TWI885055B - Crank assembly for human-powered vehicles - Google Patents

Abstract

[Topic] To provide a crank assembly for a human-powered vehicle, which has excellent assembly performance and a one-way clutch unit. [Solution] A crank assembly for a human-powered vehicle comprises: a crankshaft, a crank arm, a support body, a sprocket, and a one-way clutch unit; the support body comprises a spline opening, the spline opening engages with a spline portion formed on one of the crankshaft and the crank arm in a torque transmission state; the one-way clutch unit allows the support body and the sprocket to rotate as a whole when the crank arm rotates in the driving rotation direction, and allows the sprocket to rotate relative to the support body when at least the crank arm stops; the spline opening comprises a positioning shape, the positioning shape is formed to position the support body and one of the crankshaft and the crank arm in a circumferential direction relative to the rotation center axis.

Description

Crank assembly for human-powered vehicles

The present invention relates to a crank assembly for a human-powered vehicle.

A crank assembly for a human-powered vehicle having a one-way clutch unit is known.

One purpose of the present invention is to provide a crank assembly for a human-powered vehicle, which has excellent assembly performance and a one-way clutch unit.

The first type of crank assembly of the present invention is a crank assembly for a human-powered vehicle, and comprises: a crankshaft, a crank arm, a support body, a sprocket, and a one-way clutch unit; the crank arm is mounted on the crankshaft in a torque transmission state; the support body comprises a spline opening, and the spline opening is engaged with a spline portion formed on one of the crankshaft and the crank arm in a torque transmission state; the sprocket is arranged around the support body in a radial direction relative to the rotation center axis of the crank assembly of the human-powered vehicle; the one-way clutch unit is at least partially arranged between the support body and the sprocket in the radial direction; the one-way clutch unit comprises: a first engagement structure comprising a first engagement shape The first engaging member is engaged with the support body in the state of torque transmission, and the second engaging member is engaged with the sprocket in the state of torque transmission; the one-way clutch unit allows the support body and the sprocket to rotate as a whole when the crank arm rotates in the driving rotation direction, and allows the sprocket to rotate relative to the support body when at least the crank arm stops; the spline opening has a positioning shape, and the positioning shape is used to position the support body, the crank shaft, and the crank arm in the circumferential direction relative to the rotation center axis.

With the crank assembly of the first type described above, the support body, the crankshaft, and the crank arm can be positioned by the positioning shape, so the assembly of the crank assembly can be improved.

According to the crank assembly of the second embodiment of the first embodiment, the positioning shape includes: a plurality of spline protrusions and three spline recesses; the plurality of spline protrusions extend from the reference inner periphery of the spline opening, and the three spline recesses are arranged so that each position of the three spline recesses forms an isosceles triangle.

With the second type of crank assembly, since the three spline recesses are arranged so that each position of the three spline recesses forms an isosceles triangle, it is easy for the operator to grasp the circumferential position of the support body relative to the crank axle and the crank arm. Therefore, the assembly of the crank assembly can be further improved.

According to the third type of the crank assembly of the first type, the positioning shape includes: a plurality of first spline recesses and at least one second spline recess; the plurality of first spline recesses respectively have a first spline shape; the at least one second spline recess has a second spline shape different from the first spline shape.

By using the crank assembly of the third type described above, a positioning shape can be formed by making at least one second spline recess into a second spline shape different from the first spline shape.

According to the crank assembly of the fourth type of any one of the first to third types, the first engaging member includes a first ratchet disc, the first engaging shape includes a plurality of first ratchet teeth; the second engaging member includes a second ratchet disc, the second engaging shape includes a plurality of second ratchet teeth for engaging with the plurality of first ratchet teeth in a torque transmission state; the first ratchet disc engages with the support body in a torque transmission state; the second ratchet disc engages with the sprocket in a torque transmission state; when the sprocket rotates relative to the support body, at least one of the first ratchet disc and the second ratchet disc can move relative to the crankshaft in an axial direction relative to the rotation center axis.

By using the above-mentioned fourth type of crank assembly, the crank assembly is miniaturized. By using the above-mentioned fourth type of crank assembly, the quietness of the crank assembly is improved.

According to the crank assembly of the fifth embodiment of the fourth embodiment, the first ratchet disc has: a first engaging surface that is opposite to the second ratchet disc at least in the axial direction relative to the rotation center axis; the second ratchet disc has: a second engaging surface that is opposite to the first ratchet disc at least in the axial direction relative to the rotation center axis; the plurality of first ratchet teeth are arranged on the first engaging surface, and the plurality of second ratchet teeth are arranged on the second engaging surface.

By using the crank assembly of the fifth type described above, since many ratchet teeth can be arranged, the surface pressure on each ratchet tooth can be suppressed. Therefore, the one-way clutch unit can be made of lightweight materials such as aluminum to achieve weight reduction.

According to the crank assembly of the sixth embodiment of the fifth embodiment, the plurality of first ratchet teeth are arranged on the first engagement surface in the circumferential direction relative to the rotation center axis, and the plurality of second ratchet teeth are arranged on the second engagement surface in the circumferential direction relative to the rotation center axis.

By using the crank assembly of the sixth type described above, since many ratchet teeth can be arranged, the surface pressure on each ratchet tooth can be suppressed. Therefore, the one-way clutch unit can be made of lightweight materials such as aluminum to achieve weight reduction.

According to the crank assembly of the seventh embodiment of any one of the fourth to sixth embodiments, the first ratchet disc has: a first ratchet opening coaxial with the rotation center axis in the assembled state of the crank assembly; the second ratchet disc has: a second ratchet opening coaxial with the rotation center axis in the assembled state; the plurality of first ratchet teeth are arranged around the first ratchet opening relative to the rotation center axis, and the plurality of second ratchet teeth are arranged around the second ratchet opening relative to the rotation center axis.

By using the crank assembly of the seventh type described above, since many ratchet teeth can be arranged, the surface pressure on each ratchet tooth can be suppressed. Therefore, the one-way clutch unit can be made of lightweight materials such as aluminum to achieve weight reduction.

According to the crank assembly of the 8th type of the 7th type, the first ratchet opening and the second ratchet opening are respectively used to accommodate the crank shaft in the assembled state.

By using the above-mentioned Type 8 crank assembly, the crank assembly can be miniaturized.

The crank assembly of the 9th type according to any one of the above-mentioned types 1 to 8 further has an electric actuator, and the electric actuator causes the sprocket to rotate relative to the crank arm during the free shifting action.

By using the crank assembly of the 9th type described above, free shifting can be performed by means of an electric actuator.

The crank assembly of the tenth embodiment according to any one of the fourth to eighth embodiments further comprises an electric actuator, which causes the sprocket to rotate relative to the crank arm during the free shifting action; the electric actuator comprises an output gear, and the second ratchet disc comprises a plurality of torque transmission teeth for engaging with the output gear.

By using the above-mentioned crank assembly of type 10, free shifting can be performed by means of an electric actuator.

According to the 11th type of crank assembly of any one of the above-mentioned types 4 to 8, the above-mentioned support body has: a radial outer peripheral surface provided with a plurality of outer spiral splines, and the above-mentioned first ratchet disc has a radial inner peripheral surface, and the above-mentioned radial inner peripheral surface has a plurality of inner spiral splines for engaging with the above-mentioned plurality of outer spiral splines of the above-mentioned support body.

The above-mentioned 11th type crank assembly can improve the quietness during free shifting.

The crank assembly of the 12th embodiment according to the 11th embodiment further comprises an electric actuator, wherein the electric actuator causes the sprocket to rotate relative to the crank arm during the free shifting action; the electric actuator comprises an output gear, and the second ratchet disc comprises a plurality of torque transmission teeth engaged with the output gear; the output gear, when viewed from the axial direction, at least partially overlaps with the plurality of inner spiral splines of the first ratchet disc in the radial direction.

By using the above-mentioned twelfth type crank assembly, the crank assembly can be miniaturized.

According to the 13th type of crank assembly of the 11th or 12th type, the plurality of outer spiral splines of the support body have: a first outer pitch angle, and a second outer pitch angle different from the first outer pitch angle; the plurality of inner spiral splines of the first ratchet disc have: a first inner pitch angle, and a second inner pitch angle different from the first inner pitch angle.

By using the crank assembly of the 13th type described above, the number of helical splines can be increased, so the surface pressure on the helical splines can be suppressed. Therefore, the strength of the one-way clutch unit can be improved.

According to the crank assembly of the 14th type of the 13th type, the first outer pitch angle corresponds to the first inner pitch angle, and the second outer pitch angle corresponds to the second inner pitch angle.

By using the above-mentioned crank assembly of the 14th type, the number of helical splines can be increased, so the surface pressure on the helical splines can be suppressed. Therefore, the strength of the one-way clutch unit can be improved.

According to the 15th type crank assembly of any one of the above 4th to 8th types, the above plurality of second ratchet teeth are engaged with the above plurality of first ratchet teeth to transmit the rotational force from the above support body to the above sprocket.

By using the above-mentioned 15th type crank assembly, the free shift mechanism can be miniaturized.

According to the 16th type of crank assembly of any one of the 11th to 14th types, the support body has a guide portion, which is disposed on the radial outer peripheral surface and guides the first ratchet disc during the free shifting action to separate the first ratchet disc from the second ratchet disc.

By using the above-mentioned crank assembly of the 16th type, the guide portion can improve the quietness during the free shifting action.

According to the 17th type of the crank assembly of the 16th type, the guide portion guides the first ratchet disc during the free shifting action to release the engagement of the plurality of first ratchet teeth and the plurality of second ratchet teeth.

With the above-mentioned 17th type crank assembly, the engagement of the plurality of first ratchet teeth and the plurality of second ratchet teeth can be smoothly released by the guide portion, so the quietness during the free shifting action can be improved.

According to the crank assembly of the 18th embodiment of the 16th or 17th embodiment, the guide portion at least extends in the circumferential direction relative to the rotation center axis.

With the above-mentioned crank assembly of the 18th type, the engagement of the plurality of first ratchet teeth and the plurality of second ratchet teeth can be smoothly released by the guide part, so the quietness during the free shifting action can be improved.

According to the crank assembly of the 19th embodiment of any one of the 16th to 18th embodiments, the guide portion is configured to have at least one defined blunt angle relative to the plurality of outer spiral splines.

With the above-mentioned 19th type crank assembly, the engagement of the plurality of first ratchet teeth and the plurality of second ratchet teeth can be smoothly released by the guide portion, so the quietness during the free shifting action can be improved.

According to the crank assembly of the 20th embodiment of any one of the above embodiments 4 to 8 and 11 to 19, the sprocket has a ratchet disc engaging portion, the second ratchet disc has a sprocket engaging portion, and the sprocket engaging portion engages with the ratchet disc engaging portion of the sprocket in a torque transmission state, so as to transmit the rotational force from the second ratchet disc to the sprocket via the sprocket engaging portion.

By using the above-mentioned 20th type crank assembly, the crank assembly can be miniaturized.

The crank assembly of the 21st type according to any one of the above types 4 to 8 and 11 to 20 further has a spring member, which is arranged between the sprocket and the first ratchet disc and springs the first ratchet disc toward the second ratchet disc in the axial direction.

By means of the crank assembly of the above-mentioned type 21, torque can be surely transmitted when the crank assembly is driven to rotate.

The crank assembly of the 22nd type according to the above-mentioned types 16 to 19 further comprises a spring member, which is arranged between the sprocket and the first ratchet disc and springs the first ratchet disc toward the second ratchet disc in the axial direction; the spring member is mounted on the sprocket and rotates together with the sprocket, and the first ratchet disc contacts the guide portion during the free shifting action, and is disengaged from the second ratchet disc by the rotational friction force generated between the spring member and the first ratchet disc.

The above-mentioned crank assembly of type 22 can improve the quietness during free shifting.

According to the crank assembly of the 23rd type of any one of the above types 4 to 8, 11 to 22, the above support body has an abutment portion, the above abutment portion abuts against the above second ratchet disc to limit the axial movement of the above second ratchet disc separated from the above sprocket; the above first ratchet disc is arranged on the axial side of the above second ratchet disc opposite to the above abutment portion of the above support body in the above axial direction.

By using the above-mentioned crank assembly of type 23, the free shift mechanism can be miniaturized.

According to the crank assembly of the 24th type of any one of the above-mentioned types 9, 10, and 12, the crank arm includes an actuator configuration portion, and the actuator configuration portion is used to configure the electric actuator in the assembled state of the crank assembly.

By using the above-mentioned crank assembly of type 24, the electric free shift mechanism can be miniaturized.

The crank assembly for a human-powered vehicle of the present invention has a one-way clutch unit and has excellent assembly performance.

10: Human-powered vehicle

12: Framework

14:Wheels

14A:Rear wheel

14B:Front wheel

20: Speed transmission system

22: Chain

24:Rear sprocket

26: Pedal

28: Chainer

40: Crank assembly

40A: Spline part

40B: Spline recess

40C: Spline convex part

40D: 1st spline convex part

40E: 2nd spline convex part

42: Crankshaft

44: Crank arm

44A: Actuator configuration section

44B: Shell

44X: 1st crank arm

44Y: 2nd crank arm

46: Support body

46A: Main Path

46B: Small path

46C: Configuration Department

46D: Bearings

46V: Standard inner periphery

46W: Spline recess

46X: Flower key opening

46Y: Positioning shape

46Z: Spline convex part

48: Sprocket

48B: Ratchet disc engagement part

50: One-way clutch unit

52: The first engaging member

52A: 1st engagement shape

52B: 1st ratchet disc

52C: 1st ratchet tooth

54: Second engaging member

54A: Second engagement shape

54B: 2nd ratchet disc

54C: 2nd ratchet tooth

54D: Sprocket engagement part

54E: Torque transmission gear

56: Electric actuator

58: Reducer

60: Output gear

62: radial outer surface

62A: External helical spline

64: radial inner surface

64A: Inner helical spline

66: 1st engagement surface

68: Second engagement surface

70: 1st ratchet opening

72: Second ratchet opening

74: Guidance Department

76: Spring-loaded components

78: Contact Department

80: Buffer components

80A: Axial protrusion

82: 1st spline recess

82A: 1st flower key shape

84: 2nd spline recess

84A: 2nd flower key shape

86A: Claw component

86B: Ratchet groove

DA1: 1st outer pitch angle

DB1: 1st inner pitch angle

DA2: 2nd outer pitch angle

DB2: 2nd inner pitch angle

C1: Rotation center axis

R: Circumferential direction

R1: Drive rotation direction

[Figure 1] is a side view of a human-powered vehicle including a crank assembly for a human-powered vehicle according to an embodiment.

[Figure 2] is a side view of a crank assembly for a human-powered vehicle according to an embodiment.

[Figure 3] is a cross-sectional view of a crank assembly for a human-powered vehicle according to an implementation method.

[Figure 4] is a top view of the crank assembly for a human-powered vehicle according to the embodiment, omitting the crankshaft and crank arm.

[Figure 5] is a top view showing a partial enlargement of Figure 4.

[Figure 6] is an exploded perspective view of the crank assembly for a human-powered vehicle according to the embodiment.

[Figure 7] is a three-dimensional diagram showing the first engaging surface of the first ratchet disc in Figure 6.

[Figure 8] is a three-dimensional diagram of the support body and the first ratchet disc in Figure 6.

[Figure 9] is a cross-sectional view along the D9-D9 line in Figure 2.

[Figure 10] is a partial front view of the crank assembly for a human-powered vehicle according to the embodiment, showing the rotation state of each component when the crankshaft rotates.

[Figure 11] is a partial cross-sectional view of the crank assembly for a human-driven vehicle according to the embodiment when performing a free shifting action.

[Figure 12] is a partial front view of the crank assembly for a human-driven vehicle according to the embodiment, showing the rotation state of each component during the free shifting action.

[Figure 13] is a top view of the crank assembly for a human-powered vehicle of the first variant, omitting the crankshaft and crank arm.

[Figure 14] is a top view showing a partial enlargement of Figure 13.

[Figure 15] is a cross-sectional view of the crank assembly for a human-powered vehicle of the second variant.

<Implementation method>

A crank assembly 40 for a human-powered vehicle according to an embodiment is described with reference to FIGS. 1 to 12 . A human-powered vehicle has at least one wheel and is a vehicle that can be driven at least by human power. Human-powered vehicles include, for example, various types of bicycles such as mountain bikes, road bikes, city bikes, cargo bikes, hand-cranked bikes, and recumbent bikes. The number of wheels a human-powered vehicle has is not limited. Human-powered vehicles also include, for example, unicycles and vehicles with more than three wheels. Human-powered vehicles are not limited to vehicles that are driven only by human power. Human-powered vehicles include electric bicycles (E-bikes) that are propelled not only by human power but also by the power of an electric motor. Electric bicycles, including electric assisted bicycles propelled by electric motors. In the following implementation, human-powered bicycles are described as bicycles.

As shown in FIG. 1, the human-powered vehicle 10 includes a frame 12, wheels 14 supported by the frame 12, and a transmission system 20. The wheels 14 include a rear wheel 14A and a front wheel 14B. The transmission system 20 changes the speed of the rotation input to the human-powered vehicle 10 and transmits it to the rear wheel 14A. The frame 12 supports the rear wheel 14A of the wheels 14.

As shown in FIG. 1 and FIG. 2, the human-powered vehicle 10 has a transmission system 20. The transmission system 20 preferably has a crank assembly 40 for a human-powered vehicle. The transmission system 20 further has a shifter 28. The transmission system 20 further has a chain 22 and a rear sprocket 24. The crankshaft 42 of the crank assembly 40 and the crank arm 44 of the crank assembly 40 can be mounted on the frame 12. The crank arm 44 includes a first crank arm 44X on the right side and a second crank arm 44Y on the left side. The first crank arm 44X is mounted on one end of the crankshaft 42, and the second crank arm 44Y is mounted on the other end of the crankshaft 42. The crank arm 44 is preferably rotatable integrally with the crankshaft 42. The pedal 26 is mounted on the end of the crank arm 44. The crank axle 42 is used to transmit the rotational force to at least one sprocket 48. The sprocket 48 is a front sprocket. In this embodiment, the shifting system 20 has a sprocket 48. In the case where the shifting system 20 has a front derailleur, it is preferred that the shifting system 20 has a plurality of sprockets 48.

At least one sprocket 48 includes a plurality of sprocket teeth 48A for engaging with the chain 22. The speed change system 20 further includes a retractor 28. In the present embodiment, the retractor 28 is a rear retractor. The retractor 28 may also be a front retractor. The retractor 28 may also be actuated by an electric actuator disposed on the retractor 28, or may be connected to the speed change operating device of the human-powered vehicle 10 by a cable and actuated in response to the movement of the cable.

The speed change system 20 preferably has a free shifting action that allows the speed change of the sprocket 28 to be performed without rotating the crank arm 44 and the crank shaft 42 even when the rotation of the crank arm 44 and the crank shaft 42 stops. Specifically, the speed change system 20 has a mechanism that rotates the sprocket 48 even when the rotation of the crank arm 44 and the crank shaft 42 stops. By rotating the sprocket 48, the speed change of the sprocket 28 can be performed even when the rotation of the crank arm 44 and the crank shaft 42 stops. The free shifting action of the present invention represents an action that allows the speed change of the sprocket 28 to be performed at least when the rotation of the crank arm 44 and the crank shaft 42 stops. When the crank arm 44 and the crankshaft 42 rotate in the direction opposite to the driving rotation direction R1, the action of changing the speed by using the sprocket 28 is also included in the free shifting action of the present invention.

As shown in FIGS. 3, 4 and 6, the crank assembly 40 includes a crankshaft 42, a crank arm 44, a support body 46, a sprocket 48 and a one-way clutch unit 50. The crank arm 44 is mounted on the crankshaft 42 in a torque transmission state. The support body 46 includes a spline opening 46X. The spline opening 46X is engaged with the spline portion 40A in a torque transmission state, and the spline portion 40A is formed on one of the crankshaft 42 and the crank arm 44. The sprocket 48 is arranged around the support body 46 in a radial direction A relative to the rotation center axis C1 of the crank assembly 40. The one-way clutch unit 50 is at least partially arranged between the support body 46 and the sprocket 48 in a radial direction A. The one-way clutch unit 50 includes a first engaging member 52 and a second engaging member 54. The first engaging member 52 includes a first engaging shape 52A. The second engaging member 54 includes a second engaging shape 54A, and the second engaging shape 54A engages with the first engaging shape 52A in a torque transmission state. The first engaging member 52 engages with the support body 46 in a torque transmission state. The second engaging member 54 engages with the sprocket 48 in a torque transmission state. The one-way clutch unit 50 allows the support body 46 and the sprocket 48 to rotate integrally when the crank arm 44 rotates in the driving rotation direction R1, and allows the sprocket 48 to rotate relative to the support body 46 at least when the crank arm 44 stops. The spline opening 46X has a positioning shape 46Y. The positioning shape 46Y is used to position the support body 46, the crank shaft 42, and one of the crank arms 44 in the circumferential direction R relative to the rotation center axis C1.

As shown in FIG. 4 and FIG. 5, the positioning shape 46Y of the present embodiment includes: one or more spline protrusions 46Z, and one or more spline recesses 46W. In the present embodiment, the positioning shape 46Y includes: a plurality of spline protrusions 46Z, and three spline recesses 46W. The plurality of spline protrusions 46Z extend from the reference inner periphery 46V of the spline opening 46X. The three spline recesses 46W are configured so that each position of the three spline recesses 46W forms an isosceles triangle. The three spline recesses 46W are recessed from the reference inner periphery 46V toward the outer side of the radial direction A. For example, the three spline recesses 46W are configured so that the line connecting the bottoms of the three spline recesses 46W forms an isosceles triangle. The number of spline protrusions 46Z is preferably greater than the number of spline recesses 46W. The number of multiple spline protrusions 46Z is, for example, 7. More than 3 spline recesses 46W may be provided. The positions of the three spline recesses 46W can be appropriately changed as long as they can be configured to position the support body 46, the crankshaft 42, and one of the crank arms 44 in the circumferential direction R relative to the rotation center axis C1.

In the present embodiment, the spline portion 40A is provided on the outer periphery of one of the crankshaft 42 and the crank arm 44. The spline portion 40A has a shape corresponding to the positioning shape 46Y. The spline portion 40A preferably includes: one or more spline recesses 40B and one or more spline protrusions 40C. In the present embodiment, the spline portion 40A includes: a plurality of spline recesses 40B and three spline protrusions 40C. The number of the plurality of spline recesses 40B is equal to the number of the plurality of spline protrusions 46Z. The number of the spline protrusions 40C is equal to the number of the spline recesses 46W. The three spline protrusions 40C are arranged so that each position of the three spline protrusions 40C forms an isosceles triangle. For example, the three spline protrusions 40C are arranged so that the lines connecting the vertices of the three spline protrusions 40C form an isosceles triangle.

The torque from the crankshaft 42 and the crank arm 44 is preferably transmitted to the support body 46 by the positioning shape 46Y. The torque from the crankshaft 42 and the crank arm 44 is transmitted to the support body 46 by the engagement of the spline protrusion 46Z with the spline recess 40B, and the engagement of the three spline recesses 46W with the three spline protrusions 40C. It is preferred that one of the crankshaft 42 and the crank arm 44 and the support body 46 be mountable and removable. By making one of the crankshaft 42 and the crank arm 44 and the support body 46 mountable and removable, the crank assembly 40 can be easily repaired.

The first engaging member 52 preferably includes a first ratchet disc 52B. The first engaging shape 52A preferably includes a plurality of first ratchet teeth 52C. The second engaging member 54 preferably includes a second ratchet disc 54B. The second engaging shape 54A preferably includes a plurality of second ratchet teeth 54C for engaging with the plurality of first ratchet teeth 52C in a state of torque transmission. The first ratchet disc 52B preferably engages with the support body 46 in a state of torque transmission. The second ratchet disc 54B preferably engages with the sprocket 48 in a state of torque transmission. At least one of the first ratchet disc 52B and the second ratchet disc 54B can preferably move relative to the crankshaft 42 in the axial direction B relative to the rotation center axis C1 when the sprocket 48 rotates relative to the support body 46. At least one of the first ratchet disc 52B and the second ratchet disc 54B can preferably move relative to the crankshaft 42 in the axial direction B relative to the rotation center axis C1. The one-way clutch unit 50 is preferably arranged around the crankshaft 42 in the radial direction A.

The support body 46, the first ratchet disc 52B, and the second ratchet disc 54B preferably include metal materials. The support body 46 includes, for example, an aluminum alloy. The first ratchet disc 52B includes, for example, an aluminum alloy. The second ratchet disc 54B includes, for example, an aluminum alloy. At least one of the support body 46, the first ratchet disc 52B, and the second ratchet disc 54B may also be made of a non-metallic material.

As shown in FIG. 2 and FIG. 3, the crank assembly 40 further includes an electric actuator 56. The electric actuator 56 rotates the sprocket 48 relative to the crank arm 44 during free shifting. The electric actuator 56 includes, for example, an electric motor 56A. The electric actuator 56 may also further include a speed reducer 58. The speed reducer 58 reduces the speed of the rotation of the electric motor 56A and transmits it to the sprocket 48.

In the assembled state of the crank assembly 40, the crank arm 44 preferably includes an actuator configuration portion 44A on which the electric actuator 56 is configured. The actuator configuration portion 44A is, for example, provided on the surface of the crank arm 44 that is opposite to the front sprocket. The crank arm 44 may also have a housing 44B for covering the actuator configuration portion 44A. The reducer 58 is preferably configured on the actuator configuration portion 44A. The actuator configuration portion 44A may also be provided with at least one of a power source for supplying power to the electric actuator 56, a control device for controlling the electric actuator 56, and a communication portion for communicating with an external device. The electric motor 56A and the reducer 58 may also be provided in a single housing and detachably mounted on the actuator configuration portion 44A. The power source can also be arranged in the inner space of the crankshaft 42.

As shown in FIGS. 2 to 7, in this embodiment, the first ratchet disc 52B is engaged with the support body 46 to transmit torque. The second ratchet disc 54B is engaged with the sprocket 48 to transmit torque. The plurality of second ratchet teeth 54C are engaged with the plurality of first ratchet teeth 52C to transmit the rotational force from the support body 46 to the sprocket 48. The sprocket 48 has a ratchet disc engaging portion 48B. The second ratchet disc 54B has a sprocket engaging portion 54D and is engaged with the ratchet disc engaging portion 48B of the sprocket 48 to transmit the rotational force from the second ratchet disc 54B to the sprocket 48 via the sprocket engaging portion 54D in a state of torque transmission. The ratchet disc engagement portion 48B and the sprocket engagement portion 54D are, for example, spline engagement.

The sprocket 48 includes a first bearing 48C and a second bearing 48D. The first bearing 48C is disposed between the sprocket 48 and the first crank arm 44X, and supports the sprocket 48 so that it can rotate relative to the first crank arm 44X. The second bearing 48D is disposed between the sprocket 48 and the first ratchet disc 52B, and supports the sprocket 48 so that it can rotate relative to the first ratchet disc 52B.

The electric actuator 56 includes an output gear 60, and the second ratchet disc 54B preferably includes a plurality of torque transmission teeth 54E engaged with the output gear 60. The torque transmission teeth 54E are provided on the inner periphery of the second ratchet disc 54B. In the case where the electric actuator 56 is provided with a speed reducer 58, the output gear 60 is the final gear of the speed reducer 58 or a gear that rotates integrally with the final gear. The crankshaft 42 and the crank arm 44 are preferably rotatable integrally. The crank arm 44 and the support body 46 are preferably rotatable integrally. The first ratchet disc 52B and the second ratchet disc 54B are rotatable integrally and relatively. The one-way clutch unit 50 transmits the rotational torque from the crank assembly 40 to the sprocket 48 via the support body 46, the first ratchet disc 52B, and the second ratchet disc 54B when the crank assembly 40 rotates in the driving rotation direction R1. When the electric actuator 56 is actuated in the state where the rotation of the crank arm 44 and the crank shaft 42 stops, the electric actuator 56 rotates the second ratchet disc 54B in the driving rotation direction R1. In this case, the rider can perform a free shifting action by operating the speed change operating device to change the speed with the sprocket 28.

As shown in FIG. 8 , the support body 46 has a radial outer peripheral surface 62 provided with a plurality of outer spiral splines 62A. The first ratchet disc 52B has a radial inner peripheral surface 64 provided with a plurality of inner spiral splines 64A to engage with the plurality of outer spiral splines 62A of the support body 46. The support body 46 has a large diameter portion 46A and a small diameter portion 46B in the axial direction B. The plurality of outer outer spiral splines 62A are provided in the small diameter portion 46B. The first ratchet disc 52B is at least partially configured to overlap with the small diameter portion 46B of the support body 46 in the axial direction B. The support body 46 has a plurality of outer spiral splines 62A, and the first ratchet disc 52B has a plurality of inner spiral splines 64A, so the surface pressure of each outer spiral spline 62A and each inner spiral spline 64A can be reduced.

The plurality of outer spiral splines 62A of the support body 46 preferably have a first outer pitch angle DA1 and a second outer pitch angle DA2 different from the first outer pitch angle DA1. The plurality of inner spiral splines 64A of the first ratchet plate 52B have a first inner pitch angle DB1 and a second inner pitch angle DB2 different from the first inner pitch angle DB1. The first outer pitch angle DA1 corresponds to the first inner pitch angle DB1, and the second outer pitch angle DA2 corresponds to the second inner pitch angle DB2. The number of outer thread pitch angles having the second outer thread pitch angle DA2 among the outer thread pitch angles of the plurality of outer spiral splines 62A is equal to the number of inner thread pitch angles having the second inner thread pitch angle DB2 among the inner thread pitch angles of the plurality of inner spiral splines 64A. For example, among the outer thread pitch angles of the plurality of outer spiral splines 62A, there is one outer thread pitch angle that forms the second outer thread pitch angle DA2. Among the inner thread pitch angles of the plurality of inner spiral splines 64A, there is one inner thread pitch angle that forms the second inner thread pitch angle DB2. Among the outer thread pitch angles of the plurality of outer spiral splines 62A, there may be two or more outer thread pitch angles that form the second outer thread pitch angle DA2. Among the inner pitch angles of the plurality of inner helical splines 64A, there may be more than two inner pitch angles forming the second inner pitch angle DB2. When there are two outer pitch angles forming the second outer pitch angle DA2, the outer pitch angles forming the two second outer pitch angles DA2 may be arranged at positions 180 degrees apart from each other. When there are two inner pitch angles forming the second inner pitch angle DB2, the inner pitch angles forming the second inner pitch angle DB2 may be arranged at positions 180 degrees apart from each other.

As shown in FIG. 3 and FIG. 8, the output gear 60, when viewed from the axial direction B, at least partially overlaps with the plurality of inner spiral splines 64A of the first ratchet disc 52B in the radial direction A. The output gear 60 is arranged at positions corresponding to the outer spiral splines 62A forming the second outer pitch angle DA2 and the inner spiral splines 64A forming the second inner pitch angle DB2. The support body 46 preferably has a configuration portion 46C for configuring at least a portion of the output gear 60. The configuration portion 46C is provided at the large diameter portion 46A of the support body 46. The configuration portion 46C is a hole portion for passing the large diameter portion 46A through the axial direction B. As shown in FIG. 3, it is preferable to provide a bearing 46D on the inner periphery of the configuration portion 46C for rotatably supporting the shaft of the output gear 60.

As shown in Fig. 6, Fig. 7, and Fig. 9, the first ratchet disc 52B has: a first engaging surface 66 that is opposite to the second ratchet disc 54B at least in the axial direction B relative to the rotation center axis C1. The second ratchet disc 54B has: a second engaging surface 68 that is opposite to the first ratchet disc 52B at least in the axial direction B relative to the rotation center axis C1. The plurality of first ratchet teeth 52C are arranged on the first engaging surface 66, and the plurality of second ratchet teeth 54C are arranged on the second engaging surface 68. The plurality of first ratchet teeth 52C are arranged on the first engaging surface 66 in the circumferential direction R relative to the rotation center axis C1. The plurality of second ratchet teeth 54C are arranged on the second engaging surface 68 in the circumferential direction R relative to the rotation center axis C1.

In the present embodiment, the first engaging surface 66 is inclined from one side of the axial direction B toward the other side as it moves away from the rotation center axis C1 toward the radial direction A. In the present embodiment, the second engaging surface 68 is inclined from one side of the axial direction B toward the other side as it moves away from the rotation center axis C1. In the present embodiment, the first engaging surface 66 is inclined from the second ratchet disc 54B in the axial direction B toward the first ratchet disc 52B as it moves away from the rotation center axis C1 toward the radial direction A. In the present embodiment, the second engaging surface 68 is inclined from the second ratchet disc 54B in the axial direction B toward the first ratchet disc 52B. The plurality of first ratchet teeth 52C are preferably provided on the first engagement surface 66 to cover the entire circumference of the first ratchet disc 52B. The plurality of second ratchet teeth 54C are preferably provided on the second engagement surface 68 to cover the entire circumference of the second ratchet disc 54B. The first ratchet teeth 52C include the plurality of first ratchet teeth 52C, and the second ratchet teeth 54C include the plurality of second ratchet teeth 54C, so the surface pressure of each first ratchet tooth 52C and each second ratchet tooth 54C can be reduced. The first engagement surface 66 can also be a plane, and the second engagement surface 68 can also be a plane. The first ratchet disc 52B and the second ratchet disc 54B can also have friction surfaces that transmit torque by friction.

The first ratchet plate 52B has: a first ratchet opening 70 that is coaxial with the rotation center axis C1 in the assembled state of the crank assembly 40. The second ratchet plate 54B has: a second ratchet opening 72 that is coaxial with the rotation center axis C1 in the assembled state. A plurality of first ratchet teeth 52C are arranged around the first ratchet opening 70 relative to the rotation center axis C1. A plurality of second ratchet teeth 54C are arranged around the second ratchet opening 72 relative to the rotation center axis C1. The first ratchet opening 70 and the second ratchet opening 72 are respectively used to accommodate the crank shaft 42 in the assembled state. The first ratchet opening 70 is a through hole extending toward the rotation center axis C1. The second ratchet opening 72 is a through hole extending toward the rotation center axis C1. The crank shaft 42 is inserted into the first ratchet opening 70 and the second ratchet opening 72.

The support body 46 is provided with a guide portion 74. The guide portion 74 is provided on the radial outer peripheral surface 62 of the support body 46 and is used to guide the first ratchet disc 52B so as to separate the first ratchet disc 52B and the second ratchet disc 54B from each other during the free shifting action. The guide portion 74 guides the first ratchet disc 52B during the free shifting action so as to release the engagement of the plurality of first ratchet teeth 52C and the plurality of second ratchet teeth 54C. The guide portion 74 preferably extends at least in the circumferential direction R relative to the rotation center axis C1. The guide portion 74 is preferably provided on the support body 46 and is continuous with the plurality of outer spiral splines 62A. The guide portion 74 is disposed between the plurality of outer spiral splines 62A and the large diameter portion 46A in the axial direction B. The guide portion 74 is preferably configured to define a blunt angle DC relative to at least one of the plurality of outer spiral splines 62A.

As shown in FIG. 6 , the crank assembly 40 preferably further includes a spring member 76. The spring member 76 is disposed between the sprocket 48 and the first ratchet disc 52B, and is used to spring the first ratchet disc 52B toward the second ratchet disc 54B in the axial direction B. The spring member 76 is, for example, a coil spring. The spring member 76 may also include a plurality of spring members 76. In FIG. 6 , the spring member 76 includes six spring members 76. The plurality of spring members 76 are disposed between the sprocket 48 and the first ratchet disc 52B at predetermined intervals in the circumferential direction R. The spring member 76 is mounted on the sprocket 48 and rotates together with the sprocket 48. During the free shifting action, the first ratchet disc 52B contacts the guide portion 74 and is disengaged from the second ratchet disc 54B by the rotational friction force generated between the spring member 76 and the first ratchet disc 52B.

The support body 46 preferably has an abutment portion 78. The abutment portion 78 abuts against the second ratchet disc 54B to limit the movement of the second ratchet disc 54B separated from the sprocket 48 in the axial direction B. The first ratchet disc 52B is arranged in the axial direction B on the axial side of the second ratchet disc 54B opposite to the abutment portion 78 of the support body 46. The abutment portion 78 is provided on the end surface of the large diameter portion 46A that is continuous with the small diameter portion 46B.

The crank assembly 40 preferably has a buffer member 80. The buffer member 80 preferably includes a resin material. The buffer member 80 preferably includes a rubber material. The buffer member 80 includes at least one axial protrusion 80A. The buffer member 80 preferably includes a plurality of axial protrusions 80A. The axial protrusion 80A of the buffer member 80 is arranged between the sprocket 48 and the second ratchet plate 54B in the radial direction A. The axial protrusion 80A of the buffer member 80 is arranged between the ratchet plate engaging portion 48B of the sprocket 48 and the sprocket engaging portion 54D of the second ratchet plate 54B in the circumferential direction R. This structure can reduce the driving sound caused by the contact between the ratchet disc engagement portion 48B of the sprocket 48 and the sprocket engagement portion 54D of the second ratchet disc 54B.

Referring to Figures 9 to 12, the operation of the one-way clutch unit 50 is explained.

As shown in FIG. 9 and FIG. 10 , when the rider inputs human driving force to rotate the crank arm 44 and the crank shaft 42 in the driving rotation direction R1, the rotation torque of the crank arm 44 causes the support body 46 and the first ratchet disc 52B to rotate in the driving rotation direction R1. Since the first ratchet disc 52B is biased toward the second ratchet disc 54B by the biasing member 76, the first ratchet tooth 52C is engaged with the second ratchet tooth 54C. Therefore, the rotation torque of the first ratchet disc 52B in the driving rotation direction R1 causes the second ratchet disc 54B to rotate in the driving rotation direction R1. Since the sprocket engagement portion 54D of the second ratchet disc 54B and the ratchet disc engagement portion 48B of the sprocket 48 are engaged with each other, the rotational torque of the second ratchet disc 54B causes the sprocket 48 to rotate in the driving rotation direction R1.

As shown in FIG. 11 and FIG. 12 , when the crank arm 44 and the crank shaft 42 stop rotating and the output gear 60 rotates in the direction R3 corresponding to the driving rotation direction R1 by the electric actuator 56, the second ratchet disc 54B rotates in the driving rotation direction R1 via the torque transmission tooth 54E. Therefore, the rotation torque of the second ratchet disc 54B in the driving rotation direction R1 causes the first ratchet disc 52B to rotate in the driving rotation direction R1. By rotating the first ratchet disc 52B in the driving rotation direction R1, the first ratchet disc 52B moves in the axial direction B relative to the second ratchet disc 54B in the direction of separation from the second ratchet disc 54B along the inner spiral spline 64A of the first ratchet disc 52B and the outer spiral spline 62A of the support body 46. The engagement between the first ratchet disc 52B and the second ratchet disc 54B is thereby released. Therefore, the rotational torque of the second ratchet disc 54B does not rotate the first ratchet disc 52B, but rotates the sprocket 48 in the driving rotation direction R1 via the sprocket engagement portion 54D of the second ratchet disc 54B and the ratchet disc engagement portion 48B of the sprocket 48. Therefore, the chain 22 can be driven without rotating the crank arm 44 and the crank shaft 42 in the driving rotation direction R1. This allows free shifting. The guide portion 74 of the support body 46 has the function of enabling the first ratchet disc 52B and the second ratchet disc 54B to move rapidly in the axial direction B in a direction away from each other.

In the crank assembly 40 of this embodiment, when performing a free shifting action, since at least one of the first ratchet disc 52B and the second ratchet disc 54B moves in the axial direction B, the first ratchet disc 52B and the second ratchet disc 54B are separated from each other, the noise can be suppressed.

<Variation example>

The description of the implementation method is an example of the type of crank assembly for human-powered vehicles of the present invention, and is not intended to limit its type. The crank assembly for human-powered vehicles of the present invention can take the form of a variation of the implementation method shown below and a combination of at least two variations that do not contradict each other. In the following variations, the same symbols as the implementation method are added to the parts common to the implementation method, and their descriptions are omitted.

As shown in FIG. 13 and FIG. 14, the positioning shape 46Y may also include: a plurality of first spline recesses 82 and at least one second spline recess 84. The plurality of first spline recesses 82 respectively have a first spline profile 82A, and at least one second spline recess 84 has a second spline profile 84A different from the first spline profile 82A. In FIG. 13 and FIG. 14, the second spline profile 84A is longer in the circumferential direction R than the first spline profile 82A. The spline portion 40A includes: a plurality of first spline protrusions 40D and at least one second spline protrusion 40E. The first spline protrusion 40D has a shape corresponding to the first spline recess 82 formed on one of the crank axle 42 and the crank arm 44. The second spline protrusion 40E has a shape corresponding to the second spline recess 84 formed on one of the crank axle 42 and the crank arm 44.

As shown in FIG. 15 , the one-way clutch unit 50 may also include a pawl member 86A and a ratchet groove 86B. One of the first engaging member 52 and the second engaging member 54 includes the pawl member 86A, and the other of the first engaging member 52 and the second engaging member 54 includes the ratchet groove 86B. For example, the pawl member 86A is provided on a member that rotates integrally with the crankshaft 42 and the crank arm 44, and the ratchet groove 86B is provided on the sprocket 48 or a member that rotates integrally with the sprocket 48.

The one-way clutch unit 50 can also switch the power transmission route other than the free shifting action. For example, the one-way clutch unit 50 of the present invention can also be switched to: the first state of driving the human-powered vehicle 10 with human power only, human power and motor assistance, and the second state of driving the human-powered vehicle 10 with only the torque of the motor equipped with a high-output motor.

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

40: Crank assembly

46: Support body

46X: Flower key opening

46Y: Positioning shape

48: Sprocket

48A: Sprocket gear

60: Output gear

Claims (24)

A crank assembly for a human-powered vehicle comprises: a crankshaft, a crank arm, a support body, a sprocket, and a one-way clutch unit; The crank arm is mounted on the crankshaft in a torque transmission state; The support body comprises a spline opening, and the spline opening engages with a spline portion formed on one of the crankshaft and the crank arm in a torque transmission state; The sprocket is arranged around the support body in a radial direction relative to the rotation center axis of the crank assembly of the human-powered vehicle; The one-way clutch unit is at least partially arranged between the support body and the sprocket in the radial direction; The one-way clutch unit comprises: a first engaging member including a first engaging shape, and a second engaging member including a second engaging shape for engaging with the first engaging shape in a state of torque transmission; The first engaging member engages with the support body in a state of torque transmission, The second engaging member engages with the sprocket in a state of torque transmission; The one-way clutch unit, When the crank arm rotates in the driving rotation direction, the support body and the sprocket are allowed to rotate as a whole, When at least the crank arm stops, the sprocket is allowed to rotate relative to the support body; The spline opening has a positioning shape, and the positioning shape is used to position the support body, the crankshaft, and one of the crank arms in the circumferential direction relative to the rotation center axis. A crank assembly for a human-driven vehicle as claimed in claim 1, wherein the positioning shape comprises: a plurality of spline protrusions and three spline recesses; The plurality of spline protrusions extend from the reference inner periphery of the spline opening, The three spline recesses are arranged so that each position of the three spline recesses forms an isosceles triangle. A crank assembly for a human-powered vehicle as claimed in claim 1, wherein the positioning shape comprises: a plurality of first spline recesses and at least one second spline recess; The plurality of first spline recesses respectively have a first spline shape; The at least one second spline recess has a second spline shape different from the first spline shape. A crank assembly for a human-driven vehicle as claimed in claim 1, wherein the first engaging member includes a first ratchet disc, the first engaging shape includes a plurality of first ratchet teeth; the second engaging member includes a second ratchet disc, the second engaging shape includes a plurality of second ratchet teeth for engaging with the plurality of first ratchet teeth in a state of torque transmission; the first ratchet disc engages with the support body in a state of torque transmission; the second ratchet disc engages with the sprocket in a state of torque transmission; when the sprocket rotates relative to the support body, at least one of the first ratchet disc and the second ratchet disc can move relative to the crankshaft in an axial direction relative to the rotation center axis. A crank assembly for a human-driven vehicle as claimed in claim 4, wherein the first ratchet disc has: a first engaging surface that is at least axially opposite to the second ratchet disc relative to the rotation center axis; The second ratchet disc has: a second engaging surface that is at least axially opposite to the first ratchet disc relative to the rotation center axis; The plurality of first ratchet teeth are arranged on the first engaging surface, The plurality of second ratchet teeth are arranged on the second engaging surface. A crank assembly for a human-powered vehicle as claimed in claim 5, wherein the plurality of first ratchet teeth are arranged on the first engaging surface in the circumferential direction relative to the rotation center axis, and the plurality of second ratchet teeth are arranged on the second engaging surface in the circumferential direction relative to the rotation center axis. A crank assembly for a human-powered vehicle as claimed in claim 4, wherein the first ratchet disc has: a first ratchet opening coaxial with the rotation center axis in the assembled state of the crank assembly; The second ratchet disc has: a second ratchet opening coaxial with the rotation center axis in the assembled state; The plurality of first ratchet teeth are arranged around the first ratchet opening relative to the rotation center axis, The plurality of second ratchet teeth are arranged around the second ratchet opening relative to the rotation center axis. As for the crank assembly for a human-powered vehicle as claimed in claim 7, the above-mentioned first ratchet opening and the above-mentioned second ratchet opening are respectively used to accommodate the above-mentioned crank shaft in the above-mentioned assembled state. The crank assembly for a human-powered vehicle as claimed in claim 1 further comprises an electric actuator, wherein the electric actuator causes the sprocket to rotate relative to the crank arm during the free shifting action. The crank assembly for a human-powered vehicle as claimed in claim 4 further comprises an electric actuator, wherein the electric actuator causes the sprocket to rotate relative to the crank arm during the free shifting action; the electric actuator includes an output gear, and the second ratchet disc includes a plurality of torque transmission teeth for engaging with the output gear. A crank assembly for a human-powered vehicle as claimed in claim 4, wherein the support body has a radial outer peripheral surface provided with a plurality of outer spiral splines, and the first ratchet disc has a radial inner peripheral surface, wherein the radial inner peripheral surface has a plurality of inner spiral splines for engaging with the plurality of outer spiral splines of the support body. A crank assembly for a human-powered vehicle as claimed in claim 11, wherein the crank assembly further comprises an electric actuator, The electric actuator causes the sprocket to rotate relative to the crank arm during the free shifting action; The electric actuator comprises an output gear, The second ratchet disc comprises a plurality of torque transmission teeth engaged with the output gear; The output gear, when viewed from the axial direction, at least partially overlaps the plurality of inner spiral splines of the first ratchet disc in the radial direction. The crank assembly for a human-powered vehicle as claimed in claim 11, wherein the plurality of outer spiral splines of the support body have: a first outer pitch angle, and a second outer pitch angle different from the first outer pitch angle; The plurality of inner spiral splines of the first ratchet disc have: a first inner pitch angle, and a second inner pitch angle different from the first inner pitch angle. As in claim 13, the crank assembly for a human-powered vehicle, wherein the first outer pitch angle corresponds to the first inner pitch angle, and the second outer pitch angle corresponds to the second inner pitch angle. A crank assembly for a human-powered vehicle as claimed in claim 4, wherein the plurality of second ratchet teeth are engaged with the plurality of first ratchet teeth to transmit the rotational force from the support body to the sprocket. As in claim 11, the crank assembly for a human-driven vehicle, wherein the support body is provided with a guide portion, The guide portion is disposed on the radial outer peripheral surface and guides the first ratchet disc during the free shifting action to allow the first ratchet disc and the second ratchet disc to separate from each other. A crank assembly for a human-driven vehicle as claimed in claim 16, wherein the guide portion guides the first ratchet disc during the free shifting action to release the engagement of the plurality of first ratchet teeth and the plurality of second ratchet teeth. A crank assembly for a human-powered vehicle as claimed in claim 16, wherein the guide portion extends at least in a circumferential direction relative to the rotation center axis. A crank assembly for a human-powered vehicle as claimed in claim 16, wherein the guide portion is configured to have at least one defined blunt angle relative to the plurality of outer spiral splines. A crank assembly for a human-powered vehicle as claimed in claim 4, wherein the sprocket has a ratchet disc engaging portion, the second ratchet disc has a sprocket engaging portion, the sprocket engaging portion engages with the ratchet disc engaging portion of the sprocket in a torque transmission state, so as to transmit the rotational force from the second ratchet disc to the sprocket via the sprocket engaging portion. The crank assembly for a human-driven vehicle as claimed in claim 4 further comprises a spring-loaded member, The spring-loaded member is disposed between the sprocket and the first ratchet disc, and springs the first ratchet disc toward the second ratchet disc in the axial direction. The crank assembly for a human-driven vehicle as claimed in claim 16 further comprises a spring member, the spring member is disposed between the sprocket and the first ratchet disc, and springs the first ratchet disc toward the second ratchet disc in the axial direction; the spring member is mounted on the sprocket and rotates together with the sprocket, the first ratchet disc contacts the guide portion during the free shifting action, and is disengaged from the second ratchet disc by the rotational friction force generated between the spring member and the first ratchet disc. A crank assembly for a human-driven vehicle as claimed in claim 4, wherein the support body has an abutment portion, the abutment portion abuts against the second ratchet disc to limit the axial movement of the second ratchet disc separated from the sprocket; the first ratchet disc is arranged on the axial side of the second ratchet disc opposite to the abutment portion of the support body in the axial direction. A crank assembly for a human-powered vehicle as claimed in claim 9, wherein the crank arm includes an actuator configuration portion, and the actuator configuration portion is used to configure the electric actuator in the assembled state of the crank assembly.

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