TWI841782B - Crank assembly for human-powered vehicles - Google Patents

Abstract

[Topic] To provide a crank assembly for a human-powered vehicle, which is compact and has excellent quietness and has a one-way clutch unit. [Solution] The crank assembly comprises: a crank shaft, a crank arm, a support body, a sprocket, and a one-way clutch unit; the one-way clutch unit comprises: a first ratchet disc and a second ratchet disc; the first ratchet disc engages with one of the support body and the sprocket to transmit torque, and the second ratchet disc engages with the other of the support body and the sprocket to transmit torque; at least one of the first ratchet disc and the second ratchet disc can move relative to the crank shaft in the axial direction relative to the rotation center axis of the crank assembly, and the one-way clutch unit is radially arranged around the crank shaft.

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.

[Problems to be solved by the invention]

One object of the present invention is to provide a crank assembly for a human-powered vehicle, which is compact and has excellent quietness and has a one-way clutch unit. [Means for solving the problem]

The first type of crank assembly of the present invention is a crank assembly for a human-powered vehicle, comprising: a crank shaft, a crank arm mounted on the crank shaft, a support body mounted on the crank arm, a sprocket arranged around the support body in a radial direction relative to the rotation center axis of the crank assembly, and a one-way clutch unit at least partially arranged in the radial direction and between the support body and the sprocket; the one-way clutch unit comprises: a first ratchet disc comprising a plurality of first ratchet teeth, and a first ratchet disc comprising a first ratchet tooth for transmitting rotation. The first ratchet disc is engaged with one of the support body and the sprocket to transmit torque, and the second ratchet disc is engaged with the other of the support body and the sprocket to transmit torque; at least one of the first ratchet disc and the second ratchet disc can move relative to the crankshaft in the axial direction relative to the rotation center axis, and the one-way clutch unit is arranged around the crankshaft in the radial direction. By means of the first type of crank assembly, a compact and excellently silent crank assembly can be provided.

According to the crank assembly of the second type of the first type, 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 the crank assembly of the second type, since many ratchet teeth can be arranged, the surface pressure borne by each ratchet tooth can be suppressed. Therefore, the clutch unit can be made of lightweight materials such as aluminum to achieve lightweight.

According to the crank assembly of the third type of the second type, 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. By the crank assembly of the third type, since many ratchet teeth can be arranged, the surface pressure on each ratchet tooth can be suppressed. Therefore, the clutch unit can be made of lightweight materials such as aluminum to achieve lightweight.

According to the crank assembly of the fourth type of the third type, 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 the crank assembly of the fourth type, since many ratchet teeth can be arranged, the surface pressure borne by each ratchet tooth can be suppressed. Therefore, the clutch unit can be made of lightweight materials such as aluminum to achieve lightweight.

According to the crank assembly of the fifth type of the fourth type, the first ratchet opening and the second ratchet opening are respectively used to accommodate the crank shaft in the assembled state. The crank assembly of the fifth type is miniaturized.

According to the crank assembly of the sixth type of any one of the first to fifth types, the first ratchet disc is used to transmit torque and is engaged with the support body, and the second ratchet disc is used to transmit torque and is engaged with the sprocket. The crank assembly of the sixth type is miniaturized.

The crank assembly of the seventh type according to any one of the first to fifth types further comprises an electric actuator, which causes the sprocket to rotate relative to the crank arm during the free shifting action. The crank assembly of the seventh type can perform the free shifting action by the electric actuator.

According to the crank assembly of the eighth type of any one of the seventh types, the first ratchet disc is engaged with the support body to transmit torque, and the second ratchet disc is engaged with the sprocket to transmit torque. With the crank assembly of the eighth type, free shifting can be performed by an electric actuator.

According to the crank assembly of the 9th type of the 8th type, the electric actuator includes an output gear, and the second ratchet disc includes a plurality of torque transmission teeth engaged with the output gear. With the crank assembly of the 9th type, free shifting can be performed by the electric actuator.

According to the crank assembly of the tenth type of any one of the sixth to eighth types, 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, and 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. The crank assembly of the tenth type can improve the quietness during free shifting action.

The 11th type crank assembly according to the 10th type 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 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. The 11th type crank assembly achieves miniaturization of the crank assembly.

According to the crank assembly of the 12th type of the 10th or 11th 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 12th type, the number of spiral splines can be increased, so the surface pressure on the spiral splines can be suppressed. Therefore, the strength of the one-way clutch unit can be improved.

According to the 13th type crank assembly of the 12th 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 13th type crank assembly, 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 any one of the 1st to 13th types, 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. The free shift mechanism is miniaturized by the crank assembly of the 14th type.

According to the crank assembly of the 15th type of any one of the 10th to 13th types, the support body has a guide portion, the guide portion is provided 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. The crank assembly of the 15th type can improve the quietness during the free shifting action.

According to the 16th type of crank assembly of the 15th 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. The 16th type of crank assembly can improve the quietness during the free shifting action.

According to the 17th type crank assembly of the 15th or 16th type, the guide portion extends at least in the circumferential direction relative to the rotation center axis. The 17th type crank assembly can improve the quietness during free shifting action.

According to the crank assembly of the 18th type of any one of the 15th to 17th types, the guide portion is configured to have at least one defined blunt angle relative to the plurality of outer spiral splines. The crank assembly of the 18th type of the above can improve the quietness during the free shifting action.

According to the 19th type crank assembly of any one of the above 6th, 8th to 13th, and 15th to 18th types, the sprocket has a ratchet disc engaging portion, and the second ratchet disc has a sprocket engaging portion, which engages with the ratchet disc engaging portion of the sprocket, so as to transmit the rotational force and torque from the second ratchet disc to the sprocket via the sprocket engaging portion. By means of the 19th type crank assembly, the crank assembly is miniaturized.

The crank assembly of the 20th type according to any one of the above-mentioned types 1 to 19 further comprises: a spring member disposed between the above-mentioned sprocket and the above-mentioned first ratchet disc, and springing the above-mentioned first ratchet disc toward the above-mentioned second ratchet disc in the above-mentioned axial direction. The above-mentioned crank assembly of the 20th type can surely transmit torque when the crank assembly is driven to rotate.

The crank assembly of the 21st type according to the 15th type further comprises: a spring member disposed between the sprocket and the first ratchet disc and springing 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 the second ratchet disc is released from engagement by the rotational friction force generated between the spring member and the first ratchet disc. The crank assembly of the 21st type can improve the quietness during the free shifting action.

According to the crank assembly of the 22nd type of any one of the 1st to 21st types, the support body has: a contact portion contacting the second ratchet disc for limiting the axial movement of the second ratchet disc separated from the sprocket; the first ratchet disc is arranged on the axial direction and on the axial side of the second ratchet disc on the opposite side of the contact portion of the support body. By means of the crank assembly of the 22nd type, the free shift mechanism is miniaturized.

According to the crank assembly of the 23rd type of any one of the above-mentioned types 7 to 9, the above-mentioned crank arm includes: an actuator configuration portion for configuring the above-mentioned electric actuator in the assembled state of the above-mentioned crank assembly. By means of the above-mentioned crank assembly of the 23rd type, the miniaturization of the electric free shift mechanism is achieved. [Effect of the invention]

The crank assembly for a human-powered vehicle of the present invention has a one-way clutch unit that can be used appropriately.

＜Implementation method＞

A crank assembly 40 for a human-powered vehicle according to an embodiment is described with reference to FIGS. 1 to 10 . 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. The electric bicycle includes an electric assisted bicycle propelled by an electric motor. In the following embodiments, a human-powered bicycle is described as a bicycle.

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 human-powered vehicles. The transmission system 20 further has a derailleur 28. The derailleur 28 can be a rear derailleur or a front derailleur. 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 crankshaft 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 speed change system 20 has a sprocket 48. In the case where the speed change system 20 has a front derailleur, it is preferred that the speed change 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 shifter 28 to change speed 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 shifter 28 can change speed even when the rotation of the crank arm 44 and the crank shaft 42 stops. The free shifting action of the present invention represents the action of changing speed of the shifter 28 when the rotation of the crank arm 44 and the crank shaft 42 stops.

As shown in FIGS. 3 and 4, the crank assembly 40 for a human-powered vehicle 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. The support body 46 is mounted on the crank arm 44. The sprocket 48 is arranged around the support body 46 in the 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 the radial direction A. The one-way clutch unit 50 includes a first ratchet plate 52 including a plurality of first ratchet teeth 52A, and a second ratchet plate 54 including a plurality of second ratchet teeth 54A. The plurality of second ratchet teeth 54A are engaged with the plurality of first ratchet teeth 52A to transmit torque. The first ratchet disc 52 is engaged with one of the support body 46 and the sprocket 48 to transmit torque. The second ratchet disc 54 is engaged with the other of the support body 46 and the sprocket 48 to transmit torque. At least one of the first ratchet disc 52 and the second ratchet disc 54 can 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 arranged around the crankshaft 42 in the radial direction A.

The support body 46, the first ratchet disc 52, and the second ratchet disc 54 preferably include metal materials. The support body 46 includes, for example, an aluminum alloy. The first ratchet disc 52 includes, for example, an aluminum alloy. The second ratchet disc 54 includes, for example, an aluminum alloy. However, at least one of the support body 46, the first ratchet disc 52, and the second ratchet disc 54 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, disposed on the surface of the crank arm 44 on the front sprocket side. The crank arm 44 may also have a housing 44B for covering the actuator configuration portion 44A. The reducer 58 is preferably disposed on the actuator configuration portion 44A. The actuator configuration portion 44A may also be provided with: a power source for supplying power to the electric actuator 56, a control device for controlling the electric actuator 56, and at least one of a communication portion for communicating with an external device. The electric motor 56A and the reducer 58 may also be disposed in a single housing and detachably mounted on the actuator configuration portion 44A. The power source may also be disposed in the internal space of the crank shaft 42.

As shown in FIGS. 2 to 5, in the present embodiment, the first ratchet disc 52 is engaged with the support body 46 to transmit torque. The second ratchet disc 54 is engaged with the sprocket 48 to transmit torque. The plurality of second ratchet teeth 54A are engaged with the plurality of first ratchet teeth 52A 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 54 has a sprocket engaging portion 54B and engages with the ratchet disc engaging portion 48B of the sprocket 48 to transmit the rotational force from the second ratchet disc 54 to the sprocket 48 via the sprocket engaging portion 54B to transmit the torque. The ratchet disc engaging portion 48B and the sprocket engaging portion 54B are, for example, splined.

The sprocket 48 includes a first bearing 48C and a second bearing 48D. The first bearing 48C is provided 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 provided between the sprocket 48 and the first ratchet plate 52, and supports the sprocket 48 so that it can rotate relative to the first ratchet plate 52.

The electric actuator 56 includes an output gear 60, and the second ratchet disc 54 includes a plurality of torque transmission teeth 54C engaged with the output gear 60. The torque transmission teeth 54C are provided on the inner periphery of the second ratchet disc 54. 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 52 and the second ratchet disc 54 are rotatable integrally and relatively. When the crank assembly 40 rotates in the driving rotation direction R1, the one-way clutch unit 50 transmits the rotation torque from the crank assembly 40 to the sprocket 48 via the support body 46, the first ratchet plate 52, and the second ratchet plate 54. When the one-way clutch unit 50 operates the electric actuator 56 in a state where the rotation of the crank arm 44 and the crank shaft 42 is stopped, the electric actuator 56 rotates the second ratchet plate 54 in the driving rotation direction R1. In this case, the speed change operation device can be operated to perform a free shift operation of changing the speed by the sprocket 28.

As shown in FIG. 6 , the support body 46 has a radial outer peripheral surface 62 provided with a plurality of outer spiral splines 62A. The first ratchet disc 52 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 outer spiral spline 62A is provided in the small diameter portion 46B. The first ratchet disc 52 is at least partially configured to overlap with the small diameter portion 46B of the support body 46 in the axial direction B. The outer spline 62A includes a plurality of outer splines 62A, and the inner spline 64A includes a plurality of inner splines 64A, so that the surface pressure of each outer spline 62A and each inner 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 52 preferably 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. 6, the output gear 60, when viewed from the axial direction, at least partially overlaps with the plurality of inner spiral splines 64A of the first ratchet disc 52 in the radial direction. The output gear 60 is arranged at a position corresponding to the outer spiral spline 62A forming the second outer pitch angle DA2 and the inner spiral spline 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 Figures 4, 5, and 7, the first ratchet disc 52 has a first engaging surface 66 that is opposite to the second ratchet disc 54 at least in the axial direction B relative to the rotation center axis C1. The second ratchet disc 54 has a second engaging surface 68 that is opposite to the first ratchet disc 52 at least in the axial direction B relative to the rotation center axis C1. The plurality of first ratchet teeth 52A are arranged on the first engaging surface 66, and the plurality of second ratchet teeth 54A are arranged on the second engaging surface 68. The plurality of first ratchet teeth 52A 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 54A 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 is radially away from the rotation center axis C1. 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 is radially away from the rotation center axis C1. In the present embodiment, the first engaging surface 66 is inclined from the second ratchet disc 54 in the axial direction B toward the first ratchet disc 52 as it is radially away from the rotation center axis C1. In the present embodiment, the second engaging surface 68 is inclined from the second ratchet disc 54 in the axial direction B toward the first ratchet disc 52. The plurality of first ratchet teeth 52A are preferably provided on the first engaging surface 66 to cover the entire circumference of the first ratchet disc 52. The plurality of second ratchet teeth 54A are preferably provided on the second engaging surface 68 to cover the entire circumference of the second ratchet disc 54. The first ratchet teeth 52A have the plurality of first ratchet teeth 52A, and the second ratchet teeth 54A have the plurality of second ratchet teeth 54A, so that the surface pressure of each first ratchet tooth 52A and each second ratchet tooth 54A can be reduced. The first engaging surface 66 can also be a plane, and the second engaging surface 68 can also be a plane. The first ratchet disc 52 and the second ratchet disc 54 can also have friction surfaces that transmit torque by friction.

The first ratchet plate 52 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 54 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 52A are arranged around the first ratchet opening 70 relative to the rotation center axis C1. A plurality of second ratchet teeth 54A 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 has a guide portion 74. The guide portion 74 is provided on the radial outer peripheral surface 62, and is used to guide the first ratchet disc 52 so as to separate the first ratchet disc 52 and the second ratchet disc 54 from each other during the free shifting action. The guide portion 74 guides the first ratchet disc 52 during the free shifting action to release the engagement of the plurality of first ratchet teeth 52A and the plurality of second ratchet teeth 54A. 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 provided 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 disposed so as to define a blunt angle DC with respect to at least one of the plurality of outer spiral splines 62A.

As shown in FIG. 4 , 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 52, and is used to spring the first ratchet disc 52 toward the second ratchet disc 54 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. 4 , 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 52 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 operation, the first ratchet disc 52 comes into contact with the guide portion 74 and is disengaged from the second ratchet disc 54 by the rotational friction force generated between the spring member 76 and the first ratchet disc 52 .

The support body 46 preferably has a contact portion 78. The contact portion 78 contacts the second ratchet disc 54 to restrict the movement of the second ratchet disc 54 separated from the sprocket 48 in the axial direction B. The first ratchet disc 52 is arranged on the axial direction B and on the axial side of the second ratchet disc 54 on the opposite side of the contact portion 78 of the support body 46. The contact portion 78 is provided on the end surface of the large diameter portion 46A 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 54 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 54B of the second ratchet plate 54 in the circumferential direction R. This structure can reduce the driving sound generated by the contact between the ratchet plate engaging portion 48B of the sprocket 48 and the sprocket engaging portion 54B of the second ratchet plate 54.

Referring to FIGS. 7 to 10, the operation of the one-way clutch unit 50 is described. As shown in FIGS. 7 and 8, when the human driving force is input from the rider to rotate the crank arm 44 and the crank shaft 42 in the driving rotation direction R1, the rotation of the crank arm 44 causes the support body 46 and the first ratchet disc 52 to rotate in the driving rotation direction R1. Since the first ratchet disc 52 is pressed toward the second ratchet disc 54 by the spring member 76, the first ratchet tooth 52A is engaged with the second ratchet tooth 54A. Therefore, the rotation of the first ratchet disc 52 in the driving rotation direction R1 causes the second ratchet disc 54 to rotate in the driving rotation direction R1. Since the sprocket engaging portion 54B of the second ratchet plate 54 and the ratchet plate engaging portion 48B of the sprocket 48 are engaged with each other, the rotation of the second ratchet plate 54 causes the sprocket 48 to rotate in the driving rotation direction R1.

As shown in FIGS. 9 and 10 , when the crank arm 44 and the crank shaft 42 stop rotating and the output gear 60 is rotated in the direction R3 corresponding to the driving rotation direction R1 by the electric actuator 56, the second ratchet disc 54 is rotated in the driving rotation direction R1 via the torque transmission tooth 54C. The first ratchet disc 52 is rotated in the driving rotation direction R1 by the rotation of the second ratchet disc 54 in the driving rotation direction R1, and the first ratchet disc 52 moves relative to the second ratchet disc 54 in the axial direction B along the inner spiral spline 64A of the first ratchet disc 52 and the outer spiral spline 62A of the support body 46 in a direction in which the first ratchet disc 52 and the second ratchet disc 54 are separated from each other. The engagement between the first ratchet disc 52 and the second ratchet disc 54 is thereby released. Therefore, the rotation of the second ratchet disc 54 does not cause the first ratchet disc 52 to rotate, and the sprocket 48 is rotated in the driving rotation direction R1 via the sprocket engagement portion 54B of the second ratchet disc 54 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. In this way, a free shifting action can be performed. The guide portion 74 of the support body 46 has the function of enabling the first ratchet disc 52 and the second ratchet disc 54 to be quickly separated in the axial direction B.

In the crank assembly 40 of this embodiment, when the free shifting action is performed, since at least one of the first ratchet plate 52 and the second ratchet plate 54 moves in the axial direction B and separates, noise can be suppressed.

<Variations> The description of the embodiment is an example of the form of the crank assembly for a human-powered vehicle of the present invention, and is not intended to limit its form. The crank assembly for a human-powered vehicle of the present invention can take the form of a variation of the embodiment 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 embodiment are added to the parts that are common to the embodiment, and their description is omitted.

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 be changed to: a first state in which the human-powered vehicle 10 is driven by human power alone, human power and motor assistance, or a second state in which a high-output motor is installed to drive the human-powered vehicle 10 only by the torque of the 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 two or more options".

10: Human-powered vehicle 40: Crank assembly 42: Crank shaft 44: Crank arm 44A: Actuator configuration portion 46: Support body 48: Sprocket 48A: Sprocket gear 48B: Ratchet disc engagement portion 50: One-way clutch unit 52: First ratchet disc 52A: First ratchet gear 54: Second ratchet disc 54A: Second ratchet gear 54B: Sprocket engagement portion 54C: Torque transmission teeth 56: Electric actuator 56A: Electric motor 62: Radial outer peripheral surface 62A: Outer spiral spline 64: Radial inner peripheral surface 64A: Inner spiral spline 66: First engagement surface 68: Second engagement surface 70: First ratchet opening 72: Second ratchet opening 74: Guide part 78: Abutment part 76: Spring member 80: Buffer part

[FIG. 1] is a side view of a human-powered vehicle including a crank assembly for a human-powered vehicle according to an embodiment. [FIG. 2] is a side view of a crank assembly for a human-powered vehicle according to an embodiment. [FIG. 3] is a cross-sectional view of a crank assembly for a human-powered vehicle according to an embodiment. [FIG. 4] is an exploded perspective view of a crank assembly for a human-powered vehicle according to an embodiment. [FIG. 5] is a perspective view showing the first engaging surface of the first ratchet disc of FIG. 4. [FIG. 6] is a perspective view of the support body and the first ratchet disc of FIG. 4. [FIG. 7] is a cross-sectional view along the D6-D6 line of FIG. 2. [FIG. 8] is a partial front view showing the rotation state of each component when the crankshaft rotates for the human-powered vehicle assembly according to the embodiment. [Figure 9] is a partial cross-sectional view of the human-powered vehicle assembly of the embodiment when the free shift action is performed. [Figure 10] is a partial front view of the human-powered vehicle assembly of the embodiment, showing the rotation state of each component during the free shift action.

20: Speed transmission system

42: Crankshaft

44: Crank arm

44A: Actuator configuration unit

44B: Shell

44X: 1st crank arm

46: Support body

46C: Configuration Department

46D: Bearing

48: Sprocket

48A: Sprocket gear

48B: ratchet disc engagement portion

48C: 1st bearing

48D: 2nd bearing

52: 1st ratchet disc

54: Second ratchet disc

54B: Sprocket engagement portion

56: Electric actuator

56A: Electric Motor

58: Reducer

60: Output gear

66: 1st engagement surface

68: Second engagement surface

80: Buffer

80A: Axial protrusion

A: Radial

B: Axis direction

C1: Rotation center axis

Claims (23)

A crank assembly for a human-powered vehicle comprises: a crankshaft, a crank arm mounted on the crankshaft, a support body mounted on the crank arm, a sprocket arranged around the support body in a radial direction relative to a rotation center axis of the crank assembly, and a one-way clutch unit at least partially arranged in the radial direction and between the support body and the sprocket; the one-way clutch unit comprises: a first ratchet disc and a second ratchet disc; the first ratchet disc comprises a plurality of first ratchet teeth; the second ratchet disc, The plurality of second ratchet teeth are used to engage with the plurality of first ratchet teeth to transmit torque; the first ratchet disc is engaged with one of the support body and the sprocket to transmit torque, and the second ratchet disc is engaged with the other of the support body and the sprocket to transmit torque; at least one of the first ratchet disc and the second ratchet disc can move relative to the crankshaft in the axial direction relative to the rotation center axis, and the one-way clutch unit is arranged around the crankshaft in the radial direction. A crank assembly for a human-driven vehicle as claimed in claim 1, wherein 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. A crank assembly for a human-powered vehicle as claimed in claim 2, 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 3, 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, and the plurality of second ratchet teeth are arranged around the second ratchet opening relative to the rotation center axis. As in claim 4, the crank assembly for a human-powered vehicle, wherein the first ratchet opening and the second ratchet opening are respectively used to accommodate the crank shaft in the assembled state. As in claim 1, the crank assembly for a human-powered vehicle, wherein the first ratchet disc is engaged with the support body to transmit torque, and the second ratchet disc is engaged with the sprocket to transmit torque. 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. As in claim 7, the crank assembly for a human-powered vehicle, wherein the first ratchet disc is engaged with the support body to transmit torque, and the second ratchet disc is engaged with the sprocket to transmit torque. A crank assembly for a human-powered vehicle as claimed in claim 8, wherein the electric actuator includes an output gear, and the second ratchet disc includes a plurality of torque transmission teeth engaged with the output gear. As in claim 6, the crank assembly for a human-powered vehicle, 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, and 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-driven vehicle as claimed in claim 10, wherein the crank assembly 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. As in claim 10, the crank assembly for a human-powered vehicle, 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 12, 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. As in claim 1, the crank assembly for a human-powered vehicle, 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 10, the crank assembly for a human-driven vehicle, wherein the support body has 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. As in claim 15, the crank assembly for a human-driven vehicle, 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. As in claim 15, the crank assembly for a human-powered vehicle, wherein the guide portion extends at least in the circumferential direction relative to the rotation center axis. A crank assembly for a human-powered vehicle as claimed in claim 15, wherein the guide portion is configured to have at least one defined blunt angle relative to the plurality of outer spiral splines. As in claim 6, the crank assembly for a human-powered vehicle, wherein the sprocket has a ratchet disc engaging portion, the second ratchet disc has a sprocket engaging portion, and engages with the ratchet disc engaging portion of the sprocket, so as to transmit the rotational force and torque 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 1 further comprises a spring-loaded member, which 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 15 further comprises a spring member, the spring member being disposed between the sprocket and the first ratchet disc and springing the first ratchet disc toward the second ratchet disc in the axial direction; the spring member being mounted on the sprocket and rotating together with the sprocket, the first ratchet disc contacts the guide portion during the free shifting action, and the second ratchet disc is released from engagement by the rotational friction force generated between the spring member and the first ratchet disc. The crank assembly for a human-driven vehicle as claimed in claim 1, wherein the support body has: an abutment portion abutting against the second ratchet disc, for limiting the axial movement of the second ratchet disc separated from the sprocket; the first ratchet disc is arranged on the opposite side of the abutment portion of the support body in the axial direction and on the axial side of the second ratchet disc. A crank assembly for a human-powered vehicle as claimed in claim 7, wherein the crank arm comprises: an actuator configuration portion for configuring the electric actuator in the assembled state of the crank assembly.

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