Transmission system for human-powered vehicles

Abstract

To provide a gearshift system for a man-power drive vehicle capable of being preferably used.SOLUTION: A gearshift system for a man-power drive vehicle includes a base part, a movable part, a change guide mechanism swingably attached to the movable part, and a motor having an output shaft. The chain guide mechanism includes at least one pulley which is coupled to the output shaft of the motor. The at least one pulley drives a chain for a man-power drive vehicle by means of the motor.SELECTED DRAWING: Figure 13

Description

Technical Field

[0001] The present invention relates to a transmission system for a human-powered vehicle.

Background Art

[0002] For example, in the transmission system for a human-powered vehicle disclosed in Patent Document Ⅰ, the chain could not be shifted unless it was driven by pedaling.

Prior Art Documents

Patent Documents

[0003]

Patent Document Ⅰ

Summary of the Invention

Problems to be Solved by the Invention

[0004] One object of the present invention is to provide a transmission system for a human-powered vehicle having a mechanism for effectively driving a chain without pedaling.

Means for Solving the Problems

[0005] The transmission system according to the first aspect of the present invention is a transmission system for a human-powered vehicle, including a crank arm, at least one front sprocket including a plurality of sprocket teeth engaged with a chain for a human-powered vehicle, a front clutch mechanism, an output shaft, and a motor for applying a rotational force to the at least one front sprocket. The at least one front sprocket is configured to be relatively rotatable with respect to the crank arm by the front clutch mechanism, and the crank arm has a motor arrangement portion where the motor is disposed. According to the gear shifting system described in the first side above, the chain can be driven by rotating the front sprocket even when the rider is not pedaling. Therefore, gear shifting can be performed even when the rider is not pedaling. Furthermore, since the motor that applies rotational force to the front sprocket is located on the crank arm near the front sprocket, it is possible to miniaturize the drive mechanism that rotates the front sprocket without pedaling. In addition, by attaching the front sprocket and crank arm to a bicycle frame, the mechanism that drives the chain without pedaling can be attached to a human-powered vehicle frame, resulting in excellent assembly.

[0006] A second aspect of the present invention is a gear shift system for a human-powered vehicle, comprising: a crank arm; at least one front sprocket including a plurality of sprocket teeth that engage with a chain for a human-powered vehicle; a front clutch mechanism; and a motor including an output shaft that applies rotational force to the at least one front sprocket, wherein the at least one front sprocket is configured to be rotatable relative to the crank arm by the front clutch mechanism, and the motor is connected to the front clutch mechanism. According to the second aspect of the gear shifting system described above, the chain can be driven by rotating the front sprocket even when the pedals are not being used. Therefore, gear shifting can be performed even when the pedals are not being used. In addition, since the rotational force of the motor can be applied to the front sprocket via the front clutch mechanism, the output of the motor can be suitably transmitted to the front sprocket.

[0007] In a gear shifting system of the third side according to the second side, the front clutch mechanism comprises a first part that rotates integrally with the crank arm, a second part coupled to the inner circumference of at least one front sprocket, and a switching member for switching the transmission of power between the first part and the second part, the motor being connected to the first part. According to the third aspect of the gear shifting system described above, the power transmission between the first and second parts can be suitably switched by the switching member.

[0008] In a gear shifting system of a fourth side according to the second or third side, the crank arm has a motor arrangement portion in which the motor is located. According to the fourth aspect of the gear shifting system described above, the motor that applies rotational force to the front sprocket can be positioned on the crank arm located near the front sprocket.

[0009] A fifth-side gear shifting system according to the first or fourth side further comprises a housing in which the motor is located. According to the fifth side of the gear shifting system described above, the motor can be suitably supported by the housing.

[0010] In the gear shifting system of the sixth side according to the fifth side, the housing is arranged in the motor arrangement section. According to the sixth side of the gear shifting system described above, the motor can be suitably supported by the housing in the motor arrangement section.

[0011] In the seventh gear shifting system according to the fifth or sixth side, at least one of a reduction mechanism, a cadence sensor, a wireless unit, and an indicator is disposed within the housing. According to the seventh aspect of the gear shifting system described above, at least one of a reduction mechanism, a cadence sensor, a wireless unit, and an indicator can be placed within the housing.

[0012] The eighth aspect of the present invention is a gear shift system for a human-powered vehicle, comprising: a crankshaft having an internal space; a crank arm rotatable integrally with the crankshaft; at least one front sprocket including a plurality of sprocket teeth that engage with a chain for a human-powered vehicle; a front clutch mechanism; a motor including an output shaft that applies rotational force to the at least one front sprocket; and a battery that supplies power to the motor, wherein the at least one front sprocket is configured to rotate relative to the crank arm by the front clutch mechanism, and the battery is located in the internal space of the crankshaft. According to the eighth gear shifting system described above, the chain can be driven by rotating the front sprocket even when the pedals are not being used. Therefore, gear shifting can be performed even when the pedals are not being used. Furthermore, it becomes possible to miniaturize the drive mechanism that rotates the front sprocket without pedaling. In addition, by attaching the front sprocket and crank arm to a human-powered vehicle frame, the mechanism that drives the chain without pedaling can be attached to the human-powered vehicle frame, resulting in excellent assembly efficiency.

[0013] In the gear shifting system of the ninth side according to the eighth side, the system further includes at least one of a wireless communication unit, a cadence sensor, an indicator, and a power meter, wherein the battery supplies power to the wireless communication unit, the cadence sensor, the indicator, and the power meter. According to the gear shifting system of the ninth side described above, the battery can supply power to at least one of the wireless communication unit, cadence sensor, indicator, and power meter.

[0014] In the gear shifting system of the tenth side according to the ninth side, the battery supplies power to the wireless communication unit, the cadence sensor, the indicator, and the power meter. According to the gear shifting system on the tenth side described above, the battery can supply power to the wireless communication unit, cadence sensor, indicator, and power meter.

[0015] A gear shifting system of an eleventh side according to any one of the eighth to tenth sides further comprises a charging port for supplying power to the battery. According to the 11th side gear system described above, the battery can be charged via the charging port without having to remove it from the gear system.

[0016] In a gear shifting system of a twelfth side according to any one of the eighth to eleventh sides, the battery includes a plurality of battery elements. According to the transmission system described in the 12th side above, since the battery contains multiple battery elements, the battery's power usage time can be extended.

[0017] A thirteenth aspect of the present invention is a gear shift system for a human-powered vehicle, comprising: a crank arm that can be attached to a human-powered vehicle; at least one front sprocket including a plurality of sprocket teeth that engage with a chain for a human-powered vehicle; a front clutch mechanism that makes the at least one front sprocket rotatable integrally or relative to the crank arm; a motor including an output shaft that applies rotational force to the at least one front sprocket; a base portion; a movable portion; and a chain guide mechanism pivotably attached to the movable portion, wherein the chain guide mechanism includes at least one pulley connected to the output shaft of the motor, and the motor applies rotational force to the at least one front sprocket via the at least one pulley. According to the gear shifting system described in the 13th side above, the chain guide mechanism, such as the rear derailleur, allows the chain to rotate even when the rider is not pedaling. Therefore, the front sprocket can be rotated even when the rider is not pedaling, and thus gear shifting can be performed even when the rider is not pedaling.

[0018] In the transmission system of the 14th side surface according to the 13th side surface, the motor applies a rotational force to the at least one front sprocket via the at least one pulley and the chain for the human-powered vehicle. According to the transmission system of the 14th side surface, the rotational force can be transmitted to the front sprocket via the pulley and the chain.

[0019] In the transmission system of the 15th side surface according to the 13th or 14th side surface, the at least one pulley includes a tension pulley and a guide pulley. According to the transmission system of the 15th side surface, the rotational force of the motor can be applied to the front sprocket via the tension pulley or the guide pulley.

[0020] In the transmission system of the 16th side surface according to the 15th side surface, the output shaft of the motor is connected to the guide pulley and not connected to the tension pulley. According to the transmission system of the 16th side surface, the rotational force of the motor can be applied to the front sprocket via the guide pulley.

[0021] In the transmission system of the 17th side surface according to any one of the 13th to 16th side surfaces, it further includes at least one of a wireless communication unit, a cadence sensor, an indicator, and a power meter. According to the transmission system of the 17th side surface, at least one of the wireless communication unit, the cadence sensor, the indicator, and the power meter can be used.

[0022] The 18th aspect of the present invention is a gear shift system for a human-powered vehicle, comprising: a motor including an output shaft that applies rotational force to at least one front sprocket; a bracket member including a cover portion that overlaps with the sprocket teeth of the at least one front sprocket in the radial direction with respect to the rotational axis of the at least one front sprocket; and a rotational force transmission member connected to the output shaft of the motor, wherein the bracket member has a motor housing portion that houses the motor. According to the 18th side-mounted gear shifting system described above, the motor can be housed in a bracket member positioned close to the front sprocket, making it possible to miniaturize the drive mechanism that rotates the front sprocket without pedaling. Furthermore, it becomes easier to retrofit a drive mechanism that rotates the front sprocket without pedaling to a human-powered vehicle.

[0023] In the gear shifting system of the 19th side according to the 18th side, the bracket member includes a fixing portion that can be fixed to the bracket hanger portion of the frame for a human-powered vehicle. According to the 19th side gear shifting system described above, the bracket member can be suitably fixed to the bracket hanger portion by the fixing portion.

[0024] In the gear shifting system of the 20th side according to the 18th or 19th side, the rotational force transmission member transmits rotational force to the front sprocket without going through a chain for a human-powered vehicle. According to the gear shifting system described in the 20th side above, the rotational force transmission member can transmit rotational force to the front sprocket without going through a chain for human-powered vehicles, making it possible to efficiently rotate the front sprocket with a motor when not pedaling.

[0025] In the gear shifting system of the 21st side according to the 18th or 19th side, the rotational force transmission member transmits rotational force to the front sprocket via a chain for a human-powered vehicle. According to the 21st side gear shifting system described above, the front sprocket can be rotated via a chain for human-powered vehicles, thus increasing the flexibility of the motor's placement.

[0026] A gear shifting system according to a 22nd aspect that follows any one of the 18th to 21st aspects further includes at least one of a wireless communication unit, a cadence sensor, an indicator, and a power meter. According to the gear shifting system of the 22nd aspect described above, at least one of a wireless communication unit, a cadence sensor, an indicator, and a power meter can be used.

[0027] The 23rd side of the present invention is a gear shifting system for a human-powered vehicle, comprising: a bracket member attached to at least one of the seat tube, seat stay, and chain stay of the human-powered vehicle; a motor including an output shaft that applies rotational force to at least one front sprocket; and a rotational force transmission member connected to the output shaft of the motor, wherein the bracket member has a motor housing portion that houses the motor. According to the gear shifting system described in the 23rd side view above, the motor can be housed in the motor housing of the bracket member, allowing the chain to be driven and gear shifting performed by rotating the front sprocket even when the pedals are not being used. Furthermore, it becomes possible to miniaturize the drive mechanism that rotates the front sprocket without pedaling. Moreover, it becomes easier to retrofit a drive mechanism that rotates the front sprocket without pedaling to a human-powered vehicle.

[0028] In the gear shifting system of the 24th side according to the 23rd side, the bracket member is attached to the seat tube, and the bracket member includes a first clamp member, a second clamp member that is pivotably attached to the first clamp member, and a fastening member that fixes the first clamp member and the second clamp member while sandwiching the seat tube of the human-powered vehicle between the first clamp member and the second clamp member. According to the gear shifting system described in the 24th side view above, the bracket member can be attached to the seat tube by the first clamp member, the second clamp member, and the fastening member, making it easy to retrofit a drive mechanism that rotates the front sprocket without pedaling to a human-powered vehicle.

[0029] In the gear shifting system of the 25th side corresponding to the 24th side, the bracket member is attached to the seat tube, and the bracket member includes a bracket body having a first mounting portion and a fastening member, the fastening member passing through the first mounting portion of the bracket body and being fixed to a second mounting portion formed on the seat tube. According to the gear shifting system described in the 25th side above, the bracket member can be attached to the seat tube by inserting a fastening member into the first mounting portion of the bracket body, making it easy to retrofit a drive mechanism that rotates the front sprocket without pedaling to a human-powered vehicle.

[0030] The 26th side of the present invention is a gear shift system for a human-powered vehicle, comprising: a crankshaft; a crank arm rotatable integrally with the crankshaft; at least one front sprocket including a plurality of sprocket teeth that engage with a chain for a human-powered vehicle; a front clutch mechanism; a motor including an output shaft that applies rotational force to the at least one front sprocket; and a wireless power receiving unit that wirelessly receives power from a battery and supplies power to the motor, wherein the at least one front sprocket is configured to rotate relative to the crank arm by the front clutch mechanism. According to the gear shifting system described in the 26th side above, even when the pedals are not being used, the chain can be driven by rotating the front sprocket to perform gear shifting. In addition, wiring can be simplified by using a wireless power receiving unit that receives power wirelessly from the battery.

[0031] The 27th aspect of the present invention is a gear shift system for a human-powered vehicle, comprising: a crankshaft; a crank arm rotatable integrally with the crankshaft; at least one front sprocket including a plurality of sprocket teeth that engage with a chain for a human-powered vehicle; a front clutch mechanism; a motor including an output shaft that applies rotational force to the at least one front sprocket; and a power supply unit including a first power supply unit and a second power supply unit that rotates relative to the first power supply unit, wherein the at least one front sprocket is configured to rotate relative to the crank arm by the front clutch mechanism, the first power supply unit supplies power from a battery for a human-powered vehicle to the second power supply unit, and the second power supply unit supplies power from the first power supply unit to the motor. According to the transmission system of the 27th side described above, one of the battery and motor can be placed in one of the two locations of the human-powered vehicle that rotate relative to each other, and the other of the battery and motor can be placed in the other of the two locations of the human-powered vehicle that rotate relative to each other.

[0032] The 28th side of the present invention is a gear shift system for a human-powered vehicle, comprising: a frame for a human-powered vehicle including a first frame member and a second frame member; a crank arm; at least one front sprocket including a plurality of sprocket teeth that engage with a chain for a human-powered vehicle; a front clutch mechanism; and a motor including an output shaft that applies rotational force to the at least one front sprocket, wherein the at least one front sprocket is configured to be rotatable relative to the crank arm by the front clutch mechanism, the first frame member is pivotably mounted on the second frame member around a pivot axis, and a rotational force transmission member connected to the output shaft of the motor is positioned on the pivot axis. According to the 28th aspect of the speed change system described above, since the rotational force transmission member connected to the output shaft of the motor is positioned on the pivot axis, the change in the distance between the rotational force transmission member and the member to which the rotational force transmission member transmits rotational force can be reduced.

[0033] In a gear shifting system according to a 29th side that follows any one of the first to 28 sides described above, the output shaft of the motor extends in the direction of the output axis, and the direction of the output axis is parallel to the axial direction with respect to the rotational axis of the front sprocket. According to the gear shifting system described in the 29th side above, it becomes possible to miniaturize the drive mechanism that rotates the front sprocket without pedaling.

[0034] In a gear shifting system of a 30th side according to any one of the first to 28 sides described above, the output shaft of the motor extends in the direction of the output axis, and the direction of the output axis extends non-parallel to the axial direction with respect to the rotational axis of the front sprocket. According to the 30th side-mounted gear shifting system described above, the degree of freedom in the placement of the motor is increased.

[0035] In a gear shifting system of a 31st side according to any one of the 1st to 28th sides, the output shaft of the motor extends in the direction of the output axis, and the maximum length of the motor in the direction of the output axis is smaller than the diameter of the front sprocket. According to the 31st aspect gear shifting system described above, it becomes possible to miniaturize the drive mechanism that rotates the front sprocket without pedaling.

[0036] In a gear shifting system according to a 32nd aspect which follows any one of the first to 31 aspects described above, the motor is configured not to impart propulsion to the human-powered vehicle. According to the gear shifting system described in the 32nd side above, gear shifting can be performed by rotating the front sprocket when the pedals are not being used.

[0037] In the gear shifting system of the 33rd side according to the 32nd side, the motor rotates the at least one front sprocket at a rotational speed that does not impart thrust to the human-powered vehicle. According to the gear shifting system described in the 33rd side above, gear shifting can be performed by rotating the front sprocket while the pedals are not being used.

[0038] The 34th side of the present invention is a gear shift system for a human-powered vehicle, comprising a base, a movable part, a chain guide mechanism rotatably mounted on the movable part, and a motor including an output shaft, wherein the chain guide mechanism includes at least one pulley connected to the output shaft of the motor, and the at least one pulley drives a chain for a human-powered vehicle by the motor. According to the gear shifting system described in the 34th side above, a drive mechanism that rotates the front sprocket without pedaling can be placed on the rear wheel of a human-powered vehicle. [Effects of the Invention]

[0039] The transmission system for human-powered vehicles disclosed herein can be suitably used. [Brief explanation of the drawing]

[0040] [Figure 1] A side view of a human-powered vehicle including a transmission system for a human-powered vehicle according to the first embodiment. [Figure 2] Side view of the crank arm and crank shaft in Figure 1. [Figure 3] Rear view of the crank arm and crank shaft in Figure 1. [Figure 4] A cross-sectional view of the first example along the line D4-D4 in Figure 2. [Figure 5] A cross-sectional view of the second example along the line D4-D4 in Figure 2. [Figure 6] Figure 3 is an exploded perspective view of the front clutch mechanism. [Figure 7] A cross-sectional view along the line D7-D7 in Figure 3. [Figure 8] A schematic diagram showing the power transmission path of the human-powered vehicle in Figure 1. [Figure 9] A block diagram showing the electrical configuration of the transmission system for a human-powered vehicle shown in Figure 1. [Figure 10] A flowchart showing the process of controlling the motor when a speed change is performed while the rotation of the crank arm is stopped, as executed by the control unit in Figure 9. [Figure 11]A flowchart showing the process of controlling the relative phase between the first and second parts when the rotation of the crank arm stops, as performed by the control unit in Figure 9. [Figure 12] A side view of the area around the crankshaft of a human-powered vehicle, including a transmission system for a human-powered vehicle according to a second embodiment. [Figure 13] A side view of the area around the rear axle of a human-powered vehicle, including a transmission system for a human-powered vehicle according to a second embodiment. [Figure 14] A schematic diagram showing the power transmission path of a human-powered vehicle according to the second embodiment. [Figure 15] A side view of the area around the crankshaft of a human-powered vehicle, including a transmission system for a human-powered vehicle according to a third embodiment. [Figure 16] A side view of the bracket member of the transmission system for a human-powered vehicle according to the third embodiment. [Figure 17] A schematic diagram showing the power transmission path of a human-powered vehicle according to the third embodiment. [Figure 18] A side view of the area around the crankshaft of a human-powered vehicle, including a transmission system for a human-powered vehicle according to the fourth embodiment. [Figure 19] A side view of the bracket member of the transmission system for a human-powered vehicle according to the fourth embodiment. [Figure 20] A side view of a bracket member of a modified example of the transmission system for a human-powered vehicle according to the fourth embodiment. [Figure 21] A side view of the area around the crankshaft of a human-powered vehicle including a gear shifting system of a modified example of the first embodiment. [Figure 22] A block diagram showing the electrical configuration of the transmission system of a first modified example of each embodiment. [Figure 23] A block diagram showing the electrical configuration of the transmission system for a second modified example of each embodiment. [Figure 24] A side view of the area around the crankshaft of a human-powered vehicle including a gear shifting system of a modified example of the fourth embodiment. [Modes for carrying out the invention]

[0041] <First Embodiment> Referring to Figures 1 to 11, a first embodiment of the gear shift system 20 for a human-powered vehicle will be described. The human-powered vehicle 10 is a vehicle having at least one wheel and capable of being driven by at least human power. The human-powered vehicle 10 includes, for example, mountain bikes, road bikes, city bikes, cargo bikes, and various types of bicycles such as handbikes and recumbent bikes. The number of wheels that the human-powered vehicle 10 has is not limited. The human-powered vehicle 10 also includes, for example, unicycles and vehicles having three or more wheels. The human-powered vehicle 10 is not limited to vehicles that can be driven by human power alone. The human-powered vehicle 10 includes e-bikes that utilize the driving force of an electric motor in addition to human power for propulsion. E-bikes include electric assist bicycles in which propulsion is assisted by an electric motor. Hereinafter, in the embodiments, the human-powered vehicle 10 will be described as a bicycle.

[0042] The human-powered vehicle 10 comprises a human-powered vehicle frame 12, wheels 14 supported by the frame 12, and a gear shifting system 20. The wheels 14 include a rear wheel 14A and a front wheel 14B. The gear shifting system 20 is configured to shift the rotation input to the human-powered vehicle 10 and transmit it to the rear wheel 14A. Preferably, the frame 12 includes a bracket hanger portion 12A. The bracket hanger portion 12A supports the crankshaft 34. Preferably, the frame 12 includes a first frame member 12B and a second frame member 12C. The first frame member 12B is pivotably mounted to the second frame member 12C around a pivot axis 12F. For example, the second frame member 12C is provided with a bracket hanger portion 12A. The second frame member 12C includes a top tube 13A, a down tube 13B, and a seat tube 12D. The first frame member 12B includes a chainstay 12E. The first frame member 12B includes a seatstay 13C. The first frame member 12B supports the rear wheel 14A of the wheel 14.

[0043] The gear shifting system 20 comprises a crank arm 22, at least one front sprocket 24, a front clutch mechanism 26, and a motor 28. Preferably, the gear shifting system 20 further comprises a chain 30 for a human-powered vehicle, a rear sprocket 32, and a crankshaft 34. The crank arm 22 is configured to be attachable to the human-powered vehicle 10. The crank arm 22 includes a right crank arm 37A and a left crank arm 37B. The right crank arm 37A is attached to one end of the crankshaft 34, and the left crank arm 37B is attached to the other end of the crankshaft 34. Preferably, the crank arm 22 is rotatable integrally with the crankshaft 34. Pedals 36 are attached to the ends of the crank arm 22. The crankshaft 34 transmits rotational force to at least one front sprocket 24. In this embodiment, the gear shifting system 20 comprises one front sprocket 24. If the shifting system 20 includes a front derailleur, preferably the shifting system 20 includes a plurality of front sprockets 24.

[0044] At least one front sprocket 24 includes a plurality of sprocket teeth 24A that engage with a chain 30 for a human-powered vehicle. The motor 28 includes an output shaft 28A that imparts rotational force to at least one front sprocket 24. A front clutch mechanism 26 configures at least one front sprocket 24 to be rotatable relative to the crank arm 22.

[0045] Preferably, the crank arm 22 has a motor mounting portion 22A on which the motor 28 is located. Preferably, the motor mounting portion 22A is provided on the crank arm 22 on the side to which the front sprocket 24 is attached. Preferably, the motor mounting portion 22A is positioned to face the front sprocket 24. The motor mounting portion 22A is provided in a recess 22B of the crank arm 22.

[0046] The transmission system 20 further comprises a housing 38 in which a motor 28 is housed. Preferably, the motor 28 is housed within the housing 38. Preferably, the housing 38 is housed in the motor housing portion 22A. The shape of the housing 38 corresponds to the shape of the recess in the crank arm 22 in which the motor housing portion 22A is provided. The housing 38 is attached to the crank arm 22, for example, via bolts. However, the present invention is not limited to this embodiment. For example, the motor 28 may be housed directly in the recess 22B of the crank arm 22, and the housing 38 may be fixed to the crank arm 22 so as to cover the opening of the recess 22B.

[0047] The output shaft 28A of the motor 28 extends in the output axial direction A1. As shown in Figure 4, in the first example, the output axial direction A1 is parallel to the axial direction A2 with respect to the rotational axis C1 of the front sprocket 24. Preferably, the axial direction A2 with respect to the rotational axis C1 of the front sprocket 24 is substantially parallel to the rotational axis C1 of the front sprocket 24. More preferably, the axial direction A2 with respect to the rotational axis C1 of the front sprocket 24 is parallel to the rotational axis C1 of the front sprocket 24.

[0048] As shown in Figure 5, in the second example, the output axial direction A1 extends non-parallel to the axial direction A2 with respect to the rotational axis of the front sprocket 24. Preferably, the output axial direction A1 extends substantially perpendicular to the axial direction A2 with respect to the rotational axis of the front sprocket 24. More preferably, the output axial direction A1 extends perpendicular to the axial direction A2 with respect to the rotational axis of the front sprocket 24.

[0049] Preferably, the maximum length L1 of the motor 28 in the output axial direction A1 is smaller than the diameter L2 of the front sprocket 24. If at least one front sprocket 24 includes multiple front sprockets 24, preferably, the maximum length L1 of the motor 28 in the output axial direction A1 is smaller than the diameter L2 of all front sprockets 24. The maximum length L1 of the motor 28 in the output axial direction A1 also includes the output shaft 28A of the motor 28. Preferably, the maximum length L3 of the housing 38 in the direction in which the crank arm 22 extends is smaller than the diameter L2 of the front sprocket 24.

[0050] Preferably, the transmission system 20 further comprises a reduction mechanism 40. The reduction mechanism 40 connects the output shaft 28A of the motor 28 to the front sprocket 24. The reduction mechanism 40 reduces the rotation of the motor 28 and transmits it to the front sprocket 24. The reduction mechanism 40 may include a plurality of gears, and may also include pulleys and belts. If the output axial direction A1 extends non-parallel to the axial direction A2 with respect to the rotational axis of the front sprocket 24, preferably the reduction mechanism 40 includes at least one bevel gear and a worm gear.

[0051] Preferably, the motor 28 is connected to the front clutch mechanism 26. Preferably, the motor 28 is connected to the front clutch mechanism 26 via a reduction mechanism 40. The rotational force of the motor 28, reduced by the reduction mechanism 40, is transmitted to the front clutch mechanism 26.

[0052] Preferably, the front clutch mechanism 26 comprises a first portion 26A, a second portion 26B, and a switching member 26C. The first portion 26A rotates integrally with the crank arm 22. The second portion 26B is coupled to the inner circumference of at least one front sprocket 24. The switching member 26C switches the transmission of power between the first portion 26A and the second portion 26B. Preferably, the motor 28 is connected to the first portion 26A. The switching member 26C is, for example, located on one of the first portion 26A and the second portion 26B and configured to engage with an engagement portion 26D provided on the other of the first portion 26A and the second portion 26B. In this embodiment, the engagement portion 26D includes a plurality of engagement portions 26D. Preferably, the front clutch mechanism 26 further comprises a biasing member 26E. The biasing member 26E biases the switching member 26C to protrude toward the engagement portion 26D. In this embodiment, the biasing member 26E is arranged on the outer circumference of the first portion 26A, and the engaging portion 26D is provided on the inner circumference of the second portion 26B. Furthermore, in this embodiment, the switching member 26C is a claw member of the one-way clutch mechanism, and the multiple engaging portions 26D are ratchet members of the one-way clutch mechanism.

[0053] Preferably, the front clutch mechanism 26 further includes a transmission section 26F. The transmission section 26F transmits the output of the motor 28 to the second section 26B. The output of the motor 28 is transmitted to the transmission section 26F via the reduction mechanism 40. The transmission section 26F is provided on the first section 26A. The transmission section 26F has a projection 27 on its outer circumference that engages with the engaging section 26D. Preferably, the transmission section 26F is configured as an external gear, and the plurality of engaging sections 26D are configured as internal gears that engage with the external gear of the transmission section 26F. Preferably, the projection 27 includes a plurality of projections 27.

[0054] Preferably, the front clutch mechanism 26 further includes rolling elements 26G. The rolling elements 26G are, for example, balls. The rolling elements 26G are arranged between the outer circumference of the first portion 26A and the inner circumference of the second portion 26B. Preferably, the rolling elements 26G include a plurality of rolling elements 26G, which are arranged in the circumferential direction of the first portion 26A on the outer circumference of the first portion 26A. Preferably, the plurality of rolling elements 26G include a plurality of first rolling elements 26H arranged at one end of the switching member 26C in the axial direction of the crankshaft 34, and a plurality of second rolling elements 26J arranged at the other end of the switching member 26C in the axial direction of the crankshaft 34. That is, the switching member 26C is arranged between the plurality of first rolling elements 26H and the plurality of second rolling elements 26J in the axial direction of the crankshaft 34.

[0055] The solid line L11 in Figure 8 shows the transmission path of the driving force when the crank arm 22 rotates in the first direction B1, which is the direction in which the human-powered vehicle 10 moves forward. The dashed line L12 in Figure 8 shows the transmission path of the driving force of the motor 28 when the motor 28 rotates at least one front sprocket 24, rather than the rotation by the crank arm 22.

[0056] When the crank arm 22 rotates in the first direction B1, which is the direction in which the human-powered vehicle 10 moves forward, the switching member 26C engages with the engaging portion 26D, transmitting the rotation of the first portion 26A to the second portion 26B, which rotates at least one front sprocket 24. When the crank arm 22 rotates in the second direction B2, which is opposite to the first direction B1, relative rotation between the first portion 26A and the second portion 26B is permitted. For this reason, the rotation of the first portion 26A is not transmitted to the second portion 26B. When the motor 28 rotates the transmission portion 26F in the third direction B3, the second portion 26B rotates in the first direction B1.

[0057] When the crank arm 22 rotates in the first direction B1, and the speed R obtained by multiplying the rotational speed of the transmission unit 26F by the speed ratio N is less than the rotational speed of the crank arm 22, the first part 26A rotates the transmission unit 26F in the fourth direction B4, opposite to the third direction B3. The speed ratio N represents the ratio of the number of teeth of the multiple engaging parts 26D to the number of teeth of the transmission unit 26F. When the transmission unit 26F rotates in the third direction B3, and the speed R is greater than or equal to the rotational speed of the crank arm 22, the transmission unit 26F rotates the second part 26B through the external gear of the transmission unit 26F and the multiple engaging parts 26D, thereby rotating at least one front sprocket 24.

[0058] Preferably, the gear shifting system 20 further includes at least one of a wireless communication unit 44, a cadence sensor 42, an indicator 46, and a power meter 48. Preferably, the wireless communication unit 44 constitutes a wireless unit 44A. Preferably, at least one of the reduction mechanism 40, cadence sensor 42, wireless unit 44A, and indicator 46 is located inside the housing 38. If necessary, at least one of the cadence sensor 42, wireless unit 44A, and indicator 46 may be located outside the housing 38.

[0059] The cadence sensor 42 is configured to detect information corresponding to the rotational speed of the crankshaft 34. The cadence sensor 42 includes a magnetic sensor that outputs a signal corresponding to the strength of the magnetic field. An annular magnet M, whose magnetic field strength changes in the circumferential direction, is provided on the crankshaft 34, a member that rotates in conjunction with the crankshaft 34, or in the power transmission path between the crankshaft 34 and the front sprocket 24. The cadence sensor 42 outputs a signal corresponding to the rotational speed of the crankshaft 34. The cadence sensor 42 may include an optical sensor, an acceleration sensor, a gyro sensor, or a torque sensor instead of the magnetic sensor. The cadence sensor 42 is connected to the control unit 54 via a wireless communication device or an electrical cable.

[0060] The wireless communication unit 44 communicates wirelessly with external devices of the gear shifting system 20. The wireless communication unit 44 includes, for example, at least one of Bluetooth®, ANT+®, Wi-Fi®, and infrared communication. The external devices include, for example, at least one of a shifter for a human-powered vehicle, a cycle computer for a human-powered vehicle, a smartphone, and a personal computer.

[0061] The indicator 46 includes a display unit. The indicator 46 is provided in the housing 38 so that the user can see the display unit from outside the housing 38. The indicator 46 displays, for example, the remaining battery level of the battery 50 that supplies power to the motor 28. The display unit includes, for example, an LED (light-emitting diode). The display unit may change the color of the LED according to the remaining battery level, make the LED blink, or change the number of LEDs that light up.

[0062] The power meter 48 is configured to output a signal corresponding to the torque applied to the crank arm 22 by human power. The power meter 48 is installed, for example, upstream of the front clutch mechanism 26 in the human power transmission path. The power meter 48 includes a strain sensor, a magnetostrictive sensor, or a pressure sensor. The strain sensor includes a strain gauge. The power meter 48 is installed in the power transmission path, or in the vicinity of a component included in the power transmission path. Components included in the power transmission path are, for example, the crankshaft 34, a component that transmits human power between the crank arm 22 and the front sprocket 24, the crank arm 22, or the pedal 36. The power meter 48 is connected to the control unit 54 via a wireless communication device or an electrical cable. The power meter 48 can have any configuration as long as it can acquire information about human power, and may include, for example, a sensor that detects the pressure applied to the pedal 36, or a sensor that detects the tension of the chain 30.

[0063] Preferably, the gear shifting system 20 includes a battery 50. Preferably, the battery 50 includes a plurality of battery elements 50A. The battery elements 50A include rechargeable batteries. Preferably, the battery 50 supplies power to the motor 28. Preferably, the battery 50 supplies power to at least one of the wireless communication unit 44, cadence sensor 42, indicator 46, and power meter 48. Preferably, the battery 50 supplies power to all of the wireless communication unit 44, cadence sensor 42, indicator 46, and power meter 48. Preferably, the battery 50 is communicably connected to the control device 52 via an electrical cable or wireless communication device. The battery 50 can communicate with the control device 52 by, for example, power line communication (PLC), CAN (Controller Area Network), or UART (Universal Asynchronous Receiver / Transmitter).

[0064] Preferably, the crankshaft 34 has an internal space. Preferably, the battery 50 is located in the internal space of the crankshaft 34. For example, the battery 50 has a cylindrical shape. Preferably, the battery 50 is configured to rotate integrally with the member on which the motor 28 is provided, or is provided on the same member on which the motor 28 is provided. Preferably, the transmission system 20 further includes a charging port 51 for supplying power to the battery 50. The charging port 51 is provided, for example, on the crankshaft 34. The charging port 51 may be provided on the housing 38. The battery 50 may be configured to be connected to an external power source via the charging port 51, and power from the external power source may be supplied to the battery 50 via the charging port 51 through the control unit 54. The charging port 51 includes, for example, an electrical connector. Preferably, the battery 50, the control unit 54, and the charging port 51 are connected by wires.

[0065] Preferably, the transmission system 20 further includes a control device 52. The control device 52 includes a control unit 54. Preferably, at least a portion of the control device 52 is provided in the housing 38. Preferably, at least a portion of the control device 52 is provided inside the housing 38.

[0066] The control unit 54 includes an arithmetic processing unit that executes a predetermined control program. The arithmetic processing unit includes, for example, a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The arithmetic processing units may be located in multiple locations that are far apart from each other. The control unit 54 may include one or more microcomputers. Preferably, the control device 52 further includes a storage unit 56. The storage unit 56 stores various control programs and information used for various control processes. The storage unit 56 includes, for example, non-volatile memory and volatile memory. The non-volatile memory includes, for example, at least one of ROM (Read-Only Memory), EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), and flash memory. The volatile memory includes, for example, RAM (Random Access Memory).

[0067] The control device 52 preferably further comprises a drive circuit 58 for the motor 28. The drive circuit 58 and the control unit 54 may be provided on the same circuit board, for example. The drive circuit 58 includes an inverter circuit. The drive circuit 58 controls the power supplied from the battery 50 to the motor 28. The drive circuit 58 is connected to the control unit 54 by wire or wireless connection. The drive circuit 58 drives the motor 28 in response to control signals from the control unit 54.

[0068] The gear shifting system 20 further includes a derailleur 60. Preferably, the derailleur 60 is a rear derailleur. The derailleur 60 may be a front derailleur. The derailleur 60 may be operated by an electric actuator provided on the derailleur 60, or it may be connected by a cable to a shifter of the human-powered vehicle 10 and operate in accordance with the movement of the cable.

[0069] Preferably, the motor 28 is configured not to impart thrust to the human-powered vehicle 10. Preferably, the motor 28 rotates at least one front sprocket 24 at a rotational speed that does not impart thrust to the human-powered vehicle 10.

[0070] For example, the control unit 54 controls the motor 28 to rotate at least one front sprocket 24 at a rotational speed that does not impart propulsion to the human-powered vehicle 10. The control unit 54 controls the rotation of the motor 28 according to, for example, the rotational speed of the wheel 14. In this case, preferably the gear shifting system 20 includes a sensor for detecting the rotational speed of the wheel 14. The control unit 54 may also control the rotation of the motor 28 according to the load on the motor 28. In this case, preferably the gear shifting system 20 includes a sensor for detecting the load on the motor 28. The control unit 54 controls the motor 28 to rotate at least one front sprocket 24 at a rotational speed that does not impart propulsion to the human-powered vehicle 10 when, for example, the shifter is operated or a gear shifting condition is met. If the derailleur 60 is a cable-operated derailleur 60, preferably the gear shifting system 20 includes a shifter, a cable, and a gear shift detection unit for detecting at least one movement of the derailleur 60.

[0071] Referring to Figure 10, the process for controlling the motor 28 will be explained. When power is supplied to the control unit 54, it starts processing and moves to step S11 of the flowchart shown in Figure 10. When the flowchart in Figure 10 is completed, the control unit 54 repeats the process from step S11 at predetermined intervals until the power supply is stopped.

[0072] In step S11, the control unit 54 determines whether the rotation of the crank arm 22 is stopped or not. If the rotation of the crank arm 22 is not stopped, the process ends. If the rotation of the crank arm 22 is stopped, the control unit 54 proceeds to step S12.

[0073] In step S12, the control unit 54 determines whether or not to perform a gear change. For example, if the shifter is operated or if the gear change conditions are met, the control unit 54 determines to perform a gear change. If the control unit 54 does not perform a gear change, it terminates the process. If the control unit 54 decides to perform a gear change, it proceeds to step S13.

[0074] In step S13, the control unit 54 controls the motor 28 to rotate at least one front sprocket 24 at a rotational speed that does not impart thrust to the human-powered vehicle 10, and then terminates the process. In step S13, the control unit 54 may stop driving the motor 28 after a predetermined period of time has elapsed since the start of driving the motor 28, or it may stop driving the motor 28 in accordance with the output of a sensor that detects the state of the derailleur 60. The predetermined period is, for example, set to a period of time during which the derailleur 60 can fully complete its gear shifting operation. The predetermined period may be defined by the rotation angle of the front sprocket 24 or the rear sprocket 32, or it may be defined by time.

[0075] In the process shown in Figure 10, step S12 may be performed before step S11. In this case, when power is supplied to the control unit 54, it proceeds to step S12, and if the answer in step S12 is YES, it proceeds to step S11. If the answer in step S11 is YES, the control unit 54 proceeds to step S13. If the answer in step S12 is NO, and if the answer in step S11 is NO, the control unit 54 terminates the process.

[0076] In this embodiment, when the control unit 54 performs a gear change while the rotation of the crank arm 22 is stopped, the motor 28 rotates at least one front sprocket 24. Therefore, even when the rotation of the crank arm 22 is stopped, the derailleur 60 can perform a gear change.

[0077] Preferably, when the rotation of the crank arm 22 stops, the control unit 54 is configured to control the motor 28 so that the relative phase between the first part 26A and the second part 26B of the front clutch mechanism 26 becomes the first phase. Preferably, the first phase is the phase in which the switching member 26C engages with the engaging part 26D. Preferably, when the rotation of the crank arm 22 stops, if the relative phase between the first part 26A and the second part 26B is not the first phase, the control unit 54 is configured to control the motor 28 so that the relative phase between the first part 26A and the second part 26B becomes the first phase. When the rotation of the crank arm 22 is restarted by the control unit 54 controlling the motor 28 so that the switching member 26C engages with the engaging part 26D in the first phase, the rotation of the crank arm 22 and the crankshaft 34 is immediately transmitted to the engaging part 26D. Therefore, the rider is less likely to feel any discomfort.

[0078] Preferably, when the control unit 54 controls the motor 28 so that the relative phase between the first part 26A and the second part 26B of the front clutch mechanism 26 becomes the first phase, it is configured to control the motor 28 so that it rotates in the opposite direction to when rotational force is transmitted to at least one front sprocket 24. The control unit 54 may also control the motor 28 in accordance with the output of a position sensor that directly or indirectly detects the relative phase between the first part 26A and the second part 26B. The position sensor includes, for example, at least one of the following: a sensor provided on one of the first part 26A and the second part 26B that detects the rotational phase of the other part; a sensor that detects the rotational phase of the first part 26A and the second part 26B with respect to the respective frame 12; a sensor that detects the rotational phase of the motor 28; and a sensor that detects the load on the motor 28.

[0079] Preferably, a one-way clutch is not provided in the transmission path of the rotational force of the motor 28 from the motor 28 to the transmission unit 26F. A one-way clutch may be provided in the transmission path of the rotational force of the motor 28 from the motor 28 to the transmission unit 26F. The one-way clutch is configured to transmit rotation from the motor 28 to the transmission unit 26F, but not to transmit rotation from the transmission unit 26F to the motor 28. If a one-way clutch is not provided, when the crank arm 22 rotates in the first direction B1 in which the human-powered vehicle 10 moves forward, and the motor 28 is not driven, the transmission unit 26F revolves around the rotational axis C1 of the front sprocket 24 by the second part 26B, and the rotation of the crank arm 22 is not transmitted to the motor 28. If a one-way clutch is provided in the transmission path of the rotational force of the motor 28 from the motor 28 to the transmission unit 26F, the control unit 54 is not configured to control the motor 28 so that the relative phase between the first part 26A and the second part 26B of the front clutch mechanism 26 becomes the first phase.

[0080] Referring to Figure 11, the process for controlling the motor 28 when the rotation of the crank arm 22 stops will be described. When power is supplied to the control unit 54, it starts processing and moves to step S21 of the flowchart shown in Figure 11. When the flowchart in Figure 11 ends, the control unit 54 repeats the processing from step S21 at predetermined intervals until the power supply is stopped.

[0081] In step S21, the control unit 54 determines whether the rotation of the crank arm 22 has stopped. For example, the control unit 54 determines that the rotation of the crank arm 22 has stopped if the rotational speed of the crank arm 22 is less than or equal to a predetermined speed. The control unit 54 may also determine that the rotation of the crank arm 22 has stopped if the rotational speed of the crank arm 22 in the first direction B1 is less than or equal to a predetermined speed. The control unit 54 may also determine that the rotation of the crank arm 22 has stopped if the rotational speed of the crank arm 22 in the second direction B2 is less than or equal to a predetermined speed. Preferably, the control unit 54 determines that the rotation of the crank arm 22 has stopped if the rotational speed of the crank arm 22 in the first direction B1 or the rotational speed in the second direction B2 is less than or equal to a predetermined speed. If the rotation of the crank arm 22 has not stopped, the control unit 54 terminates the process. If the rotation of the crank arm 22 has stopped, the control unit 54 proceeds to step S22.

[0082] In step S22, the control unit 54 determines whether the relative phase between the first part 26A and the second part 26B is the first phase. If the relative phase between the first part 26A and the second part 26B is the first phase, the control unit 54 terminates the process. If the relative phase between the first part 26A and the second part 26B is not the first phase, the control unit 54 proceeds to step S23.

[0083] In step S23, the control unit 54 controls the motor 28 so that the relative phase between the first part 26A and the second part 26B becomes the first phase, and then terminates the process. For example, if the output of the position sensor becomes an output corresponding to the first phase when the relative phase between the first part 26A and the second part 26B becomes the first phase, the control unit 54 stops driving the motor 28.

[0084] Preferably, in step S23, the control unit 54 controls the motor 28 to apply a force to the transmission unit 26F in a direction that rotates the transmission unit 26F in the fourth direction B4. The control unit 54 may also control the motor 28 to achieve a predetermined output. The predetermined output is an output that prevents the switching member 26C from rotating further in the fourth direction B4 from the state in which it is engaged with the engagement unit 26D, and thus cannot overcome the wall portion of the engagement unit 26D. The control unit 54 may be configured to control the motor 28 to achieve a predetermined output for a predetermined period of time, for example. If the control unit 54 is configured to control the motor 28 to achieve a predetermined output for a predetermined period of time, the control unit 54 does not need to detect the relative phase of the first and second parts. In this case, the control unit 54 may be configured to control the motor 28 to achieve a predetermined output for a predetermined period of time when the rotation of the crank arm 22 stops. In this case, the processing in step S22 of Figure 11 may be omitted. If the control unit 54 makes an affirmative determination in step S21, it proceeds to step S23.

[0085] When the crank arm 22 starts rotating in the first direction B1 from a state where its rotation has stopped, at least one front sprocket 24 will not rotate until the relative phase between the first part 26A and the second part 26B of the front clutch mechanism 26 becomes the first phase. When the rotation of the crank arm 22 stops, the control unit 54 controls the motor 28 so that the relative phase between the first part 26A and the second part 26B of the front clutch mechanism 26 becomes the first phase, so that when the rotation of the crank arm 22 starts in the first direction B1, at least one front sprocket 24 can rotate immediately.

[0086] The control unit 54 may continue driving the motor 28 such that the relative phase between the first part 26A and the second part 26B becomes the first phase, for a period of time when the rotational speed of the crank arm 22 in the first direction B1 is within a predetermined range. The predetermined range includes 0 rpm.

[0087] <Second Embodiment> Referring to Figures 12 to 14, the second embodiment of the human-powered vehicle transmission system 20A will be described. The second embodiment of the human-powered vehicle transmission system 20A is the same as the first embodiment of the human-powered vehicle transmission system 20, except that the part in which the motor 68 is located and the member to which the motor 68 is connected are different. Therefore, components common to the first embodiment are denoted by the same reference numerals as in the first embodiment, and redundant explanations are omitted.

[0088] The transmission system 20A of the second embodiment includes a crank arm 62, at least one front sprocket 64, and a front clutch mechanism 66. Preferably, the crank arm 62 has the same configuration as the crank arm 22, except that it does not have a motor mounting portion 22A. Preferably, at least one front sprocket 64 is configured similarly to the front sprocket 24, except that a front clutch mechanism 66 is provided instead of the front clutch mechanism 26. Preferably, the transmission system 20A includes a motor 68, a base portion 70, a movable portion 72, and a chain guide mechanism 74. Preferably, the transmission system 20A further includes a chain 30, a rear sprocket 32, and a crankshaft 34. The crank arm 62 is configured to be attachable to the human-powered vehicle 10. The crank arm 62 is attached to each of the ends of the crankshaft 34. Preferably, the crank arm 62 is rotatable integrally with the crankshaft 34. A pedal 36 is attached to the end of the crank arm 62. The crank axle 34 transmits rotational force to at least one front sprocket 64. For example, the gear shifting system 20A has one front sprocket 64. If the gear shifting system 20A has a front derailleur, preferably the gear shifting system 20A has multiple front sprockets 64.

[0089] At least one front sprocket 64 includes multiple sprocket teeth that engage with a chain 30 for a human-powered vehicle. A motor 68 includes an output shaft 68A that imparts rotational force to at least one front sprocket 64.

[0090] The base portion 70 is attached to the frame 12 of the human-powered vehicle 10. The movable portion 72 is attached to the base portion 70 so as to be movable relative to the base portion 70. The base portion 70, the movable portion 72, and the chain guide mechanism 74 constitute a derailleur. The movable portion 72 of the derailleur may include a linkage mechanism. The base portion 70, the movable portion 72, and the chain guide mechanism 74 constitute a rear derailleur. The base portion 70, the movable portion 72, and the chain guide mechanism 74 may constitute a front derailleur. The derailleur may be operated by an electric actuator, or it may be connected by a cable to the shifter of the human-powered vehicle and operate in accordance with the movement of the cable. The chain guide mechanism 74 is pivotably attached to the movable portion 72. The chain guide mechanism 74 includes at least one pulley 76 connected to the output shaft 68A of the motor 68. The motor 68 applies rotational force to at least one front sprocket 24 via at least one pulley 76. In this embodiment, the motor 68 applies rotational force to at least one front sprocket 24 via at least one pulley 76 and a human-powered vehicle chain 30. Preferably, at least one pulley 76 includes a tension pulley 76A and a guide pulley 76B. Preferably, at least one pulley 76 transmits rotational force to the front sprocket 24 via the chain 30. Preferably, the output shaft 68A of the motor 68 is connected to the guide pulley 76B but not to the tension pulley 76A.

[0091] The output shaft 68A of the motor 68 extends in the output axial direction A1. In the first example, the output axial direction A1 is parallel to the axial direction A2 with respect to the rotational axis of the front sprocket 64. Preferably, the axial direction with respect to the rotational axis of the front sprocket 64 is parallel to the rotational axis of the front sprocket 64. For example, when the chain guide mechanism 74 is in a predetermined position, the output axial direction A1 is parallel to the axial direction A2 with respect to the rotational axis of the front sprocket 64. The predetermined position is, for example, the position of the chain guide mechanism 74 where the central axis of at least one pulley 76 is parallel to the rotational axis of the front sprocket 64. In the first example, preferably, the output axial direction A1 is parallel to the axial direction with respect to the rotational axis of at least one pulley 76.

[0092] In the second example, the output axial direction A1 extends non-parallel to the axial direction A2 with respect to the rotational axis of the front sprocket 64. Preferably, the output axial direction A1 extends in a direction that includes a direction perpendicular to the axial direction A2 with respect to the rotational axis of the front sprocket 64. For example, when the chain guide mechanism 74 is in a predetermined position, the output axial direction A1 extends non-parallel to the axial direction A2 with respect to the rotational axis of the front sprocket 64. The predetermined position is, for example, the position of the chain guide mechanism 74 where the central axis of at least one pulley 76 is parallel to the rotational axis of the front sprocket 64. In the second example, preferably, the output axial direction A1 is non-parallel to the axial direction with respect to the rotational axis of at least one pulley 76.

[0093] The maximum length of the motor 68 in the output axial direction A1 is smaller than the diameter of the front sprocket 64. If at least one front sprocket 64 includes multiple front sprockets 64, preferably the maximum length of the motor 68 in the output axial direction A1 is smaller than the diameter of all the front sprockets 24.

[0094] Preferably, the speed change system 20A further comprises a reduction mechanism 78. The reduction mechanism 78 connects the output shaft 68A of the motor 68 to at least one pulley 76. The reduction mechanism 78 reduces the rotation of the motor 68 and transmits it to at least one pulley 76. The reduction mechanism 78 may include a plurality of gears, and may include pulleys and a belt. Preferably, if the output axial direction A1 extends non-parallel to the axial direction with respect to the rotational axis of at least one pulley 76, the reduction mechanism 78 includes at least one bevel gear and a worm gear.

[0095] The front clutch mechanism 66 allows at least one front sprocket 64 to rotate integrally or relative to the crank arm 62. The front clutch mechanism 66 is provided, for example, between the crankshaft 34 and the front sprocket 64. The front clutch mechanism 66 is, for example, a one-way clutch. The one-way clutch may be a claw-type clutch or a roller clutch.

[0096] When the crank arm 62 rotates in the first direction B1, the rotation of the crankshaft 34 rotates the front sprocket 64 via the front clutch mechanism 66. When the crank arm 62 rotates in the second direction B2, the rotation of the crankshaft 34 is not transmitted to the front sprocket 24 via the front clutch mechanism 66.

[0097] The motor 68 is configured to rotate at least one pulley 76 in a direction corresponding to when the crank arm 62 rotates in the first direction B1. Preferably, a one-way clutch is provided in the transmission path of the rotational force of the motor 68 from the motor 68 to at least one pulley 76. The one-way clutch is configured to transmit the rotation of the motor 68 to at least one pulley 76, but not to transmit the rotation of at least one pulley 76 to the motor 68.

[0098] When at least one pulley 76 rotates the crank arm 62 in a direction corresponding to the first direction B1 by the motor 68, at least one pulley 76 drives the chain 30 and rotates the rear sprocket 32. The drive of the chain 30 is transmitted to the front sprocket 64 but not to the crankshaft 34 by the front clutch mechanism 66. In this embodiment, the front clutch mechanism 66 may be omitted.

[0099] Preferably, the gear shifting system 20A further includes at least one of a wireless communication unit 44, a cadence sensor 42, an indicator 46, and a power meter 48. Preferably, the gear shifting system 20A further includes a battery 50. Preferably, the gear shifting system 20A further includes a charging port 51 for supplying power to the battery 50. Preferably, the gear shifting system 20A further includes a control device 52. The battery 50 is provided, for example, in a housing in which a motor 68 is provided. The charging port 51 is provided in a housing in which a motor 68 is provided. In this embodiment, the battery 50 and the charging port 51 are located on the movable part 72, but the present invention is not limited thereto. At least one of the battery 50 and the charging port 51 may be located on the base part 70, if necessary.

[0100] Preferably, the motor 68 is configured not to impart thrust to the human-powered vehicle 10. Preferably, the motor 68 rotates at least one front sprocket 64 at a rotational speed that does not impart thrust to the human-powered vehicle 10.

[0101] The solid line L21 in Figure 14 shows the transmission path of the driving force when the crank arm 62 rotates in the first direction B1, which is the direction in which the human-powered vehicle 10 moves forward. The dashed line L22 in Figure 14 shows the transmission path of the driving force of the motor 68 when the rotation of the crank arm 62 stops and the motor 68 is driven. In the dashed line L22, the rotation of the motor 68 is transmitted to at least one pulley 76 via the reduction mechanism 78. The rotation of at least one pulley 76 rotates the chain 30 in the direction corresponding to the first direction B1, and rotates the front sprocket 64 in the first direction B1. As a result, the chain 30 pulls the rear sprocket 32 ​​in the direction corresponding to the first direction B1, and the rear sprocket 32 ​​rotates in the direction corresponding to the first direction B1. The rotation of the front sprocket 64 in the first direction B1 is not transmitted to the crankshaft 34 by the front clutch mechanism 66.

[0102] For example, the control unit 54 controls the motor 68 to rotate at least one front sprocket 64 at a rotational speed that does not impart propulsion to the human-powered vehicle 10. The control unit 54 controls the rotation of the motor 68 according to, for example, the rotational speed of the wheel 14. In this case, preferably the gear shifting system 20A includes a sensor for detecting the rotational speed of the wheel 14. The control unit 54 may also control the rotation of the motor 68 according to the load on the motor 68. In this case, preferably the gear shifting system 20A includes a sensor for detecting the load on the motor 68. The control unit 54 controls the motor 68 to rotate at least one front sprocket 64 at a rotational speed that does not impart propulsion to the human-powered vehicle 10 when, for example, the shifter is operated or a gear shifting condition is met. If the derailleur 60 is a cable-operated derailleur 60, preferably the gear shifting system 20A includes a gear shifting detection unit that detects the movement of the shifter, the cable, and at least one movement of the derailleur 60. The control unit 54 controls the motor 68 by a process similar to the process shown in Figure 10 of the first embodiment.

[0103] <Third Embodiment> Referring to Figures 15 to 17, the third embodiment of the human-powered vehicle transmission system 20B will be described. The third embodiment of the human-powered vehicle transmission system 20B is the same as the second embodiment of the human-powered vehicle transmission system 20A, except that the part in which the motor 80 is located and the member to which the motor 80 is connected are different. Therefore, components common to the first embodiment are denoted by the same reference numerals as in the second embodiment, and redundant explanations are omitted.

[0104] The third embodiment of the gear shifting system 20B comprises a motor 80, a bracket member 82, and a rotational force transmission member 84. Preferably, the gear shifting system 20B further comprises a crank arm 62, at least one front sprocket 64, and a front clutch mechanism 66. Preferably, the gear shifting system 20B further comprises a chain 30, a rear sprocket 32, and a crank shaft 34. Preferably, the gear shifting system 20B further comprises a derailleur 60.

[0105] The motor 80 includes an output shaft 80A. The motor 80 imparts rotational force to at least one front sprocket 64. The rotational force transmission member 84 is connected to the output shaft 80A of the motor 80.

[0106] The output shaft 80A of the motor 80 extends in the output axial direction A1. In the first example, the output axial direction A1 is parallel to the axial direction A2 with respect to the rotational axis of the front sprocket 64. In the second example, the output axial direction A1 extends non-parallel to the axial direction A2 with respect to the rotational axis of the front sprocket 64. Preferably, the maximum length of the motor 80 in the output axial direction A1 is smaller than the diameter of the front sprocket 64. If at least one front sprocket 64 includes multiple front sprockets 64, preferably, the maximum length of the motor 80 in the output axial direction A1 is smaller than the diameter of all the front sprockets 64 combined.

[0107] Preferably, the rotational force transmission member 84 transmits rotational force to the front sprocket 24 via the chain 30 for the human-powered vehicle. Preferably, the rotational force transmission member 84 includes a plurality of rotational force transmission teeth 84A that can engage with the chain 30. Preferably, the rotational force transmission member 84 is connected to the output shaft 80A of the motor 80 via a reduction mechanism 86. The reduction mechanism 86 reduces the rotation of the motor 80 and transmits it to the chain 30. The reduction mechanism 86 may include a plurality of gears, and may include pulleys and a belt.

[0108] The motor 80 is configured to rotate the front sprocket 64 in a direction corresponding to the rotation of the crank arm 62 in the first direction B1. Preferably, a one-way clutch is provided in the transmission path of the rotational force of the motor 80 to the front sprocket 64. The one-way clutch is configured to transmit the rotation of the motor 80 in the direction corresponding to the first direction B1 to the front sprocket 64, but not to transmit the rotation of the front sprocket 64 in the direction corresponding to the first direction B1 to the motor 80.

[0109] When the front sprocket 64 rotates in a direction corresponding to the first direction B1 when the crank arm 62 is rotated by the motor 80, the rotational force transmission member 84 drives the front sprocket 64 and the chain 30, causing the rear sprocket 32 ​​to rotate. When shifting gears by driving the chain while not pedaling, the drive of the chain 30 is transmitted to the front sprocket 64, but not to the crank shaft 34 by the front clutch mechanism 66.

[0110] Preferably, the gear shifting system 20B further includes at least one of a wireless communication unit 44, a cadence sensor 42, an indicator 46, and a power meter 48. Preferably, the gear shifting system 20B further includes a battery 50. Preferably, the gear shifting system 20B further includes a charging port 51 for supplying power to the battery 50. Preferably, the gear shifting system 20B further includes a control device 52. The battery 50 is provided, for example, on a bracket member 82. The charging port 51 is preferably provided on the bracket member 82.

[0111] Preferably, the motor 80 is configured not to impart thrust to the human-powered vehicle 10. Preferably, the motor 80 rotates at least one front sprocket 64 at a rotational speed that does not impart thrust to the human-powered vehicle 10.

[0112] The solid line L31 in Figure 17 shows the transmission path of the driving force when the crank arm 62 rotates in the first direction B1, which is the direction in which the human-powered vehicle 10 moves forward. The dashed line L32 in Figure 17 shows the transmission path of the driving force of the motor 80 when the rotation of the crank arm 62 stops and the motor 80 is driven. In the dashed line L32, the rotation of the motor 80 rotates the chain 30 in a direction corresponding to the first direction B1 via the reduction mechanism 86, and rotates the front sprocket 64 in the first direction B1. As a result, the chain 30 pulls the rear sprocket 32 ​​in the direction corresponding to the first direction B1, and the rear sprocket 32 ​​rotates in the direction corresponding to the first direction B1. The rotation of the front sprocket 64 in the first direction B1 is not transmitted to the crankshaft 34 by the front clutch mechanism 66.

[0113] For example, the control unit 54 controls the motor 80 to rotate at least one front sprocket 64 at a rotational speed that does not impart thrust to the human-powered vehicle 10. The control unit 54 controls the rotation of the motor 80 according to, for example, the rotational speed of the wheel 14. In this case, preferably the gear shifting system 20B includes a sensor for detecting the rotational speed of the wheel 14. The control unit 54 may also control the rotation of the motor 80 according to the load on the motor 80. In this case, preferably the gear shifting system 20B includes a sensor for detecting the load on the motor 80. The control unit 54 controls the motor 80 to rotate at least one front sprocket 64 at a rotational speed that does not impart thrust to the human-powered vehicle 10 when, for example, the shifter is operated or a gear shifting condition is met. If the derailleur 60 is a cable-operated derailleur 60, preferably the gear shifting system 20B includes a gear shifting detection unit that detects the movement of the shifter, the cable, and at least one movement of the derailleur 60. The control unit 54 controls the motor 80 by a process similar to the process shown in Figure 10 of the first embodiment, for example.

[0114] The bracket member 82 includes a cover portion 82A that overlaps with the sprocket teeth 64A of at least one front sprocket 64 in the radial direction with respect to the rotational axis of at least one front sprocket 64. The bracket member 82 has a motor housing portion 82B for housing a motor 80. Preferably, the bracket member 82 includes a fixing portion 82C that can be fixed to a bracket hanger portion 12A of a human-powered vehicle frame 12. The fixing portion 82C has, for example, an annular shape. The crankshaft 34 is inserted into the annular shape of the fixing portion 82C. For example, the bracket member 82 is fixed to the bracket hanger portion 12A of the frame 12 by inserting bolts into a plurality of holes provided in the inner circumference of the annular shape of the fixing portion 82C. Preferably, the bracket member 82 is positioned between the bracket hanger portion 12A and at least one front sprocket 64 in the axial direction of the crankshaft 34.

[0115] <Fourth Embodiment> Referring to Figures 18 and 19, the fourth embodiment of the human-powered vehicle transmission system 20C will be described. The fourth embodiment of the human-powered vehicle transmission system 20C is the same as the third embodiment of the human-powered vehicle transmission system 20B, except for the configuration of the bracket member 88. Therefore, components common to the first embodiment are denoted by the same reference numerals as in the third embodiment, and redundant explanations are omitted.

[0116] The fourth embodiment of the gear shifting system 20C comprises a bracket member 88, a motor 80, and a rotational force transmission member 84. Preferably, the gear shifting system 20C further comprises a crank arm 62, at least one front sprocket 64, and a front clutch mechanism 66. Preferably, the gear shifting system 20C further comprises a chain 30, a rear sprocket 32, and a crank shaft 34. Preferably, the gear shifting system 20C further comprises a derailleur 60.

[0117] The bracket member 88 is attached to at least one of the seat tube 12D, seat stay 13C, and chain stay 12E for a human-powered vehicle. The bracket member 88 has a motor housing 88A for housing a motor 80. For example, as shown in Figure 19, the bracket member 88 is attached to the seat tube 12D. The bracket member 88 includes a first clamp member 88B, a second clamp member 88C, and a fastening member 88D. The second clamp member 88C is pivotably attached to the first clamp member 88B. The fastening member 88D secures the first clamp member 88B and the second clamp member 88C with the seat tube 12D sandwiched between them. The fastening member 88D includes, for example, a bolt and a nut.

[0118] As shown in Figure 20, the bracket member 88 may include a bracket body 88E and a fastening member 88F. For example, the bracket body 88E has a first mounting portion 88G. The fastening member 88F is inserted through the first mounting portion 88G of the bracket body 88E and fixed to a second mounting portion 12G formed on the seat tube 12D. For example, the fastening member 88F includes a bolt, the first mounting portion 88G includes a hole, and the second mounting portion 12G includes a female threaded portion.

[0119] Preferably, the gear shifting system 20C further includes at least one of a wireless communication unit 44, a cadence sensor 42, an indicator 46, and a power meter 48. Preferably, the gear shifting system 20C further includes a battery 50. Preferably, the gear shifting system 20C further includes a charging port 51 for supplying power to the battery 50. Preferably, the gear shifting system 20C further includes a control device 52. The battery 50 is provided, for example, on a bracket member 88. The charging port 51 is preferably provided on the bracket member 88.

[0120] <Variation> The description of embodiments is illustrative of possible forms of a human-powered vehicle transmission system according to this disclosure, and is not intended to limit such forms. A human-powered vehicle transmission system according to this disclosure may take the form of, for example, a modification of the embodiments shown below, and a combination of at least two non-inconsistent modifications. In the following modifications, parts common to the embodiments are denoted by the same reference numerals as in the embodiments and their descriptions are omitted.

[0121] In the second embodiment, the motor 68 may be provided on the base portion 70, the movable portion 72, the link mechanism, or the chain guide mechanism 74. The motor 68 may also be provided on the tension pulley 76A.

[0122] As shown in Figure 21, the housing 38 of the first embodiment can also be provided on the bracket member 82 of the third embodiment. For example, the transmission system 20 includes a motor 28, a bracket member 82, and a rotational force transmission member 100. The rotational force transmission member 100 is connected to the output shaft 28A of the motor 28. In this case, the rotational force transmission member 100 is configured to transmit rotational force to the front sprocket 24 without going through the chain 30 for the human-powered vehicle. In this case, the rotational force transmission member 100 is the transmission section 26F.

[0123] As shown in Figure 22, the gear shift systems 20, 20A, 20B, and 20C of each embodiment may include a wireless power receiving unit 90 that wirelessly receives power from a battery 50 and supplies power to motors 28, 68, and 80. The wireless power receiving unit 90 receives power from an external wireless power transmission device 92, for example, by electromagnetic induction. The wireless power receiving unit 90 may be connected to a control unit 54, for example, and supply power to the battery 50 via the control unit 54. In this case, the gear shift systems 20, 20A, 20B, and 20C can be suitably used by including at least a crankshaft 34, crank arms 22 and 62, at least one front sprocket 24 or 64, a front clutch mechanism 26 or 66, motors 28, 68, and 80, and a wireless power receiving unit 90.

[0124] In each embodiment, at least one of the motors 28, 68, 80 and the battery 50 is provided on a rotating member, and the member on which one of the motors 28, 68, 80 and the battery 50 is provided may be configured to rotate relative to the member on which the other of the motors 28, 68, 80 and the battery 50 is provided. In the first and second embodiments, for example, the battery 50 is provided on the frame 12, and in the third and fourth embodiments, for example, the battery 50 is provided on the crankshaft 34. In this case, for example, as shown in Figure 23, the gear shift systems 20, 20A, 20B, 20C include a power supply unit 94. The power supply unit 94 includes a first power supply section 96 and a second power supply section 98 that rotates relative to the first power supply section 96. The first power supply section 96 supplies power from the battery 50 to the second power supply section 98. The second energizing unit 98 supplies power to the motors 28, 68, and 80 from the first energizing unit 96. The energizing unit 94 includes, for example, a slip ring. In this case, the transmission systems 20, 20A, 20B, and 20C can be suitably used by comprising at least a crankshaft 34, crank arms 22 and 62, at least one front sprocket 24 and 64, a front clutch mechanism 26 and 66, motors 28, 68, and 80, and the energizing unit 94.

[0125] As shown in Figure 24, in the third embodiment, the rotational force transmission member 84 connected to the output shaft 80A of the motor 80 may be positioned on the pivot axis 12F. In this case, the transmission system 20B can be suitably used by comprising at least a frame 12 having a first frame member 12B and a second frame member 12C, a crank arm 62, at least one front sprocket 64, a front clutch mechanism 66, a motor 80, and an energizing unit 94.

[0126] The front clutch mechanism 26 of the first embodiment may include a roller clutch or a scrub clutch.

[0127] The gear shifting systems 20, 20A, 20B, and 20C may include a hub for a human-powered vehicle, which includes at least one rear sprocket 32 ​​having a plurality of sprocket teeth that engage with a chain 30, a sprocket mounting member to which at least one rear sprocket 32 ​​is attached, a hub body that rotates integrally with a rim for a human-powered vehicle, and a rear clutch mechanism that allows at least one rear sprocket 32 ​​to rotate integrally or relative to the hub body. Preferably, the hub for a human-powered vehicle includes an actuator that switches between a state in which the hub body and at least one rear sprocket rotate integrally and a state in which the hub body and at least one rear sprocket rotate relative to each other.

[0128] As used herein, the expression "at least one" means "one or more" of the desired options. For example, as used herein, "at least one" means "only one option" or "both of the two options" if there are two options. As another example, as used herein, "at least one" means "only one option" or "a combination of two or more any options" if there are three or more options. [Explanation of Symbols]

[0129] 10...Human-powered vehicle, 12...Frame for human-powered vehicle, 12A...Bracket hanger section, 12B...First frame member, 12C...Second frame member, 12D...Seat tube, 12E...Chain stay, 12F...Oscillating axis, 12G...Second mounting section, 13C...Seat stay, 20,20A,20B,20C...Shifting system, 22,62...Crank arm, 22A...Motor placement section, 24,64...Front sprocket, 24A,64A...Sprocket teeth, 26,66...Front clutch mechanism, 26A...First part, 26B...Second part, 26C...Switching member, 28,68,80...Motor, 28A,68A,80A...Output shaft, 30...Chain for human-powered vehicle, 34...Crank shaft, 38...Housing, 40,78,86...Reduction mechanism, 42...K Dense sensor, 44... Wireless communication unit, 44A... Wireless unit, 46... Indicator, 48... Power meter, 50... Battery, 50A... Battery element, 51... Charging port, 70... Base part, 72... Movable part, 74... Chain guide mechanism, 76... Pulley, 76A... Tension pulley, 76B... Guide pulley, 82... Bracket member, 82A... Cover part, 82B... Motor housing part, 82C... Fixed part, 84... Rotational force transmission member, 88... Bracket member, 88A... Motor housing part, 88B... First clamp member, 88C... Second clamp member, 88D... Fastening member, 88E... Bracket body, 88F... Fastening member, 88G... First mounting part, 90... Wireless power receiving unit, 94... Power supply unit, 96... First power supply part, 98... Second power supply part, 100... Rotational force transmission member.

Claims

1. A transmission system for human-powered vehicles, The base part, Movable parts and A chain guide mechanism is rotatably attached to the aforementioned movable part, A motor including an output shaft, The chain guide mechanism includes at least one pulley connected to the output shaft of the motor, The at least one pulley is configured to drive a chain for a human-powered vehicle when rotated in the corresponding direction by the motor. A gear shifting system in which the corresponding direction is the direction in which the crank arm of the human-powered vehicle rotates in the first direction in which the human-powered vehicle moves forward.

2. The gear shifting system according to claim 1, wherein the base portion, the movable portion, and the chain guide mechanism constitute a rear derailleur.

3. With an additional rear sprocket, The gear shifting system according to claim 2, wherein, in the axial direction with respect to the rotational axis of the rear sprocket, the motor is located closer to the rear sprocket than a part of the movable part.

4. The speed change system according to any one of claims 1 to 3, wherein the at least one pulley includes a tension pulley and a guide pulley.

5. The speed control system according to claim 4, wherein the output shaft of the motor is connected to the guide pulley but not to the tension pulley.

6. The speed change system according to claim 5, wherein the motor is arranged such that, in the radial direction of the guide pulley, the output shaft of the motor is located inside the outer circumference of the guide pulley.

7. The speed change system according to claim 4, wherein the motor is provided in any of the base portion, the movable portion, the chain guide mechanism, and the tension pulley.

8. The output shaft of the motor extends in the direction of the output shaft, The speed change system according to any one of claims 1 to 7, wherein the output axial direction is parallel to the axial direction with respect to the rotational axis of the at least one pulley.

9. The output shaft of the motor extends in the direction of the output shaft, The speed change system according to any one of claims 1 to 7, wherein the output axial direction extends non-parallel to the axial direction with respect to the rotational axis of the at least one pulley.

10. A one-way clutch is provided in the transmission path of the rotational force of the motor from the motor to the at least one pulley. The gear shifting system according to any one of claims 1 to 9, wherein the one-way clutch is configured to transmit the rotation of the motor to the at least one pulley and not to transmit the rotation of the at least one pulley to the motor.

11. The speed change system according to any one of claims 1 to 10, further comprising a housing in which the motor is arranged.

12. The gear shift system according to any one of claims 1 to 11, further comprising a battery that supplies power to the motor.

13. A gear shifting system according to any one of claims 1 to 12, further comprising at least one of a wireless communication unit, a cadence sensor, an indicator, and a power meter.

14. The speed change system according to any one of claims 1 to 13, further comprising a reduction mechanism for connecting the output shaft of the motor to the at least one pulley.

15. The transmission system according to claim 12, further comprising a charging port for supplying power to the battery.

16. The transmission system according to claim 15, wherein the battery and the charging port are arranged in the movable part or the base part.

17. The transmission system according to any one of claims 1 to 16, wherein the motor is configured not to impart propulsion to the human-powered vehicle.

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