Drive unit for human-powered vehicles

Abstract

To provide a drive unit for a human-powered vehicle capable of suitably imparting a propulsive force to the human-powered vehicle. [Solution] A drive unit for a human-powered vehicle, comprising: a support portion; a drive shaft that receives human-powered driving force and has a first axis; an output portion provided on the drive shaft; a motor having a rotor and a stator; a transmission mechanism configured to transmit the motor torque of the motor to the output portion; and a motor output shaft connected to the rotor and having a second axis different from the first axis, wherein the transmission mechanism includes a first transmission portion having a planetary gear mechanism, at least a portion of which is configured to rotate around the second axis and overlaps with the motor when viewed from a first direction perpendicular to the second axis.

Description

[Technical Field]

[0001] The present disclosure relates to a drive unit for a human-powered vehicle. [Background technology]

[0002] Patent Document 1 discloses an example of a drive unit for a human-powered vehicle that includes a motor that provides a propulsive force to the human-powered vehicle. The torque of the motor in Patent Document 1 is transmitted to the crankshaft of the human-powered vehicle. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-196036 Summary of the Invention [Problem to be solved by the invention]

[0004] One object of the present disclosure is to provide a drive unit for a human-powered vehicle that can suitably impart propulsive force to the human-powered vehicle. [Means for solving the problem]

[0005] A drive unit according to a first aspect of the present disclosure is a drive unit for a human-powered vehicle, and comprises: a support portion; a drive shaft that receives human-powered driving force and has a first axis; an output portion provided on the drive shaft; a motor having a rotor and a stator; a transmission mechanism configured to transmit motor torque of the motor to the output portion; and a motor output shaft connected to the rotor and having a second axis different from the first axis, wherein the transmission mechanism includes a first transmission portion having a planetary gear mechanism, at least a portion of which is configured to rotate around the second axis and overlaps with the motor when viewed from a first direction perpendicular to the second axis. According to the drive unit of the first aspect, the transmission mechanism can preferably transmit motor torque to the drive shaft by the first transmission part including the planetary gear mechanism. Therefore, the drive unit can preferably provide propulsive force to the human-powered vehicle. According to the drive unit of the first aspect, at least a portion of the planetary gear mechanism is configured to rotate about the second axis and overlaps with the motor when viewed from a first direction perpendicular to the second axis, which contributes to miniaturization of the drive unit in the direction along the first axis.

[0006] In the drive unit of a second aspect according to the first aspect of the present disclosure, at least a portion of the planetary gear mechanism overlaps with the rotor when viewed from the first direction. According to the drive unit of the second aspect, at least a portion of the planetary gear mechanism overlaps with the rotor when viewed from the first direction, which can contribute to miniaturization of the drive unit in the direction along the first axis.

[0007] In the drive unit of the third aspect according to the second aspect of the present disclosure, the stator is disposed radially outside the rotor, and at least a portion of the planetary gear mechanism is disposed radially inside the rotor. According to the drive unit of the third aspect, at least a part of the planetary gear mechanism is disposed radially inside the rotor, which can contribute to miniaturization of the drive unit in the direction along the first axis.

[0008] In the drive unit of a fourth aspect according to the second aspect of the present disclosure, the rotor is disposed radially outside the stator, and at least a portion of the planetary gear mechanism is disposed radially inside the stator. According to the drive unit of the fourth aspect, at least a part of the planetary gear mechanism is disposed radially inside the stator, which can contribute to miniaturization of the drive unit in the direction along the first axis.

[0009] In a drive unit of a fifth aspect according to any one of the first to fourth aspects of the present disclosure, at least a portion of the planetary gear mechanism overlaps with the rotor radially outside the motor when viewed from the first direction. According to the drive unit of the fifth aspect, at least a portion of the planetary gear mechanism overlaps with the rotor radially outside the motor when viewed from the first direction, which contributes to miniaturization of the drive unit in the direction along the first axis.

[0010] In a drive unit of a sixth aspect according to any one of the first to fifth aspects of the present disclosure, the transmission mechanism further includes a transmission shaft having a third axis different from both the first axis and the second axis. According to the drive unit of the sixth aspect, at least a part of the transmission mechanism is provided on a transmission shaft separate from the drive shaft and the motor output shaft.

[0011] In the drive unit of the seventh aspect according to the sixth aspect of the present disclosure, the transmission mechanism further includes a second transmission part having a first transmission gear to which torque is transmitted from the planetary gear mechanism, and a second transmission gear engaged with the first transmission gear and provided on the transmission shaft. According to the drive unit of the seventh aspect, the second transmission part can suitably transmit the torque transmitted from the planetary gear mechanism.

[0012] In the drive unit of the eighth aspect according to the seventh aspect of the present disclosure, the first transmission gear has a first pitch circle diameter, and the second transmission gear has a second pitch circle diameter, and the second pitch circle diameter is larger than the first pitch circle diameter. According to the drive unit of the eighth aspect, the second transmission part is a reducer, and therefore the second transmission part can transmit the motor torque suitably.

[0013] In the drive unit of the ninth aspect according to the seventh or eighth aspect of the present disclosure, the transmission mechanism further includes a third transmission part having a third transmission gear provided on the transmission shaft and a fourth transmission gear engaged with the third transmission gear and provided on the output part. According to the drive unit of the ninth aspect, the third transmission part can suitably transmit the torque transmitted from the planetary gear mechanism.

[0014] In the drive unit of a tenth aspect according to the ninth aspect of the present disclosure, the third transmission gear has a third pitch circle diameter, and the fourth transmission gear has a fourth pitch circle diameter, and the fourth pitch circle diameter is larger than the third pitch circle diameter. According to the drive unit of the tenth aspect, the third transmission part is a reducer, and therefore the third transmission part can transmit the motor torque suitably.

[0015] In the drive unit of an eleventh aspect according to any one of the sixth to tenth aspects of the present disclosure, the second axis and the third axis are parallel to the first axis. According to the drive unit of the eleventh aspect, the motor output shaft can be arranged parallel to the drive shaft. According to the drive unit of the eleventh aspect, the transmission shaft can be arranged parallel to the drive shaft.

[0016] In the drive unit of the twelfth aspect according to the first aspect of the present disclosure, the planetary gear mechanism includes a sun gear that receives rotational torque from the motor output shaft, a ring gear that is mounted on the support portion so as not to rotate relative to the support portion, a planetary gear that is mounted between the sun gear and the ring gear and to which the rotational torque of the sun gear is transmitted, and a carrier that supports the planetary gear and outputs rotational torque to the output portion. According to the drive unit of the twelfth aspect, the planetary gear mechanism is a reducer, and therefore the planetary gear mechanism can transmit motor torque in an appropriate manner.

[0017] In the drive unit of a thirteenth aspect according to the first aspect of the present disclosure, the entire planetary gear mechanism overlaps with the motor when viewed from the first direction. According to the drive unit of the thirteenth aspect, the entire planetary gear mechanism overlaps with the motor when viewed from the first direction, which contributes to miniaturization of the drive unit in the direction along the first axis.

[0018] In a drive unit of a fourteenth aspect according to the first aspect of the present disclosure, the planetary gear mechanism includes a sun gear, a ring gear, planetary gears arranged between the sun gear and the ring gear, and a carrier supporting the planetary gears, and at least one of the sun gear, the planetary gears, and the ring gear at least partially overlaps with the motor when viewed from the first direction. According to the drive unit of the fourteenth aspect, at least one of the sun gear, planetary gears, and ring gear overlaps at least partially with the motor when viewed from the first direction, which contributes to miniaturizing the drive unit in the direction along the first axis.

[0019] In the drive unit of a fifteenth aspect according to the fourteenth aspect of the present disclosure, at least a portion of the ring gear overlaps with the motor when viewed from the first direction. According to the drive unit of the fifteenth aspect, at least a portion of the ring gear overlaps with the motor when viewed from the first direction, which can contribute to miniaturization of the drive unit in the direction along the first axis.

[0020] In the drive unit of the sixteenth aspect according to the first aspect of the present disclosure, a first bearing is further provided that rotatably supports the motor output shaft, and at least a portion of the first bearing overlaps with the rotor when viewed from the first direction. According to the drive unit of the sixteenth aspect, at least a portion of the first bearing overlaps with the rotor when viewed from the first direction, which can contribute to miniaturization of the drive unit in the direction along the first axis.

[0021] In a drive unit of a seventeenth aspect according to any one of the first to sixteenth aspects of the present disclosure, the motor has a first maximum outer diameter, the output portion has a second maximum outer diameter, and the first maximum outer diameter is larger than the second maximum outer diameter. According to the drive unit of the seventeenth aspect, the planetary gear mechanism can be disposed so that at least a portion of the planetary gear mechanism overlaps with the motor having a first maximum outer diameter larger than the second maximum outer diameter of the output portion.

[0022] In a drive unit of an 18th aspect according to any one of the 1st to 17th aspects of the present disclosure, a circuit board is further provided, the circuit board being positioned at a distance from the motor output shaft in a second direction parallel to the second axis. According to the drive unit of the eighteenth aspect, the circuit board can be disposed in a position where it is less likely to interfere with the motor output shaft.

[0023] In a drive unit of a 19th aspect according to an 18th aspect of the present disclosure, the drive unit further includes a motor rotation state detection unit that detects the rotation state of the motor output shaft, the circuit board includes a predetermined portion that faces the motor output shaft in the second direction, and the motor rotation state detection unit is provided in the predetermined portion. According to the drive unit of the nineteenth aspect, the motor rotation state detector is provided at a predetermined portion of the circuit board facing the motor output shaft, so that the motor rotation state detector can suitably detect the rotation state of the motor.

[0024] The drive unit of a twentieth aspect according to any one of the first to nineteenth aspects of the present disclosure further comprises a human-powered driving force detection unit that detects a human-powered driving force applied to the human-powered vehicle. According to the drive unit of the twentieth aspect, the manual driving force can be detected by the manual driving force detection section.

[0025] A drive unit according to a 21st aspect of the present disclosure is a drive unit for a human-powered vehicle, comprising: a support portion; a drive shaft that receives human-powered driving force and has a first axis; an output portion provided on the drive shaft; a motor having a rotor and a stator; a transmission mechanism configured to transmit motor torque of the motor to the output portion; and a motor output shaft connected to the rotor and having a second axis different from the first axis, wherein the transmission mechanism includes a first transmission portion having a reduction mechanism, at least a portion of which is configured to rotate around the second axis and overlaps with the motor when viewed from a first direction perpendicular to the second axis. According to the drive unit of the twenty-first aspect, the transmission mechanism can preferably transmit motor torque to the drive shaft by the first transmission part including the reduction mechanism. Therefore, the drive unit can preferably impart propulsive force to the human-powered vehicle. According to the drive unit of the twenty-first aspect, at least a portion of the reduction mechanism is configured to rotate about the second axis and overlaps with the motor when viewed from a first direction perpendicular to the second axis, which contributes to miniaturization of the drive unit in the direction along the first axis. [Effects of the Invention]

[0026] The drive unit for a human-powered vehicle of the present disclosure can suitably impart propulsive force to the human-powered vehicle. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a side view of a human-powered vehicle including a drive unit for a human-powered vehicle according to an embodiment. [Figure 2] FIG. 2 is a side view of the drive unit for the human-powered vehicle of FIG. 1. [Figure 3] 3 is a side view of the drive unit for the human-powered vehicle of FIG. 2, with the housing omitted, as viewed from one side in the axial direction of the drive shaft. FIG. [Figure 4] 3 is a side view of the drive unit for a human-powered vehicle in FIG. 2, with the housing omitted, as viewed from the other side in the axial direction of the drive shaft. [Figure 5] 3 is a plan view of the drive unit for the human-powered vehicle of FIG. 2 with the housing omitted. [Figure 6] 6 is a cross-sectional view of the drive unit for a human-powered vehicle taken along line D6-D6 in FIG. 4. [Figure 7] FIG. 7 is an enlarged cross-sectional view of the drive unit for the human-powered vehicle of FIG. 6. [Figure 8] FIG. 7 is an enlarged cross-sectional view of the drive unit for the human-powered vehicle of FIG. 6. [Figure 9] FIG. 10 is an enlarged cross-sectional view of a modified example of a drive unit for a human-powered vehicle. [Figure 10]FIG. 10 is an enlarged cross-sectional view of a modified example of a drive unit for a human-powered vehicle. DETAILED DESCRIPTION OF THE INVENTION

[0028] <Embodiment> A drive unit 40 for a human-powered vehicle will be described with reference to FIGS. 1 to 8. A human-powered vehicle is a vehicle that has at least one wheel and can be propelled at least by human driving force. Human-powered vehicles include various types of bicycles, such as mountain bikes, road bikes, city bikes, cargo bikes, hand bikes, and recumbents. There is no limit to the number of wheels a human-powered vehicle has. Human-powered vehicles also include, for example, one-wheeled vehicles and vehicles with two or more wheels. Human-powered vehicles are not limited to vehicles that can be propelled solely by human driving force. Human-powered vehicles include E-bikes that use not only human driving force but also the driving force of an electric motor for propulsion. E-bikes include electrically assisted bicycles whose propulsion is assisted by an electric motor. In the following embodiments, the human-powered vehicle will be described as an electrically assisted bicycle.

[0029] As shown in FIG. 1, the human-powered vehicle 10 includes, for example, a crank 12 to which human-powered driving force is input. The human-powered vehicle 10 includes, for example, wheels 14 and a vehicle body 16. The wheels 14 include, for example, drive wheels 14A and driven wheels 14B. The drive wheels 14A are, for example, rear wheels of the human-powered vehicle 10. The driven wheels 14B are, for example, front wheels of the human-powered vehicle 10. The drive wheels 14A may be front wheels of the human-powered vehicle 10. If the drive wheels 14A are front wheels, the driven wheels 14B are rear wheels.

[0030] The vehicle body 16 includes, for example, a frame 18. The crank 12 includes, for example, a crankshaft 12A that is rotatable relative to the frame 18, and crank arms 12B and 12C that are provided at each end of the crankshaft 12A in the axial direction. A pedal 20A is connected to the crank arm 12B. A pedal 20B is connected to the crank arm 12C. The drive wheel 14A is driven, for example, by the rotation of the crank 12. The drive wheel 14A is supported, for example, by the frame 18.

[0031] The crank 12 is connected to a drive wheel 14A by, for example, a drive mechanism 22. The drive mechanism 22 includes, for example, a first rotating body 24 connected to the crankshaft 12A. The crankshaft 12A is connected to the first rotating body 24 via, for example, a first one-way clutch 38 shown in FIG. 6. The crankshaft 12A may be connected to the first rotating body 24 so as to rotate integrally with the first rotating body 24. The first rotating body 24 includes, for example, a sprocket, a pulley, or a bevel gear.

[0032] The drive mechanism 22 further includes, for example, a second rotating body 26 and a connecting member 28. The connecting member 28 transmits the rotational force of the first rotating body 24 to the second rotating body 26. The connecting member 28 includes, for example, a chain, a belt, or a shaft.

[0033] The second rotating body 26 is coupled to, for example, the drive wheel 14A. The second rotating body 26 includes, for example, a sprocket, a pulley, or a bevel gear. In the power transmission path of the human-powered driving force, a second one-way clutch is provided between the second rotating body 26 and the drive wheel 14A. The second one-way clutch is configured, for example, to rotate the drive wheel 14A forward when the second rotating body 26 rotates forward. The second one-way clutch is configured, for example, to allow relative rotation between the second rotating body 26 and the drive wheel 14A when the second rotating body 26 rotates backward.

[0034] A front wheel is attached to the frame 18 via, for example, a front fork 30. A handlebar 34 is connected to the front fork 30 via a stem 32. In this embodiment, a rear wheel is connected to the crank 12 by a drive mechanism 22. In this embodiment, the rear wheel is a drive wheel 14A, and the front wheel is a driven wheel 14B.

[0035] The human-powered vehicle 10 further includes, for example, a battery 36. The battery 36 includes, for example, one or more battery elements. The battery element includes, for example, a rechargeable battery. The battery 36 is configured to supply power to, for example, the drive unit 40. The battery 36 is communicatively connected to, for example, the drive unit 40 via a wired or wireless connection. When the battery 36 is communicatively connected to the drive unit 40 via a wired connection, the battery 36 is configured to communicate with the drive unit 40 via a conductor such as a circuit board wiring or an electric wire. When the battery 36 is communicatively connected to the drive unit 40 via a wired connection, the battery 36 may be configured to communicate with the drive unit 40 via a fiber optic cable. The battery 36 can communicate with the drive unit 40 via, for example, power line communication (PLC), a controller area network (CAN), or a universal asynchronous receiver / transmitter (UART).

[0036] As shown in FIGS. 2 to 8, a drive unit 40 for a human-powered vehicle includes, for example, a support portion 42, a drive shaft 44, an output portion 46, a motor 48, a transmission mechanism 50, and a motor output shaft 52.

[0037] As shown in FIG. 6 , the drive unit 40 includes, for example, a housing 54. The housing 54 defines, for example, an accommodation space SA. The housing 54 accommodates, for example, at least one of the drive shaft 44, the output unit 46, the motor 48, the transmission mechanism 50, and the motor output shaft 52 at least partially in the accommodation space SA. The housing 54 includes, for example, a metal material. The metal material includes, for example, at least one of an aluminum alloy and a magnesium alloy. The housing 54 may include a synthetic resin instead of or in addition to a metal material.

[0038] The support portion 42 is, for example, integrally formed with at least a portion of the housing 54. The support portion 42 at least partially supports at least one of the drive shaft 44, the motor 48, the transmission mechanism 50, and the motor output shaft 52, for example.

[0039] The drive unit 40 is detachably attached to, for example, the frame 18. The housing 54 has at least one mounting portion 54A. The at least one mounting portion 54A is provided on the outer periphery of the housing 54. The at least one mounting portion 54A includes at least one of a hole and an internally threaded portion. The hole and the internally threaded portion extend, for example, in a direction parallel to the drive shaft 44. The housing 54 has, for example, three mounting portions 54A. For example, the drive unit 40 is attached to the frame 18 by engaging a fastener such as a bolt with the at least one mounting portion 54A and a portion of the frame 18 that corresponds to the at least one mounting portion 54A.

[0040] The support portion 42 includes, for example, a first support portion 42X and a second support portion 42Y. The first support portion 42X includes, for example, a wall portion of the housing 54 on one side in the axial direction X of the drive shaft 44. The second support portion 42Y includes, for example, a wall portion of the housing 54 on the other side in the axial direction X of the drive shaft 44. The second support portion 42Y is attached to the first support portion 42X by a fastener such as a bolt. For example, by attaching the first support portion 42X to the second support portion 42Y, an accommodation space SA is formed between the first support portion 42X and the second support portion 42Y. The support portion 42 includes, for example, a third support portion 42Z. The third support portion 42Z is ​​disposed in the accommodation space SA, for example. The third support portion 42Z supports, for example, at least a portion of the motor output shaft 52 and at least a portion of the transmission mechanism 50.

[0041] The drive shaft 44 receives, for example, a manual driving force and has a first axis C1. The drive shaft 44 is, for example, the crankshaft 12A. The drive shaft 44 may be a shaft different from the crankshaft 12A as long as it receives a manual driving force. If the drive shaft 44 is a shaft different from the crankshaft 12A, the drive shaft 44 may be an shaft connected to the crankshaft 12A and spaced apart from the crankshaft 12A. The drive shaft 44 is, for example, formed of metal. The drive shaft 44 is, for example, a hollow shaft. The drive shaft 44 may also be a solid shaft. The drive shaft 44 is, for example, supported by the support portion 42 so as to be rotatable relative to the support portion 42. In the radial direction of the drive shaft 44, a bearing for rotatably supporting the drive shaft 44 is provided between the drive shaft 44 and the support portion 42.

[0042] As shown in FIGS. 6 to 8, the support portion 42 is provided with a first hole 42A and a second hole 42B. The first hole 42A is provided, for example, in the first support portion 42X. The second hole 42B is provided, for example, in the second support portion 42Y. The drive shaft 44 has, for example, a first drive shaft end portion 44A and a second drive shaft end portion 44B opposite the first drive shaft end portion 44A in the axial direction X of the drive shaft 44. The drive shaft 44 passes through, for example, the first hole 42A and the second hole 42B. The first drive shaft end portion 44A and the second drive shaft end portion 44B are exposed to the outside of the support portion 42. The first drive shaft end portion 44A is exposed to the outside of the support portion 42 from the first hole 42A. The second drive shaft end portion 44B is exposed to the outside of the support portion 42 from the second hole 42B.

[0043] The output portion 46 is provided on, for example, the drive shaft 44. The output portion 46 is, for example, a hollow shaft. At least a portion of the drive shaft 44 is inserted into, for example, the output portion 46. The output portion 46 includes, for example, a metal material. The output portion 46 has a first output portion end portion 46A and a second output portion end portion 46B opposite the first output portion end portion 46A in the axial direction X of the drive shaft 44. The output portion 46 includes, for example, a connection portion 46C. The connection portion 46C is provided on, for example, the second output portion end portion 46B of the output portion 46. The connection portion 46C is provided on, for example, the outer peripheral surface of the second output portion end portion 46B of the output portion 46. The connection portion 46C has, for example, a spline. The first rotor 24 is attached to the connection portion 46C, for example.

[0044] At least a portion of the output portion 46 is disposed in, for example, the second hole 42B. The output portion 46 is supported by, for example, the second support portion 42Y so as to be rotatable relative to the second support portion 42Y. For example, a bearing is provided between the output portion 46 and the second support portion 42Y in the radial direction of the output portion 46, for example, to support the output portion 46 rotatably relative to the second support portion 42Y. The output portion 46 is disposed around the drive shaft 44. The output portion 46 is coupled to the drive shaft 44 via, for example, a first one-way clutch 38. For example, the first one-way clutch 38 is configured to rotate the output portion 46 when the drive shaft 44 rotates in a first rotational direction B1. For example, the first one-way clutch 38 is configured to allow relative rotation between the drive shaft 44 and the output portion 46 when the drive shaft 44 rotates in a second rotational direction B2 opposite to the first rotational direction B1.

[0045] The motor 48 is configured, for example, to provide a propulsive force to the human-powered vehicle 10. The motor 48 is configured to transmit a rotational force to at least one of the human-powered driving force transmission path from the pedals 20A, 20B to the driving wheel 14A and the driven wheel 14B via a motor output shaft 52. The power transmission path of the human-powered driving force from the pedals 20A, 20B to the driving wheel 14A includes the driving wheel 14A. The motor 48 is provided, for example, on the frame 18 of the human-powered vehicle 10. The motor 48 is configured, for example, to transmit a rotational force to the output unit 46 via the motor output shaft 52.

[0046] The motor 48 includes, for example, an electric motor. The motor 48 is, for example, a radial gap type motor. The motor 48 is, for example, an inner rotor type motor. The motor 48 is, for example, a brushless motor. The motor 48 may also be an axial gap type motor.

[0047] The motor 48 has, for example, a rotor 56 and a stator 58. The stator 58 is, for example, disposed radially outward of the rotor 56. The stator 58 is, for example, attached to the housing 54. The stator 58 is, for example, formed in an annular shape. The portion of the housing 54 that houses the stator 58 is, for example, formed integrally with the other portion of the housing 54. The portion of the housing 54 that houses the stator 58 may also be formed separately from the other portion of the housing 54.

[0048] The rotor 56 is configured to be rotatable relative to the stator 58, for example. The rotor 56 includes, for example, a magnet. The rotor 56 is formed to be hollow, for example. The rotor 56 has, for example, a through-hole 56A through which the motor output shaft 52 passes. The rotor 56 includes, for example, an outer circumferential portion 56B, an inner circumferential portion 56C, and a middle portion 56D.

[0049] The outer peripheral portion 56B is formed, for example, in an annular shape when viewed in a direction along the rotational axis of the rotor 56. The outer peripheral surface of the outer peripheral portion 56B faces, for example, the stator 58. The magnet is attached, for example, to the outer peripheral portion 56B. The magnet may be magnetized on the outer peripheral portion 56B. The inner peripheral portion 56C is formed, for example, in an annular shape when viewed in a direction along the rotational axis of the rotor 56. The through hole 56A is provided, for example, in the inner peripheral portion 56C. The intermediate portion 56D connects the outer peripheral portion 56B and the inner peripheral portion 56C. The intermediate portion 56D extends, for example, in the radial direction of the rotor 56. The intermediate portion 56D is formed, for example, in a rod shape or a plate shape when viewed in a direction along the rotational axis of the rotor 56. The rotor 56 includes, for example, a plurality of intermediate portions 56D. In the present embodiment, the rotor 56 includes five intermediate portions 56D. The multiple intermediate portions 56D are, for example, arranged at equal intervals in the circumferential direction of the rotor 56. The rotor 56 may include only one intermediate portion 56D.

[0050] The dimension of the intermediate portion 56D in the direction along the rotational axis of the rotor 56 is, for example, equal to or smaller than the dimension of the inner peripheral portion 56C in the direction along the rotational axis of the rotor 56. The dimension of the intermediate portion 56D in the direction along the rotational axis of the rotor 56 is, for example, equal to or smaller than the dimension of the outer peripheral portion 56B in the direction along the rotational axis of the rotor 56. The dimension of the inner peripheral portion 56C in the direction along the rotational axis of the rotor 56 is, for example, smaller than the dimension of the outer peripheral portion 56B in the direction along the rotational axis of the rotor 56. In the direction along the rotational axis of the rotor 56, the intermediate portion 56D is, for example, disposed between one end and the other end of the outer peripheral portion 56B in the direction along the rotational axis of the rotor 56. In the direction along the rotational axis of the rotor 56, the intermediate portion 56D is, for example, disposed between one end and the other end of the inner peripheral portion 56C in the direction along the rotational axis of the rotor 56.

[0051] 2, the motor 48 has, for example, a first maximum outer diameter RA. The first maximum outer diameter RA substantially coincides with, for example, the maximum outer diameter of the rotor 56. The output portion 46 has, for example, a second maximum outer diameter RB. The second maximum outer diameter RB substantially coincides with the maximum diameter of the fourth transmission gear 84B. The first maximum outer diameter RA is, for example, larger than the second maximum outer diameter RB.

[0052] As shown in FIGS. 6 to 8 , the motor output shaft 52 is connected to, for example, the rotor 56 and has a second axis C2 different from the first axis C1. The rotational axis of the rotor 56 is, for example, coincident with the second axis C2. The rotational torque of the rotor 56 is transmitted to the outside of the motor 48 via, for example, the motor output shaft 52. In this specification, the motor 48 does not include the motor output shaft 52. In this specification, the motor output shaft 52 is a member different from the members that constitute the motor 48. The motor output shaft 52 is, for example, attached to the rotor 56 so as to rotate integrally with the rotor 56.

[0053] In this embodiment, the direction perpendicular to the second axis C2 will be described as the first direction A1. In this embodiment, the direction parallel to the second axis C2 will be described as the second direction A2. The motor output shaft 52 extends, for example, in the second direction A2. The motor output shaft 52 has, for example, a first motor output shaft end 52A and a second motor output shaft end 52B opposite the first motor output shaft end 52A in the second direction A2. The first motor output shaft end 52A passes through, for example, a through hole 56A. The second motor output shaft end 52B is, for example, a free end.

[0054] The drive unit 40 further includes, for example, a first bearing 60 that rotatably supports the motor output shaft 52. The first bearing 60 rotatably supports, for example, the first motor output shaft end portion 52A. The first bearing 60 includes, for example, a radial bearing. The first bearing 60 includes, for example, an inner ring, an outer ring, and a plurality of rolling elements disposed between the inner ring and the outer ring.

[0055] The first bearing 60 is provided, for example, on the first support portion 42X. At least a portion of the first bearing 60 overlaps with the rotor 56, for example, when viewed from the first direction A1. At least a portion of the first bearing 60 is disposed, for example, in a hollow portion of the rotor 56. At least a portion of the first bearing 60 is disposed between the inner circumferential surface of the stator 58 and the motor output shaft 52. At least a portion of the first bearing 60 is disposed between the inner circumferential surface of the rotor 56, which is formed in an annular shape, and the motor output shaft 52.

[0056] The drive unit 40 further includes, for example, a second bearing 62 that rotatably supports the motor output shaft 52. The second bearing 62 rotatably supports, for example, an intermediate portion between the first motor output shaft end portion 52A and the second motor output shaft end portion 52B. The second bearing 62 includes, for example, a radial bearing. The second bearing 62 includes, for example, an inner ring, an outer ring, and a plurality of rolling elements disposed between the inner ring and the outer ring. The inner diameter of the inner ring of the second bearing 62 is smaller than the inner diameter of the inner ring of the first bearing 60. The outer diameter of the outer ring of the second bearing 62 is smaller than the outer diameter of the outer ring of the first bearing 60.

[0057] At least a portion of the second bearing 62 overlaps with the stator 58, for example, when viewed from the first direction A1. At least a portion of the second bearing 62 is disposed, for example, in a hollow portion of the rotor 56. At least a portion of the second bearing 62 is disposed between the motor output shaft 52 and the inner circumferential surface of the annular stator 58. The second bearing 62 is disposed, for example, between the carrier 76 and the motor output shaft 52 in the first direction A1. The second bearing 62 is disposed, for example, between the sun gear 70 and the carrier 76 in the second direction A2.

[0058] The transmission mechanism 50 is configured, for example, to transmit the motor torque of the motor 48 to the output unit 46. The transmission mechanism 50 is provided, for example, in a motor torque transmission path from the motor 48 to the output unit 46. The transmission mechanism 50 is configured, for example, to reduce the rotational speed of the motor 48 and transmit the motor torque to the output unit 46. The transmission mechanism 50 is configured, for example, to reduce the rotational speed of the motor 48 in two or more stages and transmit the motor torque to the output unit 46. In the present embodiment, the transmission mechanism 50 is configured to reduce the rotational speed of the motor 48 in three stages and transmit the motor torque to the output unit 46.

[0059] 6 to 8, the transmission mechanism 50 includes, for example, a first transmission unit 64. The first transmission unit 64 has, for example, a speed reduction mechanism 66. The speed reduction mechanism 66 is configured, for example, to reduce the rotational speed of the motor 48 and output the reduced rotational speed. At least a portion of the speed reduction mechanism 66 is configured, for example, to rotate about the second axis C2 and overlaps with the motor 48 when viewed from a first direction A1 perpendicular to the second axis C2.

[0060] The first transmission unit 64 has, for example, a planetary gear mechanism 68. The planetary gear mechanism 68 is configured, for example, as a speed reducer. The reduction mechanism 66 includes, for example, the planetary gear mechanism 68. The planetary gear mechanism 68 is configured, for example, so that the rotational speed of an output rotor connected to the output unit 46 of the planetary gear mechanism 68 is slower than the rotational speed of an input rotor connected to the rotor 56 of the planetary gear mechanism 68. At least a portion of the planetary gear mechanism 68 is supported, for example, by the support unit 42.

[0061] As shown in FIGS. 2, 4, and 7, at least a portion of the planetary gear mechanism 68 is disposed, for example, radially inward of the rotor 56. At least a portion of the planetary gear mechanism 68 is disposed, for example, radially inward of the outer circumferential portion 56B of the rotor 56. The planetary gear mechanism 68 includes, for example, a portion disposed adjacent to the inner circumferential portion 56C of the rotor 56 in the second direction A2, and a portion disposed not adjacent to the inner circumferential portion 56C of the rotor 56. At least a portion of the planetary gear mechanism 68 is disposed, for example, adjacent to the intermediate portion 56D of the rotor 56 in the second direction A2. At least a portion of the planetary gear mechanism 68 is disposed radially outward of the inner circumferential portion 56C of the rotor 56. The dimensions of the planetary gear mechanism 68 arranged radially inside the outer circumferential portion 56B of the rotor 56 are larger than the dimensions of the planetary gear mechanism 68 arranged radially outside the inner circumferential portion 56C of the rotor 56, for example, in the second direction A2.

[0062] 6 to 8, at least a portion of the planetary gear mechanism 68 is configured to rotate about the second axis C2, for example, and overlaps with the motor 48 when viewed from a first direction A1 perpendicular to the second axis C2. At least a portion of the planetary gear mechanism 68 overlaps with the stator 58 when viewed from the first direction A1, for example. At least a portion of the planetary gear mechanism 68 is disposed radially inward of the stator 58, for example.

[0063] At least a portion of the planetary gear mechanism 68 overlaps with the rotor 56, for example, when viewed from the first direction A1. At least a portion of the planetary gear mechanism 68 overlaps with the outer circumferential portion 56B of the rotor 56, for example, when viewed from the first direction A1. At least a portion of the planetary gear mechanism 68 overlaps with the inner circumferential portion 56C of the rotor 56, for example, when viewed from the first direction A1. The planetary gear mechanism 68 includes, for example, a portion that overlaps with the intermediate portion 56D of the rotor 56 and a portion that does not overlap with the intermediate portion 56D of the rotor 56, when viewed from the first direction A1.

[0064] In the present embodiment, a portion of the planetary gear mechanism 68 overlaps with the motor 48 when viewed from the first direction A1. The entire planetary gear mechanism 68 may overlap with the motor 48 when viewed from the first direction A1. When the entire planetary gear mechanism 68 overlaps with the motor 48 when viewed from the first direction A1, for example, the planetary gear mechanism 68 and the rotor 56 are configured so that the entire planetary gear mechanism 68 is disposed radially inward of the outer circumferential portion 56B of the rotor 56 when viewed from the first direction A1.

[0065] The planetary gear mechanism 68 includes, for example, a sun gear 70 , a ring gear 72 , a planetary gear 74 provided between the sun gear 70 and the ring gear 72 , and a carrier 76 that supports the planetary gear 74 .

[0066] The sun gear 70 is provided on, for example, the motor output shaft 52. The sun gear 70 receives rotational torque from, for example, the motor output shaft 52. The sun gear 70 may be molded integrally with the motor output shaft 52, or may be molded separately from the motor output shaft 52 and attached to the motor output shaft 52 so as to rotate integrally therewith. In this embodiment, the sun gear 70 is formed separately from the motor output shaft 52. The sun gear 70 is attached to the motor output shaft 52 so as to contact, for example, a stepped portion provided on the motor output shaft 52. The sun gear 70 is disposed, for example, between the rotor 56 and the second bearing 62 in the second direction A2. The sun gear 70 is disposed, for example, so as to be adjacent to the inner circumferential portion 56C of the rotor 56 in the second direction A2. The sun gear 70 meshes with, for example, the planetary gear 74. The axis of the sun gear 70 is substantially aligned with the second axis C2 of the motor output shaft 52.

[0067] The ring gear 72 meshes with, for example, planetary gears 74. The ring gear 72 is provided on the support portion 42 so as to be unable to rotate relative to the support portion 42. The ring gear 72 is supported by, for example, the third support portion 42Z. The ring gear 72 is attached to, for example, the third support portion 42Z. The ring gear 72 includes, for example, a flange portion 72A that protrudes radially outward. The ring gear 72 includes, for example, a ring gear attachment portion 72B for attachment to the third support portion 42Z. The ring gear attachment portion 72B is provided on, for example, the flange portion 72A. The ring gear 72 is attached to the third support portion 42Z with, for example, a bolt or the like. The ring gear 72 may be formed integrally with the support portion 42.

[0068] The planetary gear 74 is provided, for example, between the sun gear 70 and the ring gear 72, and transmits the rotational torque of the sun gear 70. The planetary gear 74 is, for example, one of the plurality of planetary gears 74. The plurality of planetary gears 74 are, for example, arranged at intervals around the second axis C2 of the motor output shaft 52. The number of the plurality of planetary gears 74 is, for example, two or more and eight or less. The number of the plurality of planetary gears 74 is, for example, four.

[0069] The carrier 76 supports, for example, the planetary gear 74 and outputs rotational torque to the output portion 46. The carrier 76 includes, for example, a carrier pin support portion 76A, a carrier shaft portion 76B, and a carrier pin 76C. The carrier pin support portion 76A is molded integrally with the carrier shaft portion 76B. The rotation axis of revolution of the carrier 76 is substantially equal to the second axis C2 of the motor output shaft 52. The carrier shaft portion 76B is disposed around, for example, the motor output shaft 52.

[0070] The carrier pin 76C rotatably supports the planetary gear 74, for example, via a bearing. The carrier pin 76C is, for example, one of the multiple carrier pins 76C. The multiple carrier pins 76C are provided on the carrier pin support portion 76A so as to be spaced apart around the second axis C2 of the motor output shaft 52, for example. The number of the multiple carrier pins 76C corresponds to the number of the multiple planetary gears 74.

[0071] At least one of the sun gear 70, the planetary gears 74, and the ring gear 72 at least partially overlaps with the motor 48, for example, when viewed from the first direction A1. At least a portion of the sun gear 70 overlaps with the motor 48, for example, when viewed from the first direction A1. At least a portion of the planetary gears 74 overlap with the motor 48, for example, when viewed from the first direction A1. At least a portion of the carrier 76 overlaps with the motor 48, for example, when viewed from the first direction A1. At least a portion of the ring gear 72 overlaps with the motor 48, for example, when viewed from the first direction A1. When at least one of the carrier 76, the sun gear 70, the planetary gears 74, and the ring gear 72 at least partially overlaps with the motor 48, when viewed from the first direction A1, the other of the carrier 76, the sun gear 70, the planetary gears 74, and the ring gear 72 may not overlap with the motor 48, when viewed from the first direction A1.

[0072] At least one of the carrier 76, the sun gear 70, the planetary gears 74, and the ring gear 72 at least partially overlaps with the stator 58 when viewed from the first direction A1, for example. At least one of the carrier 76, the sun gear 70, the planetary gears 74, and the ring gear 72 at least partially overlaps with the rotor 56 when viewed from the first direction A1, for example.

[0073] 6 to 8, at least a portion of the sun gear 70 overlaps with the stator 58, for example, when viewed from the first direction A1. In this embodiment, the entire sun gear 70 overlaps with the stator 58, when viewed from the first direction A1. Only a portion of the sun gear 70 may overlap with the stator 58, when viewed from the first direction A1. At least a portion of the sun gear 70 is disposed radially inward of the stator 58, for example.

[0074] At least a portion of the sun gear 70 overlaps with the rotor 56, for example, when viewed from the first direction A1. At least a portion of the sun gear 70 overlaps with the outer circumferential portion 56B of the rotor 56, for example, when viewed from the first direction A1. In this embodiment, only a portion of the sun gear 70 overlaps with the outer circumferential portion 56B of the rotor 56, when viewed from the first direction A1. The entire sun gear 70 may overlap with the outer circumferential portion 56B of the rotor 56, when viewed from the first direction A1. The sun gear 70 does not overlap with the inner circumferential portion 56C of the rotor 56, for example, when viewed from the first direction A1. At least a portion of the sun gear 70 may overlap with the inner circumferential portion 56C of the rotor 56, for example, when viewed from the first direction A1.

[0075] At least a portion of the ring gear 72 overlaps with the stator 58, for example, when viewed from the first direction A1. In this embodiment, the entire ring gear 72 overlaps with the stator 58, when viewed from the first direction A1. Only a portion of the ring gear 72 may overlap with the stator 58, when viewed from the first direction A1. At least a portion of the ring gear 72 is disposed radially inward of the stator 58, for example.

[0076] At least a portion of the ring gear 72 overlaps with the rotor 56, for example, when viewed from the first direction A1. At least a portion of the ring gear 72 overlaps with the outer circumferential portion 56B of the rotor 56, for example, when viewed from the first direction A1. In this embodiment, only a portion of the ring gear 72 overlaps with the outer circumferential portion 56B of the rotor 56, for example, when viewed from the first direction A1. The entire ring gear 72 may overlap with the outer circumferential portion 56B of the rotor 56, for example, when viewed from the first direction A1. At least a portion of the flange portion 72A is provided in a position adjacent to the outer circumferential portion 56B of the rotor 56, for example, in the second direction A2. The ring gear 72 does not overlap with the inner circumferential portion 56C of the rotor 56, for example, when viewed from the first direction A1. At least a portion of the ring gear 72 may overlap with the inner circumferential portion 56C of the rotor 56, for example, when viewed from the first direction A1.

[0077] At least a portion of the planetary gear 74 overlaps with the stator 58 when viewed from the first direction A1, for example. In this embodiment, the entire planetary gear 74 overlaps with the stator 58 when viewed from the first direction A1. Only a portion of the planetary gear 74 may overlap with the stator 58 when viewed from the first direction A1. At least a portion of the planetary gear 74 is disposed radially inward of the stator 58, for example.

[0078] At least a portion of the planetary gears 74 overlaps with the rotor 56, for example, when viewed from the first direction A1. At least a portion of the planetary gears 74 overlaps with the outer circumferential portion 56B of the rotor 56, for example, when viewed from the first direction A1. In this embodiment, only a portion of the planetary gears 74 overlaps with the outer circumferential portion 56B of the rotor 56, when viewed from the first direction A1. The entire planetary gears 74 may overlap with the outer circumferential portion 56B of the rotor 56, when viewed from the first direction A1. The planetary gears 74 do not overlap with the inner circumferential portion 56C of the rotor 56, for example, when viewed from the first direction A1. At least a portion of the planetary gears 74 may overlap with the inner circumferential portion 56C of the rotor 56, when viewed from the first direction A1.

[0079] At least a portion of the carrier 76 overlaps with the stator 58, for example, when viewed from the first direction A1. In the present embodiment, only a portion of the carrier 76 overlaps with the stator 58, when viewed from the first direction A1. The entire carrier 76 may overlap with the stator 58, when viewed from the first direction A1. At least a portion of the carrier 76 is disposed radially inward of the stator 58, for example.

[0080] At least a portion of the carrier 76 overlaps with the rotor 56, for example, when viewed from the first direction A1. At least a portion of the carrier 76 overlaps with the outer periphery 56B of the rotor 56, for example, when viewed from the first direction A1. In this embodiment, only a portion of the carrier 76 overlaps with the outer periphery 56B of the rotor 56, when viewed from the first direction A1. The entire carrier 76 may overlap with the outer periphery 56B of the rotor 56, when viewed from the first direction A1. At least a portion of the carrier 76 overlaps with the inner periphery 56C of the rotor 56, for example, when viewed from the first direction A1. In this embodiment, only a portion of the carrier pins 76C of the carrier 76 overlap with the inner periphery 56C of the rotor 56, when viewed from the first direction A1. The carrier 76 does not have to overlap with the inner periphery 56C of the rotor 56, when viewed from the first direction A1.

[0081] As shown in FIGS. 2 and 7 , the planetary gear mechanism 68 has, for example, a maximum outer diameter RX. The maximum outer diameter RX substantially matches the maximum outer diameter of the ring gear 72, for example. The motor 48 has, for example, a minimum inner diameter RY. The minimum inner diameter RY substantially matches the diameter of the inner circumferential surface of the rotor 56, for example. The maximum outer diameter RX of the planetary gear mechanism 68 is smaller than the minimum inner diameter RY of the motor 48, for example. The diameter of the root circle of the ring gear 72 is smaller than the diameter of the inner circumferential surface of the outer circumferential portion 56B of the rotor 56, for example. The maximum outer diameter of the ring gear 72 is larger than the diameter of the inner circumferential surface of the outer circumferential portion 56B of the rotor 56, for example. The maximum outer diameter of the ring gear 72 may be equal to or smaller than the diameter of the inner circumferential surface of the outer circumferential portion 56B of the rotor 56, for example. The outer diameter of the portion of the ring gear 72 where the teeth are provided is smaller than the diameter of the inner circumferential surface of the outer circumferential portion 56B of the rotor 56, for example.

[0082] As shown in FIGS. 2 and 6 to 8, the transmission mechanism 50 further includes, for example, a transmission shaft 78 having a third axis C3 different from both the first axis C1 and the second axis C2. The second axis C2 and the third axis C3 are parallel to the first axis C1. The drive shaft 44, the motor output shaft 52, and the transmission shaft 78 are arranged, for example, on the same plane. When viewed from the second direction A2, the first axis C1, the second axis C2, and the third axis C3 are arranged on a single straight line. The transmission shaft 78 is arranged, for example, alongside the motor 48 in the first direction A1. The distance from the drive shaft 44 to the motor output shaft 52 is, for example, greater than the distance from the drive shaft 44 to the transmission shaft 78.

[0083] The transmission shaft 78 is, for example, a hollow shaft. The transmission shaft 78 may also be a solid shaft. The transmission shaft 78 is supported, for example, by the second support portion 42Y and the third support portion 42Z. The transmission shaft 78 has, for example, a first transmission shaft end portion 78A and a second transmission shaft end portion 78B opposite the first transmission shaft end portion 78A in the second direction A2. The first transmission shaft end portion 78A is supported, for example, by the third support portion 42Z. In the first direction A1, a bearing is provided between the first transmission shaft end portion 78A and the third support portion 42Z. The second transmission shaft end portion 78B is supported, for example, by the second support portion 42Y. A bearing is provided, for example, between the second transmission shaft end portion 78B and the second support portion 42Y.

[0084] The transmission shaft 78 includes, for example, a first portion 78X and a second portion 78Y. The first portion 78X includes, for example, a first transmission shaft end portion 78A. The second portion 78Y includes, for example, a second transmission shaft end portion 78B. The first portion 78X is, for example, formed integrally with the second portion 78Y. The maximum outer diameter of the first portion 78X is, for example, larger than the maximum outer diameter of the second portion 78Y.

[0085] The transmission mechanism 50 further includes, for example, a second transmission unit 80. The second transmission unit 80 has, for example, a first transmission gear 80A to which torque is transmitted from the planetary gear mechanism 68, and a second transmission gear 80B that engages with the first transmission gear 80A and is provided on the transmission shaft 78. The first transmission gear 80A is disposed around, for example, the carrier shaft portion 76B. The axis of the first transmission gear 80A is substantially aligned with the second axis C2 of the motor output shaft 52.

[0086] The second transmission gear 80B is disposed, for example, around the transmission shaft 78. The axis of the second transmission gear 80B is substantially equal to the third axis C3 of the transmission shaft 78.

[0087] The first transmission gear 80A has, for example, a first pitch circle diameter R1. The second transmission gear 80B has, for example, a second pitch circle diameter R2. The second pitch circle diameter R2 is, for example, larger than the first pitch circle diameter R1. Because the second pitch circle diameter R2 is larger than the first pitch circle diameter R1, the rotational speed of the second transmission gear 80B is slower than the rotational speed of the first transmission gear 80A. Each of the first transmission gear 80A and the second transmission gear 80B may include, for example, a helical gear. Each of the first transmission gear 80A and the second transmission gear 80B may also include a spur gear.

[0088] The drive unit 40 further includes, for example, a third one-way clutch 82. The third one-way clutch 82 is provided, for example, in a power transmission path between the motor 48 and the drive shaft 44. The third one-way clutch 82 is provided, for example, between the second transmission gear 80B and the transmission shaft 78 in the second direction A2. The second transmission gear 80B is connected to the transmission shaft 78 via, for example, the third one-way clutch 82. The third one-way clutch 82 may be provided between the rotor 56 and the motor output shaft 52. The third one-way clutch 82 may be provided anywhere in the transmission mechanism 50. The drive unit 40 does not necessarily have to include the third one-way clutch 82. When the drive unit 40 does not include the third one-way clutch 82, for example, the motor 48 is configured to be regenerative.

[0089] The third one-way clutch 82 is configured to allow relative rotation between the drive shaft 44 and the second transmission gear 80B, for example, when the drive shaft 44 rotates in the first rotational direction B1 and the rotation of the motor output shaft 52 is stopped. The third one-way clutch 82 includes, for example, at least one of a roller clutch, a sprag clutch, and a pawl clutch.

[0090] The transmission mechanism 50 further includes, for example, a third transmission part 84. The third transmission part 84 has, for example, a third transmission gear 84A and a fourth transmission gear 84B. The third transmission gear 84A is provided on, for example, the transmission shaft 78. In the second direction A2, the distance from the third transmission gear 84A to the second support part 42Y is shorter than, for example, the distance from the second transmission gear 80B to the second support part 42Y. The third transmission gear 84A may be connected to the transmission shaft 78 via a one-way clutch, or may be connected to the transmission shaft 78 so as to rotate integrally with the transmission shaft 78. The fourth transmission gear 84B engages with, for example, the third transmission gear 84A and is provided on the output part 46. The fourth transmission gear 84B is formed on the outer circumferential surface of the output part 46, at, for example, the first output part end 46A of the output part 46. The fourth transmission gear 84B may be formed separately from the output portion 46 and attached to the output portion 46 so as to rotate integrally therewith.

[0091] The third transmission gear 84A has, for example, a third pitch circle diameter R3. The fourth transmission gear 84B has, for example, a fourth pitch circle diameter R4. The fourth pitch circle diameter R4 is, for example, larger than the third pitch circle diameter R3. Because the fourth pitch circle diameter R4 is larger than the third pitch circle diameter R3, the rotation speed of the fourth transmission gear 84B is slower than the rotation speed of the third transmission gear 84A. The third transmission gear 84A and the fourth transmission gear 84B may, for example, form helical gears. The third transmission gear 84A and the fourth transmission gear 84B may also form spur gears.

[0092] As shown in FIGS. 3 to 8 , the drive unit 40 further includes, for example, a circuit board 86. Power from the battery 36 is supplied to, for example, the circuit board 86. The drive unit 40 may include a circuit board other than the circuit board 86. The circuit board 86 is, for example, disposed in the accommodation space SA. The circuit board 86 is, for example, disposed so that the mounting surface of the circuit board 86 is substantially parallel to the first direction A1. The circuit board 86 is, for example, disposed at a position away from the motor output shaft 52 in the second direction A2 parallel to the second axis C2. The circuit board 86 is, for example, disposed so as to face the second motor output shaft end 52B of the motor output shaft 52. The stator 58 includes, for example, a plurality of coils. The stator 58 includes, for example, a plurality of connection terminals to which the plurality of coils are electrically connected. The plurality of connection terminals extend, for example, along the second direction A2 and are electrically connected to the circuit board 86.

[0093] The circuit board 86 is configured to overlap the motor 48, for example, when viewed from the second direction A2. The circuit board 86 is configured to overlap the planetary gear mechanism 68, for example, when viewed from the second direction A2. The circuit board 86 is configured not to overlap the drive shaft 44, for example, when viewed from the second direction A2. The circuit board 86 is configured not to overlap at least a portion of the transmission mechanism 50, for example, when viewed from the second direction A2. The circuit board 86 is configured not to overlap the third transmission gear 84A, for example, when viewed from the second direction A2. The circuit board 86 is configured not to overlap the fourth transmission gear 84B, for example, when viewed from the second direction A2.

[0094] The drive unit 40 further includes, for example, a control unit. The control unit is provided, for example, on the circuit board 86. The control unit includes, for example, 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 unit may be provided in multiple locations that are separate from each other. The control unit may include one or multiple microcomputers.

[0095] The drive unit 40 further includes, for example, a storage unit. The storage unit is provided, for example, on the circuit board 86. The storage unit stores, for example, various control programs and information used for various control processes. The storage unit includes, for example, a non-volatile memory and a volatile memory. The non-volatile memory includes, for example, at least one of a read-only memory (ROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), and a flash memory. The volatile memory includes, for example, a random access memory (RAM).

[0096] The drive unit 40 further includes, for example, a drive circuit for the motor 48. The drive circuit is provided, for example, on the circuit board 86. The drive circuit includes, for example, an inverter circuit. The drive circuit controls, for example, the power supplied from the battery 36 to the motor 48. The drive circuit is, for example, connected to a control unit so as to be able to communicate with the control unit via a wired or wireless connection. When the drive circuit is connected to the control unit so as to be able to communicate with the control unit via a wired connection, the drive circuit is configured to communicate with the control unit via, for example, conductors such as circuit board wiring and electric wires. When the drive circuit is connected to the control unit so as to be able to communicate with the control unit via a wired connection, the drive circuit may be configured to communicate with the control unit via an optical fiber cable. The drive circuit drives the motor 48, for example, in response to a control signal from the control unit.

[0097] The drive unit 40 further includes, for example, a motor rotation state detector 88 that detects the rotation state of the motor output shaft 52. The motor rotation state detector 88 outputs a signal in response to the rotation of the motor output shaft 52. The motor rotation state detector 88 includes, for example, a magnetic sensor. The motor rotation state detector 88 is configured to detect a magnet provided on the motor output shaft 52. The magnet is provided on the second motor output shaft end 52B of the motor output shaft 52. The circuit board 86 includes, for example, a predetermined portion 86A that faces the motor output shaft 52 in the second direction A2. The motor rotation state detector 88 is provided on the predetermined portion 86A. The motor rotation state detector 88 is connected to the control unit via, for example, a conductive wire, an electric cable, or a wireless communication device. The motor rotation state detector 88 and the control unit are provided on a single circuit board 86.

[0098] The drive unit 40 further includes a human-powered driving force detection unit 90 that detects the human-powered driving force applied to the human-powered vehicle 10. The human-powered driving force detection unit 90 includes, for example, a strain sensor. The strain sensor includes a strain gauge. The human-powered driving force detection unit 90 may include a magnetostrictive sensor. The human-powered driving force detection unit 90 is provided, for example, on the outer circumferential surface of the drive shaft 44 or around the outer circumferential surface of the drive shaft 44. The human-powered driving force detection unit 90 is provided, for example, on a circuit board separate from the circuit board 86 on which the control unit is provided. The human-powered driving force detection unit 90 is connected to the control unit, for example, by a conductive wire, an electric cable, a wireless communication device, or the like. The human-powered driving force detection unit 90 may be provided on one or both of the crank arms 12B, 12C. When the manual driving force detection unit 90 is provided on one or both of the crank arms 12B, 12C, the manual driving force detection unit 90 includes, for example, a strain sensor.

[0099] The control unit is configured to calculate the rotation speed of the motor 48 based on, for example, a signal from the motor rotation state detection unit 88. The control unit is configured to control the motor 48 based on, for example, a signal from the motor rotation state detection unit 88. The control unit is configured to control the motor 48 based on, for example, a signal from the manual driving force detection unit 90. The control unit is configured to change the assist force by the motor 48 based on, for example, the signal from the manual driving force detection unit 90.

[0100] The transmission mechanism 50 shown in FIGS. 6 to 8 reduces the rotational speed of the motor 48 and transmits the motor torque to the output unit 46 using the first transmission unit 64, the second transmission unit 80, and the third transmission unit 84. The transmission mechanism 50 reduces the rotational speed of the motor 48 using multiple transmission units and transmits the motor torque to the output unit 46, thereby effectively providing propulsive force to the human-powered vehicle 10. Because the planetary gear mechanism 68 is provided on a shaft separate from the drive shaft 44, the drive unit 40 can position the rear wheel axle and the crankshaft 12A closer to each other than when the planetary gear mechanism 68 is provided on the drive shaft 44. Because the planetary gear mechanism 68 overlaps with the motor 48 when viewed from the first direction A1, the size of the drive unit 40 in the second direction A2 can be reduced.

[0101] <Example of change> The descriptions of the embodiments are merely examples of possible forms of a drive unit for a human-powered vehicle according to the present disclosure, and are not intended to limit the forms. A drive unit for a human-powered vehicle according to the present disclosure may take the form of, for example, modified examples of the embodiments shown below, or a combination of at least two mutually consistent modified examples. In the modified examples below, parts that are common to the embodiment are given the same reference numerals as the embodiment, and descriptions thereof will be omitted.

[0102] As shown in Fig. 9, the motor 48 may be an outer rotor type motor. The rotor 56 in Fig. 9 is disposed, for example, radially outward from the stator 58. At least a portion of the planetary gear mechanism 68 is disposed, for example, radially inward from the stator 58. At least a portion of the planetary gear mechanism 68 overlaps with the stator 58 when viewed, for example, from the first direction A1.

[0103] 10, at least a portion of the planetary gear mechanism 68 may overlap with the rotor 56 on the radially outer side of the motor 48 when viewed from the first direction A1. In this modification, the motor 48 may be an inner rotor type motor or an outer rotor type motor.

[0104] The transmission mechanism 50 may have a speed-up gear. In this modified example, at least one of the second transmission unit 80 and the third transmission unit 84 is configured as, for example, a speed-up gear. The transmission mechanism 50 may have, for example, a speed-up gear in addition to at least one of the second transmission unit 80 and the third transmission unit 84. In this modified example, the transmission mechanism 50 may be configured to reduce the rotational speed of the motor 48 by combining the reduction mechanism 66 and a speed-up gear, and transmit the motor torque to the output unit 46.

[0105] Instead of the planetary gear mechanism 68, the reduction mechanism 66 may include a first outer peripheral gear provided on the outer peripheral portion 56B of the rotor 56, and a second outer peripheral gear that meshes with the first outer peripheral gear and has a larger pitch circle diameter than the first outer peripheral gear. The second outer peripheral gear is provided on, for example, the transmission shaft 78. In this modification, for example, the first outer peripheral gear is configured to at least partially overlap with the motor 48 when viewed from the first direction A1.

[0106] The planetary gear mechanism 68 may be configured to output the rotational torque input to the sun gear 70 from the ring gear 72. In this modified example, the ring gear 72 is configured to output the rotational torque to, for example, the drive shaft 44. In this modified example, the carrier 76 is configured to be non-rotatable with respect to, for example, the sun gear 70.

[0107] The planetary gear mechanism 68 may be a speed-increasing mechanism. In this modified example, the transmission mechanism 50 may be configured to reduce the rotational speed of the motor 48 and transmit the motor torque to the output unit 46 by combining, for example, the planetary gear mechanism 68 configured as a speed-increasing mechanism with the second transmission unit 80 and the third transmission unit 84 configured as speed reducers.

[0108] At least one of the second transmission part 80 and the third transmission part 84 may be omitted. In addition to the first transmission part 64, the second transmission part 80, and the third transmission part 84, the transmission mechanism 50 may further include a transmission part different from the first transmission part 64, the second transmission part 80, and the third transmission part 84.

[0109] At least one of the second transmission unit 80 and the third transmission unit 84 may include a chain and sprockets instead of gears. At least one of the second transmission unit 80 and the third transmission unit 84 may include a pulley and a belt.

[0110] The transmission mechanism 50 may further include an additional transmission shaft in addition to the transmission shaft 78. When the transmission mechanism 50 includes the additional transmission shaft, the transmission mechanism 50 includes, for example, a fourth transmission part provided on the additional transmission shaft in addition to the planetary gear mechanism 68, the second transmission part 80, and the third transmission part 84.

[0111] At least one of the second axis C2 and the third axis C3 may be configured not to be parallel to the first axis C1. In this modified example, for example, the second axis C2 and the third axis C3 may be configured to be perpendicular to the first axis C1. In this modified example, for example, the motor 48 may be configured so that the second axis C2 and the third axis C3 are perpendicular to the axial direction X of the drive shaft 44 and the first axis C1.

[0112] At least a portion of the first bearing 60 may be disposed so as not to overlap with the rotor 56 when viewed from the first direction A1.

[0113] The circuit board 86 may be arranged so as not to overlap with the motor output shaft 52 in the second direction A2.

[0114] The circuit board 86 may be disposed so as to overlap the transmission shaft 78 in the second direction A2.

[0115] The first maximum outer diameter RA may be equal to or smaller than the second maximum outer diameter RB.

[0116] The motor rotation state detection unit 88 may be provided in a location other than the predetermined portion 86A. In this modified example, for example, the motor rotation state detection unit 88 is provided radially outward from the motor 48. In other words, as long as the motor rotation state detection unit 88 is provided in a location where it can detect the rotation state of the motor 48, the location of the motor rotation state detection unit 88 in the drive unit 40 can be changed as appropriate.

[0117] The drive unit 40 does not have to include the manual driving force detection unit 90. If the drive unit 40 does not include the manual driving force detection unit 90, a detection unit that detects the manual driving force may be provided on the crank arms 12B, 12C or the pedals 20A, 20B.

[0118] The phrase "at least one" as used herein means "one or more" of the desired options. As an example, the phrase "at least one" as used herein means "only one option" or "both of two options" when the number of options is two. As another example, the phrase "at least one" as used herein means "only one option" or "any combination of two or more options" when the number of options is three or more.

[0119] As used herein, ordinal numbers such as "first" and "second" are used merely to distinguish between identical names and do not have any special meaning. [Explanation of symbols]

[0120] 10...Manually-driven vehicle, 40...Drive unit, 42...Support portion, 44...Drive shaft, 46...Output portion, 48...Motor, 50...Transmission mechanism, 52...Motor output shaft, 56...Rotor, 58...Stator, 60...First bearing, 64...First transmission portion, 66...Reduction mechanism, 68...Planetary gear mechanism, 70...Sun gear, 72...Ring gear, 74...Planetary gear, 76...Carrier, 78...Transmission shaft, 80...Second transmission portion, 80A...First transmission gear, 80B...Second transmission gear, 84...Third transmission portion, 84A...Third transmission gear, 84B...Fourth transmission gear, 86...Circuit board, 86A...Specified portion, 88...Motor rotation state detection portion, 90...Manually-driven force detection portion.

Claims

1. A drive unit for a human-powered vehicle, A support part; a drive shaft that receives a manual drive force and has a first axis; an output portion provided on the drive shaft; a motor having a rotor and a stator; a transmission mechanism configured to transmit a motor torque of the motor to the output portion; a motor output shaft connected to the rotor and having a second axis different from the first axis, the transmission mechanism includes a first transmission part having a planetary gear mechanism, a drive unit in which at least a portion of the planetary gear mechanism is configured to rotate about the second axis and overlaps with the motor when viewed from a first direction perpendicular to the second axis.

2. The drive unit according to claim 1 , wherein at least a portion of the planetary gear mechanism overlaps with the rotor when viewed from the first direction.

3. the stator is disposed radially outward of the rotor, The drive unit according to claim 2 , wherein at least a portion of the planetary gear mechanism is disposed radially inward of the rotor.

4. the rotor is disposed radially outside the stator, The drive unit according to claim 2 , wherein at least a portion of the planetary gear mechanism is disposed radially inward of the stator.

5. The drive unit according to claim 1 , wherein at least a portion of the planetary gear mechanism overlaps with the rotor on a radially outer side of the motor when viewed from the first direction.

6. The drive unit according to claim 1 , wherein the transmission mechanism further includes a transmission shaft having a third axis different from both the first axis and the second axis.

7. 7. The drive unit according to claim 6, wherein the transmission mechanism further includes a second transmission part having a first transmission gear to which torque is transmitted from the planetary gear mechanism, and a second transmission gear that engages with the first transmission gear and is provided on the transmission shaft.

8. the first transmission gear has a first pitch diameter; the second transmission gear has a second pitch diameter; The drive unit of claim 7 , wherein the second pitch diameter is greater than the first pitch diameter.

9. 8. The drive unit according to claim 7, wherein the transmission mechanism further includes a third transmission part having a third transmission gear provided on the transmission shaft and a fourth transmission gear engaged with the third transmission gear and provided on the output part.

10. the third transmission gear has a third pitch diameter; the fourth transmission gear has a fourth pitch diameter; The drive unit of claim 9 , wherein the fourth pitch diameter is greater than the third pitch diameter.

11. The drive unit according to claim 6 , wherein the second axis and the third axis are parallel to the first axis.

12. The planetary gear mechanism includes: a sun gear that receives rotational torque from the motor output shaft; a ring gear provided on the support portion so as to be non-rotatable relative to the support portion; a planetary gear provided between the sun gear and the ring gear and to which rotational torque of the sun gear is transmitted; 2. The drive unit according to claim 1, further comprising: a carrier that supports the planetary gear and outputs a rotational torque to the output portion.

13. The drive unit according to claim 1 , wherein the entire planetary gear mechanism overlaps with the motor when viewed from the first direction.

14. The planetary gear mechanism includes: Sungia and Ring gear and a planetary gear provided between the sun gear and the ring gear; a carrier supporting the planetary gear; The drive unit according to claim 1 , wherein at least one of the sun gear, the planetary gears, and the ring gear at least partially overlaps with the motor when viewed from the first direction.

15. The drive unit according to claim 14 , wherein at least a portion of the ring gear overlaps with the motor when viewed from the first direction.

16. a first bearing that rotatably supports the motor output shaft; The drive unit according to claim 1 , wherein at least a portion of the first bearing overlaps with the rotor when viewed from the first direction.

17. the motor has a first maximum outer diameter; the output portion has a second maximum outer diameter; The drive unit of claim 1 , wherein the first maximum outer diameter is greater than the second maximum outer diameter.

18. Further comprising a circuit board; The drive unit according to claim 1 , wherein the circuit board is disposed at a position spaced apart from the motor output shaft in a second direction parallel to the second axis.

19. a motor rotation state detection unit that detects the rotation state of the motor output shaft; the circuit board includes a predetermined portion facing the motor output shaft in the second direction, The drive unit according to claim 18, wherein the motor rotation state detector is provided in the predetermined portion.

20. The drive unit according to claim 1 , further comprising a human-powered driving force detector that detects a human-powered driving force applied to the human-powered vehicle.

21. A drive unit for a human-powered vehicle, A support part; a drive shaft that receives a manual drive force and has a first axis; an output portion provided on the drive shaft; a motor having a rotor and a stator; a transmission mechanism configured to transmit a motor torque of the motor to the output portion; a motor output shaft connected to the rotor and having a second axis different from the first axis, the transmission mechanism includes a first transmission part having a reduction mechanism, A drive unit in which at least a portion of the reduction mechanism is configured to rotate around the second axis and overlaps with the motor when viewed from a first direction perpendicular to the second axis.

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