DRIVE UNIT OF A HUMAN-PROPELLED VEHICLE

Abstract

A propulsion unit of a human-powered vehicle (10), comprising: an electric motor (12) configured to assist the propulsion of a human-powered vehicle; a crankshaft (14); an output section (16) coupled to the crankshaft (14), wherein the output section (16) is configured to rotate in the first direction of rotation in a case where the crankshaft (14) rotates in a first direction of rotation, and the output section (16) is configured to rotate in the second direction of rotation in a case where the crankshaft (14) rotates in a second direction of rotation; a reduction mechanism (18) configured to reduce the speed of the electric motor (12) in several steps; a coupling mechanism (20) provided between the output section (16) and the reduction mechanism (18), wherein the coupling mechanism (20) is configured to transmit a rotational force of the electric motor (12) from the reduction mechanism (18) to the output section (16); a housing (28) configured to accommodate at least part of the crankshaft (14), wherein, viewed in the axial direction of the crankshaft (14), a shortest distance (L4) on a plane which includes an axis of rotation (C1) of the crankshaft (14) and an axis of rotation (C2) of the electric motor (12) is located between the axis of rotation (C1) of the crankshaft (14) and an outer surface of the housing (28) is less than or equal to 70 mm; and a detector (62) which is provided on a transmission path of the human driving force between the crankshaft (14) and a part of the output section (16) which is coupled to the clutch mechanism (20), wherein the detector (62) is configured to detect the human driving force, wherein the detector (62) includes a torque sensor which is used to detect the torque of the human driving force and the torque sensor includes a strain sensor (62A) which is provided on an outer circumferential surface of the output section (16), wherein the detector (62) is connected to a first circuit board (64) via a flexible circuit board, wherein a first signal processing circuit, which processes a signal output of the detector (62), and a first antenna, which is connected to the first signal processing circuit, are provided on the first printed circuit board (64), and wherein a second printed circuit board (66) is provided in the cavity (S) of the housing (28) to be oriented towards the first printed circuit board (64) in the first axis of rotation (C1) and spaced apart from the first printed circuit board (64), and wherein a second antenna is provided on the second circuit board (66) which faces the first antenna, and a second signal processing circuit which processes a signal received from the second antenna, and a power supply circuit which supplies the first antenna with electrical energy are provided on the second circuit board (66).

Description

[0001] The present invention relates to a drive unit of a human-powered vehicle.

[0002] An example of a propulsion unit for a human-powered vehicle, incorporating an electric motor to assist the propulsion of the human-powered vehicle, is disclosed in JP 4 906 982 B1. The human power input into the crankshaft and the torque of the electric motor are fed into an output section. The electric motor is configured to transmit the torque to the output section via a reduction mechanism.

[0003] In the drive unit of a human-powered vehicle disclosed in JP 4 906 982 B1, human driving force is transferred to the reduction mechanism and the electric motor even when the electric motor is deactivated. This increases the loss of human driving force due to the rotational resistance of the reduction mechanism and the electric motor.

[0004] Further exemplary drive units of a human-powered vehicle, which include an electric motor that assists the propulsion of a human-powered vehicle, are known from DE 10 2014 110 707 A1, EP 2 783 972 A1, EP 3 153 393 A1 and JP 5 202 769 B1.

[0005] One objective of the present invention is to provide a drive unit for a human-powered vehicle which reduces the loss of human driving power.

[0006] A drive unit of a human-powered vehicle according to a first aspect of the present invention comprises an electric motor configured to assist the propulsion of a human-powered vehicle, a crankshaft, an output section coupled to the crankshaft, a reduction mechanism configured to reduce the rotational speed of the electric motor in several steps, and a clutch mechanism provided between the output section and the reduction mechanism. The output section is configured to rotate in the first direction of rotation when the crankshaft rotates in a first direction. The output section is configured to rotate in the second direction of rotation when the crankshaft rotates in a second direction.The clutch mechanism is configured to transmit the electric motor's torque from the reduction mechanism to the output section. In the drive unit of a human-powered vehicle, as described in the first aspect, the clutch mechanism is located between the output section and the reduction mechanism. Thus, when the electric motor is deactivated, no human power is transmitted from the output section to the electric motor. This reduces the loss of human power. Additionally, when the crankshaft is rotating in either direction, the rotation of the crankshaft is transmitted to the output section.

[0007] The drive unit of a human-powered vehicle further comprises a housing configured to accommodate at least part of the crankshaft. Viewed in the axial direction of the crankshaft, the shortest distance between a crankshaft axis of rotation and an outer surface of the housing is less than or equal to 70 mm in a plane that includes the crankshaft axis of rotation and an electric motor axis of rotation.

[0008] The drive unit of a human-powered vehicle further includes a detector located on the transmission path of the human propulsion force between the crankshaft and a portion of the output section coupled to the clutch mechanism. The detector is configured to detect the human propulsion force.

[0009] The detector includes a torque sensor. The torque sensor is used to detect the torque of the human driving force. The torque sensor includes a strain sensor. The strain sensor is located on an outer circumferential surface of the output section. The detector is connected to a primary circuit board via a flexible circuit board.

[0010] A first signal processing circuit, which processes a signal output from the detector, and a first antenna, which is connected to the first signal processing circuit, are provided on the first circuit board.

[0011] A second circuit board is provided within the housing cavity, oriented towards the first circuit board along the first axis of rotation and spaced apart from it. A second antenna is provided on the second circuit board and oriented towards the first antenna.

[0012] A second signal processing circuit, which processes a signal received from the second antenna, and a power supply circuit, which supplies the first antenna with electrical energy, are provided on the second circuit board.

[0013] According to a second aspect of the present invention, the drive unit of a human-powered vehicle according to the first aspect is configured such that the reduction mechanism includes a first gear provided on an output shaft of the electric motor and a second gear that engages with the first gear. In the drive unit of a human-powered vehicle according to the second aspect, the first gear and the second gear simplify the construction of the reduction mechanism.

[0014] A drive unit of a human-powered vehicle according to a third aspect of the present invention comprises an electric motor configured to assist the propulsion of a human-powered vehicle, a crankshaft, an output section coupled to the crankshaft, a reduction mechanism configured to reduce the rotational speed of the electric motor in several steps, and a clutch mechanism provided between the output section and the reduction mechanism. The clutch mechanism is configured to transmit a rotational force from the electric motor from the reduction mechanism to the output section. The reduction mechanism includes a first gear provided on an output shaft of the electric motor and a second gear that engages with the first gear.In the drive unit of a human-powered vehicle, as described in the third aspect, a clutch mechanism is provided between the output section and the reduction mechanism. Thus, when the electric motor is deactivated, no human power is transferred from the output section to the electric motor. This reduces the loss of human power. Additionally, the first and second gears simplify the design of the reduction mechanism.

[0015] The drive unit of a human-powered vehicle further comprises a housing configured to accommodate at least part of the crankshaft. Viewed in the axial direction of the crankshaft, the shortest distance between a crankshaft axis of rotation and an outer surface of the housing is less than or equal to 70 mm in a plane that includes the crankshaft axis of rotation and an electric motor axis of rotation.

[0016] The drive unit of a human-powered vehicle further includes a detector located on the transmission path of the human propulsion force between the crankshaft and a portion of the output section coupled to the clutch mechanism. The detector is configured to detect the human propulsion force.

[0017] The detector includes a torque sensor. The torque sensor is used to detect the torque of the human driving force. The torque sensor includes a strain sensor. The strain sensor is located on an outer circumferential surface of the output section. The detector is connected to a primary circuit board via a flexible circuit board.

[0018] A first signal processing circuit, which processes a signal output from the detector, and a first antenna, which is connected to the first signal processing circuit, are provided on the first circuit board.

[0019] A second circuit board is provided within the housing cavity, oriented towards the first circuit board along the first axis of rotation and spaced apart from it. A second antenna is provided on the second circuit board and oriented towards the first antenna.

[0020] A second signal processing circuit, which processes a signal received from the second antenna, and a power supply circuit, which supplies the first antenna with electrical energy, are provided on the second circuit board.

[0021] According to a fourth aspect of the present invention, the drive unit of a human-powered vehicle according to the third aspect further comprises a first one-way clutch provided on a transmission path of the human driving force between the crankshaft and the output section. With the drive unit of a human-powered vehicle according to the fourth aspect, in a case where the crankshaft rotates in the second direction of rotation, the rotation is not transmitted to the output section.

[0022] According to a fifth aspect of the present invention, the drive unit of a human-powered vehicle according to one of the first to fourth aspects is configured such that the clutch mechanism includes a second one-way clutch. With the drive unit of a human-powered vehicle according to the fifth aspect, the second one-way clutch transmits the rotational force of the electric motor from the reduction mechanism to the output section.

[0023] According to a sixth aspect of the present invention, the drive unit of a human-powered vehicle according to the fifth aspect is configured such that the reduction mechanism further includes a third gear, which is provided on an outer circumferential section of the second one-way coupling, and a fourth gear, which engages with the third gear. In the drive unit of a human-powered vehicle according to the sixth aspect, the third and fourth gears simplify the construction of the reduction mechanism.

[0024] According to a seventh aspect of the present invention, the drive unit of a human-powered vehicle is configured according to one of the second to fourth aspects such that the clutch mechanism includes a second one-way clutch. The reduction mechanism further includes a third gear provided on an outer circumferential section of the second one-way clutch and a fourth gear engaging with the third gear. The output section and the third gear are configured to rotate about a first axis of rotation. The output shaft of the electric motor and the first gear are configured to rotate about a second axis of rotation parallel to the first axis of rotation. The second gear and the fourth gear are configured to rotate about a third axis of rotation parallel to both the first and second axes of rotation.The first axis of rotation, the second axis of rotation, and the third axis of rotation are coplanar to each other. The drive unit of a human-powered vehicle, according to the seventh aspect, can be easily scaled down in a direction that intersects a plane containing the first axis of rotation, the second axis of rotation, and the third axis of rotation.

[0025] According to an eighth aspect of the present invention, the drive unit of a human-powered vehicle is configured according to one of the second to fourth aspects such that the clutch mechanism includes a second one-way clutch. The reduction mechanism further includes a third gear provided on an outer circumferential section of the second one-way clutch and a fourth gear engaging with the third gear. The output section and the third gear are configured to rotate about a first axis of rotation. The output shaft of the electric motor and the first gear are configured to rotate about a second axis of rotation parallel to the first axis of rotation. The second gear and the fourth gear are configured to rotate about a third axis of rotation parallel to both the first and second axes of rotation.The third axis of rotation is separated from a plane that contains the first and second axes of rotation. The drive unit of a human-powered vehicle, according to the eighth aspect, can be easily scaled down in one direction along a plane that contains the first and second axes of rotation and is orthogonal to both axes of rotation.

[0026] According to a ninth aspect of the present invention, the drive unit of a human-powered vehicle according to the seventh or eighth aspect is configured such that the shortest distance between the first axis of rotation and the second axis of rotation is greater than the shortest distance between the first axis of rotation and the third axis of rotation. In the drive unit of a human-powered vehicle according to the ninth aspect, the axis of rotation of an intermediate gear of the reduction mechanism is located in a region between the first axis of rotation and the third axis of rotation.

[0027] According to a tenth aspect of the present invention, the drive unit of a human-powered vehicle, as defined in one of the seventh to ninth aspects, is configured such that, viewed in a direction parallel to the first axis of rotation, the third gear is offset relative to the electric motor. The drive unit of a human-powered vehicle, as defined in the tenth aspect, can be easily miniaturized in a direction parallel to the first axis of rotation.

[0028] According to an eleventh aspect of the present invention, the drive unit of a human-powered vehicle according to one of the fifth to ninth aspects is configured such that the second one-way coupling includes at least one of the following components: a roller one-way coupling, a ratchet one-way coupling, and a clamp one-way coupling. With the drive unit of a human-powered vehicle according to the eleventh aspect, at least one of the roller one-way coupling, the ratchet one-way coupling, and the clamp one-way coupling restricts the transmission of the human propulsive force to the electric motor accordingly.

[0029] According to a twelfth aspect of the present invention, the reduction mechanism in the drive unit of a human-powered vehicle is configured according to one of the first to eleventh aspects to reduce the rotational speed of the electric motor using only one gear. In the drive unit of a human-powered vehicle according to the twelfth aspect, the gear simplifies the design of the reduction mechanism.

[0030] According to a thirteenth aspect of the present invention, which is not part of the invention, the drive unit of a human-powered vehicle according to any one of the first to twelfth aspects further comprises a printed circuit board on which at least part of a control unit is provided. The control unit controls the electric motor. The printed circuit board is provided on the drive unit of a human-powered vehicle according to the thirteenth aspect.

[0031] According to a fourteenth aspect of the present invention, which is not part of the invention, the drive unit of a human-powered vehicle is configured according to the thirteenth aspect such that the circuit board extends in a direction that intersects an axial direction of the crankshaft. In the drive unit of a human-powered vehicle according to the fourteenth aspect, the circuit board is expediently arranged on the drive unit.

[0032] According to a fifteenth aspect of the present invention, which is not part of the invention, the drive unit of a human-powered vehicle according to the fourteenth aspect is configured such that the circuit board overlaps the reduction mechanism in a direction that intersects the axial direction of the crankshaft. In the drive unit of a human-powered vehicle according to the fifteenth aspect, the circuit board is expediently arranged on the drive unit.

[0033] According to a sixteenth aspect of the present invention, which is not part of the invention, the drive unit of a human-powered vehicle according to one of the thirteenth to fifteenth aspects is configured such that the circuit board has a recess and a section of an output shaft of the electric motor is arranged in the recess. In the drive unit of a human-powered vehicle according to the sixteenth aspect, the circuit board is located around the output shaft of the electric motor.

[0034] The drive unit of a human-powered vehicle of the present invention reduces the loss of human driving power.

[0035] A more comprehensive assessment of the invention and many of its associated advantages is easily achieved, as it is better understood through the following detailed description when considered in conjunction with the accompanying drawings, wherein: Fig. 1 is a perspective view of an embodiment of a drive unit of a human-powered vehicle; Fig. 2 a legal opinion of the in Fig. The drive unit of a human-powered vehicle shown in 1 is; Fig. 3 a left side view of the in Fig. The drive unit of a human-powered vehicle shown in 1 is; Fig. 4 a cross-sectional view along line D4-D4 in Fig. 2 is; Fig. 5 a partially enlarged cross-sectional view of Fig. 4 is; Fig. 6 a legal opinion of the in Fig. 2 is the drive unit of a human-powered vehicle, which shows the positions of a first axis of rotation, a second axis of rotation and a third axis of rotation; Fig. 7 a legal opinion of the in Fig. 2 shown drive unit of a human-powered vehicle with the first housing removed; Fig. 8 a perspective view of a in Fig. The second housing shown in 1 is; Fig. 9 a cross-sectional view along line D9-D9 in Fig. 8 is; Fig. 10. A right-hand view of a first modified example of a propulsion unit of a human-powered vehicle, showing the positions of a first axis of rotation, a second axis of rotation, and a third axis of rotation; and Fig. Figure 11 is a cross-sectional view showing a second modified example of a drive unit for a human-powered vehicle.

[0036] Selected embodiments are now described with reference to the accompanying drawings, where identical reference numbers denote corresponding or identical elements in the different drawings.

[0037] Now, with reference to the Fig. Sections 1 to 9 describe an embodiment of a drive unit for a human-powered vehicle 10. In the following description, the drive unit of a human-powered vehicle 10 is simply referred to as the drive unit 10. The drive unit 10 is provided on a human-powered vehicle. The human-powered vehicle is a vehicle that can be propelled by at least one human force. The number of wheels on the human-powered vehicle is not limited. The human-powered vehicle includes, for example, a unicycle and a vehicle with three or more wheels. The human-powered vehicle includes, for example, various types of bicycles such as a mountain bike, a racing bike, a city bike, a cargo bike, a recumbent bike, and an electrically assisted bicycle (e-bike). In the embodiments described below, the human-powered vehicle refers to a bicycle.

[0038] The drive unit 10 includes an electric motor 12 configured to assist the propulsion of the human-powered vehicle, a crankshaft 14, an output section 16, a reduction mechanism 18 configured to reduce the rotational speed of the electric motor 12 in several steps, and a clutch mechanism 20. The output section 16 is coupled to the crankshaft 14. The output section 16 is configured to rotate in the first direction when the crankshaft 14 is rotating in the first direction and in the second direction when the crankshaft 14 is rotating in the second direction. The clutch mechanism 20 is located between the output section 16 and the reduction mechanism 18 and is configured to transmit the torque of the electric motor 12 from the reduction mechanism 18 to the output section 16.The first direction of rotation is a direction of rotation of the crankshaft 14, which moves the human-driven vehicle forward.

[0039] Preferably, the reduction mechanism 18 comprises a first gear 24, which is provided on an output shaft 22 of the electric motor 12, and a second gear 26, which engages with the first gear 24. Preferably, the first gear 24 has a smaller diameter than the second gear 26, and the first gear 24 has fewer teeth than the second gear 26.

[0040] Preferably, the drive unit 10 further comprises a housing 28 configured to accommodate at least a portion of the crankshaft 14. The housing 28 comprises a first housing 30 and a second housing 32. One of the first housing 30 and the second housing 32 encompasses a first side surface of the drive unit 10 in an axial direction A1 of the crankshaft 14. The other of the first housing 30 and the second housing 32 encompasses a second side surface of the drive unit 10 in an axial direction A1 of the crankshaft 14. The housing 28 comprises a coupling section 34 that connects the drive unit 10 to a frame of the human-powered vehicle. Preferably, the coupling section 34 is provided on the first housing 30. Preferably, a plurality of coupling sections 34 are provided. The coupling sections 34 are provided on projections 28A that extend from a circumferential section of the housing 28 around the crankshaft 14.Each coupling section 34 includes a bore 34A into which a bolt is inserted to connect the drive unit 10 to the frame.

[0041] As in Fig. As shown in Figure 4, the first housing 30 and the second housing 32 are connected to each other by screws 28B in a state in which a first coupling surface 30S of the first housing 30 overlaps with a second coupling surface 32S of the second housing 32. A cavity S is formed by the first housing 30 and the second housing 32 and accommodates a section of the electric motor 12, a section of the crankshaft 14, a section of the output section 16, the reduction mechanism 18, and the clutch mechanism 20. The section of the electric motor 12 in the cavity S includes a section of the output shaft 22 of the electric motor 12. The section of the crankshaft 14 located in the cavity S includes an intermediate section without a first end 14A and a second end 14B of the crankshaft 14 in the axial direction A1.The section of the output section 16 located in the cavity S includes a section without a first end 16A of the output section 16 in the axial direction A1 of the crankshaft.

[0042] The housing 28 further includes a motor housing 36, which accommodates the electric motor 12. The motor housing 36 is mounted on an outer surface of the second housing 32. The motor housing 36 can be integral with the second housing 32. The housing 28 can be made of metal, resin, or both. For example, in a case where the housing 28 is made of both metal and resin, the first housing 30 and the second housing 32 can be made of metal, and the motor housing 36 can be made of resin.

[0043] As in the Fig. 2 and Fig. As shown in Figure 4, the first housing 30 includes a first hole 30A from which the first end 14A of the crankshaft 14 and the first end 16A of the output section 16 protrude. A first sealing element 29A is provided in the cavity S and is in contact with the first housing 30 and the output section 16 near the first end 14A.

[0044] As in the Fig. 3 and Fig. As shown in Figure 4, the second housing 32 includes a second bore 32A from which the second end 14B of the crankshaft 14 protrudes. A second sealing element 29B is provided in the cavity S and is located near the second bore 32A in contact with the second housing 32 and the crankshaft 14. The second housing 32 includes a third bore 32B into which the output shaft 22 of the electric motor 12 is inserted. The first sealing element 29A and the second sealing element 29B are made of an elastic resin material. The elastic resin material includes, for example, a synthetic rubber.

[0045] As in Fig. As shown in Figure 4, the output section 16 is a hollow shaft and is arranged around the crankshaft 14 such that a first axis of rotation C1 of the crankshaft 14 corresponds to an axis of rotation of the output section 16. Preferably, the output section 16 is provided on the crankshaft 14 to rotate integrally with the crankshaft 14. The output section 16 is, for example, toothed with the crankshaft 14. Preferably, the output section 16 is coupled to the crankshaft 14 to prevent rotation relative to the crankshaft 14 about the first axis of rotation C1. The output section 16 can be coupled to the crankshaft 14 to be rotatable at a predetermined angle relative to the crankshaft 14. The predetermined angle is, for example, less than ten degrees. The output section 16 is rotatably mounted relative to the housing 28 by a first bearing 38, which is provided near the first end 14A of the first housing 30 in the housing 28.The first bearing 38 comprises, for example, a rolling bearing. In the present embodiment, the output section 16 has a second end 16B which, in the axial direction A1 of the crankshaft 14, is arranged on one side closer to the second end 14B of the crankshaft 14 than an intermediate section of the crankshaft 14. The inner circumferential section of the second end 16B of the output section 16 includes a toothed section and is coupled to the outer circumferential section of the crankshaft 14.

[0046] The first end 14A of the crankshaft 14 is supported by a second bearing 40 through the output section 16, which is provided on the inner circumferential section of the output section 16. The second bearing 40 comprises, for example, a plain bearing. The second end 14B of the crankshaft 14 is rotatably supported relative to the housing 28 by a third bearing 42, which is provided in the housing 28 near the second bore 32A of the second housing 32. The third bearing 42 comprises, for example, a roller bearing.

[0047] Preferably, the electric motor 12 is an internal rotor motor. The electric motor 12 comprises a stator 12A and a rotor 12B. In the present embodiment, the output shaft 22 is attached to the rotor 12B. The stator 12A and the rotor 12B are housed in the motor casing 36. The stator 12A is attached to an inner surface of the motor casing 36. The output shaft 22 has an intermediate section which is rotatably mounted with respect to the casing 2 by a fourth bearing 44, which is provided on an inner circumferential section of the second casing 32, defining the third hole 32B. The fourth bearing 44 comprises, for example, a rolling bearing. The output shaft 22 has a first end 22A which is supported by a fifth bearing 46, which is provided on the motor casing 36 and is rotatable with respect to the casing 28. The fifth bearing 46 comprises, for example, a rolling bearing.

[0048] Preferably, the coupling mechanism 20 includes a second one-way coupling 48. Preferably, the second one-way coupling 48 includes at least one roller one-way coupling, one ratchet one-way coupling, and one clamping one-way coupling. The second one-way coupling 48 includes, for example, an inner race 48A, an outer race 48B, and a gear body 48C located between the inner race 48A and the outer race 48B. The gear body 48C includes, for example, a roller, a pawl, and a clamping element. The second one-way coupling 48 is located on the outer circumferential section of the output section 16 around the first axis of rotation C1. The inner race 48A of the second one-way coupling 48 is located on the outer circumferential section of the output section 16. The inner race 48A of the second one-way coupling 48 can be formed integrally with the output section 16.The inner barrel 48A of the second one-way coupling 48 has a larger outer diameter than the output section 16.

[0049] Preferably, the reduction mechanism 18 further comprises a third gear 50, which is provided on the outer circumferential section of the second one-way clutch 48, and a fourth gear 52, which engages with the third gear 50. Preferably, the third gear 50 has a larger diameter than the fourth gear 52, and the third gear 50 has fewer teeth than the fourth gear 52. The outer race 48B of the second one-way clutch 48 is provided on an inner circumferential section of the third gear 50. The outer race 48B of the second one-way clutch 48 can be formed integrally with the third gear 50. Preferably, the reduction mechanism 18 is configured to reduce the speed of the electric motor 12 using only gears. In the present embodiment, the reduction mechanism 18 reduces the speed of the electric motor 12 in two steps, but can be configured to reduce the speed in three or more steps.Preferably, the first gear 24 and the second gear 26 comprise helical gears. The first gear 24 can be integrally formed with the output shaft 22 of the electric motor 12 or separate from the output shaft 22 of the electric motor 12 and coupled to the output shaft 22. The first gear 24 and the second gear 26 can comprise spur gears. Preferably, the third gear 50 and the fourth gear 52 comprise helical gears. The third gear 50 and the fourth gear 52 can comprise spur gears.

[0050] The reduction mechanism 18 further comprises a rotating body 54 on which the second gear 26 and the fourth gear 52 are provided. The second gear 26 and the fourth gear 52 are configured to rotate together. Preferably, the second gear 26 has a larger diameter than the fourth gear, and the second gear 26 has more teeth than the fourth gear 52. Preferably, the rotating body 54 is made of a metallic material. The rotating body 54 has a first end 54A, which is rotatably mounted relative to the housing 28 by a sixth bearing 56 provided on an inner surface of the first housing 30. The sixth bearing 56 comprises, for example, a rolling bearing. The sixth bearing 56 is arranged in a position that overlaps at least partially with the first bearing 38 in the axial direction A1 of the crankshaft 14.The rotating body 54 has a second end 54B which is rotatably mounted relative to the housing 28 by a seventh bearing 58 provided on an inner surface of the second housing 32. The seventh bearing 58 comprises, for example, a rolling bearing. The second gear 26 is configured to have, in the axial direction A1 of the crankshaft 14, an outer diameter section and an inner diameter section with a smaller width than the outer diameter section. Preferably, the seventh bearing 58 is arranged in the axial direction A1 of the crankshaft 14 between the wide, opposing ends of the second gear 26. The substantially entire seventh bearing 58 is located in a space formed between the outer diameter section of the second gear 26 and the outer circumferential section of the second end 54B of the rotating body 54.Thus, even in a case where the outer diameter section of the second gear 26 is increased in width in the axial direction A1 of the crankshaft 14, the extension of the rotating body 54 to the second housing 32 in the axial direction A1 of the crankshaft 14 is limited. This allows for a reduction in the width of the drive unit 10 in the axial direction A1 of the crankshaft 14. Preferably, the diameter of the first end 54A and the second end 54B is substantially equal to the diameter of the fourth gear 52. Preferably, the outer diameter of the outer races of the sixth bearing 56 and the seventh bearing 58 is substantially equal to the diameter of the second gear 26. The rotating body 54 has a third axis of rotation C3. The second gear 26 is located in a position that is closer to the electric motor 12 in the axial direction A1 of the crankshaft 14 than the fourth gear 52.The inner diameter section of the third gear 50 has an end 50A in the axial direction A1 of the crankshaft 14. The end 50A is located in the axial direction A1 of the crankshaft 14 between the inner race 48A of the second one-way clutch 48 and the inner race of the first bearing 38. In the present embodiment, the end 50A of the inner diameter section of the third gear 50 is located in the axial direction A1 of the crankshaft 14 between a step 16D (see . Fig. 5) of the outer circumferential section of the output section 16 and the inner running of the first bearing 38. This positions the third gear 50 in the axial direction A1 of the crankshaft 14.

[0051] Preferably, the fourth gear 52 is formed integrally with the outer circumferential section of the rotating body 54 around the third axis of rotation C3. Preferably, the fourth gear 52 is made of a metallic material. The fourth gear 52 and the second gear 26 are arranged side by side in the direction in which the third axis of rotation C3 of the rotating body 54 extends. Preferably, the second gear 26 comprises a resin material. The ridges and valleys forming the fourth gear 52 extend in the direction of the third axis of rotation C3 and are formed where the second gear 26 is located. These ridges and valleys forming the fourth gear 52 function as the fourth gear 52 at a section that is closer to the first end 54A than where the second gear 26 is located.The inner circumferential section of the second gear 26 is provided on the ridges and valleys that form the fourth gear 52 in order to limit the rotation of the second gear 26 with respect to the rotating body 54. The outer circumferential section of the rotating body 54 around the third axis of rotation C3 includes a radially recessed notch 54C. The notch 54C may be annular. The notch 54C may be provided intermittently around the third axis of rotation C3. Only one notch 54C may be provided. The inner circumferential section of the second gear 26 is provided at the notch 54C in order to limit the movement of the second gear 26 in the direction in which the third axis of rotation C3 extends with respect to the rotating body 54. Preferably, the first end 54A and the second end 54B of the rotating body 54 are configured to have a smaller outer diameter than the fourth gear 52.In the present embodiment, the rotating body 54 and the fourth gear 52 are integrally formed from a metal material, and the second gear 26 is formed from a resin material. Preferably, the second gear 26 is provided on the outer circumferential section of the rotating body 54 by overmolding. More precisely, for example, machining and rolling are carried out to form the rotating body 54 integrally from a metal with the recess 54C and the ridges and valleys that form the fourth gear 52, and overmolding is carried out on the rotating body 54 so that the resin enters the recess 54C and the ridges and valleys form the fourth gear 52. This provides the second gear 26 on the outer circumferential section of the rotating body 54. Preferably, the recess 54C is formed in the axial direction A1 of the crankshaft 14 in a central section of the rotating body 54.

[0052] Now, with reference to the Fig. 4 and Fig. 6 the positional relationship of the electric motor 12, the crankshaft 14, the output section 16 and the reduction mechanism 18 is described.

[0053] Output section 16 and the third gear 50 are configured to rotate about the first axis of rotation C1. The output shaft 22 of the electric motor 12 and the first gear 24 are configured to rotate about a second axis of rotation C2, which is parallel to the first axis of rotation C1. The second gear 26 and the fourth gear 52 are configured to rotate about the third axis of rotation C3, which is parallel to the first axis of rotation C1 and the second axis of rotation C2. The first axis of rotation C1, the second axis of rotation C2, and the third axis of rotation C3 are coplanar with each other.

[0054] Preferably, the shortest distance L1 between the first axis of rotation C1 and the second axis of rotation C2 is greater than the shortest distance L2 between the first axis of rotation C1 and the third axis of rotation C3. Preferably, the shortest distance L3 between the second axis of rotation C2 and the third axis of rotation C3 is less than the shortest distance L2 between the first axis of rotation C1 and the third axis of rotation C3. The shortest distance L1 between the first axis of rotation C1 and the second axis of rotation C2 can be equal to the shortest distance L2 between the first axis of rotation C1 and the third axis of rotation C3. The shortest distance L3 between the second axis of rotation C2 and the third axis of rotation C3 can be equal to the shortest distance L2 between the first axis of rotation C1 and the third axis of rotation C3.

[0055] Preferably, the shortest distance L4 from a rotational axis C1 of the crankshaft 14 to an outer surface of the housing 28 on a plane with the rotational axis C1 of the crankshaft 14 and a rotational axis C2 of the electric motor 12, viewed in the axial direction A1 of the crankshaft 14, is less than or equal to 70 mm. Preferably, in a case where the human-propelled vehicle includes a front wheel and a rear wheel, and the rear wheel is the drive wheel, the drive unit 10 is coupled to the frame of the human-propelled vehicle in a state where the crankshaft 14 on the human-propelled vehicle is arranged at a rear end of the output shaft 22 of the electric motor 12.

[0056] Preferably, the third gear 50 is offset relative to the electric motor 12 when viewed in a direction parallel to the first axis of rotation C1. Viewed in a direction parallel to the first axis of rotation C1, the third gear 50 is arranged so that it does not overlap with the stator 12A of the electric motor 12. In this case, the gears of the reduction mechanism 18 may be enlarged. This increases the degree of freedom for designing the reduction ratio of the reduction mechanism 18. Alternatively, the third gear 50 may be arranged, viewed in a direction parallel to the first axis of rotation C1, so that it overlaps with the stator 12A of the electric motor 12. In this case, the drive unit 10 may be reduced in size in a direction extending along a plane that includes the first axis of rotation C1 and the third axis of rotation C3.

[0057] As in the Fig. 4 and Fig. As shown in Figure 7, the drive unit 10 preferably also includes a printed circuit board 60 on which at least part of a control system for controlling the electric motor 12 is provided. The control system includes an arithmetic processing unit that executes predefined control programs. The arithmetic processing unit includes, for example, a central processing unit (CPU) or a microprocessor unit (MPU). The control system can include one or more microcomputers. Preferably, a memory unit is also provided on the printed circuit board 60. The memory unit stores information that is used in various control programs and control processes. The memory unit includes, for example, non-volatile memory and volatile memory. An electronic component 61 is mounted on the printed circuit board 60.The electronic component 61 can be mounted on any of the opposite surfaces of the printed circuit board 60 in the thickness direction. The electronic component 61 includes, for example, a microprocessor, a capacitor, and a resistor.

[0058] Preferably, the circuit board 60 extends in a direction that intersects the axial direction A1 of the crankshaft 14. In a direction that intersects the axial direction A1 of the crankshaft 14, the circuit board 60 is arranged such that it overlaps the electric motor 12. The circuit board 60 is housed in the cavity S formed by the first housing 30 and the second housing 32. Preferably, the circuit board 60 is arranged such that it overlaps the reduction mechanism 18 in a direction that intersects the axial direction of the crankshaft 14. For example, the circuit board 60 is arranged such that it overlaps the first gear 24 and the second gear 26 in a direction that intersects the axial direction A1 of the crankshaft 14. The direction that intersects with the axial direction A1 of the crankshaft 14 includes a direction orthogonal to the crankshaft 14.Preferably, the printed circuit board 60 includes a recess 60A, and part of the output shaft 22 of the electric motor 12 is located in the recess 60A. The recess 60A is formed in a circumferential section of the printed circuit board 60. The printed circuit board 60 has an edge located near the outer circumferential sections of the first gear 24 and the second gear 26, such that the edge extends along a section of the outer circumferential areas of the first gear 24 and the second gear 26. The electric motor 12 has an electrical connection 12C that extends through a through-hole in the second gear 32 and is directly connected to the printed circuit board 60.

[0059] Preferably, the drive unit 10 includes a detector 62 configured to detect human driving forces. Preferably, the detector 62 is located on a human driving force transmission path between the crankshaft 14 and a part 16C of the output section 16, which is coupled to the clutch mechanism 20. The detector 62 includes a torque sensor. The torque sensor is used to detect the torque of the human driving force. The torque sensor includes, for example, a strain sensor 62A. The strain sensor 62A comprises, for example, a strain gauge and a semiconductor strain gauge. The strain sensor 62A is located on an outer circumferential surface of the output section 16. A plurality of strain sensors 62A can be provided.In a case where, for example, two strain sensors 62A are provided, the strain sensors 62A are located at positions 180° apart around the first axis of rotation C1. The detector 62 is connected to a first circuit board 64 via a flexible printed circuit board. A first signal processing circuit, which processes a signal output from the detector 62, and a first antenna, which is connected to the first signal processing circuit, are provided on the first circuit board 64. The first circuit board 64 is coupled to the output section 16 via a circuit board holder 65. A second circuit board 66 is provided in the cavity S of the housing 28, facing the first circuit board 64 along the first axis of rotation C1 and spaced apart from the first circuit board 64. The second circuit board 66 is mounted on the housing 28, for example, via a circuit board holder 67. However, the second circuit board 66 can also be mounted directly on the housing 28.A second antenna is provided on the second circuit board 66 and faces the first antenna. A second signal processing circuit, which processes a signal received from the second antenna, and a power supply circuit, which supplies the first antenna with electrical energy, are provided on the second circuit board 66. The second circuit board 66 is electrically connected to the circuit board 60 via an electrical cable. The detector 62 transmits an output to the second antenna via wireless communication through the first antenna. Preferably, the control unit controls the electric motor 12 according to the output of the detector 62. For example, the control unit drives the electric motor such that the ratio of human driving force to the driving force of the electric motor 12 is adjusted to a predetermined ratio according to a signal corresponding to the human driving force detected by the detector 62.The torque sensor can incorporate a magnetostriction sensor instead of the strain sensor 62A. In this case, a magnetostrictive element can be located on the transmission path of the human driving force, and the magnetostrictive sensor can be positioned around the magnetostrictive element. This allows the first circuit board 64 and the second circuit board 66 to be omitted.

[0060] Now, with reference to the Fig. 3, Fig. 8 and Fig. 9 a method for manufacturing the second housing 32 is described.

[0061] The process for manufacturing the second housing 32 includes a first step and a second step.

[0062] The first step involves manufacturing the second housing 32. In this first step, projections 32C are formed on the circumferential section of the second housing 32, projecting towards an outer circumference. Preferably, two or more projections 32C are formed. The projections 32C are located at positions separated from the second coupling surface 32S of the second housing 32. The projections 32C are located at positions facing the projections 28A in the axial direction A1 of the crankshaft 14. The projections 28A project towards a side that is closer to the second housing 32 than the first coupling surface 32S. Fig. The three depicted projections 28A include recesses 28C to which the projections 32C are attached. Attaching the projections 32C to the recesses 28C in a state where the first housing 30 is coupled to the second housing 32 reduces the influence of the projections 32C on the external appearance of the housing 28.

[0063] The second step involves machining the second coupling surface 32S of the second housing 32. In this second step, with the projections 32C of the second housing 32 clamped by a device D, the second coupling surface 32S is machined to flatten it. The device D is located on a side closer to the projections 32C than to the second coupling surface 32S. This limits the interference of the projections 32C and the device D with the machining of the second coupling surface 32S.

[0064] The description of the embodiment illustrates, without intending to limit, the applicable forms of a propulsion unit for a human-powered vehicle according to the present invention. The propulsion unit for a human-powered vehicle according to the present invention can, for example, be applicable to modified examples described below and combinations of at least two of the modified examples that do not contradict each other. In the following modified examples, the same reference symbols are given to the elements that are identical to the corresponding elements of the embodiment. Such elements are not described in detail.

[0065] As in Fig. As shown in Figure 10, the third axis of rotation C3 can be spaced apart from a plane containing the first axis of rotation C1 and the second axis of rotation C2. In this case, too, the shortest distance L1 between the first axis of rotation C1 and the second axis of rotation C2 is preferably greater than the shortest distance L2 between the first axis of rotation C1 and the third axis of rotation C3. In a state where the drive unit 10 is coupled to the frame, the third axis of rotation C3 can be located below the plane containing the first axis of rotation C1 and the second axis of rotation C2 in the axial direction A1 of the crankshaft 14. Preferably, the first axis of rotation C1 is arranged in a triangular region R in the axial direction A1 of the crankshaft 14, which connects the centers of the holes 34A of the coupling sections 34. Viewed in the axial direction A1 of the crankshaft 14, a third axis of rotation C3X can be arranged in the triangular area R, which connects the centers of the holes 34A of the coupling sections 34.Preferably, the shortest distance L3 between the second axis of rotation C2 and the third axis of rotation C3 is smaller than the distance L2 between the first axis of rotation C1 and the third axis of rotation C3. In the figure in . Fig. In the modified example shown in Figure 10, the third gear 50 can be arranged such that it overlaps with the stator 12A of the electric motor 12 in a direction parallel to the first axis of rotation C1. Viewed in a direction parallel to the first axis of rotation C1, at least a portion of the second gear 26 is arranged such that it overlaps with an area where the third gear 50 overlaps with the electric motor 12.

[0066] As in Fig. As shown in Figure 11, the drive unit 10 can further include a first one-way coupling 68, which is provided on the transmission path of the human driving force between the crankshaft 14 and the output section 16. In the modified example in Fig.The first one-way coupling 68 is provided on output section 16. Output section 16 is divided into a first part 16X with the first end 16A and a second part 16Y with the second end 16B. The first one-way coupling 68 is provided between the first part 16X and the second part 16Y. The first one-way coupling 68 allows, in the case where the crankshaft 14 rotates in the first direction of rotation, the rotation of the second part 16Y about the first axis of rotation C1 in the first direction of rotation, and prevents the rotation of the second part 16Y about the first axis of rotation C1 in the second direction of rotation. The first one-way coupling 68 includes at least one roller one-way coupling, one ratchet one-way coupling, and one clamp one-way coupling. In this case, the detector 62 is provided on the second part 16Y of output section 16.A section of the first one-way coupling 68 can be integrally formed with at least one of the first parts 16X and the second part 16Y.

[0067] The coupling mechanism 20 can be configured to switch between a state in which the rotational force between the output section 16 and the reduction mechanism 18 is transmissible and a state in which the rotational force is not transmissible. In this case, the drive unit 10 preferably also includes an actuator that actuates the coupling mechanism 20, and the actuator is controlled by the controller provided on the circuit board 60 to switch the state of the coupling mechanism 20. The coupling mechanism 20 can include a two-way coupling instead of a one-way coupling.

[0068] The reduction mechanism 18 can include a configuration that reduces the speed of the electric motor 12 without the use of gears. The reduction mechanism 18 can reduce the speed via a pulley and a belt. For example, the third gear 50 and the fourth gear 52 can be replaced by pulleys, and the two pulleys can be coupled by a belt or a chain. The first gear 24 and the second gear 26 can be replaced by pulleys, and the two pulleys can be coupled by a belt or a chain. The reduction mechanism 18 can include a planetary gear set. The expression "at least one of" used in this disclosure means "one or more" of a desired selection.For example, the phrase “at least one of,” as used in this revelation, means “only a single choice” or “both of two choices” when the number of choices is two. Similarly, the phrase “at least one of,” as used in this revelation, means “only a single choice” or “any combination of two or more choices” when the number of choices is three or more. REFERENCE MARK 10 Drive unit of a human-powered vehicle 12 Electric motor 12A Stator 12B Rotor 12C electric motor 14 crankshafts 14A first end 14B second end 16 Output section 16A first end 16B second end 16C Part 16D Stage 16X Part One 16Y Part Two 18 Reduction mechanism 20 Clutch mechanism 22nd wave of publication 22A first end 24 first gear 26 second gear 28 cases 28A advantage 28B screw 28C recess 29A first sealing element 29B second sealing element 30 first case 30A first hole 30S first coupling surface 32 second case 32A second hole 32B third hole 32°C advantage 32S second coupling surface 34 Coupling section 34A Hole 36 Engine housings 38 first camp 40 second camp 42 third camp 44 fourth camp 46 fifth camp 48 second one-way coupling 48A internal barrel 48B Outer Barrel 48C Gearbox Housing 50 third gear 50A End 52 fourth gear 54 Rotating Bodies 54A first end 54B second end 54C recess 56 sixth camp 58 seventh camp 60 circuit boards 60A recess 61 electronic component 62 Detector 62A strain sensor 64 first circuit board 65 circuit board holders 66 second circuit board 67 circuit board holders 68 first one-way coupling A1 axial direction C1 first axis of rotation C2 second axis of rotation C3 third axis of rotation C3X third axis of rotation D clamping device L1 shortest distance L2 shortest distance L3 shortest distance L4 shortest distance R triangle area S cavity

Claims

[1] A propulsion unit of a human-powered vehicle (10), comprising: an electric motor (12) configured to assist the propulsion of a human-powered vehicle; a crankshaft (14); an output section (16) coupled to the crankshaft (14), wherein the output section (16) is configured to rotate in the first direction of rotation in a case where the crankshaft (14) rotates in a first direction of rotation, and the output section (16) is configured to rotate in the second direction of rotation in a case where the crankshaft (14) rotates in a second direction of rotation; a reduction mechanism (18) configured to reduce the speed of the electric motor (12) in several steps; a coupling mechanism (20) provided between the output section (16) and the reduction mechanism (18), wherein the coupling mechanism (20) is configured to transmit a rotational force of the electric motor (12) from the reduction mechanism (18) to the output section (16); a housing (28) configured to accommodate at least part of the crankshaft (14), wherein, viewed in the axial direction of the crankshaft (14), a shortest distance (L4) on a plane which includes an axis of rotation (C1) of the crankshaft (14) and an axis of rotation (C2) of the electric motor (12) is located between the axis of rotation (C1) of the crankshaft (14) and an outer surface of the housing (28) is less than or equal to 70 mm; and a detector (62) which is provided on a transmission path of the human driving force between the crankshaft (14) and a part of the output section (16) which is coupled to the clutch mechanism (20), wherein the detector (62) is configured to detect the human driving force, wherein the detector (62) includes a torque sensor which is used to detect the torque of the human driving force and the torque sensor includes a strain sensor (62A) which is provided on an outer circumferential surface of the output section (16), wherein the detector (62) is connected to a first circuit board (64) via a flexible circuit board, wherein a first signal processing circuit, which processes a signal output of the detector (62), and a first antenna, which is connected to the first signal processing circuit, are provided on the first printed circuit board (64), and wherein a second printed circuit board (66) is provided in the cavity (S) of the housing (28) to be oriented towards the first printed circuit board (64) in the first axis of rotation (C1) and spaced apart from the first printed circuit board (64), and wherein a second antenna is provided on the second circuit board (66) which faces the first antenna, and a second signal processing circuit which processes a signal received from the second antenna, and a power supply circuit which supplies the first antenna with electrical energy are provided on the second circuit board (66). [2] The drive unit of a human-powered vehicle (10) according to claim 1, wherein the reduction mechanism (18) includes a first gear (24) which is provided on an output shaft (22) of the electric motor (12), and a second gear (26) that engages with the first gear (24). [3] A propulsion unit of a human-powered vehicle (10), comprising: an electric motor (12) configured to assist the propulsion of a human-powered vehicle; a crankshaft (14); an output section (16) coupled to the crankshaft (14); a reduction mechanism (18) configured to reduce the speed of the electric motor (12) in several steps; and a coupling mechanism (20) provided between the output section (16) and the lowering mechanism (18), wherein the coupling mechanism (20) is configured to transmit a rotational force of the electric motor (12) from the reduction mechanism (18) to the output section (16), and the reduction mechanism (18) includes a first gear (24) which is provided on an output shaft (22) of the electric motor (12), and a second gear (26) which engages with the first gear (24) a housing (28) which is configured to accommodate at least part of the crankshaft (14) wherein, viewed in the axial direction of the crankshaft (14), a shortest distance (L4) on a plane which includes an axis of rotation (C1) of the crankshaft (14) and an axis of rotation (C2) of the electric motor (12) between the axis of rotation (C1) of the crankshaft (14) and an outer surface of the housing (28) is less than or equal to 70 mm; and a detector (62) which is provided on a transmission path of the human driving force between the crankshaft (14) and a part of the output section (16) which is coupled to the clutch mechanism (20), wherein the detector (62) is configured to detect the human driving force, wherein the detector (62) includes a torque sensor which is used to detect the torque of the human driving force and the torque sensor includes a strain sensor (62A) which is provided on an outer circumferential surface of the output section (16), wherein the detector (62) is connected to a first circuit board (64) via a flexible circuit board, wherein a first signal processing circuit, which processes a signal output of the detector (62), and a first antenna, which is connected to the first signal processing circuit, are provided on the first printed circuit board (64), and wherein a second printed circuit board (66) is provided in the cavity (S) of the housing (28) to be oriented towards the first printed circuit board (64) in the first axis of rotation (C1) and spaced apart from the first printed circuit board (64), and wherein a second antenna is provided on the second circuit board (66) which faces the first antenna, and a second signal processing circuit which processes a signal received from the second antenna, and a power supply circuit which supplies the first antenna with electrical energy are provided on the second circuit board (66). [4] The drive unit of a human-powered vehicle (10) according to claim 3, further comprising a first one-way coupling (68) which is provided between the crankshaft (14) and the output section (16) on a transmission path of human propulsion force. [5] The drive unit of a human-powered vehicle (10) according to any one of claims 1 to 4, wherein the coupling mechanism (20) includes a second one-way coupling (48). [6] The drive unit of a human-powered vehicle (10) according to claim 5, wherein the reduction mechanism (18) further comprises a third gear (50) provided on an outer circumferential section of the second one-way coupling (48) and a fourth gear (52) which engages with the third gear (50). [7] The drive unit of a human-powered vehicle (10) according to any one of claims 2 to 4, wherein the coupling mechanism (20) includes a second one-way coupling (48), wherein the reduction mechanism (18) further includes a third gear (50) provided on an outer circumferential section of the second one-way coupling (48) and a fourth gear (52) which engages with the third gear (50), the output section (16) and the third gear (50) are configured to rotate about a first axis of rotation (C1), the output shaft (22) of the electric motor (12) and the first gear (24) are configured to rotate about a second axis of rotation (C2) that runs parallel to the first axis of rotation (C1), the second gear (26) and the fourth gear (52) are configured to rotate about a third axis of rotation (C3) that is parallel to the first axis of rotation (C1) and the second axis of rotation (C2), and the first axis of rotation (C1), the second axis of rotation (C2) and the third axis of rotation (C3) are coplanar to each other. [8] The drive unit of a human-powered vehicle (10) according to any one of claims 2 to 4, wherein the coupling mechanism (20) includes a second one-way coupling (48), the reduction mechanism (18) further comprises a third gear (50) which is provided on an outer circumferential section of the second one-way coupling (48), and a fourth gear (52) which engages with the third gear (50), the output section (16) and the third gear (50) are configured to rotate about a first axis of rotation (C1), the output shaft (22) of the electric motor (12) and the first gear (24) are configured to rotate about a second axis of rotation (C2) that runs parallel to the first axis of rotation (C1), the second gear (26) and the fourth gear (52) are configured to rotate about a third axis of rotation (C3) that is parallel to the first axis of rotation (C1) and the second axis of rotation (C2), and the third axis of rotation (C3) is separated from a plane which contains the first axis of rotation (C1) and the second axis of rotation (C2). [9] The drive unit of a human-powered vehicle (10) according to claim 7 or 8, wherein a shortest distance between the first axis of rotation (C1) and the second axis of rotation (C2) is greater than a shortest distance between the first axis of rotation (C1) and the third axis of rotation (C3). [10] The drive unit of a human-powered vehicle (10) according to one of claims 7 to 9, wherein the third gear (50), viewed in a direction parallel to the first axis of rotation (C1), is offset relative to the electric motor (12). [11] The drive unit of a human-powered vehicle (10) according to any one of claims 5 to 9, wherein the second one-way coupling (48) includes at least one of a roller one-way coupling, a ratchet one-way coupling and a clamp one-way coupling. [12] The drive unit of a human-powered vehicle (10) according to any one of claims 1 to 11, wherein the reduction mechanism (18) is configured to reduce the rotational speed of the electric motor (12) using only one gear.

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