JP2024149551A - Drive unit for human-powered vehicles - Google Patents

Abstract

To provide a drive unit for a man-powered vehicle capable of being downsized in a direction in which a reduction shaft extends.SOLUTION: A drive unit includes a base, motor, and a speed reducer. The motor includes an output shaft extending in a predefined direction, a rotor, and a stator. The speed reducer includes on its periphery a first tooth formed at a first end of the output shaft, at least one bearing which bears a reduction shaft, and a second tooth which is engaged with the first tooth, a second gear mounted on the reduction shaft, and a third tooth, and further includes a third gear which is mounted on the reduction shaft and to which the torque of the second gear is transmitted. The at least one bearing includes a first bearing and a second bearing disposed at a position in the predefined direction which is closer to the rotor and stator than to the first bearing. In the predefined direction, the third tooth is located at a position which is closer to the rotor and stator than to the second tooth. The second gear has a diameter larger than the diameter of the third gear. At least a part of the first bearing is disposed inside the second tooth in a radial direction of the second gear.SELECTED DRAWING: Figure 7

Description

The present invention relates to a drive unit for a human-powered vehicle.

For example, the component for a human-powered vehicle disclosed in Patent Document 1 includes a reduction gear. The reduction gear includes a reduction shaft supported by a bearing.

JP 2018-158695 A

One of the objectives of this disclosure is to provide a drive unit for a human-powered vehicle that can be made compact in the direction in which the reduction shaft extends.

A drive unit according to a first aspect of the present disclosure is a drive unit for a human-powered vehicle, comprising: a base portion; a motor provided on the base portion and configured to provide a propulsive force to the human-powered vehicle; and a reducer provided on the base portion and configured to transmit the driving force of the motor to a rotating body, the motor having an output shaft extending in a predetermined direction and having a free end at a first end in the predetermined direction, a rotor fixed to the output shaft, and a stator facing the rotor, the reducer having a first tooth portion provided at the first end of the output shaft, a reduction shaft extending substantially parallel to the predetermined direction, at least one bearing supporting the reduction shaft, and the reduction gear has a second gear provided on the reduction shaft and has a second tooth portion on its outer periphery that meshes with the first tooth portion; and a third gear has a third tooth portion on its outer periphery, is provided on the reduction shaft, and the rotational force of the second gear is transmitted, the at least one bearing of the reduction gear has a first bearing and a second bearing arranged at a position closer to the rotor and the stator than the first bearing in the predetermined direction, the third tooth portion is arranged at a position closer to the rotor and the stator than the second tooth portion in the predetermined direction, the second gear has a diameter larger than a diameter of the third gear, and at least a portion of the first bearing is arranged inside the second tooth portion in the radial direction of the second gear.
According to the drive unit of the first side surface, at least a portion of the first bearing is disposed inside the second teeth portion in the radial direction of the second gear, so that the size of the drive unit can be reduced in the extension direction of the reduction shaft. According to the drive unit of the first side surface, it is easy to dispose the first teeth portion close to the end face of the first end of the output shaft in the predetermined direction.

The drive unit of the second aspect according to the first aspect of the present disclosure further includes an output portion having a connection portion to which the rotating body is connected and connected to the reducer.
According to the drive unit of the second aspect, the driving force of the motor can be suitably transmitted to the rotating body by the output portion.

In a drive unit of a third aspect according to the second aspect of the present disclosure, the output portion is configured to rotate about a rotation axis extending in the predetermined direction, and the connection portion of the output portion is positioned in a position closer to the second gear than the third gear in the predetermined direction.
According to the drive unit of the third aspect, it is easy to shorten the distance of the power transmission path from the first gear to the connection part of the output portion.

A drive unit according to a fourth aspect of the present disclosure is a drive unit for a human-powered vehicle, comprising: a base portion; a motor provided on the base portion and configured to apply a propulsive force to the human-powered vehicle; a reducer provided on the base portion and configured to transmit the driving force of the motor; and an output portion having a connection portion to which a rotating body is connected and connected to the reducer, wherein the motor has an output shaft extending in a predetermined direction, a rotor fixed to the output shaft, and a stator facing the rotor, and the reducer has a first tooth portion provided on the output shaft, a reduction shaft extending parallel to the predetermined direction, at least one bearing supporting the reduction shaft, a second gear provided on the reduction shaft and having a second tooth portion on an outer periphery thereof that meshes with the first tooth portion, and a third tooth portion provided on the reduction shaft. and a third gear having a first tooth portion on its outer periphery and to which the rotational force of the second gear is transmitted, the at least one bearing of the reducer includes a first bearing and a second bearing arranged at a position closer to the rotor and the stator than the first bearing in the predetermined direction, the second tooth portion is arranged at a position closer to the rotor and the stator than the third tooth portion in the predetermined direction, the second gear has a diameter larger than a diameter of the third gear, at least a portion of the first bearing is arranged inside the second tooth portion in the radial direction of the second gear, the output portion is configured to rotate around a rotation axis extending in the predetermined direction, and the connection portion of the output portion is arranged at a position closer to the second gear than the third gear in the predetermined direction.
According to the drive unit of the fourth aspect, at least a portion of the first bearing is disposed inside the second tooth portion in the radial direction of the second gear, so that the size of the drive unit can be reduced in the extension direction of the reduction shaft. According to the drive unit of the fourth aspect, the distance of the power transmission path from the first gear to the connection part of the output part can be easily shortened.

The drive unit of a fifth aspect according to the third or fourth aspect of the present disclosure further comprises a third bearing provided in the base portion and rotatably supporting the output portion.
According to the drive unit of the fifth aspect, the output portion can be smoothly rotated.

In a drive unit of a sixth aspect according to the fifth aspect of the present disclosure, the second gear includes a first end face and a second end face in the predetermined direction, and at least a portion of the third bearing is disposed between a first plane that includes the first end face and is perpendicular to the predetermined direction, and a second plane that includes the second end face and is perpendicular to the predetermined direction.
According to the drive unit of the sixth aspect, the portion in which the third bearing is disposed in the predetermined direction can be made compact.

In the drive unit of a seventh aspect according to the sixth aspect of the present disclosure, the third bearing is entirely disposed between the first plane and the second plane.
According to the drive unit of the seventh aspect, the portion in which the third bearing is disposed in the predetermined direction can be made compact.

In the drive unit of an eighth aspect according to any one of the fifth to seventh aspects of the present disclosure, the third bearing includes a radial bearing.
According to the drive unit of the eighth aspect, the power loss caused by the rotation of the output part can be reduced.

In a drive unit of a ninth aspect according to any one of the fifth to eighth aspects of the present disclosure, the drive unit further includes a sealing member arranged adjacent to the third bearing, and a portion of the base portion is arranged between the sealing member and the third bearing.
According to the drive unit of the ninth aspect, the seal member is prevented from being crushed by the third bearing.

In a drive unit of a tenth aspect according to any one of the fifth to ninth aspects of the present disclosure, the reducer has a fourth tooth portion that meshes with the third tooth portion and further includes a fourth gear provided on the output portion, and in the predetermined direction, the third bearing is provided between the connection portion and the fourth gear.
According to the drive unit of the tenth aspect, a third bearing is provided between the part of the output section to which the rotational force is input and the part from which the rotational force is output, so that the output section is stably supported.

In the drive unit of an eleventh aspect according to the tenth aspect of the present disclosure, the drive unit further includes an input rotating shaft provided on the base portion, extending in the predetermined direction, and into which a manual driving force is input, and a one-way clutch provided between the fourth gear and the output portion, wherein the input rotating shaft is connected to the output portion so as to transmit the manual driving force to the output portion when it rotates at least in a predetermined first rotational direction, and the one-way clutch is configured to allow relative rotation between the input rotating shaft and the fourth gear when the input rotating shaft rotates in the predetermined first rotational direction and the motor is stopped.
According to the drive unit of the eleventh aspect, when the input rotating shaft is rotated in a predetermined first rotation direction while the motor is stopped, the transmission of driving force from the input rotating shaft to the fourth gear is suppressed, thereby suppressing loss of manual driving force.

In a drive unit of a twelfth aspect according to any one of the second to tenth aspects of the present disclosure, an input rotating shaft is provided on the base portion, extends in the predetermined direction, and receives a manual driving force, and the input rotating shaft is connected to the output portion so as to transmit the manual driving force to the output portion when rotating at least in a predetermined first rotational direction.
According to the drive unit of the twelfth aspect, the output portion can be rotated by rotating the input rotating shaft in a predetermined direction by manual driving force.

In the drive unit of a thirteenth aspect according to the eleventh or twelfth aspect of the present disclosure, the input rotating shaft and the output portion are provided coaxially.
According to the drive unit of the thirteenth aspect, the drive unit can be made compact.

In the drive unit of a fourteenth aspect according to the thirteenth aspect of the present disclosure, the output portion is configured to rotate integrally with the input rotating shaft.
According to the drive unit of the fourteenth aspect, loss of manual driving force between the input rotating shaft and the output portion can be reduced.

In a drive unit of a fifteenth aspect according to any one of the first to fourteenth aspects of the present disclosure, more than half of the first bearing in the predetermined direction is positioned inside the second tooth portion in the radial direction of the second gear.
According to the drive unit of the fifteenth aspect, the size can be further reduced in the extension direction of the reduction shaft.

In the drive unit of a sixteenth aspect according to any one of the first to fifteenth aspects of the present disclosure, the first bearing includes a radial bearing, and the second bearing includes a radial bearing.
According to the drive unit of the sixteenth aspect, the power loss caused by the rotation of the reduction shaft can be reduced.

The drive unit for a human-powered vehicle disclosed herein can be made smaller in size in the direction in which the reduction shaft extends.

1 is a side view of a human-powered vehicle including a drive unit for a human-powered vehicle according to an embodiment. FIG. 2 is a perspective view of a drive unit for a human-powered vehicle according to the embodiment. FIG. 3 is a first side view of the drive unit for the human-powered vehicle of FIG. 2 in a first direction. FIG. 3 is a second side view of the drive unit for the human-powered vehicle of FIG. 2 in a second direction. FIG. 3 is a plan view of a drive unit for the human-powered vehicle of FIG. 2 . FIG. 5 is a side view of the state where a cover portion is removed from FIG. 4 . 4 is a cross-sectional view taken along line D7-D7 in FIG. 3;

<Embodiment>
A drive unit 40 for a human-powered vehicle according to an embodiment will be described with reference to Figs. 1 to 7. The human-powered vehicle 10 is a vehicle that has at least one wheel and can be driven at least by human-powered driving force. The human-powered vehicle 10 includes various types of bicycles, such as mountain bikes, road bikes, city bikes, cargo bikes, hand bikes, and recumbents. The number of wheels that the human-powered vehicle 10 has is not limited. The human-powered vehicle 10 also includes, for example, one-wheeled vehicles and vehicles with three or more wheels. The human-powered vehicle 10 is not limited to vehicles that can be driven only by human-powered driving force. The human-powered vehicle 10 includes not only human-powered driving force but also E-bikes that use 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 embodiment, the human-powered vehicle 10 will be described as an electrically assisted bicycle, and an example of an electrically assisted bicycle will be described as a road bike.

The human-powered vehicle 10 includes a crank 12 to which a human-powered driving force is input. The human-powered vehicle 10 further includes at least one wheel 14 and a vehicle body 16. The at least one wheel 14 includes a rear wheel 14A and a front wheel 14B. The vehicle body 16 includes a frame 18. The crank 12 includes an input rotating shaft 56 that can rotate relative to the frame 18, and a pair of crank arms 12A that are respectively provided at the axial ends of the input rotating shaft 56. In this embodiment, the input rotating shaft 56 is a crank shaft. A pair of pedals 20 are respectively connected to each crank arm 12A. The rear wheel 14A is driven by the rotation of the crank 12. The rear wheel 14A is supported by the frame 18. The crank 12 and the rear wheel 14A are connected by a drive mechanism 22. The drive mechanism 22 includes a rotating body 24 that is connected to the input rotating shaft 56. The rotating body 24 includes a sprocket, a pulley, or a bevel gear. The rotating body 24 is connected to the rear wheel 14A via a connecting member. The connecting member includes, for example, a chain, a belt, or a shaft.

The human-powered vehicle 10 may include a front derailleur. If the human-powered vehicle 10 includes a front derailleur, the rotating body 24 may include multiple sprockets. A front wheel 14B is attached to the frame 18 via a front fork 30. A handlebar is connected to the front fork 30 via a stem. In this embodiment, the rear wheel 14A is connected to the crank 12 by the drive mechanism 22, but at least one of the rear wheel 14A and the front wheel 14B may be connected to the crank 12 by the drive mechanism 22.

Preferably, the human-powered vehicle 10 further includes a battery 36. The battery 36 includes one or more battery elements. The battery elements include a rechargeable battery. The battery 36 is configured to supply power to the drive unit 40. The battery 36 is preferably communicatively connected to the drive unit 40 via an electric cable or a wireless communication device. The battery 36 can communicate with the drive unit 40, for example, by power line communication (PLC), a controller area network (CAN), or a universal asynchronous receiver/transmitter (UART).

The drive unit 40 includes a base portion 42, a motor 44, and a reducer 46. The base portion 42 constitutes, for example, a housing of the drive unit 40. The base portion 42 is provided on the frame 18. The base portion 42 is, for example, detachably attached to the frame 18. The base portion 42 has at least one mounting portion 42A. The at least one mounting portion 42A is provided on the outer periphery of the base portion 42. Each of the at least one mounting portion 42A includes at least one of a hole and a female thread portion. Preferably, the hole and the female thread portion extend in a direction parallel to the rotation axis CA of the input rotation shaft 56. The base portion 42 is attached to the frame 18 by engaging a bolt with the at least one mounting portion 42A and the frame 18.

At least one mounting portion 42A is provided on each of the first side wall portion 40A of the base portion 42 and the second side wall portion 40B of the base portion 42 in the direction in which the rotation axis CA of the input rotation shaft 56 extends. Preferably, three mounting portions 42A are provided on the first side wall portion 40A. Preferably, two mounting portions 42A are provided on the second side wall portion 40B. Preferably, two of the three mounting portions 42A provided on the first side wall portion 40A are arranged at positions overlapping with the two mounting portions 42A provided on the second side wall portion 40B when viewed from a direction parallel to the rotation axis CA of the input rotation shaft 56. The three mounting portions 42A provided on the first side wall portion 40A are arranged at intervals around the rotation axis CA of the input rotation shaft 56. Preferably, the three mounting portions 42A of the first side wall portion 40A are provided on the first side wall portion 40A such that, when viewed from a direction parallel to the rotation axis CA of the input rotation shaft 56, the rotation axis CA of the input rotation shaft 56 is located in a triangular area connecting the centers of the three mounting portions 42A.

Preferably, the base portion 42 includes a first housing 42X and a second housing 42Y. The first housing 42X includes a first side wall portion 40A of the base portion 42. The second housing 42Y includes a second side wall portion 40B of the base portion 42. The first housing 42X and the second housing 42Y are attached to each other, for example, by bolts or the like. The first housing 42X and the second housing 42Y form an accommodation space 42Z. The motor 44 is disposed in the accommodation space 42Z. In this embodiment, the base portion 42 is formed of a metal. The metal forming the base portion 42 includes, for example, an aluminum alloy or a magnesium alloy. The base portion 42 may be formed of a synthetic resin.

The motor 44 is provided on the base portion 42 and is configured to provide a propulsive force to the human-powered vehicle 10. The motor 44 includes an electric motor. The electric motor is, for example, a brushless motor. The motor 44 is configured to transmit a rotational force to the rotating body 24.

The motor 44 has an output shaft 48, a rotor 50, and a stator 52. The output shaft 48 extends in a predetermined direction A and has a free end at a first end 48A in the predetermined direction A. The rotor 50 is fixed to the output shaft 48. The stator 52 faces the rotor 50. The output shaft 48 has a second end 48B opposite to the first end 48A in the predetermined direction A. Of the predetermined direction A, the direction from the first end 48A of the output shaft 48 to the second end 48B is defined as a first direction A1. Of the predetermined direction A, the direction from the second end 48B of the output shaft 48 to the first end 48A is defined as a second direction A2. Preferably, the motor 44 is a radial gap type motor. Preferably, the motor 44 is an inner rotor type motor. The motor 44 may be an outer rotor type motor. The motor 44 may be an axial gap type motor. The first end 48A faces the inner surface of the first side wall 40A of the base 42. A gap is formed between the first end 48A and the inner surface of the first side wall 40A of the base 42. In the predetermined direction A, the distance between the first end 48A and the inner surface of the first side wall 40A of the base 42 is 1 mm or more and 10 mm or less, and preferably 1 mm or more and 5 mm or less.

The motor 44 further includes at least one motor bearing 45. The at least one motor bearing 45 includes a first motor bearing 45A and a second motor bearing 45B. The first motor bearing 45A rotatably supports an intermediate portion between a first end 48A of the output shaft 48 in a predetermined direction A and a second end 48B of the output shaft 48 in a predetermined direction A. The second motor bearing 45B rotatably supports the second end 48B of the output shaft 48 in the predetermined direction A. Preferably, the first motor bearing 45A includes a radial bearing. Preferably, the second motor bearing 45B includes a radial bearing. The first motor bearing 45A includes an inner ring, an outer ring, and a plurality of rolling elements arranged between the inner ring and the outer ring. The second motor bearing 45B includes an inner ring, an outer ring, and a plurality of rolling elements arranged between the inner ring and the outer ring. The inner diameter of the inner ring of the first motor bearing 45A is larger than the inner diameter of the inner ring of the second motor bearing 45B. The outer diameter of the outer ring of the first motor bearing 45A is larger than the outer diameter of the outer ring of the second motor bearing 45B. The first motor bearing 45A is supported by a recess 43A formed on the inner surface of the second side wall portion 40B.

In this embodiment, a part of the rotor 50 is disposed between the first motor bearing 45A and the second motor bearing 45B in the predetermined direction A. The outer diameter of the part of the output shaft 48 where the rotor 50 is provided is smaller than the outer diameter of the part of the output shaft 48 where the first motor bearing 45A is provided. A positioning portion that contacts the inner ring of the first motor bearing 45A from the downstream side of the first direction A1 is provided between the part of the output shaft 48 where the rotor 50 is provided and the part of the output shaft 48 where the first motor bearing 45A is provided. The outer diameter of the positioning portion is larger than the outer diameter of the part of the output shaft 48 where the first motor bearing 45A is provided. In this embodiment, at least a part of the first motor bearing 45A and at least a part of the second motor bearing 45B are disposed between the inner peripheral surface of the stator 52 formed in an annular shape and the output shaft 48.

The reducer 46 is provided on the base 42 and configured to transmit the driving force of the motor 44 to the rotating body 24. Preferably, the drive unit 40 further includes an output section 54. The reducer 46 is disposed in the accommodation space 42Z of the base 42. The output section 54 has a connection section 54A to which the rotating body 24 is connected, and is connected to the reducer 46. The output section 54 is configured to rotate about a rotation axis C1 extending in a predetermined direction A.

Preferably, the drive unit 40 further includes an input rotating shaft 56. The input rotating shaft 56 is provided on the base portion 42, extends in a predetermined direction A, and receives a manual driving force. The input rotating shaft 56 is connected to the output portion 54 so as to transmit the manual driving force to the output portion 54 when rotating at least in a predetermined first rotation direction R1. Preferably, the input rotating shaft 56 and the output portion 54 are provided coaxially. Preferably, the output portion 54 is provided on the outer periphery of the input rotating shaft 56. The input rotating shaft 56 is preferably formed of a metal. In this embodiment, the input rotating shaft 56 is formed of a hollow shaft. The input rotating shaft 56 may be formed of a solid shaft.

The base portion 42 is formed with a first hole 42B and a second hole 42C. The first hole 42B is formed in the first side wall portion 40A. The second hole 42C is formed in the second side wall portion 40B. The input rotation shaft 56 has a first end 56A and a second end 56B in the direction in which the input rotation shaft 56 extends. The input rotation shaft 56 passes through the first hole 42B and the second hole 42C and protrudes from the storage space 42Z of the base portion 42 to the outside of the base portion 42. The first end 56A is exposed to the outside of the base portion 42 from the first hole 42B. The second end 56B is exposed to the outside of the base portion 42 from the second hole 42C.

At least a part of the output part 54 is arranged around the first end 56A. At least a part of the output part 54 is arranged in the first hole 42B, and the connection part 54A is exposed to the outside of the base part 42. The output part 54 has a substantially cylindrical shape. Preferably, the output part 54 is formed of metal. The connection part 54A is provided at the first end 54C of the output part 54 in a predetermined direction A. The connection part 54A is provided on the outer periphery of the first end 54C. The connection part 54A has, for example, a spline groove. The inner periphery of the first end 54C is formed with a female thread configured to couple with a lock ring that restricts the movement of the rotating body 24 in the predetermined direction A when the rotating body 24 is connected to the connection part 54A. The first end 54C of the output part 54 passes through the first hole 42B formed in the base part 42 and protrudes to the outside from the accommodation space 42Z of the base part 42. Preferably, the connection portion 54A is disposed outside the housing included in the base portion 42.

Preferably, the output unit 54 is configured to rotate integrally with the input rotating shaft 56. The output unit 54 is configured to rotate integrally with the input rotating shaft 56 at least when the input rotating shaft 56 rotates in a predetermined first rotation direction R1. In this embodiment, the output unit 54 rotates integrally with the input rotating shaft 56 when the input rotating shaft 56 rotates in the predetermined first rotation direction R1, and also rotates integrally with the input rotating shaft 56 when the input rotating shaft 56 rotates in a predetermined second rotation direction R2 opposite to the predetermined first rotation direction R1.

For example, one of the outer periphery of the input rotating shaft 56 and the inner periphery of the output section 54 has at least one convex portion, and the other of the outer periphery of the input rotating shaft 56 and the inner periphery of the output section 54 has at least one concave portion that engages with the at least one convex portion. In this embodiment, first serrations are formed on the outer periphery of the input rotating shaft 56, and second serrations that fit with the first serrations are formed on the inner periphery of the output section 54. The first serrations may be press-fitted into the second serrations or fixed by adhesive.

The reducer 46 is configured to reduce the rotation speed of the motor 44 in two or more stages and transmit the driving force of the motor 44 to the rotating body 24. In this embodiment, the reducer 46 is configured to reduce the rotation speed of the motor 44 in two stages and transmit the driving force of the motor 44 to the rotating body 24. The reducer 46 has a first tooth portion 58, a reduction shaft 60, at least one bearing 62, a second gear 64, and a third gear 66. The first tooth portion 58 is provided on the first end 48A of the output shaft 48. The reduction shaft 60 extends substantially parallel to a predetermined direction A. The second gear 64 has a second tooth portion 64A on its outer periphery that meshes with the first tooth portion 58, and is provided on the reduction shaft 60. The third gear 66 has a third tooth portion 66A on its outer periphery, and is provided on the reduction shaft 60, to which the rotation force of the second gear 64 is transmitted. In the predetermined direction A, the third tooth portion 66A is disposed at a position closer to the rotor 50 and the stator 52 than the second tooth portion 64A. The second gear 64 has a diameter larger than the diameter of the third gear 66.

The second gear 64 has a diameter larger than the diameter of the first toothed portion 58. Therefore, the rotation speed of the second gear 64 is lower than the rotation speed of the first toothed portion 58. The first toothed portion 58 and the second toothed portion 64A may form a spur gear or may form a helical gear. Preferably, the reducer 46 further includes a fourth gear 68 having a fourth toothed portion 68A meshing with the third toothed portion 66A and provided on the output portion 54. The fourth gear 68 has a diameter larger than the diameter of the third gear 66. Therefore, the rotation of the third gear 66 is transmitted to the fourth gear 68 at a reduced speed. The third toothed portion 66A and the fourth toothed portion 68A may form a spur gear or may form a helical gear.

The first teeth portion 58 is configured to rotate integrally with the output shaft 48. Preferably, the first teeth portion 58 is formed integrally with the output shaft 48 as a single member. Preferably, the first teeth portion 58 is formed so as to reach the end face 48C of the first end 48A of the output shaft 48 in the predetermined direction A. The output shaft 48 is formed of metal. When the first teeth portion 58 is formed integrally with the output shaft 48 as a single member, the output shaft 48 is processed to form the first teeth portion 58. When the output shaft 48 is processed, for example, by cutting to form the first teeth portion 58, the output shaft 48 is cut from the end face 48C of the output shaft 48 toward the second end 48B in the predetermined direction A. When the output shaft 48 is cut from the end face 48C of the output shaft 48 toward the second end 48B in the predetermined direction A, it is preferable to gradually make the cutting groove shallower at the end of the cutting groove on the side of the second end 48B in the predetermined direction A. The strength of the output shaft 48 can be ensured by gradually making the cutting groove shallower at the end of the cutting groove on the second end 48B side in the predetermined direction A. The part of the cutting groove where the cutting groove becomes gradually shallower cannot be used as the first teeth 58. By forming the first teeth 58 at the first end 48A of the output shaft 48, the part where the cutting groove becomes gradually shallower can be arranged in the intermediate part between the first teeth 58 and the rotor 50, which is necessary for the arrangement of the third teeth 66A. By forming the first teeth 58 on the output shaft 48, the number of parts can be reduced compared to when the first teeth 58 is provided separately from the output shaft 48 and attached to the output shaft 48.

The first teeth portion 58 may be formed separately from the output shaft 48 and fixed to the first end 48A of the output shaft 48. When the first teeth portion 58 is formed separately from the output shaft 48, the first teeth portion 58 may be formed from a metal or a synthetic resin.

In this embodiment, the second gear 64 is configured to rotate integrally with the reduction shaft 60. Preferably, the second gear 64 is formed separately from the reduction shaft 60 and fixed to the reduction shaft 60. For example, the reduction shaft 60 is formed of metal. Preferably, the second gear 64 is formed of synthetic resin. The second gear 64 may be formed of metal. The second gear 64 may be formed integrally with the reduction shaft 60 as a single member. In this embodiment, the third gear 66 is configured to rotate integrally with the reduction shaft 60. Preferably, the third gear 66 is formed integrally with the reduction shaft 60. The third gear 66 may be formed separately from the reduction shaft 60 and fixed to the reduction shaft 60. The third gear 66 may be formed of synthetic resin or may be formed of metal. Preferably, the reduction shaft 60 is formed hollow. The reduction shaft 60 may be formed solid.

Preferably, the fourth gear 68 is formed separately from the output unit 54 and attached to the output unit 54. Preferably, the fourth gear 68 is formed from metal. The fourth gear 68 may be formed from a synthetic resin. The fourth gear 68 is disposed such that a portion of the fourth gear 68 overlaps with the stator 52 when viewed from the predetermined direction A.

Preferably, the connection portion 54A of the output portion 54 is disposed in a position closer to the second gear 64 than the third gear 66 in the predetermined direction A. In the first direction A1, the third gear 66 is disposed adjacent to the downstream side of the second gear 64. At least a portion of the connection portion 54A of the output portion 54 is disposed in a position farther from the rotor 50 and the stator 52 than the second gear 64 in the predetermined direction A.

In this embodiment, when viewed from a direction parallel to the predetermined direction A, the output shaft 48, the reduction shaft 60, and the output section 54 are arranged such that the rotation axis C2 of the output shaft 48, the rotation axis C3 of the reduction shaft 60, and the rotation axis C1 of the output section 54 are substantially on a straight line. When viewed from a direction parallel to the predetermined direction A, the output shaft 48, the reduction shaft 60, and the output section 54 may be arranged such that the rotation axis C2 of the output shaft 48, the rotation axis C3 of the reduction shaft 60, and the rotation axis C1 of the output section 54 are vertices of a triangle.

For example, the distance from the rotation axis C2 of the output shaft 48 to the rotation axis C3 of the reduction shaft 60 is shorter than the distance from the rotation axis C3 of the reduction shaft 60 to the rotation axis C1 of the output section 54. When viewed from a direction parallel to the predetermined direction A, the reduction shaft 60 is arranged at a position overlapping at least one of the rotor 50 and the stator 52. When viewed from a direction parallel to the predetermined direction A, the second gear 64 is arranged at a position overlapping at least one of the rotor 50 and the stator 52. When viewed from a direction parallel to the predetermined direction A, the third gear 66 is arranged at a position overlapping at least one of the rotor 50 and the stator 52.

At least one bearing 62 supports the reduction shaft 60. At least one bearing 62 of the reducer 46 has a first bearing 62A and a second bearing 62B that is positioned closer to the rotor 50 and the stator 52 than the first bearing 62A in the predetermined direction A. Preferably, the first bearing 62A supports the first end 60A of the reduction shaft 60 in the predetermined direction A. Preferably, the second bearing 62B supports the second end 60B of the reduction shaft 60 in the predetermined direction A.

Preferably, the first bearing 62A includes a radial bearing. Preferably, the second bearing 62B includes a radial bearing. Preferably, the first bearing 62A is a ball bearing or a roller bearing. The first bearing 62A includes an inner ring, an outer ring, and a plurality of rolling elements arranged between the inner ring and the outer ring. For example, the inner ring of the first bearing 62A is fixed to the reduction shaft 60, and preferably, the inner ring of the first bearing 62A is pressed into the reduction shaft 60. Preferably, the outer ring of the first bearing 62A is clearance-fitted into the first recess 43B formed in the base portion 42. The first bearing 62A may be a sliding bearing. Preferably, the second bearing 62B is a ball bearing or a roller bearing. The second bearing 62B includes an inner ring, an outer ring, and a plurality of rolling elements arranged between the inner ring and the outer ring. For example, the inner ring of the second bearing 62B is fixed to the reduction shaft 60, and the outer ring of the second bearing 62B is held by the base portion 42. Preferably, the inner ring of the second bearing 62B is press-fitted to the reduction shaft 60. Preferably, the outer ring of the second bearing 62B is clearance-fitted into the second recess 43C formed in the base portion 42. The second bearing 62B may be a sliding bearing. The second recess 43C is formed in the inner wall portion 40C of the base portion 42. In this embodiment, the outer diameter of the outer ring of the first bearing 62A and the outer diameter of the outer ring of the second bearing 62B are larger than the diameter of the third gear 66. In this embodiment, the outer diameter of the outer ring of the first bearing 62A is equal to the outer diameter of the outer ring of the second bearing 62B. In this embodiment, the inner diameter of the inner ring of the first bearing 62A is smaller than the inner diameter of the inner ring of the second bearing 62B.

At least a portion of the first bearing 62A is disposed inside the second tooth portion 64A in the radial direction of the second gear 64. Preferably, more than half of the first bearing 62A in the predetermined direction A is disposed inside the second tooth portion 64A in the radial direction of the second gear 64. The second gear 64 includes a central portion 64E attached to the reduction shaft 60, an outer peripheral portion 64F on which the second tooth portion 64A is provided, and an intermediate portion 64B connecting the central portion 64E and the outer peripheral portion 64F. In this embodiment, a female thread is formed on the inner peripheral surface of the central portion 64E. A male thread is formed on the portion of the reduction shaft 60 to which the central portion 64E is fixed, to which the female thread of the central portion 64E is coupled. When the motor 44 is driven to provide a propulsive force to the human-powered vehicle 10, a force is applied to the second gear 64 by the rotational force of the output shaft 48 in a direction in which the second gear 64 is coupled to the reduction shaft 60.

The width L1 of the central portion 64E in the predetermined direction A and the width L2 of the intermediate portion 64B in the predetermined direction A are smaller than the width L3 of the outer peripheral portion 64F in the predetermined direction A. The width L1 of the central portion 64E in the predetermined direction A is smaller than the width L2 of the intermediate portion 64B in the predetermined direction A. The width L1 of the central portion 64E in the predetermined direction A may be equal to the width L2 of the intermediate portion 64B in the predetermined direction A. Preferably, the width L1 is 1/5 or more and 2/3 or less of the width L3. Preferably, the width L1 is 1/5 or more and 2/3 or less of the width L2. The central portion 64E of the second gear 64 may be formed of metal. When the central portion 64E of the second gear 64 is formed of metal and the intermediate portion 64B and the outer peripheral portion 64F are formed of synthetic resin, the intermediate portion 64B is insert molded into the central portion 64E. The central portion 64E may be fixed to the reduction shaft 60 by press-fitting. At least one of a recess and a protrusion may be formed in the central portion 64E and in the portion of the reduction shaft 60 where the central portion 64E is formed, to prevent relative rotation between the second gear 64 and the reduction shaft 60.

A second tooth portion 64A is formed on the outer periphery 64F of the second gear 64. A first arrangement space 42W is formed between the inner periphery of the outer periphery 64F and the reduction shaft 60, in which at least a portion of the first bearing 62A is arranged. At least a portion of the base portion 42 is also arranged in the first arrangement space 42W. At least a portion of the first recess 43B of the base portion 42 is arranged in the first arrangement space 42W. In the predetermined direction A, the entire first bearing 62A may be arranged in the first arrangement space 42W.

The base portion 42 includes an inner wall portion 40C disposed between the first side wall portion 40A and the second side wall portion 40B in a predetermined direction A. The inner wall portion 40C is disposed in the accommodation space 42Z. The inner wall portion 40C is formed so as to separate the accommodation space 42Z into a first accommodation space in which the rotor and the stator are disposed, and a second accommodation space in which the reducer 46 is disposed. The inner wall portion 40C is formed separately from the first housing 42X and the second housing 42Y. The inner wall portion 40C is detachably fixed to the second housing 42Y, for example, by a bolt. The inner wall portion 40C is formed with a through hole 40D through which the output shaft 48 of the motor 44 passes. The first motor bearing 45A is supported by a recess 43D formed in the inner wall portion 40C. The through hole 40D is formed in the recess 43D. The outer ring of the first motor bearing 45A contacts the inner wall portion 40C from the downstream side in the first direction A1.

Preferably, the drive unit 40 further includes a third bearing 70. The third bearing 70 is provided on the base portion 42 and rotatably supports the output portion 54. Preferably, the third bearing 70 includes a radial bearing. Preferably, the third bearing 70 is a ball bearing or a roller bearing. The third bearing 70 includes an inner ring, an outer ring, and a plurality of rolling elements disposed between the inner ring and the outer ring. For example, the inner ring of the third bearing 70 is fixed to the output portion 54, and the outer ring of the third bearing 70 is held by the base portion 42. Preferably, the inner ring of the third bearing 70 is press-fitted into the output portion 54. Preferably, the outer ring of the third bearing 70 is clearance-fitted into a third recess 43E formed in the base portion 42. The third bearing 70 may be a sliding bearing.

The second gear 64 includes a first end surface 64C and a second end surface 64D in the predetermined direction A. In this embodiment, the end surface of the second gear 64 on the upstream side in the first direction A1 is the first end surface 64C, and the end surface of the second gear 64 on the downstream side in the first direction A1 is the second end surface 64D. Preferably, at least a part of the third bearing 70 is disposed between a first plane S1 including the first end surface 64C and perpendicular to the predetermined direction A, and a second plane S2 including the second end surface 64D and perpendicular to the predetermined direction A. Preferably, the third bearing 70 is disposed entirely between the first plane S1 and the second plane S2. A cylindrical member 57 may be provided between the input rotating shaft 56 and an intermediate portion of the output portion 54 between the first end 54C of the output portion 54 and the second end 54B of the output portion 54. The cylindrical member 57 includes a sleeve or a needle bearing. The cylindrical member 57 contacts the inner peripheral surface of the middle part of the output portion 54 and the outer peripheral surface of the input rotation shaft 56. At least a portion of the cylindrical member 57 is disposed between the first plane S1 and the second plane S2. At least a portion of the cylindrical member 57 is disposed at least radially inside the third bearing 70. At least a portion of the cylindrical member 57 is disposed radially inside the fourth gear 68.

Preferably, the drive unit 40 further includes a seal member 72 disposed adjacent to the third bearing 70. Preferably, a part of the base portion 42 is disposed between the seal member 72 and the third bearing 70. The third recess 43E includes an inner peripheral surface 43X that contacts the outer peripheral surface of the outer ring of the third bearing 70, and a first side portion 43Y that is disposed between the third bearing 70 and the seal member 72. For example, the outer ring of the third bearing 70 contacts the first side portion 43Y from the downstream side of the first direction A1. The inner peripheral surface of the first side wall portion 40A defines the first hole 42B. The inner diameter of the first hole 42B is slightly larger than the outer diameter of the portion of the output portion 54 that faces the first hole 42B. The seal member 72 is disposed between the base portion 42 and the output portion 54. The seal member 72 has elasticity. The seal member 72 is formed, for example, of rubber. The seal member 72 is formed in a substantially annular shape. The outer periphery of the seal member 72 is fixed to the base portion 42. For example, the outer periphery of the seal member 72 is press-fitted into the fourth recess 43F formed in the base portion 42. The inner periphery of the seal member 72 contacts the outer periphery of the output portion 54. The seal member 72 is fixed to the base portion 42 from the outside of the first housing 42X, so that it is easy to install and replace. The seal member 72 prevents foreign matter from entering the accommodation space 42Z from the first hole 42B. Preferably, in the predetermined direction A, the third bearing 70 is provided between the connection portion 54A and the fourth gear 68.

Preferably, the drive unit 40 further includes a fourth bearing 74. The fourth bearing 74 is provided on the base portion 42 and rotatably supports the second end 56B of the input rotating shaft 56. Preferably, the fourth bearing 74 includes a radial bearing. Preferably, the fourth bearing 74 is a ball bearing or a roller bearing. For example, an inner ring of the fourth bearing 74 is fixed to the input rotating shaft 56, and an outer ring of the fourth bearing 74 is held by the base portion 42. Preferably, the inner ring of the fourth bearing 74 is press-fitted into the input rotating shaft 56. Preferably, the outer ring of the fourth bearing 74 is clearance-fitted into the fifth recess 43G formed in the base portion 42. The fourth bearing 74 may be a plain bearing.

Preferably, the drive unit 40 further includes a seal member 72A disposed adjacent to the fourth bearing 74. Preferably, a portion of the base portion 42 is disposed between the seal member 72A and the fourth bearing 74. The fifth recess 43G includes an inner peripheral surface 43V that contacts the outer peripheral surface of the outer ring of the fourth bearing 74, and a second side portion 43W that is disposed between the fourth bearing 74 and the seal member 72A.

Preferably, at least one of a leaf spring or a washer is provided between at least one of the outer ring of the fourth bearing 74 and the inner ring of the fourth bearing 74 and the second side portion 43W in the predetermined direction A. The at least one of the leaf spring or the washer suppresses the rattle of the input rotating shaft 56 and the output portion 54 in the predetermined direction A. The inner circumferential surface of the second side portion 43W defines the second hole 42C. The inner diameter of the second hole 42C is slightly larger than the outer diameter of the portion of the input rotating shaft 56 facing the second hole 42C. The seal member 72A is disposed between the base portion 42 and the input rotating shaft 56. The seal member 72A has elasticity. The seal member 72A is formed, for example, of rubber. The seal member 72A is formed in a substantially annular shape. The outer circumferential portion of the seal member 72A is fixed to the base portion 42. For example, the outer periphery of the seal member 72A is press-fitted into the sixth recess 43H formed in the base portion 42. The inner periphery of the seal member 72A contacts the outer periphery of the input rotating shaft 56. The seal member 72A is fixed to the base portion 42 from the outside of the second housing 42Y, making it easy to install and replace.

Preferably, the drive unit 40 further includes a one-way clutch 78. The one-way clutch 78 is provided between the fourth gear 68 and the output portion 54. The one-way clutch 78 is configured to allow relative rotation between the input rotating shaft 56 and the fourth gear 68 when the input rotating shaft 56 rotates in a predetermined first rotation direction R1 and the motor 44 is stopped. The one-way clutch 78 includes, for example, at least one of a roller clutch, a sprag clutch, and a claw clutch. The one-way clutch 78 is provided, for example, between an inner periphery of the fourth gear 68 and the output portion 54. The one-way clutch 78 includes an inner ring, an outer ring, and a plurality of rolling elements disposed between the inner ring and the outer ring. The outer ring of the one-way clutch 78 may be formed integrally with the fourth gear 68 as a single member. The inner ring of the one-way clutch 78 may be formed integrally with the output portion 54 as a single member. The inner and outer rings of the one-way clutch 78 are made of metal. Preferably, the multiple rolling elements of the one-way clutch 78 are held by a carrier. The one-way clutch 78 is provided in the intermediate portion between the first end 54C and the second end 54B of the output portion 54 in the predetermined direction A.

Preferably, the drive unit 40 includes a control device 80. The control device 80 includes a control unit. The control unit includes an arithmetic processing device that executes a predetermined control program. The arithmetic processing device includes, for example, a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). The arithmetic processing device may be provided in multiple locations that are separated from each other. The control unit may include one or multiple microcomputers. Preferably, the control device 80 further includes a memory unit. The memory unit stores various control programs and information used in various control processes. The memory unit includes, for example, a non-volatile memory and a volatile memory. The non-volatile memory includes, for example, at least one of a ROM (Read-Only Memory), an EPROM (Erasable Programmable Read Only Memory), an EEPROM (Electrically Erasable Programmable Read-Only Memory), and a flash memory. The volatile memory includes, for example, a RAM (Random access memory).

The control device 80 is disposed in the accommodation space 42Z. The control device 80 includes a circuit board 80A. The circuit board 80A is disposed in the accommodation space 42Z. The circuit board 80A is disposed in the first accommodation space. The circuit board 80A is disposed so that the mounting surface of the circuit board 80A is substantially perpendicular to the predetermined direction A. When viewed from the predetermined direction A, the circuit board 80A is disposed so that the circuit board 80A and at least a portion of the stator 52 overlap. The stator 52 includes a plurality of coils. The stator 52 includes a plurality of connection terminals to which the plurality of coils are electrically connected. The plurality of connection terminals extend along the predetermined direction A and are electrically connected to the circuit board 80A. In the predetermined direction A, at least a portion of the circuit board 80A is disposed in the area between the second plane S2 and the inner wall portion 40C.

The control device 80 preferably further includes a drive circuit for the motor 44. The drive circuit and the control unit may be provided, for example, on the same circuit board 80A. The drive circuit includes an inverter circuit. The drive circuit controls the power supplied from the battery 36 to the motor 44. The drive circuit is connected to the control unit via a conductive wire, an electric cable, a wireless communication device, or the like. The drive circuit drives the motor 44 in response to a control signal from the control unit.

Preferably, the drive unit 40 further includes a first sensor 86 that detects the human driving force input to the crank 12. The first sensor 86 is disposed, for example, between the second end 54B of the output unit 54 and the one-way clutch 78 in a predetermined direction A. The first sensor 86 may include a strain sensor or may include a magnetostrictive sensor. The strain sensor includes a strain gauge. The first sensor 86 is provided on or around the outer periphery of the output unit 54. The first sensor 86 is connected to the control device 80 via a conductive wire, an electric cable, a wireless communication device, or the like. The first sensor 86 may be provided on one or both of the pair of crank arms 12A. When the first sensor 86 is provided on one or both of the pair of crank arms 12A, the first sensor 86 includes a strain sensor.

Preferably, the drive unit 40 further includes a second sensor that detects the rotation state of the crank 12. The second sensor outputs a signal in response to the rotation of the input rotating shaft 56 or the output unit 54. The second sensor includes, for example, a magnetic sensor or an optical sensor. The second sensor is configured to detect a detected portion provided on the input rotating shaft 56 or the output unit 54. The detected portion is, for example, a ring-shaped magnet or an annular member including a slit. The second sensor is connected to the control device 80 via a conductive wire, an electric cable, a wireless communication device, or the like. The second sensor may be provided upstream or downstream of the first sensor 86 in the first direction A1.

Preferably, the drive unit 40 further includes an electrical connector 82. The electrical connector 82 is connected to the control device 80. The electrical connector 82 is configured to be connectable to at least one of an electrical cable connected to the battery 36 and an electrical cable connected to a component of the human-powered vehicle, for example. The electrical connector 82 is provided, for example, on the outer surface of the second side wall portion 40B. Preferably, the drive unit 40 further includes a cover portion 84 that covers at least a portion of the electrical connector 82. The cover portion 84 is attached to the outer surface of the second side wall portion 40B. The cover portion 84 has a hole 84A in which the second end portion 56B of the input rotating shaft 56 is disposed. The cover portion 84 is formed, for example, in a disk shape.

<Modification>
The description of the embodiments is merely an example of possible forms of a drive unit for a human-powered vehicle according to the present disclosure, and is 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, a modified version of the embodiment shown below, or a combination of at least two mutually compatible modified versions. In the following modified versions, parts common to the embodiment will be given the same reference numerals as in the embodiment, and descriptions thereof will be omitted.

The output shaft 48 does not have to have a free end at the first end 48A in the predetermined direction A. In this case, the drive unit 40 includes a base portion 42, a motor 44 provided on the base portion 42 and configured to provide a propulsive force to the human-powered vehicle 10, a reducer 46 provided on the base portion 42 and configured to transmit the driving force of the motor 44, and an output portion 54 having a connection portion 54A to which the rotating body 24 is connected and connected to the reducer 46. The motor 44 has an output shaft 48 extending in the predetermined direction A, a rotor 50 fixed to the output shaft 48, and a stator 52 facing the rotor 50. The reducer 46 includes a first toothed portion 58 provided on the output shaft 48, a reduction shaft 60 extending parallel to a predetermined direction A, a bearing 62 supporting the reduction shaft 60, a second gear 64 provided on the reduction shaft 60 and having a second toothed portion 64A meshing with the first toothed portion 58 on its outer periphery, and a third gear 66 provided on the reduction shaft 60 and having a third toothed portion 66A on its outer periphery to which the rotational force of the second gear 64 is transmitted. The bearing 62 of the reducer 46 includes a first bearing 62A and a second bearing 62B disposed at a position closer to the rotor 50 and the stator 52 than the first bearing 62A in the predetermined direction A. In the predetermined direction A, the second toothed portion 64A is disposed at a position closer to the rotor 50 and the stator 52 than the third toothed portion 66A. The second gear 64 has a diameter larger than the diameter of the third gear 66. At least a portion of the first bearing 62A is disposed inside the second tooth portion 64A in the radial direction of the second gear 64. The output portion 54 is configured to rotate about a rotation axis extending in a predetermined direction A. The connection portion 54A of the output portion 54 is disposed in a position closer to the second gear 64 than the third gear 66 in the predetermined direction A. For example, the first motor bearing 45A may be disposed to rotatably support the first end portion 48A of the output shaft 48, rather than supporting the middle portion of the output shaft 48.

The reduction shaft 60 may be supported non-rotatably on the base portion 42. In this case, the bearing 62 supports the reduction shaft 60 non-rotatably on the base portion 42. The second gear 64 and the third gear 66 are provided so that the second gear 64 and the third gear 66 rotate integrally and are rotatable relative to the reduction shaft 60.

The second gear 64 may be attached to the reduction shaft 60 via a one-way clutch. In this case, for example, the one-way clutch 78 is omitted, and a one-way clutch similar to the one-way clutch 78 is provided between the second gear 64 and the reduction shaft 60. When the one-way clutch 78 is omitted, the fourth gear 68 may be formed integrally with the output section 54.

The third gear 66 may be attached to the reduction shaft 60 via a one-way clutch. In this case, for example, the one-way clutch 78 is omitted, and a one-way clutch similar to the one-way clutch 78 is provided between the third gear 66 and the reduction shaft 60.

The reducer 46 may be configured to reduce the rotational speed of the motor 44 in three or more stages and transmit the driving force of the motor 44 to the rotating body 24. In this case, for example, the reducer 46 includes a reduction section between the third gear 66 and the fourth gear 68, the reduction section including a fifth gear meshing with the third gear 66 and a sixth gear meshing with the fourth gear 68, and a shaft member on which the fifth gear and the sixth gear are provided. The fifth gear rotates integrally with the sixth gear. The reducer 46 may include a reduction section composed of components other than gears between the third gear 66 and the fourth gear 68. The reduction section composed of components other than gears includes, for example, a pulley and a belt. The reduction section composed of components other than gears includes, for example, a sprocket and a chain.

- A second one-way clutch may be provided between the input rotating shaft 56 and the output section 54. The second one-way clutch is configured to transmit a manual driving force from the input rotating shaft 56 to the output section 54 when the input rotating shaft 56 rotates in the first rotation direction R1, and to allow relative rotation between the input rotating shaft 56 and the output section 54 when the input rotating shaft 56 rotates in a second rotation direction R2 opposite to the first rotation direction R1. The second one-way clutch may be provided between the first end 54C and the second end 54B of the output section 54. The output section 54 may be formed of a single member, or may be formed by combining a plurality of members that are divided in a predetermined direction A. When the second one-way clutch is provided in the drive unit 40, a bearing similar to the third bearing 70 is provided between the outer periphery of the first end 56A of the input rotating shaft 56 and the inner periphery of the first end 54C of the output section 54.

Two of the three mounting portions 42A provided on the first side wall portion 40A include, for example, the rotation axis CA of the input rotating shaft 56, and are provided between a fourth plane perpendicular to the third plane including the rotation axis CA of the input rotating shaft 56 and the rotation axis C2 of the output shaft 48 of the motor 44, and a fifth plane perpendicular to the third plane including the rotation axis C2 of the output shaft 48 of the motor 44. One of the three mounting portions 42A provided on the first side wall portion 40A is, for example, disposed in an area opposite to the area in which the rotation axis C2 of the output shaft 48 of the motor 44 is disposed with respect to the fourth plane. One of the two mounting portions 42A provided on the second side wall portion 40B is provided, for example, between a fourth plane perpendicular to the third plane including the rotation axis CA of the input rotating shaft 56 and the rotation axis C2 of the output shaft 48 of the motor 44, and a fifth plane perpendicular to the third plane including the rotation axis CA of the input rotating shaft 56 and the rotation axis C2 of the output shaft 48 of the motor 44. One of the two mounting portions 42A provided on the second side wall portion 40B is provided, for example, in an area opposite to the area where the rotation axis C2 of the output shaft 48 of the motor 44 is provided with respect to the fourth plane.

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

10...human-powered vehicle, 24...rotating body, 40...drive unit, 42...base portion, 44...motor, 46...reduction gear, 48...output shaft, 48A...first end portion, 50...rotor, 52...stator, 54...output portion, 54A...connection portion, 56...input rotating shaft, 58...first teeth portion, 60...reduction shaft, 62...bearing, 62A...first bearing, 62B...second bearing, 64...second gear, 64A...second teeth portion, 64C...first end surface, 64D...second end surface, 66...third gear, 66A...third teeth portion, 68...fourth gear, 70...third bearing, 72...sealing member, 78...one-way clutch.

The base portion 42 includes an inner wall portion 40C disposed between the first side wall portion 40A and the second side wall portion 40B in a predetermined direction A. The inner wall portion 40C is disposed in the accommodation space 42Z. The inner wall portion 40C is formed so as to divide the accommodation space 42Z into a first accommodation space in which the rotor 50 and the stator 52 are disposed, and a second accommodation space in which the reducer 46 is disposed. The inner wall portion 40C is formed separately from the first housing 42X and the second housing 42Y. The inner wall portion 40C is detachably fixed to the second housing 42Y, for example, by a bolt. The inner wall portion 40C is formed with a through hole 40D through which the output shaft 48 of the motor 44 passes. The first motor bearing 45A is supported by a recess 43D formed in the inner wall portion 40C. The through hole 40D is formed in the recess 43D. The outer ring of the first motor bearing 45A comes into contact with the inner wall portion 40C from the downstream side in the first direction A1.

Preferably, at least one of a leaf spring or a washer is provided between at least one of the outer ring of the fourth bearing 74 and the inner ring of the fourth bearing 74 and the second side portion 43W in the predetermined direction A. The at least one of the leaf spring or the washer suppresses rattling of the input rotating shaft 56 and the output portion 54 in the predetermined direction A. The inner peripheral surface of the second side portion 43W defines the second hole 42C. The inner diameter of the second hole 42C is slightly larger than the outer diameter of the portion of the input rotating shaft 56 facing the second hole 42C. The seal member 72A is disposed between the base portion 42 and the input rotating shaft 56. The seal member 72A has elasticity. The seal member 72A is formed of, for example, rubber. The seal member 72A is formed in a substantially annular shape. The outer peripheral portion of the seal member 72A is fixed to the base portion 42. For example, the outer periphery of the seal member 72A is press-fitted into the sixth recess 43H formed in the base portion 42. The inner periphery of the seal member 72A contacts the outer periphery of the input rotation shaft 56. The seal member 72A is fixed to the base portion 42 from the outside of the second housing 42Y, and therefore can be easily attached and replaced.

Preferably, the drive unit 40 further includes a one-way clutch 78. The one-way clutch 78 is provided between the fourth gear 68 and the output portion 54. The one-way clutch 78 is configured to allow relative rotation between the input rotating shaft 56 and the fourth gear 68 when the input rotating shaft 56 rotates in a predetermined first rotation direction R1 and the motor 44 is stopped. The one-way clutch 78 includes at least one of a roller clutch, a sprag clutch, and a pawl clutch. The one-way clutch 78 is provided between an inner periphery of the fourth gear 68 and the output portion 54, for example. The one-way clutch 78 includes an inner ring, an outer ring, and a plurality of rolling elements disposed between the inner ring and the outer ring. The outer ring of the one-way clutch 78 may be formed integrally with the fourth gear 68 as a single member. The inner ring of the one-way clutch 78 may be formed integrally with the output portion 54 as a single member. The inner ring and the outer ring of the one-way clutch 78 are made of metal. Preferably, the rolling elements of the one-way clutch 78 are held by a carrier. The one-way clutch 78 is provided in a middle portion between the first end 54C and the second end 54B of the output portion 54 in the predetermined direction A.

Claims (16)

A drive unit for a human-powered vehicle,
A base portion;
a motor provided on the base and configured to provide a propulsive force to the human-powered vehicle;
a reducer provided on the base portion and configured to transmit a driving force of the motor to a rotating body;
The motor is
an output shaft extending in a predetermined direction and having a free end at a first end in the predetermined direction;
A rotor fixed to the output shaft;
a stator facing the rotor,
The reducer includes:
A first tooth portion provided on the first end of the output shaft;
a reduction shaft extending substantially parallel to the predetermined direction;
At least one bearing supporting the reduction shaft;
a second gear having a second toothed portion on an outer periphery thereof, the second toothed portion meshing with the first toothed portion, the second gear being provided on the reduction shaft;
a third gear having a third tooth portion on an outer periphery thereof, the third gear being provided on the reduction shaft and receiving a rotational force of the second gear;
The at least one bearing of the reducer is
A first bearing;
a second bearing disposed closer to the rotor and the stator than the first bearing in the predetermined direction,
In the predetermined direction, the third teeth portion is disposed at a position closer to the rotor and the stator than the second teeth portion,
the second gear has a diameter greater than a diameter of the third gear,
A drive unit, wherein at least a portion of the first bearing is disposed inside the second tooth portion in a radial direction of the second gear. The drive unit according to claim 1 , further comprising an output portion having a connection portion to which the rotating body is connected and connected to the reducer. The output portion is configured to rotate about a rotation axis extending in the predetermined direction,
The drive unit according to claim 2 , wherein the connection portion of the output portion is disposed at a position closer to the second gear than to the third gear in the predetermined direction. A drive unit for a human-powered vehicle,
A base portion;
a motor provided on the base and configured to provide a propulsive force to the human-powered vehicle;
A reducer provided on the base portion and configured to transmit a driving force of the motor;
an output portion having a connection portion to which a rotating body is connected and connected to the reducer,
The motor is
an output shaft extending in a predetermined direction;
A rotor fixed to the output shaft;
a stator facing the rotor,
The reducer includes:
A first tooth portion provided on the output shaft;
A reduction shaft extending parallel to the predetermined direction;
At least one bearing supporting the reduction shaft;
a second gear provided on the reduction shaft and having a second tooth portion on an outer periphery thereof that meshes with the first tooth portion;
a third gear provided on the reduction shaft, the third gear having a third tooth portion on an outer periphery thereof, and to which a rotational force of the second gear is transmitted,
The at least one bearing of the reducer is
A first bearing;
a second bearing disposed closer to the rotor and the stator than the first bearing in the predetermined direction,
In the predetermined direction, the second teeth portion is disposed at a position closer to the rotor and the stator than the third teeth portion,
the second gear has a diameter greater than a diameter of the third gear,
At least a portion of the first bearing is disposed inside the second tooth portion in a radial direction of the second gear,
The output portion is configured to rotate about a rotation axis extending in the predetermined direction,
A drive unit, wherein the connection portion of the output portion is disposed at a position closer to the second gear than to the third gear in the predetermined direction. The drive unit according to claim 3 or 4, further comprising a third bearing provided in the base portion and rotatably supporting the output portion. the second gear includes a first end surface and a second end surface in the predetermined direction,
6. The drive unit of claim 5, wherein at least a portion of the third bearing is disposed between a first plane including the first end face and perpendicular to the predetermined direction, and a second plane including the second end face and perpendicular to the predetermined direction. The drive unit according to claim 6, wherein the third bearing is entirely disposed between the first plane and the second plane. The drive unit according to any one of claims 5 to 7, wherein the third bearing includes a radial bearing. a seal member disposed adjacent to the third bearing;
The drive unit according to claim 5 , wherein a part of the base portion is disposed between the seal member and the third bearing. the reducer further includes a fourth gear having a fourth tooth portion meshing with the third tooth portion and provided at the output portion,
The drive unit according to claim 5 , wherein the third bearing is provided between the connection portion and the fourth gear in the predetermined direction. an input rotation shaft provided on the base portion, extending in the predetermined direction, and into which a manual driving force is input;
a one-way clutch provided between the fourth gear and the output portion,
the input rotation shaft is connected to the output portion so as to transmit a manual drive force to the output portion when the input rotation shaft rotates at least in a predetermined first rotation direction;
11. The drive unit according to claim 10, wherein the one-way clutch is configured to allow relative rotation between the input rotating shaft and the fourth gear when the input rotating shaft rotates in the predetermined first rotational direction and the motor is stopped. an input rotation shaft provided on the base portion, extending in the predetermined direction, and into which a manual driving force is input;
The drive unit according to claim 2 , wherein the input rotating shaft is connected to the output portion so as to transmit a manual driving force to the output portion when the input rotating shaft rotates at least in a predetermined first rotation direction. The drive unit according to claim 11 or 12, wherein the input rotating shaft and the output section are provided coaxially. The drive unit according to claim 13, wherein the output section is configured to rotate integrally with the input rotating shaft. A drive unit according to any one of claims 1 to 14, wherein at least half of the first bearing in the predetermined direction is disposed inside the second tooth portion in the radial direction of the second gear. the first bearing includes a radial bearing;
16. A drive unit according to claim 1, wherein the second bearing comprises a radial bearing.