Human-powered vehicle rear sprocket and human-powered vehicle rear sprocket assembly

Abstract

Provided is a rear sprocket for a human-powered vehicle and a rear sprocket assembly for a human-powered vehicle that can ensure the performance of a shift. 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 is 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 are arranged at a first pitch angle in a circumferential direction about a rotational center axis. 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 is different from the first pitch angle. 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 is different from each of the first pitch angle and the second pitch angle.

Description

Technical Field

[0001] This disclosure relates to a human-powered rear sprocket for vehicles and a human-powered rear sprocket assembly for vehicles. Background Technology

[0002] Patent Document 1 discloses a rear sprocket for a manually driven vehicle. The rear sprocket of Patent Document 1 has a structure for improving shifting performance and multiple fastening holes.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Chinese Patent Application Publication No. 102328724. Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] If multiple fastening holes are located in positions that affect the structure used to improve shifting performance, it may inhibit the improvement of shifting performance of the rear sprocket in a manually driven vehicle.

[0008] One of the purposes of this disclosure is to provide a manually operated rear sprocket for automobiles and a manually operated rear sprocket assembly that can ensure the shifting performance of the rear sprocket.

[0009] means for solving problems

[0010] According to a first aspect of this disclosure, a rear sprocket is a rear sprocket for a manually driven vehicle, wherein the rear sprocket has an axially outward surface and an axially inward surface, the axially inward surface being disposed on the opposite side of the axially outward surface in an axial direction about the rotational center axis of the rear sprocket, the axially inward surface being configured to face the axial center surface of the manually driven vehicle in an axial direction when the rear sprocket is mounted on the manually driven vehicle. The rear sprocket comprises: a sprocket body; a plurality of sprocket teeth extending radially outward from the sprocket body about the rotational center axis; and a plurality of fastening holes disposed on the sprocket body, each of the plurality of fastening holes being configured to receive a fastening member for fastening the rear sprocket to an adjacent sprocket, the adjacent sprockets being adjacent to each other in an axial direction such that there are no other sprockets between the adjacent sprocket and the rear sprocket, and two first adjacent fastening holes of the plurality of fastening holes being located about the rotational center axis. The mandrel is arranged with a first rounded angle in the circumferential direction. The two first adjacent fastening holes are adjacent to each other in the circumferential direction such that there are no other fastening holes among the plurality of fastening holes between the two first adjacent fastening holes. The two second adjacent fastening holes among the plurality of fastening holes are arranged with a second rounded angle in the circumferential direction, the second rounded angle being different from the first rounded angle. The two second adjacent fastening holes are adjacent to each other in the circumferential direction such that there are no other fastening holes among the plurality of fastening holes between the two second adjacent fastening holes. The two third adjacent fastening holes among the plurality of fastening holes are arranged with a third rounded angle in the circumferential direction, the third rounded angle being different from each of the first rounded angle and the second rounded angle. The two third adjacent fastening holes are adjacent to each other in the circumferential direction such that there are no other fastening holes among the plurality of fastening holes between the two third adjacent fastening holes.

[0011] According to the rear sprocket of the first aspect, since multiple fastening holes can be configured with different pitch circle angles depending on the configuration of the structure used to improve shifting performance, the multiple fastening holes are less likely to be positioned in a way that would affect the structure used to improve shifting performance. Therefore, the shifting performance of the rear sprocket can be ensured. According to the rear sprocket of the first aspect, since multiple fastening holes can be configured with different pitch circle angles, the flexibility in the configuration of the structure used to improve shifting performance is beneficial. According to the rear sprocket of the first aspect, since multiple fastening holes can be configured with different pitch circle angles depending on the shape of the rear sprocket, the strength of the rear sprocket can be ensured.

[0012] In the rear sprocket of the second aspect of the first aspect of this disclosure, the two first adjacent fastening holes include a first fastening hole having a first hole central axis and a second fastening hole having a second hole central axis; the two second adjacent fastening holes include a third fastening hole having a third hole central axis and a fourth fastening hole having a fourth hole central axis; the two third adjacent fastening holes include a fifth fastening hole having a fifth hole central axis and a sixth fastening hole having a sixth hole central axis; the first section radius angle is defined by a first reference line passing through the first hole central axis and the rotation central axis, and a second reference line passing through the second hole central axis and the rotation central axis; the second section radius angle is defined by a third reference line passing through the third hole central axis and the rotation central axis, and a fourth reference line passing through the fourth hole central axis and the rotation central axis; the third section radius angle is defined by a fifth reference line passing through the fifth hole central axis and the rotation central axis, and a sixth reference line passing through the sixth hole central axis and the rotation central axis.

[0013] According to the second aspect of the rear sprocket, the speed-changing performance of the rear sprocket can be ensured, and the freedom of configuration of the structure used to improve the speed-changing performance is beneficial.

[0014] In the rear sprocket of a third aspect according to the first or second aspect of this disclosure, the plurality of sprocket teeth include a plurality of downshift actuating teeth configured to facilitate a downshifting action of the drive chain moving from an adjacent small sprocket to the rear sprocket. The plurality of downshift actuating teeth include: a downshift initiating tooth that engages with the drive chain first during the downshifting action; and a downshift recessing tooth, the downshift recessing tooth being adjacent to the downshift initiating tooth on the downstream side of the downshift initiating tooth about the drive rotation direction of the rear sprocket in the circumferential direction, such that no other sprocket teeth of the plurality of sprocket teeth are between the downshift initiating tooth and the downshift recessing tooth. The downshift recessing tooth has a downshift recess that is recessed in the axial direction from the axially outward surface toward the axially inward surface. The plurality of fastening holes are configured to avoid overlapping with the downshift recess.

[0015] According to the third aspect of the rear sprocket, since the multiple fastening holes are configured to avoid overlapping with the downshift recess, the shifting performance of the multiple downshift facilitator teeth is less affected by the multiple fastening holes. Therefore, smooth downshifting with minimal shifting impact can be achieved during downshifting.

[0016] In the rear sprocket of the fourth aspect of any one of the first to third aspects of this disclosure, the plurality of sprocket teeth include a plurality of upshift promoting teeth configured to promote an upshifting action in which the drive chain moves from the rear sprocket to an adjacent pinion. The plurality of upshift promoting teeth include: an upshift displacement tooth configured to displace the drive chain toward the adjacent pinion during the upshifting action; an upshift initiation tooth configured to disengage from the drive chain first during the upshifting action; and an upshift recess tooth having a first upshift recess located on the axially outer surface of the upshift initiation tooth in a manner that recesses from the axially outer surface toward the axially inner surface in the axial direction. The upshift initiation tooth is positioned such that, in the circumferential direction, during the upshifting action... The gear shifting tooth is adjacent to the shifting tooth on the upstream side of the drive rotation direction of the rear sprocket, with no other sprocket teeth between the gear shifting tooth and the shifting tooth. The shifting tooth has a second shifting recess, which is recessed from the axially outward face to the axially inward face in the axial direction. The shifting tooth is adjacent to the shifting tooth on the upstream side of the drive rotation direction of the rear sprocket, with no other sprocket teeth between the shifting tooth and the shifting tooth in the circumferential direction. The plurality of fastening holes are configured to avoid overlapping with the first shifting recess and the second shifting recess.

[0017] According to the fourth aspect of the rear sprocket, since the multiple fastening holes are configured to avoid overlapping with the first and second upshift recesses, the shifting performance of the multiple upshift promoting teeth is less affected by the multiple fastening holes. Therefore, smooth upshifting with minimal shifting impact can be achieved during upshifting.

[0018] In the rear sprocket of the fifth aspect according to any one of the first to fourth aspects of this 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, wherein the maximum radial length is greater than the maximum axial length.

[0019] According to the fifth aspect of the rear sprocket, since the maximum axial length can be shortened, the number of sprockets included in the rear sprocket assembly can be increased.

[0020] The rear sprocket assembly according to the sixth aspect of this disclosure is a rear sprocket assembly for a manually driven vehicle, and includes: the rear sprocket, which is the rear sprocket described in any one of the first to fifth aspects of this disclosure and has a first pitch circle diameter; and the adjacent sprocket, which is the adjacent sprocket having a second pitch circle diameter larger than the first pitch circle diameter, and is coaxially configured with the rear sprocket in the assembled state of the rear sprocket assembly.

[0021] According to the rear sprocket assembly in the sixth aspect, a rear sprocket assembly that ensures both shifting performance and excellent strength can be achieved.

[0022] In the rear sprocket assembly of the sixth and seventh aspects of this disclosure, the adjacent sprocket has an additional sprocket body and a plurality of additional sprocket teeth that extend radially outward from the additional sprocket body in the radial direction.

[0023] According to the rear sprocket assembly in the seventh aspect, a rear sprocket assembly that ensures both shifting performance and excellent strength can be achieved.

[0024] In the rear sprocket assembly according to the seventh aspect of the present disclosure, the adjacent sprocket has an additional axial outward surface and an additional axial inward surface, the additional axial inward surface being disposed on the opposite side of the additional axial outward surface in the axial direction, the additional axial inward surface being configured to face the axial center surface of the manually driven vehicle in the axial direction in the installed state, the plurality of additional sprocket teeth including a plurality of additional downshift promoting teeth, the plurality of additional downshift promoting teeth being configured to promote an additional downshifting action of the drive chain moving from the rear sprocket to the adjacent sprocket, the plurality of additional downshift promoting teeth including: an additional downshift initiation tooth, which is configured to... The additional downshift action first engages with the drive chain; and the additional downshift recessed tooth is positioned such that, in the circumferential direction, there are no other additional sprocket teeth among the plurality of additional sprocket teeth between the additional downshift initiation tooth and the additional downshift recessed tooth, and is adjacent to the additional downshift initiation tooth on the downstream side of the additional downshift initiation tooth with respect to the drive rotation direction of the adjacent sprocket, the additional downshift recessed tooth having an additional downshift recess, which is provided on the additional axial outward surface of the additional downshift recessed tooth in the axial direction such that it is recessed from the additional axial outward surface toward the additional axial inward surface.

[0025] According to the rear sprocket assembly in aspect eight, multiple additional downshifting facilitators can reduce shifting shock during additional downshifting. Therefore, adjacent sprockets can perform smooth additional downshifting.

[0026] In the rear sprocket assembly of the ninth aspect of the eighth aspect of this disclosure, when viewed from the axial direction, at least a portion of at least one of the plurality of fastening holes is disposed in the circumferential direction between the additional downshift initiation tooth and the additional downshift recess tooth.

[0027] According to the rear sprocket assembly of the ninth aspect, the axial rigidity of the portion of the adjacent sprocket corresponding to the fastening member in the radial direction of the adjacent sprocket is increased by the fastening member.

[0028] In the rear sprocket assembly of the eighth or ninth aspect of this disclosure, the plurality of additional sprocket teeth include adjacent teeth, the adjacent teeth being adjacent to the additional downshift initiation tooth on the upstream side of the additional downshift initiation tooth with respect to the drive rotation direction of the adjacent sprocket in the circumferential direction, such that no other additional sprocket teeth of the plurality of additional sprocket teeth are between the additional downshift initiation tooth and the adjacent teeth, and when viewed from the axial direction, at least a portion of at least one of the plurality of fastening holes is disposed in the circumferential direction between the adjacent teeth and the additional downshift recess teeth.

[0029] According to the rear sprocket assembly of the tenth aspect, the axial rigidity of the portion of the adjacent sprocket corresponding to the fastening member in the radial direction of the adjacent sprocket can be improved by means of a fastening member.

[0030] In the eleventh aspect of the tenth aspect of this disclosure, when viewed from the axial direction, at least a portion of at least one of the plurality of fastening holes is disposed in the circumferential direction between the adjacent tooth and the additional downshift initiation tooth.

[0031] According to the rear sprocket assembly of aspect eleven, the axial rigidity of the portion of the adjacent sprocket corresponding to the fastening member in the radial direction of the adjacent sprocket can be improved by the fastening member.

[0032] In the rear sprocket assembly of the twelfth aspect according to any one of the seventh to eleventh aspects of this disclosure, each of the plurality of additional sprocket teeth has the additional maximum radial length in the radial direction and the additional maximum axial length in the axial direction, the additional maximum radial length being greater than the additional maximum axial length.

[0033] According to the twelfth aspect of the rear sprocket assembly, since the maximum additional axial length can be shortened, the number of sprockets included in the rear sprocket assembly can be increased.

[0034] Invention Effects

[0035] The manually operated rear sprocket and its assembly disclosed herein ensure the speed-changing performance of the rear sprocket and increase the flexibility in configuring multiple fastening holes. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of a human-powered vehicle including a human-powered rear sprocket assembly, wherein the human-powered rear sprocket assembly has the human-powered rear sprocket in the embodiment.

[0037] Figure 2 yes Figure 1 Side view of a human-powered vehicle rear sprocket assembly;

[0038] Figure 3 yes Figure 2 Side view of the rear sprocket of a human-powered vehicle;

[0039] Figure 4 yes Figure 2 A sectional view of line D4-D4;

[0040] Figure 5 It means Figure 3 A top view of the multiple downshifting facilitators and chain;

[0041] Figure 6 It means Figure 3 A top view of the multiple upshifting teeth and chain;

[0042] Figure 7 yes Figure 2 Side view of the adjacent sprocket;

[0043] Figure 8 yes Figure 2 A first side view of the rear sprocket, adjacent sprocket, and fastening components of a human-powered vehicle;

[0044] Figure 9 yes Figure 2 A second side view of the rear sprocket, adjacent sprocket, and fastening components of a human-powered vehicle;

[0045] Figure 10 It means Figure 7 A top view of the multiple additional downshifting accelerator teeth and chain;

[0046] Figure 11 It means Figure 7 A top view of the multiple additional upshifting teeth and chain;

[0047] Figure 12 This is a top view showing an example of a state in which the drive chain is about to move from the adjacent sprocket to the manually driven rear sprocket in a manually driven vehicle assembly according to an embodiment, by adding an upshifting action. Detailed Implementation

[0048] <First Implementation>

[0049] Reference Figures 1 to 12 The following describes the human-powered rear sprocket 30 and the human-powered rear sprocket assembly 26 of the embodiments. Figure 1The human-powered vehicle 10 shown is a vehicle having at least one wheel and capable of being driven by human power. The human-powered vehicle 10 includes various types of bicycles, such as mountain bikes, road bikes, city bikes, freight bikes, push bikes, and recumbent bikes. The number of wheels in the human-powered vehicle 10 is not limited. The human-powered vehicle 10 includes, for example, unicycles and vehicles with two or more wheels. The human-powered vehicle 10 is not limited to vehicles capable of being driven solely by human power. The human-powered vehicle 10 includes electric bicycles (E-bikes) that are propelled not only by human power but also by the driving force of an electric motor. Electric bicycles (E-bikes) include electric-assisted bicycles that are propelled with the assistance of an electric motor. Hereinafter, in each embodiment, the human-powered vehicle 10 will be described as a bicycle.

[0050] In this specification, the following terms indicating direction, such as “front,” “back,” “in front,” “rear,” “left,” “right,” “horizontal,” “above,” and “below,” as well as any other similar terms indicating direction, refer to these directions as determined from the reference position of the human-powered vehicle 10 (e.g., on the saddle or seat) with the rider facing the handlebars as the reference.

[0051] like Figure 1 As shown, for example, the 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 on the crank 12.

[0052] The crank 12 includes a crankshaft 20 and a pair of crank arms 22. Each of the pair of crank arms 22 is mounted on the crankshaft 20. The pedal 24 is rotatably connected to each of the pair of crank arms 22.

[0053] For example, the human-powered vehicle 10 includes a rear sprocket assembly 26. For example, the rear hub assembly 16 includes the 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 wheel of the human-powered vehicle 10.

[0054] The rear sprocket assembly 26 includes multiple sprockets of different sizes. The number of sprockets can be arbitrarily selected. For example, Figure 2 The rear sprocket assembly 26 shown includes 10 sprockets. The rear sprocket assembly 26 may include 2 or more but less than 10 sprockets, or it may include 11 or more sprockets.

[0055] like Figure 5As shown, the drive chain 18 includes multiple rollers 18A, multiple outer links 18B, and multiple inner links 18C. The outer links 18B are configured as a pair of paddles arranged axially along AD. The inner links 18C are configured as a pair of paddles arranged axially along AD. The drive chain 18 is wound around the front sprocket 14 and the rear sprocket assembly 26. The drive chain 18 transmits the human driving force applied to the pedal 24 from the front sprocket 14 to the rear sprocket assembly 26. The rear sprocket assembly 26 transmits the human driving force to the rear wheel of the human-powered vehicle 10 via the hub shaft 28.

[0056] For example, the human-powered vehicle 10 also includes a rear derailleur. The rear derailleur performs a shifting action by moving the drive chain 18 so that the drive chain 18, which is engaged with one of the sprockets, moves from one sprocket to another.

[0057] like Figure 2 As shown, in this embodiment, the sprocket with the second largest diameter among the plurality of sprockets will be described as the rear sprocket 30. In this embodiment, the sprocket with the largest diameter among the plurality of sprockets will be described as the adjacent sprocket 70. The adjacent sprocket 70 is adjacent to the rear sprocket 30. In this embodiment, the sprocket with the third largest diameter among the plurality of sprockets will be described as the adjacent small sprocket 26A. The adjacent small sprocket 26A is adjacent to the rear sprocket 30 and is smaller than the rear sprocket 30.

[0058] like Figure 2 As shown, for example, the rear sprocket assembly 26 includes a rear sprocket 30 and an adjacent sprocket 70. In Figure 2 The diagram shows the rear sprocket assembly 26 in its assembled state. For example, the adjacent sprocket 70 is coaxially configured 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.

[0059] like Figure 3 As shown, for example, the rear sprocket 30 has a first pitch circle diameter D1. The first pitch circle diameter D1 is the diameter of the first pitch circle P1 passing through the central axis of the roller 18A of the drive chain 18, assuming that the drive chain 18 is configured on the rear sprocket 30.

[0060] like Figure 9 As shown, for example, the adjacent sprocket 70 has a second section circle diameter D2. The second section circle diameter D2 is the diameter of the second section circle P2 passing through the central axis of the roller 18A of the drive chain 18, assuming the drive chain 18 is positioned adjacent to the sprocket 70. For example, the second section circle diameter D2 is larger than the first section circle diameter D1.

[0061] like Figure 1 and Figure 4As shown, the rear sprocket 30 has an axially outward surface 30A and an axially inward surface 30B. The axially inward surface 30B is located on the opposite side of the axially outward surface 30A along the axial direction AD about the rotation center axis X1 of the rear sprocket 30. The axially inward surface 30B is configured to face the axial center surface CS of the manual drive vehicle 10 along the axial direction AD in the installed state. For example, the axial center surface CS of the manual drive vehicle 10 substantially coincides with the lateral center of the manual drive vehicle 10. The installed state is the state in which the rear sprocket 30 is mounted on the manual drive vehicle 10. In the installed state, the rear sprocket assembly 26 is in an assembled state. In the installed state, the adjacent sprocket 70 is coaxially configured with the rear sprocket 30.

[0062] like Figure 3 As shown, 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 the portion of the outer annular portion 32A facing the hub shaft 28 in the installed state. The outer peripheral portion 32E is the portion of the outer annular portion 32A located on the opposite side of the inner peripheral portion 32D in the radial direction about the rotation center axis X1 in the installed state. The inner annular portion 32B has a plurality of spline teeth 32F that engage with 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 about the rotation center axis X1 of the rear sprocket 30.

[0063] like Figures 4 to 6 As shown, a plurality of sprocket teeth 34 extend radially outward from the sprocket body 32 about the rotation center axis X1. The rear sprocket 30 engages with the drive chain 18 by interlocking the plurality of sprocket teeth 34 between a pair of outer chain plates of the outer link 18B and between a pair of inner chain plates of the inner link 18C. For example, each sprocket tooth 34 has a driving surface and a non-driving surface, the non-driving surface being located on the opposite side of the driving surface in the circumferential direction CD about the rotation center axis X1. The driving surface is located on the side upstream of the sprocket tooth 34 in the drive rotation direction RD1 of the rear sprocket 30. When the rear sprocket 30 rotates in the drive rotation direction RD1, each sprocket tooth 34 engages with the rollers 18A of the drive chain 18 on the driving surface.

[0064] like Figure 4 As shown, for example, each of the plurality of sprocket teeth 34 has a maximum radial length L1 and a maximum axial length L2 in the axial direction AD. For example, the maximum radial length L1 is the length from the outer periphery 32E of the sprocket body 32 to the tooth tip. For example, the maximum axial length L2 is the length from the axially outward surface 30A to the axially inward surface 30B. The maximum radial length L1 is greater than the maximum axial length L2.

[0065] like Figure 3 As shown, 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 member 38 fastens the rear sprocket 30 and the adjacent sprocket 70 to each other. The adjacent sprocket 70 is abutted in such a manner that there are no other sprockets between the adjacent sprocket 70 and the rear sprocket 30 in the axial direction AD. 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 held by the rear sprocket 30 and the adjacent sprocket 70 is, for example, larger than the inner diameter of the fastening hole 36.

[0066] The inner diameter of the fastening hole 36 is larger than the maximum axial length L2 of the sprocket tooth 34. For example, the inner diameters of the plurality of fastening holes 36 are all 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.

[0067] Each of the plurality of fastening holes 36 has a central axis C. The central axes C of the plurality of fastening holes 36 are arranged at the same position radially about the rotational central axis X1. A plurality of pitch circle angles are defined by the angles formed by two reference lines A corresponding to two adjacent fastening holes 36, respectively. The plurality of reference lines A pass through the rotational central axis X1 and the respective central 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 circle angles.

[0068] 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 this embodiment, a combination of two fastening holes 36 that are adjacent to each other in such a way that there are no other fastening holes 36 in the plurality of fastening holes 36 on the circumferential direction CD is defined as two adjacent fastening holes. The plurality of fastening holes 36 includes three or more sets of two adjacent fastening 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 fastening holes 36 may include four or more sets of two adjacent fastening holes. For example, the plurality of fastening holes 36 may also include two fourth adjacent fastening holes 46. The number of sets of two adjacent fastening holes is 3 or more and the number of the plurality of fastening holes 36 is less than. In this embodiment, the number of sets of two adjacent fastening holes is 14.

[0069] Two first adjacent fastening holes 40, two second adjacent fastening holes 42, and two third adjacent fastening holes 44 are arbitrarily selected from a plurality of fastening holes 36. At least one of the two fastening holes 36 included in each of the two first adjacent fastening holes 40, two second adjacent fastening holes 42, and two third adjacent fastening holes 44 may be different from the other two groups. One of the plurality of fastening holes 36 may be selected as one of the two first adjacent fastening holes 40 and 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 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 one of the two third adjacent fastening holes 44.

[0070] Two first adjacent fastening holes 40 are adjacent to each other in a manner such that there are no other fastening holes 36 among a plurality of fastening holes 36 between the two first adjacent 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 central axis C1. For example, the second fastening hole 40B has a second hole central axis C2.

[0071] Two first adjacent fastening holes 40 of the plurality of fastening holes 36 are arranged with a first circular angle B1 on the circumferential direction CD about the rotation center axis X1. For example, the first circular 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 circular angle B1 is the angle formed by the first reference line A1 and the second reference line A2.

[0072] Two second adjacent fastening holes 42 are adjacent to each other in the circumferential direction CD such that there are no other fastening holes 36 among the plurality of fastening holes 36 between the two second adjacent fastening holes 42. 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 central axis C3. For example, the fourth fastening hole 42B has a fourth hole central axis C4. Figure 3 In the middle, the fastening hole 36, which is selected as the third fastening hole 42A, also serves as the second fastening hole 40B.

[0073] Two second adjacent fastening holes 42 of the plurality of fastening holes 36 are arranged in the circumferential direction CD with a second rounded angle B2. For example, the second rounded angle B2 is defined by a third reference line A3 and a fourth reference line A4. For example, the third reference line A3 passes through the central axis C3 of the third hole and the central axis X1 of the rotation. For example, the fourth reference line A4 passes through the central axis C4 of the fourth hole and the central axis X1 of the rotation. The second rounded angle B2 is the angle formed by the third reference line A3 and the fourth reference line A4.

[0074] Two third adjacent fastening holes 44 are adjacent to each other in the circumferential direction CD such that there are no other fastening holes 36 among the plurality of fastening holes 36 between the two third adjacent fastening holes 44. 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. Figure 3 In the middle, the fastening hole 36, which is selected as the fifth fastening hole 44A, also serves as the fourth fastening hole 42B.

[0075] Two third adjacent fastening holes 44 of the plurality of fastening holes 36 are arranged in the circumferential direction CD with a third rounded angle B3. For example, the third rounded angle B3 is defined by a fifth reference line A5 and a sixth reference line A6. For example, the fifth reference line A5 passes through the central axis C5 of the fifth hole and the rotation center axis X1. For example, the sixth reference line A6 passes through the central axis C6 of the sixth hole and the rotation center axis X1. The third rounded angle B3 is the angle formed by the fifth reference line A5 and the sixth reference line A6.

[0076] For example, two fourth adjacent fastening holes 46 are adjacent to each other in the circumferential direction CD such that there are no other fastening holes 36 among the plurality of fastening holes 36 between the two fourth adjacent fastening holes 46. 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 this embodiment, the fastening hole 36 selected as the eighth fastening hole 46B also serves as the first fastening hole 40A.

[0077] Two fourth adjacent fastening holes 46 of the plurality of fastening holes 36 are arranged in the circumferential direction CD with a fourth rounded angle B4. For example, the fourth rounded angle B4 is defined by a seventh reference line A7 and an eighth reference line A8. For example, the seventh reference line A7 passes through the central axis C7 of the seventh hole and the rotation center axis X1. For example, the eighth reference line A8 passes through the central axis C8 of the eighth hole and the rotation center axis X1. The fourth rounded angle B4 is the angle formed by the seventh reference line A7 and the eighth reference line A8.

[0078] For example, the multiple pitch circle angles include pitch circle angles with three or more values. For example, the number of different types of pitch circle angle values ​​is three or more but the number of pitch circle angles is less than or equal to the number of pitch circle angles in total. In this embodiment, the multiple pitch circle angles include pitch circle angles with four values. The four pitch circle angle values ​​in this embodiment correspond to the first pitch circle angle B1, the second pitch circle angle B2, the third pitch circle angle B3, and the fourth pitch circle angle B4, respectively.

[0079] The second rounded angle B2 differs from the first rounded angle B1. In this embodiment, the second rounded angle B2 is larger than the first rounded angle B1. The third rounded angle B3 differs from each of the first rounded angle B1 and the second rounded angle B2. Figure 3 In this case, the third circular angle B3 is greater than either the first circular angle B1 or the second circular angle B2. Figure 3 In this context, the fourth circular angle B4 differs from each of the first circular angle B1, the second circular angle B2, and the third circular angle B3. Figure 3 In the middle, the fourth circular angle B4 is greater than any of the first circular angle B1, the second circular angle B2, and the third circular angle B3.

[0080] exist Figure 3 In addition to the first circular angle B1, the second circular angle B2, the third circular angle B3, and the fourth circular angle B4, the multiple circular angles also include the fifth circular angle B5, the sixth circular angle B6, the seventh circular angle B7, the eighth circular angle B8, the ninth circular angle B9, the tenth circular angle B10, the eleventh circular angle B11, the twelfth circular angle B12, the thirteenth circular angle B13, and the fourteenth circular angle B14.

[0081] exist Figure 3 In this diagram, the first circular angle B1 is 13 degrees, the second circular angle B2 is 22 degrees, the third circular angle B3 is 34 degrees, and the fourth circular angle B4 is 39 degrees. For example, the sixth circular angle B6, the tenth circular angle B10, and the fourteenth circular angle B14 are the same angle as the first circular angle B1. Similarly, the seventh circular angle B7 and the eleventh circular angle B11 are the same angle as the second circular angle B2. Furthermore, the fifth circular angle B5, the eighth circular angle B8, the ninth circular angle B9, the twelfth circular angle B12, and the thirteenth circular angle B13 are the same angle as the third circular angle B3.

[0082] like Figure 1 , Figure 3 as well as Figure 5As shown, for example, multiple sprocket teeth 34 include multiple downshift actuating teeth 48. For example, the multiple downshift actuating teeth 48 are configured to actuate a downshifting action. For example, the downshifting action is the action of moving the drive chain 18 from the adjacent pinion sprocket to the rear sprocket 30. The adjacent pinion sprocket is adjacent to the axially outward surface 30A side of the rear sprocket 30 in the installed state. For example, in the downshifting action, the drive chain 18 is moved from the adjacent pinion sprocket 26A to the rear sprocket 30 by manually driving the rear derailleur of the vehicle 10.

[0083] For example, the plurality of downshift actuating teeth 48 include a downshift initiation tooth 50 and a downshift recessed tooth 52. For example, the downshift initiation tooth 50 is configured to engage with the drive chain 18 first during the downshifting operation. The tooth tip of the downshift initiation tooth 50 is inclined in the axial direction AD, approaching the axial outward surface 30A from the drive surface of the downshift initiation tooth 50 toward the non-drive surface of the downshift initiation tooth 50.

[0084] For example, the downshift recessed tooth 52 is configured such that, during downshifting, the drive chain 18 can move in the axial direction AD from the axially outward surface 30A to the axially inward surface 30B. For example, the downshift recessed tooth 52 is adjacent to the downshift initiation tooth 50 in the circumferential direction CD, such that there are no other sprocket teeth 34 among the plurality of sprocket teeth 34 between the downshift initiation tooth 50 and the downshift recessed tooth 52. For example, the downshift recessed tooth 52 is adjacent to the downshift initiation tooth 50 downstream of the downshift initiation tooth 50 in the drive rotation direction RD1 with respect to the rear sprocket 30. The tooth tip of the downshift recessed tooth 52 is inclined in the axial direction AD such that it approaches the axially inward surface 30B from the drive surface toward the non-drive surface.

[0085] For example, the downshifting recess 52 has a downshifting recess 54. For example, the downshifting recess 54 is provided on the axially outward surface 30A of the downshifting recess 52, recessed from the axially outward surface 30A toward the axially inward surface 30B in the axial direction AD. For example, the downshifting recess 54 includes a first downshifting recess 54A and a second downshifting recess 54B. The depth of the second downshifting recess 54B in the axial direction AD is different from the depth of the first downshifting recess 54A in the axial direction AD. For example, the depth of the second downshifting recess 54B in the axial direction AD is greater than the depth of the first downshifting recess 54A in the axial direction AD. The depth of the second downshifting recess 54B in the axial direction AD can also be the same as the depth of the first downshifting recess 54A in the axial direction AD. For example, the first downshifting recess 54A and the second downshifting recess 54B are formed by a stepped punching process.

[0086] Multiple downshifting actuating teeth 48 form a downshifting region of the rear sprocket 30. The downshifting region has a downshifting recess 54, serving as a structure to improve the shifting performance of the rear sprocket 30 during downshifting. The rear sprocket 30 has multiple downshifting regions. Each of the multiple downshifting regions has a downshifting initiation tooth 50 and a downshifting recess tooth 52 among the multiple downshifting actuating teeth 48. Figure 3 The rear sprocket 30 has three downshifting zones.

[0087] The operation of the drive chain 18 during downshifting is explained.

[0088] During downshifting, the drive chain 18, engaged with the adjacent pinion 26A, moves toward the downshift recess tooth 52 of the rear sprocket 30 via the rear derailleur. The inner link 18C of the drive chain 18 moves toward a position opposite to the first downshift recess 54A, and the outer link 18B of the drive chain 18 moves toward a position opposite to the second downshift recess 54B. Via the rear derailleur, the drive chain 18 moves toward the rear sprocket 30 and is guided along the downshift recess 54 to the radially outer side of the adjacent pinion 26A. The tooth tip of the downshift initiation tooth 50 is inclined such that it approaches the axially outward face 30A from the driving surface of the downshift initiation tooth 50 toward the non-driving surface of the downshift initiation tooth 50, thus facilitating the engagement of the drive chain 18 with the downshift initiation tooth 50. By engaging the tooth tip of the downshift initiation tooth 50 with the drive chain 18, which has been guided radially outward, the downshift initiation tooth 50 engages with the drive chain 18. Subsequently, as the rear sprocket 30 rotates in the drive rotation direction RD1, the drive chain 18 disengages from the adjacent small sprocket 26A. The drive chain 18, now disengaged from the adjacent small sprocket 26A, engages with the rear sprocket 30, thus ending the downshifting action.

[0089] For example, multiple fastening holes 36 are configured to avoid overlapping with the downshift recess 54. Multiple fastening holes 36 are configured not to overlap with the downshift recess 54 in the circumferential direction CD. For example, multiple reference lines A are configured not to overlap with the downshift recess 54. Multiple fastening holes 36 are configured not to overlap with the downshift recess 54 in the radial direction.

[0090] like Figure 1 , Figure 3 ,as well as Figure 6 As shown, for example, multiple sprocket teeth 34 include multiple upshift actuating teeth 56. The multiple upshift actuating teeth 56 are configured to facilitate an upshifting action. An upshifting action is the movement of the drive chain 18 from the rear sprocket 30 to the adjacent pinion sprocket. For example, in an upshifting action, the drive chain 18 is moved from the rear sprocket 30 to the adjacent pinion sprocket 26A by manually driving the rear derailleur of the vehicle 10.

[0091] For example, the multiple upshift actuating teeth 56 include an upshift displacement tooth 58, an upshift initiation tooth 60, and an upshift recess tooth 62. For example, the upshift displacement tooth 58 is configured to displace the drive chain 18 toward an adjacent small sprocket during the upshift operation. The tooth tip of the upshift displacement tooth 58 is inclined in the axial direction AD, approaching the axial inward surface 30B from the drive surface of the upshift displacement tooth 58 toward the non-drive surface of the upshift displacement tooth 58.

[0092] For example, the upshift initiation tooth 60 is configured to be the first to disengage from the drive chain 18 during the upshift operation. For example, the upshift initiation tooth 60 is adjacent to the upshift shifting tooth 58 in the circumferential direction CD, such that there are no other sprocket teeth 34 among the plurality of sprocket teeth 34 between the upshift initiation tooth 60 and the upshift shifting tooth 58. For example, the upshift initiation tooth 60 is adjacent to the upshift shifting tooth 58 upstream of the upshift shifting tooth 58 in the drive rotation direction RD1 with respect to the rear sprocket 30.

[0093] For example, the upshift initiation tooth 60 has a first upshift recess 60A. For example, the first upshift recess 60A is provided on the axially outward surface 30A of the upshift initiation tooth 60 such that it is recessed from the axially outward surface 30A toward the axially inward surface 30B in the axial direction AD. The first upshift recess 60A extends from the driving surface of the upshift initiation tooth 60 to the non-driving surface of the upshift initiation tooth 60. For example, the first upshift recess 60A is formed by a stepped punching process.

[0094] For example, the upshift recessed tooth 62 is configured such that it does not engage with the drive chain 18 after disengaging from the upshift initiation tooth 60 during the upshift operation. For example, the upshift recessed tooth 62 is adjacent to the upshift initiation tooth 60 in the circumferential direction CD, such that there are no other sprocket teeth 34 among the plurality of sprocket teeth 34 between the upshift recessed tooth 62 and the upshift initiation tooth 60. For example, the upshift recessed tooth 62 is adjacent to the upshift initiation tooth 60 upstream of the upshift initiation tooth 60 in the drive rotation direction RD1 with respect to the rear sprocket 30.

[0095] For example, the shifting tooth 62 has a second shifting recess 62A. For example, the second shifting recess 62A is provided on the axially outward surface 30A of the shifting tooth 62 in a manner that it is recessed from the axially outward surface 30A toward the axially inward surface 30B in the axial direction AD. The second shifting recess 62A extends from the driving surface of the shifting tooth 62 to the non-driving surface of the shifting tooth 62. For example, the second shifting recess 62A is formed by a stepped punching process.

[0096] The depth of the second upshift recess 62A in the axial direction AD is set to be different from the depth of the first upshift recess 60A in the axial direction AD. For example, the depth of the second upshift recess 62A in the axial direction AD is less than the depth of the first upshift recess 60A in the axial direction AD. The depth of the second upshift recess 62A in the axial direction AD can also be set to be the same as the depth of the first upshift recess 60A in the axial direction AD.

[0097] Multiple upshifting actuating teeth 56 form the upshifting region of the rear sprocket 30. The upshifting region has a first upshifting recess 60A and a second upshifting recess 62A, serving as a structure to improve the shifting performance of the rear sprocket 30 during upshifting. The rear sprocket 30 has multiple upshifting regions. Each of the multiple upshifting regions has an upshifting shifting tooth 58, an upshifting initiation tooth 60, and an upshifting recess tooth 62, all part of the multiple upshifting actuating teeth 56. Figure 3 The rear sprocket 30 has four upshift zones.

[0098] The operation of the drive chain 18 during the upshifting action is explained.

[0099] During upshifting, the drive chain 18, engaged with the rear sprocket 30, moves toward the adjacent pinion sprocket 26A via the rear derailleur. If the drive chain 18 engages with the upshift shifter tooth 58, the tooth tip of the upshift shifter tooth 58 is inclined toward the axially inward surface 30B from the driving surface of the upshift shifter tooth 58 toward the non-driving surface of the upshift shifter tooth 58, thus the drive chain 18 moves closer to the adjacent pinion sprocket 26A. The tooth tip of the upshift initiation tooth 60 moves toward the axially inward surface 30B through the first upshift recess 60A, thus the drive chain 18, moving toward the adjacent pinion sprocket 26A, easily disengages from the upshift initiation tooth 60. The tooth tip of the upshift recess tooth 62 moves toward the axially inward surface 30B further than the tooth tip of the upshift initiation tooth 60 through the second upshift recess 62A. Therefore, the drive chain 18, disengaged from the upshift initiation tooth 60, does not engage with the upshift recess tooth 62. Subsequently, as the rear sprocket 30 rotates in the drive rotation direction RD1, the drive chain 18 disengages from the rear sprocket 30. The upshifting action ends when the drive chain 18, now disengaged from the rear sprocket 30, engages with the adjacent small sprocket 26A.

[0100] For example, the plurality of fastening holes 36 are configured to avoid overlapping with the first riser recess 60A and the second riser recess 62A. For example, the plurality of fastening holes 36 are configured to avoid overlapping with either the first riser recess 60A or the second riser recess 62A. The plurality of fastening holes 36 may be configured to avoid overlapping only a portion of the first riser recess 60A and the second riser recess 62A. The plurality of fastening holes 36 are configured not to overlap with the first riser recess 60A and the second riser recess 62A in the circumferential direction CD. For example, multiple reference lines A are configured not to overlap with the first riser recess 60A and the second riser recess 62A. The plurality of fastening holes 36 are configured not to overlap with the first riser recess 60A and the second riser recess 62A in the radial direction.

[0101] like Figure 7 As shown, 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 the portion of the additional outer annular portion 72A facing the hub shaft 28 in the installed state. The additional outer peripheral portion 72D is the portion of the additional outer annular portion 72A located on the opposite side of the additional inner peripheral portion 72C in the radial direction about the rotation center axis X1 in the installed state. The plurality of additional connecting arms 72B are located inside the additional outer annular portion 72A in the radial direction about the rotation center axis X1.

[0102] like Figure 7 and Figure 10 As shown, 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 engage with the drive chain 18 by interlocking between a pair of outer chain plates of the outer link 18B and between a pair of inner chain plates of the inner link 18C. For example, each additional sprocket tooth 74 has an additional driving surface and an additional non-driving surface, the non-driving surface being located 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 tooth 74 in the drive rotation direction RD1 of the additional sprocket tooth 74. When the adjacent sprocket 70 rotates in the drive rotation direction RD1, each additional sprocket tooth 74 engages with the roller 18A of the drive chain 18 at the additional driving surface.

[0103] like Figure 4As shown, 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 the length from the additional outer periphery 72D of the additional sprocket body 72 to the tooth tip. For example, the additional maximum axial length L4 is the length from the additional axial outer surface 70A to the additional axial inner surface 70B. For example, the additional maximum radial length L3 is greater than the additional maximum axial length L4.

[0104] like Figure 8 and Figure 9 As shown, for example, the adjacent sprocket 70 has 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 in such a manner that they correspond to the plurality of fastening holes 36 in the axial direction AD. By configuring the plurality of fastening members 38 to pass through the fastening holes 36 and the additional fastening holes 76, the adjacent sprocket 70 is fastened to the rear sprocket 30.

[0105] For example, the number of additional fastening holes 76 is determined by the number of additional fastening holes 36. For example, the inner diameter of the additional fastening holes 76 is equal to the inner diameter of the fastening holes 36. For example, the multiple additional fastening holes 76 may include 14 additional fastening holes 76. For example, the inner diameters of the multiple additional fastening holes 76 are all equal to each other. At least one of the inner diameters of the multiple additional fastening holes 76 may differ from the others.

[0106] like Figure 1 and Figure 4 As shown, for example, the adjacent sprocket 70 has an additional axial outward surface 70A and an additional axial inward surface 70B. For example, the additional axial inward surface 70B is provided on the opposite side of the additional axial outward surface 70A in the axial direction AD. For example, the additional axial inward surface 70B is configured such that, in the installed state, it faces the axial center surface CS of the manually driven vehicle 10 in the axial direction AD.

[0107] like Figure 1 , Figure 7 and Figure 10 As shown, for example, the plurality of additional sprocket teeth 74 include a plurality of additional downshift actuating teeth 78. For example, the plurality of additional downshift actuating teeth 78 are configured to actuate an additional downshift action. For example, the additional downshift action is the action of moving the drive chain 18 from the rear sprocket 30 to the adjacent sprocket 70. For example, during the additional downshift action, the drive chain 18 is moved from the rear sprocket 30 to the adjacent sprocket 70 by manually driving the rear derailleur of the vehicle 10.

[0108] For example, the plurality of additional downshift facilitating teeth 78 include an additional downshift initiating tooth 80 and an additional downshift recessed tooth 82. For example, the additional downshift initiating tooth 80 is configured to engage with the drive chain 18 first during the additional downshift operation. The tooth tip of the additional downshift initiating tooth 80 is inclined in the axial direction AD towards the additional axial outward surface 70A from the additional drive surface of the additional downshift initiating tooth 80 toward the additional non-drive surface of the additional downshift initiating tooth 80.

[0109] For example, the additional downshift recessed tooth 82 is configured such that, during the additional downshift operation, the drive chain 18 can move in the axial direction AD from the additional axial outward surface 70A toward the additional axial inward surface 70B. For example, the additional downshift recessed tooth 82 is adjacent to the additional downshift start tooth 80 in the circumferential direction CD, such that there are no other additional sprocket teeth 74 among the plurality of additional sprocket teeth 74 between the additional downshift start tooth 80 and the additional downshift recessed tooth 82. For example, the additional downshift recessed 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 drive rotation direction RD1 of the adjacent sprocket 70.

[0110] For example, the additional downshifting recess 82 has an additional downshifting recess 84. For example, the additional downshifting recess 84 is provided on the additional axial outward surface 70A of the additional downshifting recess 82 such that it is recessed in the axial direction AD from the additional axial outward surface 70A toward the additional axial inward surface 70B. For example, the additional downshifting recess 84 includes a first additional downshifting recess 84A and a second additional downshifting recess 84B. The depth of the second additional downshifting recess 84B in the axial direction AD is different from the depth of the first additional downshifting recess 84A in the axial direction AD. For example, the depth of the second additional downshifting recess 84B in the axial direction AD is greater than the depth of the first additional downshifting recess 84A in the axial direction AD. The depth of the second additional downshifting recess 84B in the axial direction AD can also be set to be the same as the depth of the first additional downshifting recess 84A in the axial direction AD. For example, the first additional lowering recess 84A and the second additional lowering recess 84B are formed by a stepped punching process.

[0111] Multiple additional downshifting actuating teeth 78 form an additional downshifting region adjacent to the sprocket 70. Each additional downshifting region has an additional downshifting recess 84, serving as a structure to improve the shifting performance of the adjacent sprocket 70 during additional downshifting. The adjacent sprocket 70 has multiple additional downshifting regions. Each of the multiple additional downshifting regions has an additional downshifting initiation tooth 80 and an additional downshifting recess tooth 82 among the multiple additional downshifting actuating teeth 78. Figure 7 The adjacent sprocket 70 forms three additional downshifting zones.

[0112] The operation of the drive chain 18 during the additional downshifting action is explained.

[0113] During the additional downshift operation, the drive chain 18, which engages with the rear sprocket 30, moves toward the additional downshift recess tooth 82 of the adjacent sprocket 70 via the rear derailleur. The inner link 18C of the drive chain 18 moves toward a position opposite to the first additional downshift recess 84A, and the outer link 18B of the drive chain 18 moves toward a position opposite to the second additional downshift recess 84B. The drive chain 18 moves toward the adjacent sprocket 70 via the rear derailleur and is guided along the additional downshift recess 84 to the radially outer side of the rear sprocket 30. Because the tooth tip of the additional downshift initiation tooth 80 is inclined from the additional drive surface of the additional downshift initiation tooth 80 toward the additional non-drive surface of the additional downshift initiation tooth 80 towards the additional axial outward surface 70A, the drive chain 18 easily engages with the additional downshift initiation tooth 80. The additional downshift initiation tooth 80 engages with the drive chain 18 by inserting its tooth tip into the drive chain 18, which has been guided radially outward. Then, as the adjacent sprocket 70 rotates in the drive rotation direction RD1, the drive chain 18 disengages from the rear sprocket 30. The additional downshifting action ends when the drive chain 18, now disengaged from the rear sprocket 30, engages with the adjacent sprocket 70.

[0114] For example, when viewed from the axial direction AD, at least a portion of at least one of the plurality of fastening holes 36 is disposed in the circumferential direction CD between the additional downshift initiation tooth 80 and the additional downshift recess tooth 82. For example, the plurality of fastening holes 36 includes a predetermined fastening hole 36A. At least a portion 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 drive rotation direction RD1. The first additional reference line AL1 passes through the tooth tip of the additional downshift initiation tooth 80 and the rotation center axis X1. The second additional reference line AL2 passes through the tooth tip of the additional downshift recess tooth 82 and the rotation center axis X1. For example, the predetermined fastening hole 36A is configured to overlap with the first additional reference line AL1 in the axial direction AD.

[0115] For example, the plurality of additional sprocket teeth 74 include an adjacent tooth 86. For example, the adjacent tooth 86 abuts the additional downshift start tooth 80 in the circumferential direction CD such that there are no other additional sprocket teeth 74 among the plurality of additional sprocket teeth 74 between the additional downshift start tooth 80 and the adjacent tooth 86. For example, the adjacent tooth 86 abuts the additional downshift start tooth 80 upstream of the additional downshift start tooth 80 with respect to the drive rotation direction RD1 of the adjacent sprocket 70.

[0116] For example, when viewed from the axial direction AD, at least a portion of at least one of the plurality of fastening holes 36 is disposed on the circumferential direction CD between the adjacent tooth 86 and the additional lowering recess tooth 82. At least a portion of a 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 drive rotation direction RD1. The third additional reference line AL3 passes through the tooth tip of the adjacent tooth 86 and the rotation center axis X1.

[0117] For example, when viewed from the axial direction AD, at least a portion of at least one of the plurality of fastening holes 36 is disposed on the circumferential direction CD between the adjacent tooth 86 and the additional downshift initiation tooth 80. A portion of a predetermined fastening hole 36A is disposed between the first additional reference line AL1 and the third additional reference line AL3, and on the downstream side of the third additional reference line AL3 with respect to the drive rotation direction RD1.

[0118] like Figure 1 , Figure 7 as well as Figure 11 As shown, for example, the plurality of additional sprocket teeth 74 include a plurality of additional upshift actuating teeth 88. The plurality of additional upshift actuating teeth 88 are configured to actuate an additional upshift action. The additional upshift action is the action of moving the drive chain 18 from the adjacent sprocket 70 to the adjacent small sprocket. For example, in the additional upshift action, the drive chain 18 is moved from the adjacent sprocket 70 to the rear sprocket 30 by manually driving the rear derailleur of the vehicle 10.

[0119] For example, the additional upshift promoting teeth 88 include an additional upshift shifting tooth 90, an additional upshift initiation tooth 92, and an additional upshift recessed tooth 94. For example, the additional upshift shifting 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 shifting tooth 90 is inclined in the axial direction AD towards the additional axial inward surface 70B from the additional drive surface of the additional upshift shifting tooth 90 toward the additional non-drive surface of the additional upshift shifting tooth 90.

[0120] For example, the additional upshift initiation tooth 92 is configured to be the first to disengage from the drive chain 18 during the additional upshift operation. For example, the additional upshift initiation tooth 92 is adjacent to the additional upshift shifting tooth 90 in the circumferential direction CD, such that there are no other additional sprocket teeth 74 among the plurality of additional sprocket teeth 74 between the additional upshift initiation tooth 92 and the additional upshift shifting tooth 90. For example, the additional upshift initiation tooth 92 is adjacent to the additional upshift shifting tooth 90 on the upstream side of the additional upshift shifting tooth 90 with respect to the drive rotation direction RD1.

[0121] For example, the additional upshift start 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 in a manner that recesses from the additional axial outward surface 70A toward the additional axial inward surface 70B in the axial direction AD. The first additional upshift recess 92A extends from the additional driving surface of the additional upshift start tooth 92 to the additional non-driving surface of the additional upshift start tooth 92. For example, the first additional upshift recess 92A is formed by a stepped punching process.

[0122] For example, the additional upshift recessed tooth 94 is configured such that it does not engage with the drive chain 18 that has disengaged from the additional upshift initiation tooth 92 during the additional upshift operation. For example, the additional upshift recessed tooth 94 is adjacent to the additional upshift initiation tooth 92 in the circumferential direction CD, such that there are no other additional sprocket teeth 74 among the plurality of additional sprocket teeth 74 between the additional upshift recessed tooth 94 and the additional upshift initiation tooth 92. For example, the additional upshift recessed tooth 94 is adjacent to the additional upshift initiation tooth 92 on the upstream side of the additional upshift initiation tooth 92 with respect to the drive rotation direction RD1.

[0123] For example, the additional shifting recess 94 has a second additional shifting recess 94A. For example, the second additional shifting recess 94A is provided on the additional axial outward surface 70A of the additional shifting recess 94 in a manner that it is recessed in the axial direction AD from the additional axial outward surface 70A toward the additional axial inward surface 70B. The second additional shifting recess 94A extends from the additional driving surface of the additional shifting recess 94 to the additional non-driving surface of the additional shifting recess 94. For example, the second additional shifting recess 94A is formed by a stepped punching process.

[0124] For example, the plurality of additional upshift promoting teeth 88 includes a reverse upshift shifting tooth 96. For example, the reverse upshift shifting tooth 96 is configured such that, during the additional upshift operation, the drive chain 18 engaging with the adjacent sprocket 70 is moved axially AD towards the opposite side of the rear sprocket 30. For example, the reverse upshift shifting tooth 96 is configured such that, in the circumferential direction CD, between the reverse upshift shifting tooth 96 and the additional upshift shifting tooth 90, two other additional sprocket teeth 74 from a plurality of additional sprocket teeth 74 are arranged. For example, the reverse upshift shifting tooth 96 is located downstream of the additional upshift initiation tooth 92 with respect to the drive rotation direction RD1.

[0125] For example, the reverse upshifting gear 96 has a third additional upshifting recess 96A. For example, the third additional upshifting recess 96A is provided on the additional axial outward surface 70A of the reverse upshifting gear 96 in such a way that it is recessed in the axial direction AD from the additional axial outward surface 70A toward the additional axial inward surface 70B. The third additional upshifting recess 96A extends from the additional driving surface of the reverse upshifting gear 96 to the additional non-driving surface of the reverse upshifting gear 96.

[0126] Multiple additional upshift promoting teeth 88 form an additional upshift region adjacent to the sprocket 70. The additional upshift region has a first additional upshift recess 92A and a second additional upshift recess 94A, serving as a structure to improve the shifting performance of the adjacent sprocket 70 during upshifting. The adjacent sprocket 70 has multiple additional upshift regions. Each of the multiple additional upshift regions has an additional upshift shifting tooth 90, an additional upshift initiation tooth 92, and an additional upshift recess tooth 94 among the multiple additional upshift promoting teeth 88. Figure 7 The adjacent sprocket 70 forms four additional upshift zones.

[0127] Reference Figure 12 The operation of the drive chain 18 during the additional upshifting action will be explained.

[0128] During the upshift operation, the drive chain 18, which engages with the adjacent sprocket 70, moves towards the rear sprocket 30 via the rear derailleur. The outer link 18B of the drive chain 18 engages with the upshift shifter tooth 90. When the drive chain 18 engages with the upshift shifter tooth 90, the tooth tip of the upshift shifter tooth 90 is inclined towards the additional axial inward surface 70B from the additional drive surface of the upshift shifter tooth 90 towards the additional non-drive surface of the upshift shifter tooth 90, thus the drive chain 18 moves closer to the rear sprocket 30. The inner link 18C of the drive chain 18 disengages from the upshift initiation tooth 92. Because the tooth tip of the upshift initiation tooth 92 approaches the additional axial inward surface 70B via the first upshift recess 92A, the drive chain 18, moving towards the rear sprocket 30, easily disengages from the upshift initiation tooth 92. The drive chain 18, having disengaged from the additional upshift initiation tooth 92, moves radially inward about the rotation center axis X1. The outer link 18B of the drive chain 18 disengages from the additional upshift initiation tooth 92. Through the second additional upshift recess 94A, the tooth tip of the additional upshift recess tooth 94 is brought closer to the additional axial inward surface 70B than the tooth tip of the additional upshift initiation tooth 92. Therefore, the drive chain 18, having disengaged from the additional upshift initiation tooth 92, does not engage with the additional upshift recess tooth 94. Subsequently, as the adjacent sprocket 70 rotates in the drive rotation direction RD1, the drive chain 18 disengages from the adjacent sprocket 70. The additional upshift operation ends when the drive chain 18, having disengaged from the adjacent sprocket 70, engages with the rear sprocket 30.

[0129] When the drive chain 18 disengages from the additional upshift initiation tooth 92 during an additional upshift operation, the drive chain 18, engaged with the additional sprocket tooth 74 located downstream of the drive rotation direction RD1 (which is further downstream than the additional upshift initiation tooth 92), rotates towards the additional axial inward surface 70B with the additional upshift shifting tooth 90 as its fulcrum. During the additional upshift operation, the inner link 18C of the drive chain 18 engages with the reverse upshift shifting tooth 96. Because the tooth tip of the reverse upshift shifting tooth 96 is brought close to the additional axial inward surface 70B via the third additional upshift recess 96A, the drive chain 18 easily moves towards the additional axial inward surface 70B. Through the reverse upshift shifting tooth 96, the drive chain 18, engaged with the additional sprocket tooth 74 located downstream of the drive rotation direction RD1 (which is further downstream than the additional upshift initiation tooth 92), easily rotates towards the additional axial inward surface 70B. Therefore, by using the reverse upshift shifter 96, the shift shock during additional upshifting can be reduced.

[0130] By configuring the fastening member in the fastening hole, the axial rigidity of the rear sprocket is increased. In the rear sprocket 30, the fastening hole 36 is provided in the sprocket body 32 in a manner that does not overlap with the downshift recess 54, the first upshift recess 60A, and the second upshift recess 62A. Therefore, with the fastening member 38 configured in the fastening hole 36, the rear sprocket 30 has sufficient shifting performance and its rigidity is increased by the fastening member 38.

[0131] <Variation Example>

[0132] The description of the embodiments is an example of the possible ways in which the manually driven rear sprocket for vehicles disclosed herein can be adopted, and is not intended to limit the ways in which it can be adopted. For example, the manually driven rear sprocket for vehicles according to this disclosure can be adopted in the form of variations of the embodiments shown below, as well as combinations of at least two non-contradictory variations. In the following variations, the same reference numerals as in the embodiments are added to the parts that are common to the embodiments, and their descriptions are omitted.

[0133] Each of the multiple fastening holes 36 can be configured to receive fastening components that fasten the rear sprocket 30 and the adjacent small sprocket 26A to each other.

[0134] • At least one of the plurality of fastening holes 36 may be arranged in a different position from the other fastening holes in the radial direction about the rotation center axis X1. Preferably, even if at least one of the plurality of fastening holes 36 is arranged in a different position from the other fastening holes in the radial direction about the rotation center axis X1, the plurality of fastening holes 36 are configured to respectively receive fastening members 38 for fastening the rear sprocket 30 and the adjacent sprocket 70 to each other.

[0135] • In the adjacent sprocket 70, an additional downshift starting tooth 80 can be configured with the first additional reference line AL1 passing through the center axis C of the specified fastening hole 36A. When the additional downshift starting tooth 80 is configured with the first additional reference line AL1 passing through the center axis C of the specified 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.

[0136] • A reverse upshift shifting tooth 96 can be configured on the rear sprocket 30. For example, a plurality of upshift promoting teeth 56 include a reverse upshift shifting tooth. For example, the reverse upshift shifting tooth 96 is configured such that, during upshifting, the drive chain 18 engaging with the rear sprocket 30 is positioned axially AD closer to the axially inward face 30B. For example, the reverse upshift shifting tooth 96 is configured such that, in the circumferential direction CD, two other sprocket teeth 34 from a plurality of sprocket teeth 34 are disposed between the reverse upshift shifting tooth 96 and the upshift shifting tooth 58. For example, the reverse upshift shifting tooth 96 is disposed downstream of the upshift shifting tooth 58 with respect to the drive rotation direction RD1.

[0137] As used in this specification, the term "at least one" refers to "more than one" of the desired options. For example, if there are two options, the term "at least one" as used in this specification refers to "only one option" or "both of the two options." As another example, if there are three or more options, the term "at least one" as used in this specification refers to "only one option" or "any combination of two or more options."

[0138] Symbol explanation:

[0139] 10…Manually driven vehicle, 18…Drive chain, 26…Rear sprocket assembly, 30…Rear sprocket, 30A…Outer axial surface, 30B…Inner axial surface, 32…Sprocket body, 34…Sprocket teeth, 36…Fasting hole, 38…Fasting component, 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…Downshift facilitator tooth, 50… Downshift initiation tooth, 52… Downshift recess tooth, 54… Downshift recess, 56… Upshift facilitator tooth, 58… Upshift shifting tooth, 60… Upshift initiation tooth, 60A… First upshift recess, 62… Upshift recess tooth, 62A… Second upshift recess, 70… Adjacent sprocket, 70A… Additional axial outward surface, 70B… Additional axial inward surface, 72… Additional sprocket body, 74… Additional sprocket tooth, 78… Additional downshift facilitator tooth, 80… Additional downshift initiation tooth, 82… Additional downshift recess tooth, 84… Additional downshift recess, 86… Adjacent tooth.

Claims

1. A rear sprocket that is a rear sprocket for a human-powered vehicle, wherein the rear sprocket has an axially outward face and an axially inward face that is provided on the opposite side of the axially outward face in the axial direction about a rotation center axis of the rear sprocket, the axially inward face is configured to face an axially central plane of the human-powered vehicle in the axial direction in a state in which the rear sprocket is mounted to the human-powered vehicle, the rear sprocket includes: a sprocket body; a plurality of sprocket teeth that extend from the sprocket body to the radially outward side in the radial direction about the rotation center axis; and a plurality of fastening holes that are provided to the sprocket body, each of the plurality of fastening holes is configured to receive a fastening member that fastens the rear sprocket having a first pitch diameter and an adjacent sprocket having a second pitch diameter that is larger than the first pitch diameter to each other, the adjacent sprocket is adjacent in a manner in which 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 the circumferential direction about the rotation center axis, the two first adjacent fastening holes are adjacent to each other in a manner in which there is no other fastening hole of the plurality of fastening holes 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 is different from the first pitch angle, the two second adjacent fastening holes are adjacent to each other in a manner in which there is no other fastenings hole of the plurality of fastening holes 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 is different from each of the first pitch angle and the second pitch angle, the two third adjacent fastening holes are adjacent to each other in a manner in which there is no other fastenin hole of the plurality of fastening holes between the two third adjacent fastening holes in the circumferential direction.

2. The rear sprocket according to 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 that passes through the first hole center axis and the rotation center axis and a second reference line that passes through the second hole center axis and the rotation center axis, the second pitch angle is defined by a third reference line that passes through the third hole center axis and the rotation center axis and a fourth reference line that passes through the fourth hole center axis and the rotation center axis, the third pitch angle is defined by a fifth reference line that passes through the fifth hole center axis and the rotation center axis and a sixth reference line that passes through the sixth hole center axis and the rotation center axis. The third angle of the corner is defined by a fifth reference line passing through the center axis of the fifth hole and the center axis of rotation, and a sixth reference line passing through the center axis of the sixth hole and the center axis of rotation.

3. The rear sprocket according to claim 1, wherein the plurality of sprocket teeth includes a plurality of downshift promoting teeth configured to promote a downshift operation of the drive chain from an adjacent small sprocket to the rear sprocket, the plurality of downshift promoting teeth includes: a downshift start tooth configured to first engage with the drive chain in the downshift operation, and a downshift recess tooth, the downshift recess tooth is adjacent to the downshift start tooth on a downstream side of the drive rotation direction of the rear sprocket in the circumferential direction without other sprocket teeth of the plurality of sprocket teeth between the downshift start tooth and the downshift recess tooth, the downshift recess tooth has a downshift recess recessed from the axially outward face toward the axially inward face in the axial direction on the axially outward face of the downshift recess tooth, the plurality of fastening holes are configured to avoid overlapping with the downshift recess.

4. The rear sprocket according to claim 1, wherein the plurality of sprocket teeth includes a plurality of upshift promoting teeth configured to promote an upshift operation of the drive chain from the rear sprocket to an adjacent small sprocket, the plurality of upshift promoting teeth includes: an upshift displacement tooth configured to displace the drive chain toward the adjacent small sprocket in the upshift operation, an upshift start tooth configured to first disengage from the drive chain in the upshift operation, and an upshift recess tooth, the upshift start tooth has a first upshift recess recessed from the axially outward face toward the axially inward face in the axial direction on the axially outward face of the upshift start tooth, the upshift start tooth is adjacent to the upshift displacement tooth on an upstream side of the drive rotation direction of the rear sprocket in the circumferential direction without other sprocket teeth of the plurality of sprocket teeth between the upshift start tooth and the upshift displacement tooth, the upshift recess tooth has a second upshift recess recessed from the axially outward face toward the axially inward face in the axial direction on the axially outward face of the upshift recess tooth, the upshift recess tooth is adjacent to the upshift start tooth on the upstream side of the drive rotation direction of the rear sprocket in the circumferential direction without other sprocket teeth of the plurality of sprocket teeth between the upshift recess tooth and the upshift start tooth, the plurality of fastening holes are configured to avoid overlapping with the first upshift recess and the second upshift recess.

5. The rear sprocket according to 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 larger than the maximum axial length.

6. A rear sprocket assembly for a human-powered vehicle, comprising: the rear sprocket being the rear sprocket of any one of claims 1 to 5 and having a first pitch diameter; and the adjacent sprocket being 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.

7. The rear sprocket assembly according to claim 6, wherein the adjacent sprocket is provided with: an additional sprocket body; and a plurality of additional sprocket teeth extending radially outward from the additional sprocket body in the radial direction.

8. The rear sprocket assembly according to claim 7, wherein the adjacent sprocket has an additional axially outward facing surface and an additional axially inward facing surface disposed on the opposite side of the additional axially outward facing surface in the axial direction, the additional axially inward facing surface is configured to face the axially central surface of the human-powered vehicle in the axial direction in the mounted state, the plurality of additional sprocket teeth includes a plurality of additional downshift promoting teeth configured to promote an additional downshift action of moving a drive chain from the rear sprocket to the adjacent sprocket, the plurality of additional downshift promoting teeth includes: an additional downshift start tooth configured to first engage with a drive chain in the additional downshift action; and an additional downshift recess tooth, the additional downshift recess tooth is adjacent to the additional downshift start tooth on a downstream side of the additional downshift start tooth with respect to a driving rotation direction of the adjacent sprocket in the circumferential direction without other additional sprocket teeth of the plurality of additional sprocket teeth therebetween, the additional downshift recess tooth has an additional downshift recess recessed from the additional axially outward facing surface toward the additional axially inward facing surface in the axial direction.

9. The rear sprocket assembly according to claim 8, wherein 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 recess tooth in the circumferential direction when viewed in the axial direction.

10. The rear sprocket assembly according to claim 8, wherein the plurality of additional sprocket teeth includes an adjacent tooth, the adjacent tooth is adjacent to the additional downshift start tooth on an upstream side of the additional downshift start tooth with respect to the driving rotation direction of the adjacent sprocket in the circumferential direction without other additional srocket teeth of the plurality of additional sprocket teeth therebetween, at least a portion of at least one of the plurality of fastening holes is arranged between the adjacent tooth and the additional downshift recess tooth in the circumferential direction when viewed in the axial.

11. The rear sprocket assembly according to claim 10, wherein at least a portion of at least one of the plurality of fastening holes is arrranged between the adjacent tooth and the additional downshift start tooth in the circumferential direction when viewed in the axial direction.

12. The rear sprocket assembly according to claim 7, wherein 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 is greater than the additional maximum axial length.

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