direction AD, at least a part of at least one of the plurality of fastening holes 36 is arranged between the adjacent tooth 86 and the additional downshift concave tooth 82 in the circumferential direction CD. At least a part of the predetermined fastening hole 36A is disposed between the second additional reference line AL2 and the third additional reference line AL3 and downstream of the third additional reference line AL3 with respect to the driving rotation direction RD 1. The third additional reference line AL3 passes through the tip of the adjacent tooth 86 and the rotation center axis X1.

For example, when viewed from the axial direction AD, at least a part of at least one of the plurality of fastening holes 36 is arranged between the adjacent tooth 86 and the additional downshift start tooth 80 in the circumferential direction CD. A part of the predetermined fastening hole 36A is disposed between the first additional reference line AL1 and the third additional reference line AL3 and downstream of the third additional reference line AL3 with respect to the driving rotation direction RD 1.

As shown in fig. 1, 7 and 11, for example, the plurality of additional sprocket teeth 74 include a plurality of additional upshift promoting teeth 88. The plurality of additional upshift promoting teeth 88 are configured to promote an additional upshift operation. The additional upshift operation is an operation of driving the chain 18 to move from the adjacent sprocket 70 to the adjacent small sprocket. For example, in the additional upshift operation, the drive chain 18 is moved from the adjacent sprocket 70 to the rear sprocket 30 by the rear derailleur of the manually driven vehicle 10.

For example, the plurality of additional upshift promoting teeth 88 include additional upshift shifting teeth 90, additional upshift starting teeth 92, and additional upshift recess teeth 94. For example, the additional upshift shift tooth 90 is configured to shift the drive chain 18 toward the adjacent rear sprocket 30 during the additional upshift operation. The tooth tip of the additional upshift displacement tooth 90 is inclined in the axial direction AD so as to approach the additional axial inward surface 70B from the additional driving surface of the additional upshift displacement tooth 90 toward the additional non-driving surface of the additional upshift displacement tooth 90.

For example, the additional upshift starting tooth 92 is configured to be first disengaged from the drive chain 18 in the additional upshift operation. For example, the additional upshift starting tooth 92 is adjacent to the additional upshift displacement tooth 90 in the circumferential direction CD so that no additional sprocket 74 out of the plurality of additional sprockets 74 is located between the additional upshift starting tooth 92 and the additional upshift displacement tooth 90. For example, the additional upshift start tooth 92 is adjacent to the additional upshift shift tooth 90 on the upstream side of the additional upshift shift tooth 90 with respect to the driving rotation direction RD 1.

For example, the additional upshift starting tooth 92 has a first additional upshift recess 92A. For example, the first additional upshift recess 92A is provided on the additional axial outward surface 70A of the additional upshift start tooth 92 so as to be recessed in the axial direction AD from the additional axial outward surface 70A toward the additional axial inward surface 70B. The first additional upshift recess 92A extends from an additional driving surface of the additional upshift starting tooth 92 to an additional non-driving surface of the additional upshift starting tooth 92. For example, the first additional upshift recess portion 92A is formed by a step-type blanking process.

For example, the additional upshift recess tooth 94 is configured not to engage with the drive chain 18 from which the additional upshift start tooth 92 is disengaged during the additional upshift operation. For example, the additional upshift recess tooth 94 is adjacent to the additional upshift start tooth 92 in the circumferential direction CD such that no additional sprocket 74 of the plurality of additional sprockets 74 is located between the additional upshift recess tooth 94 and the additional upshift start tooth 92. For example, the additional upshift recess tooth 94 is adjacent to the additional upshift start tooth 92 on the upstream side of the additional upshift start tooth 92 with respect to the driving rotation direction RD 1.

For example, the additional upshift recess tooth 94 has a second additional upshift recess 94A. For example, the second additional upshift recess portion 94A is provided on the additional axially outward surface 70A of the additional upshift recess portion tooth 94 so as to be recessed in the axial direction AD from the additional axially outward surface 70A toward the additional axially inward surface 70B. The second additional upshift recess 94A extends from an additional driving surface of the additional upshift recess tooth 94 to an additional non-driving surface of the additional upshift recess tooth 94. For example, the second additional upshift recess portion 94A is formed by a step-type blanking process.

For example, the plurality of additional upshift facilitating teeth 88 include reverse upshift shift teeth 96. For example, the reverse upshift shift tooth 96 is configured to bring the drive chain 18 engaged with the adjacent sprocket 70 to the opposite side of the rear sprocket 30 in the axial direction AD in the additional upshift operation. For example, the reverse upshift shift tooth 96 is arranged such that 2 other additional sprocket teeth 74 among the plurality of additional sprocket teeth 74 are arranged between the reverse upshift shift tooth 96 and the additional upshift shift tooth 90 in the circumferential direction CD. For example, the reverse upshift displacement tooth 96 is disposed downstream of the additional upshift starting tooth 92 with respect to the driving rotation direction RD 1.

For example, the reverse upshift shift tooth 96 has a third additional upshift recess 96A. For example, the third additional upshift recess 96A is provided on the additional axially outward surface 70A of the reverse upshift shift tooth 96 so as to be recessed in the axial direction AD from the additional axially outward surface 70A toward the additional axially inward surface 70B. The third additional upshift recess 96A extends from an additional driving surface of the reverse upshift shift tooth 96 to an additional non-driving surface of the reverse upshift shift tooth 96.

The plurality of additional upshift promoting teeth 88 form an additional upshift area adjacent to sprocket 70. The additional upshift region is formed with a first additional upshift recess 92A and a second additional upshift recess 94A as a structure for improving the shifting performance of the adjacent sprocket 70 during the upshift operation. A plurality of additional upshift areas are formed adjacent to the sprocket 70. Each of the plurality of additional upshift regions is formed with an additional upshift displacement tooth 90, an additional upshift starting tooth 92, and an additional upshift recess tooth 94 among the plurality of additional upshift promoting teeth 88. Four additional upshift areas are formed in the adjacent sprocket 70 of fig. 7.

The operation of the drive chain 18 in the additional upshift operation will be described with reference to fig. 12.

In the additional upshift operation, the drive chain 18 engaged with the adjacent sprocket 70 is moved toward the rear sprocket 30 by the rear derailleur. The outer link 18B of the drive chain 18 engages with the additional upshift shift tooth 90. When the drive chain 18 engages with the additional upshift shift tooth 90, the tooth top of the additional upshift shift tooth 90 is inclined so as to approach the additional axial inward surface 70B from the additional drive surface of the additional upshift shift tooth 90 toward the additional non-drive surface of the additional upshift shift tooth 90, and therefore the drive chain 18 approaches the rear sprocket 30. Inner link 18C of drive chain 18 is disengaged from additional upshift starting tooth 92. Since the tooth top of the additional upshift starting tooth 92 is made to approach the additional axially inward surface 70B by the first additional upshift concave portion 92A, the drive chain 18 approaching the rear sprocket 30 is easily disengaged from the additional upshift starting tooth 92. The drive chain 18, from which the additional upshift starting tooth 92 is disengaged, moves radially inward with respect to the rotation center axis X1. Outer link 18B of drive chain 18 is disengaged from additional upshift starting tooth 92. The second additional upshift recess portion 94A brings the tip of the additional upshift recess portion tooth 94 closer to the additional axially inward surface 70B than the tip of the additional upshift start tooth 92. Therefore, the drive chain 18 that has disengaged the additional upshift starting tooth 92 does not engage with the additional upshift recess tooth 94. Thereafter, as the adjacent sprocket 70 rotates in the driving rotation direction RD1, the driving chain 18 is disengaged from the adjacent sprocket 70. The drive chain 18, which is disengaged from the adjacent sprocket 70, engages with the rear sprocket 30, and the additional upshift operation is completed.

When the drive chain 18 is disengaged from the additional upshift starting tooth 92 in the additional upshift operation, the drive chain 18 engaged with the additional sprocket tooth 74 located downstream of the additional upshift starting tooth 92 in the drive rotation direction RD1 rotates toward the additional axially inward surface 70B with the additional upshift displacement tooth 90 as a fulcrum. In the additional upshift operation, inner link 18C of drive chain 18 engages reverse upshift shift tooth 96. Since the tooth tip of the reverse upshift displacement tooth 96 is brought close to the additional axially inward surface 70B by the third additional upshift recess portion 96A, the drive chain 18 is easily moved toward the additional axially inward surface 70B side. The drive chain 18 engaged with the additional sprocket tooth 74 located downstream of the additional upshift start tooth 92 in the drive rotation direction RD1 is easily rotated toward the additional axially inward surface 70B by the reverse upshift shift tooth 96. Therefore, the reverse upshift shift tooth 96 can reduce the shift shock during the additional upshift operation.

The fastening member is disposed in the fastening hole, so that the rigidity of the rear sprocket in the axial direction is improved. In the rear sprocket 30, the fastening hole 36 is provided in the sprocket body 32 so as not to overlap the downshift concave portion 54, the first upshift concave portion 60A, and the second upshift concave portion 62A. Therefore, when the fastening member 38 is disposed in the fastening hole 36, the rear sprocket 30 has sufficient shifting performance and rigidity is improved by the fastening member 38.

< modification >

The description of the embodiments is an example of the manner in which the rear sprocket of the human-powered vehicle of the present disclosure may take, and is not intended to be limiting in its manner. For example, the rear sprocket for a human-powered vehicle according to the present disclosure may be configured by combining at least two modifications of the embodiments shown below, which are not contradictory to each other. In the following modification, the same reference numerals as those of the respective embodiments are given to the portions common to the respective embodiments, and the description thereof is omitted.

The plurality of fastening holes 36 may each be configured to receive a fastening member for fastening the rear sprocket 30 and the adjacent small sprocket 26A to each other.

At least one of the plurality of fastening holes 36 may be disposed at a position different from the other fastening holes in the radial direction with respect to the rotation center axis X1. Preferably, even when at least one of the plurality of fastening holes 36 is disposed at a position different from the other fastening holes in the radial direction with respect to the rotation center axis X1, each of the plurality of fastening holes 36 is configured to receive the fastening member 38 that fastens the rear sprocket 30 and the adjacent sprocket 70 to each other.

In the adjacent sprocket 70, the additional downshift start tooth 80 may be disposed so that the first additional reference line AL1 passes through the center axis C of the predetermined fastening hole 36A. When the additional downshift starting tooth 80 is disposed such that the first additional reference line AL1 passes through the center axis C of the predetermined fastening hole 36A, the rigidity of the additional downshift starting tooth 80 in the axial direction AD can be further improved by the fastening member 38.

The reverse upshift shift teeth 96 may be arranged on the rear sprocket 30. For example, the plurality of upshift facilitating teeth 56 includes reverse upshift shifting teeth. For example, the reverse upshift shift tooth 96 is configured to bring the drive chain 18 engaged with the rear sprocket 30 to the axially inward surface 30B side in the axial direction AD during the upshift operation. For example, the reverse upshift shift tooth 96 is arranged such that 2 other sprocket teeth 34 among the plurality of sprocket teeth 34 are arranged between the reverse upshift shift tooth 96 and the upshift shift tooth 58 in the circumferential direction CD. For example, the reverse upshift displacement tooth 96 is disposed downstream of the upshift displacement tooth 58 with respect to the driving rotation direction RD 1.

The expression "at least one" as used in the present specification refers to "one or more" of the desired options. As an example, if the number of options is two, the expression "at least one" used in the present specification means "only one option" or "both options". As another example, if the number of options is three or more, the expression "at least one" used in the present specification means "one only option" or "a combination of any two or more options".

Symbol description:

a 10-man power drive vehicle, 18 drive chain, 26 rear sprocket assembly, 30 rear sprocket, 30A axially outward facing surface, 30B axially inward facing surface, 32 sprocket body, 34 sprocket tooth, 36 fastening hole, 38 fastening member, 40 first adjacent fastening hole, 40A first fastening hole, 40B second fastening hole, 42 second adjacent fastening hole, 42A third fastening hole, 42B fourth fastening hole, 44 third adjacent fastening hole, 44A fifth fastening hole, 44B sixth fastening hole, 48 shift-down promoting tooth, 50 shift-down starting tooth, 52 shift-down recess tooth, 54 shift-down recess tooth, 56 shift-up promoting tooth, 58 shift-up shifting tooth, 60 shift-up starting tooth, 60A first shift-up recess tooth, 62A second shift-up recess tooth, 70 adjacent sprocket, 70A additional axially outward facing surface, 70B additional axially inward facing surface, 72 additional sprocket body, 74 additional sprocket tooth, 78 additional shift-down promoting tooth, 80 additional shift-down starting tooth, 82 additional shift-down recess tooth, 84 additional recess tooth, 86 additional recess tooth.

Claims

1. A rear sprocket for a human-powered vehicle, wherein,

the rear sprocket has an axially outward facing surface and an axially inward facing surface provided on opposite sides of the axially outward facing surface in an axial direction with respect to a rotation center axis of the rear sprocket,

the axially inward surface is configured to face an axially center surface of the manual drive vehicle in the axial direction in a mounted state in which the rear sprocket is mounted on the manual drive vehicle,

the rear sprocket includes:

a sprocket body;

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

a plurality of fastening holes provided in the sprocket body,

each of the plurality of fastening holes is configured to receive a fastening member that fastens the rear sprocket and the adjacent sprocket to each other,

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

two first adjacent fastening holes of the plurality of fastening holes are arranged at a first pitch angle in a circumferential direction about the rotation center axis, the two first adjacent fastening holes being adjacent to each other in such a manner that no other fastening hole of the plurality of fastening holes is located between the two first adjacent fastening holes in the circumferential direction,

Two second adjacent fastening holes of the plurality of fastening holes are arranged at a second pitch angle in the circumferential direction, the second pitch angle being different from the first pitch angle, the two second adjacent fastening holes being adjacent to each other in such a manner that no other fastening hole of the plurality of fastening holes is located between the two second adjacent fastening holes in the circumferential direction,

two third adjacent fastening holes of the plurality of fastening holes are arranged at a third pitch angle in the circumferential direction, the third pitch angle being different from each of the first pitch angle and the second pitch angle, the two third adjacent fastening holes being adjacent to each other in such a manner that no other fastening hole of the plurality of fastening holes is between the two third adjacent fastening holes in the circumferential direction.

2. The rear sprocket as set forth in claim 1, wherein,

the two first adjacent fastening holes include a first fastening hole having a first hole center axis and a second fastening hole having a second hole center axis,

the two second adjacent fastening holes include a third fastening hole having a third hole center axis and a fourth fastening hole having a fourth hole center axis,

The two third adjacent fastening holes include a fifth fastening hole having a fifth hole center axis and a sixth fastening hole having a sixth hole center axis,

the first pitch angle is defined by a first reference line passing through the first hole center axis and the rotation center axis, and a second reference line passing through the second hole center axis and the rotation center axis,

the second pitch angle is defined by a third reference line passing through the third hole center axis and the rotation center axis, and a fourth reference line passing through the fourth hole center axis and the rotation center axis,

the third pitch angle is defined by a fifth reference line passing through the fifth hole center axis and the rotation center axis, and a sixth reference line passing through the sixth hole center axis and the rotation center axis.

3. The rear sprocket as set forth in claim 1, wherein,

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

the plurality of downshift promoting teeth includes:

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

The gear of the gear-down concave part,

the downshift concave tooth is adjacent to the downshift start tooth on a downstream side of the downshift start tooth with respect to a driving rotation direction of the rear sprocket in such a manner that no other sprocket tooth of the plurality of sprocket teeth is located between the downshift start tooth and the downshift concave tooth in the circumferential direction,

the downshift concave teeth have downshift concave portions provided on the axially outward surfaces of the downshift concave teeth so as to be recessed in the axial direction from the axially outward surfaces toward the axially inward surfaces,

the plurality of fastening holes are configured to avoid overlapping with the downshift recess.

4. The rear sprocket as set forth in claim 1, wherein,

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

the plurality of upshift facilitating teeth includes:

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

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

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

The upshift starting tooth has a first upshift recess portion provided on the axially outward surface of the upshift starting tooth so as to be recessed in the axial direction from the axially outward surface toward the axially inward surface,

the upshift start tooth is adjacent to the upshift shift tooth on an upstream side of the upshift shift tooth with respect to a driving rotation direction of the rear sprocket in such a manner that no other sprocket tooth of the plurality of sprocket teeth is located between the upshift start tooth and the upshift shift tooth in the circumferential direction,

the upshift recess teeth have second upshift recesses provided on the axially outward surfaces of the upshift recess teeth so as to be recessed in the axial direction from the axially outward surfaces toward the axially inward surfaces,

the upshift recess tooth is adjacent to the upshift start tooth on an upstream side of the upshift start tooth with respect to a driving rotation direction of the rear sprocket in such a manner that no other sprocket tooth of the plurality of sprocket teeth is located between the upshift recess tooth and the upshift start tooth in the circumferential direction,

the plurality of fastening holes are configured to avoid overlapping with the first upshift recess portion and the second upshift recess portion.

5. The rear sprocket as set forth in claim 1, wherein,

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

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

6. A rear sprocket assembly for a human-powered vehicle, comprising:

the rear sprocket of any one of claims 1 to 5 and having a first pitch diameter; and

the adjacent sprocket is the adjacent sprocket having a second pitch diameter larger than the first pitch diameter and is coaxially arranged with the rear sprocket in an assembled state of the rear sprocket assembly.

7. The rear sprocket assembly as set forth in claim 6, wherein,

the adjacent sprocket is provided with:

adding a sprocket body; and

and a plurality of additional sprocket teeth extending radially outward from the additional sprocket body in the radial direction.

8. The rear sprocket assembly of claim 7, wherein,

the adjacent sprocket has an additional axially outward surface and an additional axially inward surface, the additional axially inward surface being provided on an opposite side of the additional axially outward surface in the axial direction,

The additional axially inward surface is configured to face the axially central surface of the manually driven vehicle in the axial direction in the mounted state,

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

the plurality of additional downshift promoting teeth includes:

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

the gear-down concave part teeth are added,

the additional downshift concave tooth is adjacent to the additional downshift concave tooth on the downstream side of the additional downshift concave tooth with respect to the driving rotation direction of the adjacent sprocket in a manner that no other additional sprocket tooth of the plurality of additional sprocket teeth is located between the additional downshift concave tooth and the additional downshift concave tooth in the circumferential direction,

the additional downshift concave tooth has an additional downshift concave portion provided on the additional axially outward surface of the additional downshift concave tooth so as to be recessed in the axial direction from the additional axially outward surface toward the additional axially inward surface.

9. The rear sprocket assembly of claim 8, wherein,

at least a part of at least one of the plurality of fastening holes is arranged between the additional downshift start tooth and the additional downshift concave tooth in the circumferential direction when viewed from the axial direction.

10. The rear sprocket assembly of claim 8, wherein,

the plurality of additional sprocket teeth includes abutting teeth,

the adjacent tooth is adjacent to the additional downshift start tooth on an upstream side of the additional downshift start tooth with respect to a driving rotation direction of the adjacent sprocket in such a manner that no other additional sprocket tooth of the plurality of additional sprocket teeth is located between the additional downshift start tooth and the adjacent tooth in the circumferential direction,

at least a part of at least one of the plurality of fastening holes is disposed between the adjacent tooth and the additional downshift concave tooth in the circumferential direction when viewed in the axial direction.

11. The rear sprocket assembly of claim 10, wherein,

at least a part of at least one of the plurality of fastening holes is disposed between the adjacent tooth and the additional downshift start tooth in the circumferential direction when viewed from the axial direction.

12. The rear sprocket assembly of claim 7, wherein,

each of the plurality of additional sprocket teeth having an additional maximum radial length in the radial direction and an additional maximum axial length in the axial direction,

the additional maximum radial length is greater than the additional maximum axial length.