Components for human-powered vehicles, cover members for drive units, gear assemblies for human-powered vehicles, and drive units for human-powered vehicles

Abstract

To provide a component that can improve assembly performance.SOLUTION: A component for a human-powered vehicle comprises a rotary shaft having a rotation central shaft center, on which an annular rotation transmission body can be mounted, and an intermediate member provided in the rotary shaft. The rotary shaft has an outer periphery part disposed around the rotation central shaft center. The outer periphery part has a first outer periphery portion having a first diameter with respect to the rotation central shaft center, and a second outer periphery portion having a second diameter smaller than the first diameter with respect to the rotation central shaft center, which is arranged adjacent to the first outer periphery portion in a shaft direction with respect to the rotation central shaft center and on which the rotation transmission body can be mounted. The intermediate member has a first side surface contacting the first outer periphery portion in the shaft direction, and a second side surface, arranged at the opposite side of the first side surface in the shaft direction, and configured so that the rotation transmission body can contact the surface, with the rotation transmission body mounted on the second outer periphery portion. Areas of a first contact surface which can contact the rotation transmission body of the second side surface are larger than areas of a second contact surface that contacts the first outer periphery portion of the first side surface.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present disclosure relates to the technology of a human-powered vehicle component, a cover member for a drive unit, a gear assembly for a human-powered vehicle, and a drive unit for a human-powered vehicle.

Background Art

[0002] Conventionally, human-powered vehicle components are known. For example, the human-powered vehicle component disclosed in Patent Document 1 includes a drive unit. The drive unit includes a rotating shaft connected to an electric motor via a reduction gear, and a housing that rotatably supports the rotating shaft via a bearing. The rotating shaft is inserted through a through hole of the housing. The housing may be provided with a gear assembly that constitutes at least a part of the reduction gear. The drive unit may be provided with a cover member that suppresses intrusion of foreign matter through a gap between the through hole of the housing and the rotating shaft.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0004] It is desired to improve assemblability in at least one of the component, the gear assembly, the cover member, and the drive unit.

[0005] One of the objects of the present disclosure is to improve assemblability in at least one of a human-powered vehicle component, a cover member for a drive unit, a gear assembly for a human-powered vehicle, and a drive unit for a human-powered vehicle.

Means for Solving the Problem

[0006] A component according to the first aspect of this disclosure is a component for a human-powered vehicle, comprising: a rotating shaft having a rotational axis and to which an annular rotational transmission body can be attached; and an intermediate member provided on the rotating shaft, wherein the rotating shaft has an outer circumference about the rotational axis, the outer circumference having a first outer circumference having a first diameter with respect to the rotational axis, and a second outer circumference having a second diameter smaller than the first diameter with respect to the rotational axis, adjacent to the first outer circumference in the axial direction with respect to the rotational axis, and to which a rotational transmission body can be attached; the intermediate member has a first surface in the axial direction that contacts the first outer circumference, and a second surface in the axial direction that is located on the opposite side from the first surface, and configured to allow contact with the rotational transmission body when the rotational transmission body is attached to the second outer circumference, wherein the area of ​​the first contact surface of the second surface that can contact the rotational transmission body is larger than the area of ​​the second contact surface of the first surface that contacts the first outer circumference. The component further comprises a housing that forms an internal space and has a through hole connecting the internal space and the external space, and a bearing provided in the housing that rotatably supports a rotating shaft, the rotating shaft being positioned partially in the internal space and projecting outwards from the housing through the through hole, and further comprising a cover member, the intermediate member constituting at least a part of the cover member, the cover member being positioned at a distance from the housing and at least a part of the cover member being positioned in the external space of the housing, and covering the gap between a first outer periphery and an inner circumferential surface of the housing that defines the through hole, the cover member including a seal member formed to extend radially outward from the intermediate member with respect to the axis of rotation, the seal member and the intermediate member having an annular shape, the inner circumferential portion of the seal member having a first engaging portion, and the outer circumferential portion of the intermediate member having a second engaging portion that engages with the first engaging portion . According to the component on the first side, since the area of ​​the first contact surface is larger than the area of ​​the second contact surface, the surface pressure applied to the rotary transmission from the rotating shaft when attaching the rotary transmission to the rotating shaft can be reduced. When the surface pressure applied to the rotary transmission from the rotating shaft is reduced, damage to the rotary transmission can be suppressed when fixing the rotary transmission to the rotating shaft, thus improving ease of assembly. Furthermore, a portion of the rotating shaft can be protected by the housing. Also, the intrusion of foreign matter through the gap between the housing and the rotating shaft can be suppressed. Additionally, the sealing member can further suppress the intrusion of foreign matter through the gap between the housing and the rotating shaft. Furthermore, the sealing member can be made less likely to detach from the intermediate member.

[0008] The 1 The side following the 2 In the side components, at least a portion of the second outer periphery is positioned in the external space of the housing. The 2 According to the side components, the housing is less likely to get in the way when the rotary transmission is attached to the rotating shaft, thus further improving ease of assembly.

[0009] The On one side The following 3 In the side components, the first contact surface is substantially parallel to the second contact surface. The 3 The side components make it easy to control the surface pressure at the first contact surface and the surface pressure at the second contact surface.

[0010] The On 3 sides following 4 In the side component, the first contact surface and the second contact surface are orthogonal to the axial direction. The 4 According to the side component, it is easier to further control the surface pressure at the first contact surface and the surface pressure at the second contact surface.

[0011] The On one side following 5 In the side component, the first contact surface and the second contact surface are formed in an annular shape when viewed from the axial direction, and the outer diameter of the first contact surface is larger than the outer diameter of the second contact surface. The 5 According to the side component, deformation of the rotation transmission body and the intermediate member can be suppressed.

[0012] The On one side following 6 In the side component, the intermediate member is formed of a material harder than the material forming the rotation transmission body. The 6 According to the side component, deformation of the intermediate member can be suppressed.

[0015] The 1 according to the side 7 In the side component, the seal member is formed of a resin material. The 7 According to the side component, an increase in the weight of the component can be suppressed.

[0016] The On one side following 8 In the side component, the intermediate member is formed of a metal material. The 8 According to the side component, deformation of the intermediate member can be suppressed.

[0018] The 1 according to the side 9In a lateral component, one of the first engaging portion and the second engaging portion includes at least one protrusion projecting in a radial direction about the rotation center axis, or at least one recess recessed in the radial direction about the rotation center axis, and the other of the first engaging portion and the second engaging portion has at least one protrusion or at least one recess that engages with said one of the first engaging portion and the second engaging portion in the radial direction about the rotation center axis. Aspect 9 According to the lateral component, the seal member can be made less likely to come off from the intermediate member.

[0019] According to a 10 aspect of the present disclosure, there is provided a cover member for a drive unit of a manually-driven vehicle, the drive unit comprising: a housing that forms an internal space and has a through-hole formed that connects the internal space and an external space; and a rotating shaft that has a rotation center axis, is partially disposed in the internal space, and projects into the external space of the housing via the through-hole, wherein the cover member is provided on an outer peripheral portion around the rotation center axis of the rotating shaft and is disposed spaced apart from the housing, and the cover member comprises: an intermediate member formed of a metal material and provided on the outer peripheral portion; and a seal member formed of a resin material and formed to extend radially outward about the rotation center axis from the intermediate member. According to a 10 aspect of the cover member, since the intermediate member provided on the rotating shaft is formed of a metal material and the seal member is formed of a resin material, deformation of the cover member when assembling the cover member to the rotating shaft is suppressed, and assemblability can be improved.

[0020] According to a 10 aspect, in the cover member according to the aforementioned 11 aspect, the seal member and the intermediate member each have an annular shape, an inner peripheral portion of the seal member has a first engaging portion, and an outer peripheral portion of the intermediate member has a second engaging portion that engages with the first engaging portion. According to a 11 aspect of the cover member, the seal member can be made less likely to come off from the intermediate member.

[0021] According to a 11The side following the 12 In the side cover member, one of the first engaging portion and the second engaging portion includes at least one protrusion projecting radially with respect to the axis of rotation, or at least one recess recessing radially with respect to the axis of rotation, and the other of the first engaging portion and the second engaging portion has at least one protrusion or at least one recess that engages with one of the first engaging portion and the second engaging portion in the radial direction with respect to the axis of rotation. The 12 The side cover member makes it difficult for the sealing member to detach from the intermediate member. [Effects of the Invention]

[0027] The assembly of at least one of the human-powered vehicle component, gear assembly, cover member, and human-powered vehicle drive unit of this disclosure can be improved. [Brief explanation of the drawing]

[0028] [Figure 1] A side view showing a component according to the first embodiment. [Figure 2] A cross-sectional view along the line D5-D5 in Figure 1. [Figure 3] A cross-sectional view showing the area around the second end of the crankshaft. [Figure 4] A cross-sectional view showing the state in which the rotary transmission body is attached to the output shaft. [Figure 5] A perspective view showing the cover component. [Figure 6] A perspective cross-sectional view showing the gear assembly. [Figure 7] Cross-sectional view showing the gear assembly. [Figure 8] A diagram showing the gear assembly in an axial view of the shaft member. [Figure 9] Cross-sectional view showing the shaft member, annular member, and mold. [Modes for carrying out the invention]

[0029] (First Embodiment) Component 1 according to the first embodiment will be described. Figures 1 to 9 will be used to describe component 1 according to the first embodiment. Component 1 shown in Figure 1 is installed in a human-powered vehicle.

[0030] A human-powered vehicle is a vehicle having at least one wheel and capable of being driven by at least human power. Human-powered vehicles include various types of bicycles, such as mountain bikes, road bikes, city bikes, cargo bikes, handbikes, and recumbent bikes. The number of wheels a human-powered vehicle may have is not limited. Human-powered vehicles include, for example, unicycles and vehicles having two or more wheels. Human-powered vehicles are not limited to vehicles that can be driven solely by human power. Human-powered vehicles include e-bikes that utilize the driving force of an electric motor 50 for propulsion in addition to human power. E-bikes include electric assist bicycles whose propulsion is assisted by an electric motor 50. In the following embodiments, a human-powered vehicle will be described as an electric assist bicycle.

[0031] Component 1 is configured to be mounted on a human-powered vehicle. Component 1 is a component for a human-powered vehicle and comprises a rotating shaft 20 having a rotational axis C20 and to which an annular rotational transmission body 27 can be attached, and an intermediate member 41 provided on the rotating shaft 20. The rotational axis C20 defines the axial direction AD20, radial direction RD20, and circumferential direction CD20 of the rotating shaft 20. In this embodiment, the rotational transmission body 27 includes a front sprocket of the human-powered vehicle.

[0032] Component 1 further comprises a housing 10 that forms an internal space 13 and has through holes 11b and 12b that connect the internal space 13 and the external space, and a bearing 30 provided in the housing 10 that rotatably supports the rotating shaft 20. Component 1 further comprises a cover member 40.

[0033] Figure 1 shows an example of Component 1. Component 1 includes a drive unit 2 for a human-powered vehicle, configured to provide propulsion to the human-powered vehicle. In this specification, the drive unit 2 for a human-powered vehicle is referred to as drive unit 2. Drive unit 2 includes a reduction gear 60 and an electric motor 50. The type of Component 1 is not limited to drive unit 2. For example, Component 1 may include an internal gear hub.

[0034] As shown in Figures 1 and 2, the drive unit 2 includes a housing 10, a rotating shaft 20, a bearing 30, a cover member 40, an electric motor 50, and a reduction gear 60. As shown in Figure 2, the housing 10 is formed to be hollow. The housing 10 includes a first side wall 11 and a second side wall 12 with respect to the axial direction AD 20 of the rotating shaft 20. The first side wall 11 includes a first inner surface 11a. The first inner surface 11a defines a first through hole 11b. The first through hole 11b is formed to penetrate the first side wall 11 in the axial direction AD 20.

[0035] As shown in Figure 4, the second side wall 12 includes a second inner surface 12a and a groove 12c. The second inner surface 12a defines a second through hole 12b. The second through hole 12b is formed to penetrate the second side wall 12 in the axial direction AD20 of the rotating shaft 20. The groove 12c faces the external space of the housing 10. The groove 12c is formed in an annular shape centered on the rotational axis C20 of the rotating shaft 20. The groove 12c is located radially outward from the second through hole 12b in the radial direction RD20 of the rotating shaft 20. The first side wall 11 shown in Figure 2 includes a groove formed similarly to the groove 12c of the second side wall 12.

[0036] The rotating shaft 20 shown in Figures 2 and 3 has an outer circumference 23 around the rotational axis C20. Part of the rotating shaft 20 is located in the internal space 13 and protrudes into the external space of the housing 10 through through holes 11b and 12b. The rotating shaft 20 includes at least one of the crankshaft 21 and the output shaft 22.

[0037] The crankshaft 21 has a substantially cylindrical shape. The crankshaft 21 may be solid. The crankshaft 21 has a rotational axis and is mounted rotatably relative to the housing 10 around the rotational axis. The crankshaft 21 protrudes into the external space of the housing 10 through a first through-hole 11b and a second through-hole 12b. The first end 21a of the crankshaft 21 with respect to the axial AD20 of the rotational axis 20 protrudes into the external space of the housing 10 through the first through-hole 11b. The second end 21b of the crankshaft 21, positioned opposite to the first end 21a in the axial AD20, protrudes into the external space of the housing 10 through the second through-hole 12b.

[0038] The output shaft 22 is connected directly or indirectly to the crankshaft 21. The output shaft 22 has a substantially cylindrical shape. The output shaft 22 and the crankshaft 21 are arranged coaxially. The output shaft 22 has a rotational axis and is rotatably mounted relative to the housing 10 around the rotational axis. In the radial direction RD20 of the rotating shaft 20, the output shaft 22 is positioned radially outward from the crankshaft 21. In the axial direction AD20 of the rotating shaft 20, the output shaft 22 is located on the second end 21b side of the crankshaft 21. A portion of the output shaft 22 in the axial direction AD20 protrudes into the external space of the housing 10 through the second through hole 12b.

[0039] In this embodiment, the rotating shaft 20 includes an output shaft 22. As shown in Figures 3 and 4, the output shaft 22 has an outer circumference 23 and an inner circumference 24. The outer circumference 23 has a first outer circumference 23a having a first diameter D23a with respect to the rotational axis C20, and a second outer circumference 23b having a second diameter D23b smaller than the first diameter D23a with respect to the rotational axis C20, and is adjacent to the first outer circumference 23a in the axial direction AD20 with respect to the rotational axis C20, and to which a rotational transmission body 27 can be attached. The first diameter D23a of the first outer circumference 23a is smaller than the inner diameter of the second through hole 12b.

[0040] At least a portion of the first outer periphery 23a is positioned within the internal space 13 of the housing 10. By positioning at least a portion of the first outer periphery 23a within the internal space 13, at least a portion of the first outer periphery 23a can be protected by the housing 10. Because the second diameter D23b of the second outer periphery 23b is smaller than the first diameter D23a of the first outer periphery 23a, a stepped surface 23c is formed on the first outer periphery 23a perpendicular to the axial direction AD20 of the rotation axis 20. The stepped surface 23c is formed in an annular shape when viewed from the axial direction AD20.

[0041] The second outer periphery 23b is positioned further away from the internal space 13 of the housing 10 than the first outer periphery 23a in the axial direction AD20 of the rotating shaft 20. At least a portion of the second outer periphery 23b is positioned in the external space of the housing 10. In this embodiment, the outer periphery 23 further has an outer serration 23d. The outer serration 23d is formed to extend radially outward from the second outer periphery 23b in the radial direction RD20 of the rotating shaft 20. The outer serration 23d is positioned at a distance from the stepped surface 23c in the axial direction AD20 of the rotating shaft 20. The outer serration 23d is positioned in the external space of the housing 10.

[0042] The inner diameter of the inner circumference portion 24 is larger than the outer diameter of the crankshaft 21. The inner circumference portion 24 has an internal thread 24a. The internal thread 24a is formed on the end of the output shaft 22 that is farther from the internal space 13 of the housing 10 in the axial direction AD20 of the rotating shaft 20.

[0043] The crankshaft 21 and the rear wheel are connected by a drive mechanism. The rear wheel is driven by the rotation of the crankshaft 21. The drive mechanism includes a rotational transmission 27 connected to the crankshaft 21. The rotational transmission 27 may include a sprocket, pulley, or bevel gear. The crankshaft 21 and the rotational transmission 27 may be connected to rotate together, or they may be connected via a one-way clutch 25 shown in Figure 2. The one-way clutch 25 includes, for example, a roller clutch, sprag clutch, pawl ratchet clutch, or face ratchet clutch. The one-way clutch 25 is configured to allow the rotational transmission 27 to rotate forward when the crankshaft 21 rotates forward, and to allow relative rotation between the crankshaft 21 and the rotational transmission 27 when the crankshaft 21 rotates backward.

[0044] The one-way clutch 25 is positioned between the crankshaft 21 and the output shaft 22 in the transmission path for human-powered driving force. A transmission shaft 26 may be provided between the crankshaft 21 and the one-way clutch 25, configured to transmit human-powered driving force from the crankshaft 21 to the one-way clutch 25. For example, the transmission shaft 26 is formed by a hollow shaft and is positioned coaxially with the crankshaft 21. The transmission shaft 26 may be provided with a detection unit for detecting human-powered driving force. The detection unit for detecting human-powered driving force may be positioned on the outer circumference of the transmission shaft 26. The detection unit may include a strain sensor or a magnetostrictive sensor.

[0045] The bearing 30 includes a first bearing 31, a second bearing 32, and a third bearing 33. The first bearing 31 is located in the internal space 13 of the housing 10, in the first through hole 11b, or in both the internal space 13 and the first through hole 11b of the housing 10. The first bearing 31 rotatably supports the crankshaft 21 relative to the housing 10. The second bearing 32 is located in the internal space 13 of the housing 10, in the second through hole 12b, or in both the internal space 13 and the second through hole 12b of the housing 10. The second bearing 32 rotatably supports the output shaft 22 relative to the housing 10.

[0046] The third bearing 33 is positioned between the inner circumference 24 of the output shaft 22 and the outer circumference of the crankshaft 21. The output shaft 22 rotatably supports the crankshaft 21 via the third bearing 33. The first bearing 31, the second bearing 32, and the third bearing 33 may each be ball bearings, roller bearings, or sliding bearings. In this embodiment, the first bearing 31 and the second bearing 32 are radial bearings, and the third bearing 33 is a needle bearing.

[0047] The cover member 40 is provided on the outer circumference 23 of the rotation axis 20 around the rotation center axis C20. The cover member 40 is spaced apart from the housing 10, with at least a portion of it positioned in the external space of the housing 10, and covers the gap between the first outer circumference 23a and the inner circumferential surfaces 11a, 12a of the housing 10 that define the through holes 11b, 12b, as viewed from the axial direction AD20. In this embodiment, the cover member 40 covers the gap between the first outer circumference 23a and the second inner circumferential surface 12a that defines the second through hole 12b. As shown in Figure 4, the intermediate member 41 constitutes at least a portion of the cover member 40. The cover member 40 includes a sealing member 45 formed to extend radially outward from the intermediate member 41 with respect to the rotation center axis C20.

[0048] Figures 4 and 5 show an example of the cover member 40. The cover member 40 includes an intermediate member 41 and a sealing member 45. The sealing member 45 and the intermediate member 41 have an annular shape. The output shaft 22, the intermediate member 41, and the sealing member 45 are arranged coaxially.

[0049] As shown in Figure 4, the intermediate member 41 has a first side surface 43 that contacts the first outer peripheral portion 23a in the axial AD20, and a second side surface 44 that is located on the opposite side from the first side surface 43 in the axial AD20, and is configured to allow contact with the rotary transmission body 27 when the rotary transmission body 27 is attached to the second outer peripheral portion 23b. In this embodiment, the intermediate member 41 further has an outer peripheral portion 42 around the rotational center axis C20 of the rotating shaft 20. The outer peripheral portion 42 has a tapered surface 42a that inclins to approach the rotational center axis C20 as it approaches the internal space 13 of the housing 10 in the axial AD20 of the rotating shaft 20. In this specification, the state in which the rotary transmission body 27 is attached to the second outer peripheral portion 23b may be described as the transmission body mounting state.

[0050] The first side surface 43 is formed at the end of the intermediate member 41 that is closer to the internal space 13 of the housing 10, in the axial direction AD20 of the rotating shaft 20. The first side surface 43 is perpendicular to the axial direction AD20. The first side surface 43 is formed in an annular shape when viewed from the axial direction AD20. The inner diameter of the first side surface 43 is smaller than the first diameter D23a of the first outer circumference 23a of the output shaft 22. The outer diameter of the first side surface 43 is larger than the first diameter D23a. Because the output shaft 22 and the intermediate member 41 are arranged coaxially, and the inner diameter of the first side surface 43 is smaller than the first diameter D23a, and the outer diameter of the first side surface 43 is larger than the first diameter D23a, a part of the first side surface 43 is in contact with the stepped surface 23c of the first outer circumference 23a.

[0051] The second side surface 44 is perpendicular to the axial direction AD20. The second side surface 44 is substantially parallel to the first side surface 43. The second side surface 44 is formed in an annular shape when viewed from the axial direction AD20. The inner diameter of the second side surface 44 is equal to the inner diameter of the first side surface 43. The outer diameter of the second side surface 44 is greater than the outer diameter of the first side surface 43.

[0052] The intermediate member 41 is made of a material harder than the material forming the rotational transmission body 27. The intermediate member 41 is made of a metallic material and is provided on the outer periphery 23. In this embodiment, the intermediate member 41 is provided on the second outer periphery 23b of the outer periphery 23. For example, the intermediate member 41 is provided on the second outer periphery 23b by press-fitting. On the second outer periphery 23b, a mounting portion 23e is formed between the outer serration 23d and the first outer periphery 23a, to which the intermediate member 41 is provided. The intermediate member 41 is press-fitted into the mounting portion 23e. The outer diameter of the mounting portion 23e is slightly larger than the outer diameter of the outer serration 23d. The outer circumferential surface of the mounting portion 23e with respect to the rotational axis C20 of the rotating shaft 20 is formed in an annular shape. The outer circumferential surface of the mounting portion 23e may have irregularities such as knurling.

[0053] A first groove 23f is formed between the mounting portion 23e and the first outer circumference portion 23a, forming an annular shape with respect to the rotation axis C20 of the rotating shaft 20. A second groove 23g is formed between the mounting portion 23e and the outer serration 23d, forming an annular shape with respect to the rotation axis C20. In this embodiment, the second groove 23g is deeper than the first groove 23f. At the rotation axis C20, the length of the mounting portion 23e is shorter than the length of the intermediate member 41. At the rotation axis C20, one end of the intermediate member 41 overlaps with the first groove 23f in a direction perpendicular to the rotation axis C20. At the rotation axis C20, the other end of the intermediate member 41 overlaps with the second groove 23g in a direction perpendicular to the rotation axis C20. The formation of a first groove 23f and a second groove 23g on both sides of the mounting portion 23e with respect to the rotational axis C20 facilitates press-fitting the intermediate member 41 into the mounting portion 23e. The intermediate member 41 may be provided on the second outer circumference 23b by a method other than press-fitting.

[0054] The rotary transmission body 27 is made of a material with lower rigidity than the intermediate member 41. The rotary transmission body 27 is formed, for example, from a soft metal. The soft metal includes, for example, aluminum. In this embodiment, the rotary transmission body 27 is made of an aluminum alloy. If the rotary transmission body 27 is made from a soft metal, the intermediate member 41 is made from, for example, a hard metal. The hard metal includes, for example, iron. The rotary transmission body 27 may be made from a different type of material than the soft metal. The intermediate member 41 may be made from a different type of material than the hard metal.

[0055] The sealing member 45 shown in Figures 4 and 5 is formed separately from the intermediate member 41. The sealing member 45 is made of a resin material. The resin material may be a synthetic resin or a natural resin such as rubber. The sealing member 45 is formed to extend radially outward from the intermediate member 41 with respect to the rotational axis C20. The sealing member 45 may be made of a material different from the resin material. The sealing member 45 includes a cylindrical portion 46, a wall portion 47, and a projection portion 48. The cylindrical portion 46 is formed in a cylindrical shape. The inner diameter of the cylindrical portion 46 is larger than the outer diameter of the outer circumference 42 of the intermediate member 41. The cylindrical portion 46 is attached to the outer circumference 42 of the intermediate member 41. Of the cylindrical portion 46, the inner circumference 46a around the rotational axis C20 of the rotation shaft 20 contacts the outer circumference 42 of the intermediate member 41 in the radial direction RD20 of the rotation shaft 20.

[0056] The wall portion 47 is formed to extend radially outward from the cylindrical portion 46 in the radial direction RD20 of the rotation axis 20. The wall portion 47 is formed in an annular shape. For example, the wall portion 47 is formed in an annular shape when viewed from the axial direction AD20 of the rotation axis 20. The wall portion 47 is positioned at a distance from the second side wall 12 of the housing 10.

[0057] The projection 48 is formed to extend from the radially outer end of the wall portion 47 toward the internal space 13 of the housing 10 in the axial direction AD20 of the rotation axis 20. The projection 48 is formed in an annular shape. For example, the projection 48 is formed in an annular shape when viewed from the axial direction AD20 of the rotation axis 20. At least a portion of the projection 48 is positioned in the internal space of the groove 12c of the housing 10. The projection 48 is positioned at a distance from the groove 12c in the axial direction AD20.

[0058] In this embodiment, the cover member 40 covers the gap between the outer circumferential surface of the output shaft 22 and the second inner circumferential surface 12a of the housing 10, thereby suppressing the intrusion of foreign matter such as water, mud, and dust through the gap. The projection 48 and the groove 12c cause the gap between the cover member 40 and the groove 12c to curve, forming a labyrinth structure, which further suppresses the intrusion of foreign matter.

[0059] The cylindrical portion 46 of the sealing member 45 is configured to engage with the outer peripheral portion 42 of the intermediate member 41. In this embodiment, the inner peripheral portion 46a of the sealing member 45 has a first engaging portion 49. The outer peripheral portion 42 of the intermediate member 41 has a second engaging portion 42b that engages with the first engaging portion 49.

[0060] One of the first engaging portion 49 and the second engaging portion 42b includes at least one protrusion 49a projecting in the radial direction RD20 with respect to the rotational axis C20, or at least one recess 42c recessing in the radial direction RD20 with respect to the rotational axis C20. The other of the first engaging portion 49 and the second engaging portion 42b has at least one protrusion 49a or at least one recess 42c that engages with one of the first engaging portion 49 and the second engaging portion 42b in the radial direction RD20 with respect to the rotational axis C20. The at least one protrusion 49a and the at least one recess 42c have complementary shapes. In this embodiment, the outer surface of the at least one protrusion 49a and the outer surface of the at least one recess 42c are each formed by a curved surface. The outer surface of at least one protrusion 49a and the outer surface of at least one recess 42c are each formed by curved surfaces, which makes it easier to engage the sealing member 45 with the intermediate member 41.

[0061] As shown in Figure 4, in this embodiment, the first engaging portion 49 includes one protrusion 49a. The protrusion 49a is formed in an annular shape when viewed from the axial direction AD20 of the rotating shaft 20. In this embodiment, the second engaging portion 42b has one recess 42c. The recess 42c is formed in an annular shape when viewed from the axial direction AD20 of the rotating shaft 20. At least a portion of the protrusion 49a is located in the internal space of the recess 42c. In this embodiment, the entire protrusion 49a is located in the internal space of the recess 42c. By having at least a portion of the protrusion 49a located in the internal space of the recess 42c, when an external force acts on the sealing member 45 in the axial direction AD20, the protrusion 49a catches on the recess 42c, making it difficult for the sealing member 45 to detach from the intermediate member 41.

[0062] The configurations of the first engaging portion 49 and the second engaging portion 42b are not limited to this embodiment. For example, the combination of at least one recess 42c and at least one protrusion 49a is not limited to this embodiment. For example, the first engaging portion 49 may include at least one recess 42c. If the first engaging portion 49 includes at least one recess 42c, the second engaging portion 42b may include at least one protrusion 49a. For example, the shape of at least one recess 42c and at least one protrusion 49a is not limited to this embodiment. For example, at least one recess 42c and at least one protrusion 49a may be formed in an arc shape in which a part of the ring is cut out when viewed from the axial direction AD20 of the rotation axis 20.

[0063] For example, the number of at least one recess 42c and at least one protrusion 49a is not limited to this embodiment. For example, the intermediate member 41 may have a plurality of recesses 42c formed thereon, spaced apart from each other, in at least one of the axial AD20 and circumferential CD20 of the rotation axis 20. The sealing member 45 may have a plurality of protrusions 49a formed thereon, spaced apart from each other, in at least one of the axial AD20 and circumferential CD20. If the plurality of recesses 42c and the plurality of protrusions 49a are formed in an annular shape when viewed from the axial AD20, they may be spaced apart from each other in the axial AD20. If the plurality of recesses 42c and the plurality of protrusions 49a are formed in a shape other than an annular shape when viewed from the axial AD20, they may be spaced apart from each other in at least one of the axial AD20 and circumferential CD20.

[0064] In this embodiment, since the sealing member 45 of the cover member 40 is made of resin material, it is easy to attach the sealing member 45 to the intermediate member 41. The ease of attaching the sealing member 45 to the intermediate member 41 improves assembly efficiency. The intermediate member 41 is press-fitted into the mounting portion 23e and is therefore difficult to replace, but the sealing member 45 can be easily replaced. Since the sealing member 45 of the cover member 40 is made of resin material, the cover member 40 can be made lighter. The lighter cover member 40 can be made lighter, which in turn can lighten the drive unit 2.

[0065] The intermediate member 41 and the sealing member 45 may be formed integrally with each other. For example, the intermediate member 41 and the sealing member 45 may be formed integrally by insert molding. The intermediate member 41 and the sealing member 45 may be formed from the same material. If the intermediate member 41 and the sealing member 45 are formed from the same material, they may be formed integrally as a one-piece member. If the intermediate member 41 and the sealing member 45 are formed as a one-piece member, the sealing member 45 is formed from the same metal material as the intermediate member 41.

[0066] Figure 4 is used to illustrate the transmission mounting state in which the rotary transmission body 27 is attached to the second outer circumference 23b of the output shaft 22. In the transmission mounting state, the rotary transmission body 27 is arranged coaxially with the output shaft 22. The rotary transmission body 27 is adjacent to the cover member 40 in the axial direction AD20 of the rotary shaft 20. In the axial direction AD20, the rotary transmission body 27 is positioned further away from the cover member 40 than the internal space 13 of the housing 10. The rotary transmission body 27 includes an internal serration 27a, a first axial surface 27b, and a second axial surface 27c.

[0067] The internal serrations 27a are formed on the inner circumference of the rotary transmission body 27 around the rotational axis C20 of the rotating shaft 20. The internal serrations 27a engage with the external serrations 23d of the output shaft 22. By engaging the internal serrations 27a with the external serrations 23d, the rotary transmission body 27 is configured to rotate integrally with the output shaft 22. In this embodiment, since the external serrations 23d are located in the external space of the housing 10, the housing 10 is less likely to interfere when the internal serrations 27a engage with the external serrations 27d.

[0068] The first axial surface 27b is formed at the end of the rotational transmission body 27 on the cover member 40 side, in the axial direction AD20 of the rotational shaft 20. The first axial surface 27b is perpendicular to the axial direction AD20. The first axial surface 27b is formed in an annular shape when viewed from the axial direction AD20. The outer diameter of the first axial surface 27b is larger than the first diameter D23a of the first outer circumference 23a of the output shaft 22 and the outer diameter of the first side surface 43 of the intermediate member 41. The first axial surface 27b is in contact with the second side surface 44 of the intermediate member 41.

[0069] The area of ​​the first contact surface 44a of the second side surface 44 that can contact the rotational transmission body 27 is larger than the area of ​​the second contact surface 43a of the first side surface 43 that contacts the first outer circumference 23a. The first contact surface 44a and the second contact surface 43a are formed in an annular shape when viewed from the axial direction AD20. The outer diameter of the first contact surface 44a is larger than the outer diameter of the second contact surface 43a. The inner diameter of the first contact surface 44a is larger than the inner diameter of the second contact surface 43a. The first contact surface 44a is substantially parallel to the second contact surface 43a. The first contact surface 44a and the second contact surface 43a are perpendicular to the axial direction AD20.

[0070] The second axial surface 27c is formed on the side of the rotational transmission body 27 opposite to the first axial surface 27b in the axial direction AD20 of the rotation axis 20. The second axial surface 27c is perpendicular to the axial direction AD20. The second axial surface 27c is substantially parallel to the first axial surface 27b. The second axial surface 27c is formed in an annular shape when viewed from the axial direction AD20. The second axial surface 27c is in contact with the lock ring 28 in the axial direction AD20.

[0071] The lock ring 28 is configured to fix the rotary transmission body 27 to the output shaft 22. The lock ring 28 includes a ring-shaped cylindrical portion 28a, an external thread 28b, and a radial extension portion 28c. The ring-shaped cylindrical portion 28a is formed in a cylindrical shape. When the transmission body is mounted, the ring-shaped cylindrical portion 28a is positioned coaxially with the output shaft 22. The external thread 28b is formed on the outer circumferential surface of the ring-shaped cylindrical portion 28a. The external thread 28b is configured to screw into the internal thread 24a of the output shaft 22. The external thread 28b is formed on the side of the ring-shaped cylindrical portion 28a closer to the cover member 40 in the axial direction AD20 of the rotary shaft 20.

[0072] The radial extension portion 28c is formed to extend radially outward from the ring-shaped cylindrical portion 28a in the radial direction RD20 of the rotating shaft 20. The radial extension portion 28c is formed on the side of the ring-shaped cylindrical portion 28a opposite to the external thread 28b in the axial direction AD20 of the rotating shaft 20. The radial extension portion 28c is formed in an annular shape when viewed from the axial direction AD20. The outer diameter of the radial extension portion 28c is larger than the outer diameter of the second outer circumference 23b of the output shaft 22. In the axial direction AD20 with the transmission body installed, the rotating transmission body 27 is positioned between the cover member 40 and the radial extension portion 28c.

[0073] In the transmission unit mounting state, the external thread 28b of the lock ring 28 is screwed onto the internal thread 24a of the output shaft 22. When the external thread 28b is screwed onto the internal thread 24a, the radial extension 28c contacts the second axial surface 27c of the rotary transmission unit 27. The screwing of the external thread 28b onto the internal thread 24a generates an axial force in the lock ring 28. Due to the axial force of the lock ring 28, the rotary transmission unit 27 is pressed against the second side surface 44 of the cover member 40 in the axial direction AD20 of the rotary shaft 20, with its first axial surface 27b pressed against the second outer circumference 23b of the output shaft 22.

[0074] In this embodiment, since the area of ​​the first contact surface 44a is larger than the area of ​​the second contact surface 43a, the surface pressure acting on the rotational transmission body 27 can be reduced compared to when the first axial surface 27b is pressed against the stepped surface 23c of the first outer circumference 23a. By reducing the surface pressure acting on the rotational transmission body 27, deformation of the rotational transmission body 27 can be suppressed.

[0075] In the transmission body mounting state, the first side surface 43 of the intermediate member 41 is pressed against the stepped surface 23c of the first outer circumference 23a by the axial force of the lock ring 28. In this embodiment, since the intermediate member 41 is made of a material harder than the rotation transmission body 27, deformation of the intermediate member 41 can be suppressed even if the area of ​​the second contact surface 43a is smaller than the area of ​​the first contact surface 44a.

[0076] The relationship between the area of ​​the second contact surface 43a and the reduction in diameter of the output shaft 22 will be explained. As the first diameter D23a of the first outer circumference 23a of the output shaft 22 becomes smaller than the outer diameter of the first side surface 43 of the intermediate member 41, the area of ​​the second contact surface 43a decreases. When the area of ​​the second contact surface 43a decreases, the surface pressure acting on the intermediate member 41 in the transmission body mounting state increases.

[0077] In this embodiment, since the intermediate member 41 is formed from a material harder than the rotational transmission body 27, the intermediate member 41 is less likely to deform even when the surface pressure acting on it is high. Because the intermediate member 41 is less likely to deform even when the surface pressure acting on it is high, the diameter of the output shaft 22 can be reduced until the first diameter D23a is smaller than the outer diameter of the first side surface 43. By reducing the diameter of the output shaft 22, assembly ease can be improved. For example, the output shaft 22 can be easily inserted into the housing 10, thus improving assembly ease. By reducing the diameter of the output shaft 22, the drive unit 2 can be made lighter, making it easier to mount the drive unit 2 on a human-powered vehicle.

[0078] Figure 2 is used to illustrate the electric motor 50 and the reduction gear 60. The electric motor 50 is configured to provide propulsion to the human-powered vehicle. The electric motor 50 is configured to transmit rotational force to the rear wheels of the human-powered vehicle, for example, via an output shaft 22. The electric motor 50 is housed in the housing 10. The electric motor 50 is located in the internal space 13 of the housing 10. The electric motor 50 includes a motor output shaft 51.

[0079] The motor output shaft 51 has a rotational axis C51 that is different from the rotational axis C20 of the rotating shaft 20. The rotational axis C51 of the motor output shaft 51 is substantially parallel to the rotational axis C20 of the rotating shaft 20. The motor output shaft 51 is formed of, for example, a metallic material. The motor output shaft 51 is rotatably supported in the housing 10 via a pair of sixth bearings 36. The sixth bearings 36 may be ball bearings, roller bearings, or sliding bearings.

[0080] The reduction gear 60 is configured to connect the electric motor 50 and the output shaft 22. The reduction gear 60 is housed in the housing 10. The reduction gear 60 is located in the internal space 13 of the housing 10. The reduction gear 60 includes a first rotating body 61, a first reduction rotating shaft 62, a second rotating body 63, a third rotating body 64, a second reduction rotating shaft 65, a fourth rotating body 66, a fifth rotating body 67, and a sixth rotating body 68.

[0081] The first rotating body 61 is mounted on the output shaft 22 so as to rotate integrally with the output shaft 22. The first rotating body 61 and the output shaft 22 are formed from, for example, the same metal material. The first rotating body 61 and the output shaft 22 are formed integrally as, for example, a one-piece member. The first rotating body 61 and the output shaft 22 may be formed as separate parts and fixed so as not to rotate relative to each other. The first rotating body 61 may be formed from, for example, a resin material.

[0082] The first reduction rotating shaft 62 has a rotational axis C62 that is different from the rotational axis C20 of the rotating shaft 20 and the rotational axis C51 of the motor output shaft 51. The rotational axis C62 of the first reduction rotating shaft 62 is substantially parallel to the rotational axis C20 of the rotating shaft 20 and the rotational axis C51 of the motor output shaft 51. The first reduction rotating shaft 62 is rotatably supported in the housing 10 via a pair of fourth bearings 34. The first reduction rotating shaft 62 is formed of, for example, a metallic material. The pair of fourth bearings 34 support the axial ends of the first reduction rotating shaft 62 in the axial direction with respect to the rotational axis C62 of the first reduction rotating shaft 62. The pair of fourth bearings 34 may be ball bearings, roller bearings, or sliding bearings.

[0083] The second rotating body 63 is mounted on the first reduction rotating shaft 62 via a one-way clutch 63a. The second rotating body 63 is connected to the first rotating body 61 directly or via a ring member. In this embodiment, the first rotating body 61 and the second rotating body 63 include gears with gear teeth on their outer circumference. The gear teeth of the first rotating body 61 and the gear teeth of the second rotating body 63 mesh together, thereby directly connecting the first rotating body 61 and the second rotating body 63.

[0084] The one-way clutch 63a includes, for example, a roller clutch, a sprag clutch, a pawl ratchet clutch, or a face ratchet clutch. The one-way clutch 63a is configured to rotate the second rotating body 63 when the first reduction rotating shaft 62 rotates in a first rotational direction, and to allow relative rotation between the first reduction rotating shaft 62 and the second rotating body 63 when the first reduction rotating shaft 62 rotates in a second rotational direction opposite to the first rotational direction. The one-way clutch 63a may be provided between the first reduction rotating shaft 62 and the third rotating body 64, rather than between the first reduction rotating shaft 62 and the second rotating body 63.

[0085] The first rotating body 61 and the second rotating body 63 may include pulleys. The first rotating body 61 and the second rotating body 63 may be indirectly connected by a ring member. The ring member includes, for example, a chain and a belt. The first rotating body 61 and the second rotating body 63 may be indirectly connected by, for example, a chain that engages with the first rotating body 61 and the second rotating body 63. If the first rotating body 61 and the second rotating body 63 include pulleys, the first rotating body 61 and the second rotating body 63 may be indirectly connected by, for example, a belt that circles around the first rotating body 61 and the second rotating body 63.

[0086] The third rotating body 64 is configured to rotate integrally with the first reduction shaft 62. The third rotating body 64 is formed from, for example, a resin material or a metal material. The third rotating body 64 and the first reduction shaft 62 are formed separately and fixed so as not to rotate relative to each other. The third rotating body 64 and the first reduction shaft 62 may be formed integrally as a one-piece member. The second rotating body 63 and the third rotating body 64 are positioned between a pair of fourth bearings 34 in the axial direction of the first reduction shaft 62.

[0087] The second reduction rotating shaft 65 has a rotational axis C65 that is different from the rotational axis C20 of the rotating shaft 20, the rotational axis C51 of the motor output shaft 51, and the rotational axis C62 of the first reduction rotating shaft 62. The rotational axis C65 of the second reduction rotating shaft 65 is substantially parallel to the rotational axis C20 of the rotating shaft 20, the rotational axis C51 of the motor output shaft 51, and the rotational axis C62 of the first reduction rotating shaft 62. The second reduction rotating shaft 65 is rotatably supported in the housing 10 via a pair of fifth bearings 35. The pair of fifth bearings 35 support the axial ends of the second reduction rotating shaft 65, respectively, in the axial direction with respect to the rotational axis C65 of the second reduction rotating shaft 65. The fifth bearings 35 may be ball bearings, roller bearings, or sliding bearings.

[0088] The fourth rotating body 66 is mounted on the second reduction shaft 65 so as to rotate integrally with the second reduction shaft 65. The fourth rotating body 66 and the second reduction shaft 65 are integrally formed, for example, as a one-piece member. The fourth rotating body 66 is connected to the third rotating body 64 directly or via a ring member. In this embodiment, the third rotating body 64 and the fourth rotating body 66 include gears with gear teeth on their outer circumference. The gear teeth of the third rotating body 64 and the gear teeth of the fourth rotating body 66 mesh together to directly connect the third rotating body 64 and the fourth rotating body 66.

[0089] The third rotating body 64 and the fourth rotating body 66 may include pulleys. The third rotating body 64 and the fourth rotating body 66 may be indirectly connected by a ring member. The ring member includes, for example, a chain and a belt. The third rotating body 64 and the fourth rotating body 66 may be indirectly connected by, for example, a chain that engages with the third rotating body 64 and the fourth rotating body 66. If the third rotating body 64 and the fourth rotating body 66 include pulleys, the third rotating body 64 and the fourth rotating body 66 may be indirectly connected by, for example, a belt that circles around the third rotating body 64 and the fourth rotating body 66.

[0090] The fifth rotating body 67 is configured to rotate integrally with the second reduction shaft 65. The fifth rotating body 67 is formed of, for example, a resin material or a metal material. The fifth rotating body 67 and the second reduction shaft 65 are formed separately and fixed so as not to rotate relative to each other. The fifth rotating body 67 and the second reduction shaft 65 may be formed integrally as a one-piece member. The fourth rotating body 66 and the fifth rotating body 67 are positioned between a pair of fifth bearings 35 in the axial direction of the second reduction shaft 65.

[0091] The sixth rotating body 68 is mounted on the motor output shaft 51 of the electric motor 50 so as to rotate integrally with the motor output shaft 51. The sixth rotating body 68 is formed of, for example, a metal material. The sixth rotating body 68 and the motor output shaft 51 are formed integrally as, for example, a one-piece member. The sixth rotating body 68 and the motor output shaft 51 may be formed separately and fixed so as not to rotate relative to each other. The sixth rotating body 68 may be formed of, for example, a resin material.

[0092] The sixth rotating body 68 is connected to the fifth rotating body 67 either directly or via a ring member. In this embodiment, the fifth rotating body 67 and the sixth rotating body 68 include gears with gear teeth on their outer circumference. The gear teeth of the fifth rotating body 67 and the gear teeth of the sixth rotating body 68 mesh together, thereby directly connecting the fifth rotating body 67 and the sixth rotating body 68.

[0093] The fifth rotating body 67 and the sixth rotating body 68 may include pulleys. The fifth rotating body 67 and the sixth rotating body 68 may be indirectly connected by a ring member. The ring member includes, for example, a chain and a belt. The fifth rotating body 67 and the sixth rotating body 68 may be indirectly connected by, for example, a chain that engages with the fifth rotating body 67 and the sixth rotating body 68. If the fifth rotating body 67 and the sixth rotating body 68 include pulleys, the fifth rotating body 67 and the sixth rotating body 68 may be indirectly connected by, for example, a belt that circulates around the fifth rotating body 67 and the sixth rotating body 68. The configuration of the reduction gear 60 is not limited to this embodiment. The reduction gear 60 may, for example, include only one pair of rotating bodies, only two pairs of rotating bodies, or include a planetary gear mechanism.

[0094] When the electric motor 50 is driven, the rotational force of the electric motor 50 is transmitted to the output shaft 22 via the reduction gear 60, so that the rotational speed of the output shaft 22 decreases relative to the rotational speed of the motor output shaft 51. The reduction gear 60 includes a gear assembly 70. The gear assembly 70 includes at least two rotating bodies from the first rotating body 61 to the sixth rotating body 68. In this embodiment, the gear assembly 70 includes a fourth rotating body 66 and a fifth rotating body 67. Figures 2, 6 to 9 are used to illustrate the gear assembly 70 included in the reduction gear 60. In Figure 6, the first gear teeth 75 and the second gear teeth 84a are shown in a simplified manner.

[0095] The gear assembly 70 is a gear assembly for a human-powered vehicle and comprises: a shaft member 71 having a rotational axis C71 and formed of a metal material; a first gear 74 having first gear teeth 75 formed integrally with the shaft member 71 and made of a metal material on a first outer circumference 72a of the shaft member 71 in an axial AD71 with respect to the rotational axis C71 in a first portion 72 of the shaft member 71 in an axial AD71; a second gear 80 having second gear teeth 84a formed of a resin material and in contact with the shaft member 71 on a second outer circumference 73a of the shaft member 71 adjacent to the first portion 72 in an axial AD71 in a second portion 73 of the shaft member 71 in an axial AD71 in a second portion 73a of the shaft member 71 in an axial direction with respect to the rotational axis C71 in a second outer circumference 73a of the shaft member 71; and an annular member 76 in contact with the shaft member 71 and at least a portion of which is disposed between the second gear 80 and the shaft member 71 in a radial direction RD71 with respect to the rotational axis C71.

[0096] In this embodiment, the shaft member 71 includes the second reduction rotating shaft 65 shown in Figure 2. The first gear 74 includes the fourth rotating body 66. The second gear 80 includes the fifth rotating body 67. Figures 6 and 7 show an example of the gear assembly 70. The gear assembly 70 includes the shaft member 71, the first gear 74, the annular member 76, and the second gear 80.

[0097] The shaft member 71 is formed in a cylindrical shape. In this embodiment, in the axial AD 71 of the shaft member 71, one axial side of the shaft member 71 is formed as a first portion 72. In the axial AD 71 of the shaft member 71, the other axial side of the shaft member 71 is formed as a second portion 73. The first outer circumference 72a of the first portion 72 includes a first small diameter portion 72b and a first large diameter portion 72c.

[0098] The first small-diameter portion 72b is formed at one axial end of the shaft member 71 in the axial direction AD 71 of the shaft member 71. The outer diameter of the first small-diameter portion 72b is smaller than the inner diameter of one of the pair of fifth bearings 35 shown in Figure 2. The first small-diameter portion 72b is supported by one of the pair of fifth bearings 35. The first large-diameter portion 72c is formed on a different part of the first outer circumference 72a from the first small-diameter portion 72b. The outer diameter of the first large-diameter portion 72c is larger than the outer diameter of the first small-diameter portion 72b.

[0099] The second outer circumference 73a of the second portion 73 includes a second small diameter portion 73b, a second large diameter portion 73c, an intermediate portion 73d, and an outer serration 73e. The second small diameter portion 73b is formed at the other axial end of the shaft member 71 in the axial AD 71 of the shaft member 71. The outer diameter of the second small diameter portion 73b is smaller than the inner diameter of the other of the pair of fifth bearings 35 shown in Figure 2. The second small diameter portion 73b is supported by the other of the pair of fifth bearings 35.

[0100] The second large-diameter portion 73c is positioned at a distance from the second small-diameter portion 73b in the axial AD 71 of the shaft member 71. The outer diameter of the second large-diameter portion 73c is larger than the outer diameter of the second small-diameter portion 73b. The second large-diameter portion 73c is positioned next to the first outer circumference portion 72a in the axial AD 71 of the shaft member 71.

[0101] The intermediate portion 73d is positioned between the second small diameter portion 73b and the second large diameter portion 73c in the axial AD 71 of the shaft member 71. The outer diameter of the intermediate portion 73d is larger than the outer diameter of the second small diameter portion 73b. The outer diameter of the intermediate portion 73d is smaller than the outer diameter of the second large diameter portion 73c. ​​The outer serrations 73e are formed to extend radially outward from the intermediate portion 73d in the radial direction RD 71 with respect to the rotational axis C71 of the shaft member 71.

[0102] The first gear 74 is formed, for example, from the same metal material as the shaft member 71. The metal material forming the shaft member 71 and the first gear 74 includes, for example, iron. The shaft member 71 and the first gear 74 are integrally formed from a one-piece member. The material forming the shaft member 71 and the material forming the first gear 74 are not limited to this embodiment.

[0103] For example, the shaft member 71 and the first gear 74 may be formed from a metal material other than iron. The shaft member 71 and the first gear 74 may be formed from different metal materials. If the shaft member 71 and the first gear 74 are formed from different metal materials, the shaft member 71 and the first gear 74 may be formed as separate parts and fixed so as not to rotate relative to each other.

[0104] The first gear teeth 75 of the first gear 74 are formed to extend radially outward from the first outer circumference 72a of the shaft member 71 in the radial direction RD71 of the shaft member 71. In this embodiment, the first gear teeth 75 are formed to extend radially outward from the first large diameter portion 72c of the first outer circumference 72a. The first gear teeth 75 reach one axial end and the other axial end of the first large diameter portion 72c in the axial direction AD71 of the shaft member 71. The first gear teeth 75 include, for example, a spur gear. Multiple first gear teeth 75 are arranged at intervals in the circumferential direction CD71 with respect to the rotational axis C71 of the shaft member 71. In Figures 6 and 8, for the sake of simplicity in the drawings, the first gear teeth 75 are depicted in an annular shape covering the entire circumference of the first large diameter portion 72c. The first gear teeth 75 may include gears other than spur gears. For example, the first gear teeth 75 may include a helical gear.

[0105] The annular member 76 shown in Figures 7 and 8 is formed in an annular shape when viewed from the axial direction AD 71 of the shaft member 71. The annular member 76 is arranged coaxially with the shaft member 71. The annular member 76 is formed of a metal material, for example. The annular member 76 is formed of iron, for example. The annular member 76 may be formed of a metal material other than iron. As shown in Figures 6 and 7, the annular member 76 is provided on the second large diameter portion 73c of the second outer circumference 73a. The annular member 76 is provided on the second large diameter portion 73c, for example by press-fitting it into the second large diameter portion 73c. ​​The annular member 76 is adjacent to the first gear 74 in the axial direction AD 71 of the shaft member 71. The annular member 76 may be provided on the second outer circumference 73a by a method other than press-fitting.

[0106] The annular member 76 includes a first axial end 77 and a second axial end 78 with respect to the axial AD 71 of the shaft member 71. The annular member 76 further includes a projection 79. The first axial end 77 is formed on the end of the annular member 76 that is closer to the first gear 74 in the axial AD 71 of the shaft member 71. The first axial end 77 contacts the first gear 74.

[0107] The second axial end 78 is formed on the annular member 76 opposite to the first axial end 77 in the axial AD 71 of the shaft member 71. The second axial end 78 contacts the second gear 80. The annular member 76 is positioned at the boundary between the first gear 74 and the second gear 80 in the axial AD 71.

[0108] The protruding portion 79 is formed to protrude from the second large-diameter portion 73c toward the second small-diameter portion 73b in the axial direction of the shaft member 71. The protruding portion 79 is positioned radially outward from the intermediate portion 73d in the radial direction RD71 of the shaft member 71.

[0109] The outer radius L76a of the annular member 76, which indicates the radius of the outer surface of the annular member 76, is greater than the radial length L75 of the first gear teeth, which indicates the length along the radial direction RD71 of the shaft member 71 from the rotational axis C71 of the shaft member 71 to the tip of the first gear teeth 75. The inner radius L76b of the annular member 76, which indicates the radius of the inner surface of the annular member 76, is smaller than the radial length L75 of the first gear teeth.

[0110] In this embodiment, the shaft member 71 and the annular member 76 are arranged coaxially, and since the outer radius L76a of the annular member is greater than the radial length L75 of the first gear teeth, as shown in Figure 8, the first gear 74 is positioned radially inward from the annular member 76 when viewed from the axial direction AD71. As shown in Figure 7, one end of the first gear tooth 75 of the first gear 74 contacts the annular member 76 in the axial direction AD71. In this embodiment, one end of the axial direction AD71 of the first gear tooth 75 contacts the first axial end 77 of the annular member 76.

[0111] By having one end of the axial AD71 of the first gear tooth 75 contact the first axial end 77, the first gear tooth 75 can be positioned closer to the second gear tooth 84a in the axial AD71. By positioning the first gear tooth 75 closer to the second gear tooth 84a, the length of the axial AD71 of the shaft member 71 can be shortened, thus allowing the gear assembly 70 to be miniaturized.

[0112] The second gear 80 shown in Figures 6 and 7 is arranged coaxially with the shaft member 71. The second gear 80 includes a small-diameter cylindrical portion 81, a large-diameter cylindrical portion 84, and a radially extended portion 85. The small-diameter cylindrical portion 81 is formed in a cylindrical shape. The small-diameter cylindrical portion 81 is formed radially inward of the second gear 80 in the radial direction RD71 of the shaft member 71. The small-diameter cylindrical portion 81 includes a first small-diameter cylindrical portion 82 and a second small-diameter cylindrical portion 83.

[0113] The first small-diameter cylindrical portion 82 is formed in a cylindrical shape. The first small-diameter cylindrical portion 82 is provided on the intermediate portion 73d of the second portion 73 of the shaft member 71. A part of the first small-diameter cylindrical portion 82 is positioned between the projection 79 of the annular member 76 and the intermediate portion 73d in the radial direction RD71 of the shaft member 71. By positioning a part of the first small-diameter cylindrical portion 82 between the projection 79 of the annular member 76 and the intermediate portion 73d, when an external force in the radial direction RD71 acts on the second gear 80, the first small-diameter cylindrical portion 82 of the second gear 80 catches on the projection 79 of the annular member 76. The first small-diameter cylindrical portion 82 catching on the projection 79 makes it difficult for the second gear 80 to detach from the shaft member 71.

[0114] The first small-diameter cylindrical portion 82 includes internal serrations 82a. The internal serrations 82a are formed on the inner circumferential surface of the first small-diameter cylindrical portion 82. The internal serrations 82a engage with the external serrations 73e of the shaft member 71. The engagement of the internal serrations 82a with the external serrations 73e configures the second gear 80 to rotate integrally with the shaft member 71. The second small-diameter cylindrical portion 83 is formed in a cylindrical shape. The second small-diameter cylindrical portion 83 is provided on the second large-diameter portion 73c of the second portion 73 of the shaft member 71 via an annular member 76.

[0115] The large-diameter cylindrical portion 84 is formed in a cylindrical shape. The outer diameter and inner diameter of the large-diameter cylindrical portion 84 are larger than the outer diameter of the annular member 76, the outer diameter of the first small-diameter cylindrical portion 82, and the outer diameter of the second small-diameter cylindrical portion 83. The large-diameter cylindrical portion 84 is positioned radially outward from the small-diameter cylindrical portion 81 in the radial direction RD71 of the shaft member 71. In this embodiment, the second gear teeth 84a are provided on the large-diameter cylindrical portion 84.

[0116] The second gear teeth 84a are formed to extend radially outward from the large-diameter cylindrical portion 84 in the radial direction RD71 of the shaft member 71. The second gear teeth 84a reach one axial end and the other axial end of the large-diameter cylindrical portion 84 in the axial direction AD71 of the shaft member 71. The second gear teeth 84a include, for example, a helical gear. Multiple second gear teeth 84a are arranged at intervals in the circumferential direction CD71 of the shaft member 71. In Figures 6 and 8, for the sake of simplicity in the drawings, the second gear teeth 84a are depicted in an annular shape covering the entire circumference of the outer surface of the large-diameter cylindrical portion 84. The second gear teeth 84a may include gears other than helical gears. For example, the second gear teeth 84a may include a spur gear.

[0117] The radial extension portion 85 is formed to extend radially outward from the small-diameter cylindrical portion 81 in the radial direction RD71 of the shaft member 71. The radial extension portion 85 reaches both the small-diameter cylindrical portion 81 and the large-diameter cylindrical portion 84 in the radial direction RD71. The radial extension portion 85 is formed in an annular shape when viewed from the axial direction AD71 of the shaft member 71. The radial extension portion 85 includes a plurality of ribs 85a.

[0118] Multiple ribs 85a are formed to bulge out from the radial extension portion 85 in the axial direction AD71. Multiple ribs 85a are formed to extend radially RD71 of the shaft member 71. As shown in Figure 8, multiple ribs 85a are formed spaced apart from each other in the circumferential direction CD71 of the shaft member 71. Multiple ribs 85a are formed on one axial side and the other axial side of the radial extension portion 85 in the axial direction AD71 of the shaft member 71. The multiple ribs 85a can reduce the deflection of the second gear 80.

[0119] In this embodiment, the shaft member 71, the second gear 80, and the annular member 76 are integrally formed with each other by insert molding. An example of insert molding is illustrated using Figure 9.

[0120] In insert molding, a shaft member 71 is inserted into a mold D, the shaft member having a first gear 74 on its first outer circumference 72a and an annular member 76 press-fitted into its second large-diameter portion 73c. ​​The mold D has an internal space D1 for forming a second gear 80 on the second outer circumference 73a of the shaft member 71. The mold D includes a fixed mold D10 and a movable mold D20.

[0121] The movable mold D20 is configured to move relative to the fixed mold D10. The contact between the movable mold D20 and the fixed mold D10 forms an internal space D1 in the mold D. The movable mold D20 includes a housing portion D21 and a contact portion D22.

[0122] The housing portion D21 is formed to accommodate the first gear 74 when the shaft member 71 is inserted into the mold D. The housing portion D21 is formed in a circular shape, for example, when viewed from the axial direction AD71 of the shaft member 71 in the inserted state. The radius of the housing portion D21 is greater than the length L75 in the radial direction of the first gear teeth. When the shaft member 71 is inserted, it is positioned so that its rotational axis C71 passes through the center of the housing portion D21. Because the rotational axis C71 of the shaft member 71 passes through the center of the housing portion D21, and because the radius of the housing portion D21 is greater than the length L75 in the radial direction of the first gear teeth, a clearance C is formed between the housing portion D21 and the first gear teeth 75.

[0123] The contact portion D22 is formed to extend radially outward from the housing portion D21 in the radial direction RD71 of the shaft member 71 in the inserted state. The contact portion D22 is formed in an annular shape when viewed from the axial direction AD71 in the inserted state. The contact portion D22 contacts the first axial end 77 of the annular member 76 in the axial direction AD71 in the inserted state.

[0124] In the inserted state, the internal space D1 of the mold D is filled with resin material that forms the second gear 80. In this embodiment, since the contact portion D22 contacts the first axial end 77 of the annular member 76, leakage of resin material from the second outer circumference 73a to the first outer circumference 72a of the shaft member 71 can be suppressed. By suppressing leakage of resin material using the annular member 76, the shaft member 71 and the second gear 80 can be easily connected. For example, the shaft member 71 and the second gear 80 can be connected without forming an internal tooth portion that meshes with the first gear teeth 75 of the first gear 74 in the housing portion D21 of the movable mold D20. The ability to easily connect the shaft member 71 and the second gear 80 improves ease of assembly. The ability to easily assemble the gear assembly 70 improves the ease of assembly of the drive unit 2 equipped with the gear assembly 70.

[0125] Since the contact portion D22 and the annular member 76 are formed in an annular shape when viewed from the axial direction AD71 of the shaft member 71 in the inserted state, a gap is less likely to occur between the annular member 76 and the movable type D20 in the inserted state. By making it less likely for a gap to occur between the annular member 76 and the movable type D20 in the inserted state, leakage of resin material from the second outer circumference 73a to the first outer circumference 72a can be effectively suppressed. By effectively suppressing leakage of resin material from the second outer circumference 73a to the first outer circumference 72a, the generation of burrs can be suppressed and the quality of the gear assembly 70 can be improved.

[0126] The resin material of the second gear 80, which is filled into the internal space D1 of mold D, is cured. As the resin material hardens, the shaft member 71, the second gear 80, and the annular member 76 are integrally formed with each other by insert molding. Because the shaft member 71, the second gear 80, and the annular member 76 are formed by insert molding, the second gear 80 is difficult to detach from the shaft member 71 and the annular member 76.

[0127] The second gear 80 may be annealed. Annealing can reduce residual stress in the second gear 80, thereby improving its quality. In insert molding, the mold D, shaft member 71, and annular member 76 may be preheated. Preheating the mold D, shaft member 71, and annular member 76 makes it less likely for the resin material to harden when it comes into contact with the mold D, shaft member 71, and annular member 76, thus allowing the resin material to spread more easily throughout the entire internal space D1 of the mold D. This allows the resin material to spread more easily throughout the entire internal space D1, enabling the second gear 80 to be molded with high precision.

[0128] (modified version) The description relating to this embodiment is illustrative of possible forms of the present invention and is not intended to limit it. The present invention may take the form of, for example, variations of each of the embodiments shown below, and combinations of at least two non-inconsistent variations.

[0129] For example, the configuration of component 1 in this embodiment is just one example, and component 1 may include various devices not shown in this embodiment, or it may not include some of the devices shown in this embodiment. For example, component 1 may not include the speed reducer 60 shown in Figure 2.

[0130] For example, the configuration of the cover member 40 in this embodiment is just one example, and the cover member 40 may include various members not shown in this embodiment, or it may not include some of the various members shown in this embodiment. For example, the cover member 40 may include only the intermediate member 41 among the intermediate member 41 and sealing member 45 shown in Figures 4 and 5.

[0131] The intermediate member 41 and the sealing member 45 may be formed in a shape other than an annular shape, for example. For example, the first contact surface 44a may not be substantially parallel to the second contact surface 43a. The first contact surface 44a and the second contact surface 43a may not be perpendicular to the axial direction AD20 of the rotation axis 20. The first contact surface 44a and the second contact surface 43a may be formed in a shape other than an annular shape when viewed from the axial direction AD20.

[0132] For example, the configuration of the gear assembly 70 in this embodiment is just one example, and the gear assembly 70 may include various components not shown in this embodiment, or it may not include some of the components shown in this embodiment.

[0133] For example, the shaft member 71, second gear 80, and annular member 76 of the gear assembly 70 shown in Figures 6 and 7 may be integrally formed by a method other than insert molding. For example, the shaft member 71 and the second gear 80 may be formed separately and fixed so as not to rotate relative to each other. For example, the first gear 74 may be positioned outside the annular member 76 in the radial RD71 of the shaft member 71 when viewed from the axial AD71 of the shaft member 71. The first gear 74 may be positioned at a distance from the annular member 76 in the axial AD71 of the shaft member 71.

[0134] For example, the annular member 76 of the gear assembly 70 may be made of a multi-pole magnetized magnet. When the annular member 76 is made of a multi-pole magnetized magnet, the annular member 76 is formed of, for example, a plastic magnet. The plastic magnet includes a structure in which an annular member made of, for example, iron, is encased in resin. Because the annular member 76 is made of a multi-pole magnetized magnet, the rotational speed of the annular member 76 can be detected by the detection unit, and thus the rotational speed of the gear assembly 70 can be determined.

[0135] As used herein, the expression "at least one" means "one or more" of the desired options. For example, as used herein, "at least one" means "only one option" or "both of the two options" if there are two options. As another example, as used herein, "at least one" means "only one option" or "a combination of two or more any options" if there are three or more options. [Explanation of Symbols]

[0136] 1...Component, 2...Drive unit, 10...Housing, 11a,12a...Inner circumferential surface, 11b,12b...Through hole, 13...Internal space, 20...Rotation shaft, 23...Outer circumferential part, 23a...First outer circumferential part, 23b...Second outer circumferential part, 27...Rotational transmission body, 30...Bearing, 40...Cover member, 41...Intermediate member, 42b...Second engaging part, 42c...Recess, 43...First side surface, 43a...First contact surface, 44...Second side surface, 44a...Second contact surface, 45...Seal member 49...First engaging part, 49a...Protrusion, 50...Electric motor 50, 60...Reduction gear 60, 70...Gear assembly, 71...Shaft member, 72...First part, 72a...First outer circumference, 73...Second part, 73a...Second outer circumference, 74...First gear, 75...First gear teeth, 80...Second gear, 84a...Second gear teeth, 76...Annular member, AD20, AD71...Axial direction, C20, C71...Rotation center axis, D23a...First diameter, D23b...Second diameter, RD71...Radial direction

Claims

1. A component for a human-powered vehicle, A rotating shaft having a rotational axis and to which an annular rotational transmission body can be attached, The rotating shaft comprises an intermediate member provided on the aforementioned rotating shaft, The rotating shaft has an outer circumference around the axis of rotation, The outer periphery is, A first outer circumference having a first diameter with respect to the axis of rotation, The second outer circumference has a second diameter smaller than the first diameter with respect to the axis of rotation, and is adjacent to the first outer circumference in the axial direction with respect to the axis of rotation, and to which the rotational transmission body can be attached. The aforementioned intermediate member is In the axial direction, the first surface that contacts the first outer circumference, In the axial direction, it is positioned on the opposite side from the first side surface, and has a second side surface that is configured to be contactable by the rotational transmission body when the rotational transmission body is attached to the second outer circumference, The area of ​​the first contact surface of the second side surface that can contact the rotational transmission body is larger than the area of ​​the second contact surface of the first side surface that contacts the first outer circumference. The aforementioned component is A housing that forms an internal space and has through holes connecting the internal space and the external space, The housing further comprises a bearing provided therein that rotatably supports the rotating shaft, The rotating shaft is positioned such that a portion of it is located within the internal space and protrudes into the external space of the housing through the through hole. Further equipped with a cover member, The intermediate member constitutes at least a part of the cover member, The cover member is positioned at a distance from the housing, with at least a portion of it located in the external space of the housing, and, when viewed from the axial direction, covers the gap between the first outer periphery and the inner circumferential surface of the housing that defines the through hole. The cover member includes a sealing member formed to extend radially outward from the intermediate member with respect to the axis of rotation, The sealing member and the intermediate member have an annular shape. The inner circumference of the sealing member has a first engaging portion, The component wherein the outer periphery of the intermediate member has a second engaging portion that engages with the first engaging portion.

2. The component according to claim 1, wherein at least a portion of the second outer periphery is disposed in the external space of the housing.

3. The component according to claim 1, wherein the first contact surface is substantially parallel to the second contact surface.

4. The component according to claim 3, wherein the first contact surface and the second contact surface are perpendicular to the axial direction.

5. The first contact surface and the second contact surface are formed in an annular shape when viewed from the axial direction, The component according to claim 1, wherein the outer diameter of the first contact surface is larger than the outer diameter of the second contact surface.

6. The component according to claim 1, wherein the intermediate member is made of a material harder than the material forming the rotational transmission body.

7. The component according to claim 1, wherein the sealing member is formed of a resin material.

8. The component according to claim 1, wherein the intermediate member is formed of a metal material.

9. The first engaging portion and the second engaging portion include at least one convex portion projecting radially with respect to the axis of rotation, or at least one concave portion recessed radially with respect to the axis of rotation, The component according to claim 1, wherein the other of the first engaging portion and the second engaging portion has at least one convex portion or at least one concave portion that engages with the one of the first engaging portion and the second engaging portion in the radial direction with respect to the axis of rotation.

10. A housing having an internal space formed and through holes formed to connect the internal space and the external space, A rotating shaft having a rotational axis, a portion of which is located in the internal space, and which protrudes into the external space of the housing through the through hole, A drive unit for a human-powered vehicle comprising the following, wherein a cover member for the drive unit is provided on the outer circumference of the rotational axis of the rotating shaft and is arranged at a distance from the housing, The cover member is An intermediate member formed of a metal material and provided on the outer periphery, A cover member for a drive unit, comprising a sealing member formed of a resin material and extending radially outward from the intermediate member with respect to the axis of rotation.

11. The sealing member and the intermediate member have an annular shape, The inner circumference of the sealing member has a first engaging portion, The cover member according to claim 10, wherein the outer periphery of the intermediate member has a second engaging portion that engages with the first engaging portion.

12. One of the first engaging portion and the second engaging portion includes at least one convex portion projecting radially with respect to the axis of rotation, or at least one concave portion recessed radially with respect to the axis of rotation, The cover member according to claim 11, wherein the other of the first engaging portion and the second engaging portion has at least one convex portion or at least one concave portion that engages with the one of the first engaging portion and the second engaging portion in the radial direction with respect to the axis of rotation.

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