Drive unit for human-powered vehicles
The drive unit for human-powered vehicles uses a heat transfer body and airflow management to dissipate heat from electronic components, addressing temperature rise issues and maintaining performance.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- SHIMANO INC
- Filing Date
- 2024-12-02
- Publication Date
- 2026-06-12
Smart Images
Figure 2026096041000001_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the technology of drive units for human-powered vehicles.
Background Art
[0002] Conventionally, drive units for human-powered vehicles are known. For example, Patent Document 1 describes a drive unit including a motor and a substrate. Electronic components for controlling the motor are provided on the substrate.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] When the motor is driven, heat is generated from the electronic components, and the temperature of the electronic components rises.
[0005] One object of this disclosure is to provide a drive unit capable of suppressing an increase in the temperature of electronic components.
Means for Solving the Problems
[0006] A drive unit according to a first aspect of this disclosure is a drive unit for a human-powered vehicle, including a housing defining an internal space, a motor provided in the internal space and having a motor output shaft including a motor output shaft central axis, a crankshaft mounting portion configured to attach a crankshaft inserted through the housing and including a crankshaft mounting portion central axis, a substrate provided in the internal space and provided with electronic components for controlling the motor, and a heat transfer body provided to transfer heat generated from the electronic components to the housing, the heat transfer body including at least one of a copper plate and a vapor chamber. According to the drive unit on the first side, heat generated from electronic components can be transferred to the housing, thereby suppressing the rise in temperature of the electronic components.
[0007] In a drive unit of the second side following the first side, the heat transfer body includes a vapor chamber. According to the drive unit on the second side, the vapor chamber can transfer heat generated from the electronic components to the housing, thereby suppressing the rise in temperature of the electronic components.
[0008] In a drive unit of the first or third side according to the second side, at least a portion of the substrate is positioned in front of the crankshaft mounting portion when the drive unit is mounted on a human-powered vehicle and all the wheels of the human-powered vehicle are in contact with a level ground. According to the drive unit on the third side, the circuit board can be placed in a part of the housing that is easily exposed to airflow, thus suppressing the rise in the temperature of the circuit board.
[0009] In the drive unit of the fourth side corresponding to the third side, the motor output shaft is positioned in front of the crankshaft mounting portion when horizontally mounted, and at least a portion of the circuit board is positioned in front of the motor output shaft when horizontally mounted. The drive unit on the fourth side further suppresses the rise in temperature of the circuit board.
[0010] In the drive unit of the fifth side following the fourth side, at least a portion of the heat transfer element is positioned in front of the motor output shaft when horizontally mounted. According to the drive unit on the fifth side, heat generated from electronic components can be transferred to the part of the housing that is easily dissipated by the airflow while driving, thus suppressing the rise in temperature of the electronic components.
[0011] In a drive unit with a sixth side conforming to any one of the first to fifth sides, the housing is configured such that the internal space is defined by the first housing and the second housing, the motor is mounted in the first housing, and heat generated from the electronic components is transferred to the second housing by a heat transfer body. According to the drive unit on the sixth side, heat generated from electronic components can be transferred to the second housing, which is less susceptible to heat from the motor, thus efficiently transferring heat generated from electronic components to the housing.
[0012] In the drive unit of the seventh side following the sixth side, the circuit board is mounted on the first housing. According to the drive unit on the seventh side, heat generated from electronic components can be transferred not only to the second housing but also to the first housing, thereby suppressing the rise in temperature of the electronic components.
[0013] In a drive unit of the eighth side that conforms to either the sixth or seventh side, heat dissipation fins are provided on the outer surface of the portion of the second housing to which heat generated from electronic components is transferred by a heat transfer body. According to the drive unit on the eighth side, heat generated from electronic components can be efficiently transferred to the housing, thereby suppressing the rise in temperature of the electronic components.
[0014] In a drive unit of the ninth side following the eighth side, a cover is further provided to cover the housing, the cover having an intake section for introducing air into the cover space defined by the cover and the housing, and an exhaust section located behind the intake section for discharging air from the cover space when the drive unit is mounted on a human-powered vehicle and all wheels of the human-powered vehicle are in contact with a level ground in a horizontal mounting state, the heat dissipation fins are provided on the air flow path from the intake section to the exhaust section. According to the drive unit on the ninth side, in a configuration where the housing is protected by a cover, it is easier to direct the airflow onto the heat dissipation fins, thereby suppressing the rise in temperature of the electronic components.
[0015] In the drive unit of the 10th side following the 9th side, the intake section and the exhaust section are formed in both the part of the cover that covers the first housing and the part that covers the second housing. According to the drive unit on the 10th side, airflow can easily reach both the first and second housings, thus suppressing the rise in temperature of the electronic components and the motor.
[0016] In a drive unit of an eleventh side conforming to any one of the first to tenth sides, at least a portion of the substrate is positioned below the straight line passing through the central axis of the crankshaft mounting portion and the central axis of the motor output shaft, when viewed from the direction in which the central axis of the crankshaft mounting portion extends, in a horizontal mounting state in which the drive unit is attached to a human-powered vehicle and all wheels of the human-powered vehicle are in contact with a horizontal ground. According to the drive unit on the 11th side, the circuit board can be placed in a part of the housing that is well-ventilated, thus suppressing the rise in the temperature of the circuit board.
[0017] In the drive unit of the 12th side corresponding to the 11th side, at least a portion of the heat transfer body is positioned below the straight line passing through the central axis of the crankshaft mounting portion and the central axis of the motor output shaft, when viewed from the direction in which the central axis of the crankshaft mounting portion extends, in a horizontally mounted state. According to the drive unit on the 12th side, heat generated from the electronic components can be transferred to the part of the housing that dissipates heat easily, thereby suppressing the rise in temperature of the electronic components.
[0018] In a drive unit of a thirteenth side that follows any one of the first to twelfth sides, the substrate extends in a direction intersecting the direction in which the central axis of the crankshaft mounting portion extends. According to the drive unit on the 13th side, the circuit board can be suitably arranged in the internal space of the housing.
[0019] In the drive unit of the 14th side surface according to any one of the 1st to 13th side surfaces, at least a part of the substrate is arranged so as to overlap at least a part of the motor when viewed from the direction in which the center axis of the crankshaft mounting portion extends. According to the drive unit of the 14th side surface, the substrate can be suitably arranged in the internal space of the housing.
Effect of the Invention
[0020] According to the drive unit of the present disclosure, an increase in the temperature of the electronic components can be suppressed.
Brief Description of the Drawings
[0021] [Figure 1] Right side view showing a human-powered vehicle equipped with the drive unit according to the first embodiment. [Figure 2] Left side view showing the drive unit. [Figure 3] Bottom view showing the drive unit. [Figure 4] Cross-sectional view of the cover along the D4-D4 line in FIG. 3. [Figure 5] Left side view showing the drive unit with the cover removed. [Figure 6] Cross-sectional view along the D6-D6 line in FIG. 5. [Figure 7] Left side view showing the drive unit with the second housing removed. [Figure 8] Left side view showing the drive unit with the second housing and the first substrate removed. [Figure 9] Cross-sectional view along the D9-D9 line in FIG. 5. [Figure 10] Explanatory view showing a drive unit including one printed wiring board. [Figure 11] Cross-sectional view showing the second substrate fixed to the second housing. [Figure 12] Perspective view showing the heat dissipation fins formed in a hedgehog shape.
Modes for Carrying Out the Invention
[0022] (First Embodiment) A human-powered vehicle 1 equipped with a drive unit 20 according to the first embodiment will be described. Figures 1 and 2 will be used to describe the human-powered vehicle 1.
[0023] Human-powered vehicle 1 is a vehicle having at least one wheel and capable of being driven by at least human power. Human-powered vehicle 1 includes various types of bicycles, such as mountain bikes, road bikes, city bikes, cargo bikes, handbikes, and recumbent bikes. The number of wheels that human-powered vehicle 1 has is not limited. Human-powered vehicle 1 includes, for example, unicycles and vehicles having two or more wheels. Human-powered vehicle 1 is not limited to vehicles that can be driven solely by human power. Human-powered vehicle 1 includes e-bikes that utilize the driving force of an electric motor in addition to human power for propulsion. E-bikes include electric assist bicycles in which propulsion is assisted by an electric motor. Hereinafter, in embodiments, human-powered vehicle 1 will be described as a bicycle.
[0024] In this specification, the following directional terms, “front,” “rear,” “forward,” “backward,” “left,” “right,” “side,” “up,” and “down,” as well as any other similar directional terms, refer to those directions determined with respect to the rider facing the handlebars 5 at a reference position (e.g., on the saddle or seat 4) of the human-powered vehicle 1.
[0025] The human-powered vehicle 1 comprises a crank 2, a frame 3, a seat 4, handlebars 5, a front fork 6, a front wheel 7, a rear wheel 8, a drive mechanism 9, a transmission 10, a battery 11, and a drive unit 20. The crank 2 shown in Figure 1 includes a crank shaft 2a that is rotatable relative to the frame 3, and a pair of crank arms 2b provided at both axial ends of the crank shaft 2a. Pedals 2c are connected to each of the pair of crank arms 2b.
[0026] The frame 3 rotatably supports the handlebars 5 and the front fork 6. As shown in Figures 1 and 2, the frame 3 includes a down tube 3a, a seat tube 3b, a pair of chainstays 3c, and a support section 3d. In Figure 2, the frame 3 is schematically represented. The seat 4 is provided on the seat tube 3b via a seat post 4a. One end of the down tube 3a, one end of the seat tube 3b, and one end of the pair of chainstays 3c are connected to each other.
[0027] The support portion 3d shown in Figure 2 is configured to support the drive unit 20. The support portion 3d is provided, for example, at the connection point between the down tube 3a, the seat tube 3b, and the pair of chainstays 3c of the frame 3. The support portion 3d is formed to follow a part of the outer edge of the drive unit 20. The support portion 3d is formed to sandwich the drive unit 20 from both sides. For example, the cross-section of the support portion 3d is formed in an inverted U shape.
[0028] The handlebar 5 shown in Figure 1 is configured to be gripped by the rider. When the handlebar 5 rotates relative to the frame 3, the front fork 6 rotates, and the direction of travel of the human-powered vehicle 1 changes.
[0029] The front wheel 7 is rotatably mounted to the front fork 6. The rear wheel 8 is rotatably mounted to the frame 3. The drive mechanism 9 connects the crank 2 and the rear wheel 8 to each other. The drive mechanism 9 includes a first rotating body 9a, a second rotating body 9b, and a chain 9c.
[0030] The first rotating body 9a includes, for example, one front sprocket 9d. The first rotating body 9a may include multiple front sprockets 9d. One front sprocket 9d is configured to rotate integrally with the crankshaft 2a when the crankshaft 2a rotates in a first rotational direction. The first rotational direction is the direction in which the rear wheel 8 rotates so that it moves forward when the rotation of one front sprocket 9d is transmitted to the rear wheel 8.
[0031] As the crankshaft 2a rotates in a first rotational direction, one front sprocket 9d rotates, and the human-powered driving force is transmitted to the rear wheel 8. The human-powered vehicle 1 moves forward as the human-powered driving force is transmitted to the rear wheel 8. The one front sprocket 9d may be connected to the crankshaft 2a via a one-way clutch 13 that allows the crankshaft 2a and the one front sprocket 9d to rotate together when the crankshaft 2a rotates in a first rotational direction, and prohibits the crankshaft 2a and the one front sprocket 9d to rotate together when the crankshaft 2a rotates in a second rotational direction opposite to the first rotational direction.
[0032] The second rotating body 9b is configured to output human-powered driving force to the rear wheel 8. The second rotating body 9b includes, for example, a plurality of rear sprockets 9e. The second rotating body 9b may include one rear sprocket 9e. The plurality of rear sprockets 9e are connected to the rear wheel 8. The chain 9c transmits the rotational force of one front sprocket 9d to the plurality of rear sprockets 9e. The configuration of the drive mechanism 9 is not limited to this embodiment. The drive mechanism 9 may connect the crank 2 and the rear wheel 8 to each other by, for example, pulleys and a belt.
[0033] The transmission 10 changes the gear ratio of the human-powered vehicle 1. The gear ratio represents the ratio of the rotational speed of the rear wheel 8 to the rotational speed of the crankshaft 2a. The transmission 10 includes at least one of an external gear shifter and an internal gear shifter. In this embodiment, the transmission 10 includes an external gear shifter. When the transmission 10 includes an external gear shifter, the gear ratio is calculated, for example, by dividing the number of teeth on the front sprocket 9d, with which the chain 9c engages, by the number of teeth on the rear sprocket 9e, with which the chain 9c engages. The external gear shifter includes at least one of a front derailleur and a rear derailleur 10a. In this embodiment, the external gear shifter includes a rear derailleur 10a. The rear derailleur 10a is configured to allow the chain 9c to be re-engaged between a plurality of rear sprockets 9e when a gear shifting device provided on the handlebars 5 is operated by the rider.
[0034] The battery 11 supplies power to components mounted on the human-powered vehicle 1. These components include, for example, a drive unit 20. The battery 11 includes, for example, at least one non-rechargeable battery and a rechargeable battery. The rechargeable battery is configured to be rechargeable by power from an external power source. The battery 11 is mounted on the frame 3. In this embodiment, at least a portion of the battery 11 is located in the internal space of the frame 3. The drive unit 20 is configured to provide propulsion to the human-powered vehicle 1.
[0035] Figures 2 to 9 are used to describe the drive unit 20. The drive unit 20 is a drive unit 20 for a human-powered vehicle and comprises a housing 30 that defines an internal space S30, a motor 50 provided in the internal space S30 and having a motor output shaft 51 including a motor output shaft central axis CA51, a crankshaft mounting portion configured to attach a crankshaft 2a inserted into the housing 30 and including a crankshaft mounting portion central axis CA40, a substrate 70 provided in the internal space S30 and having electronic components 73 that control the motor 50, and a heat transfer body 80 provided to transfer heat generated from the electronic components 73 to the housing 30. In this embodiment, the drive unit 20 further comprises a cover 90 that covers the housing 30. The motor output shaft central axis CA51 is the rotational center axis of the motor output shaft 51. The crankshaft mounting portion includes a bearing 40 shown in Figures 6 and 7.
[0036] As shown in Figures 2, 6, and 7, in this embodiment, the drive unit 20 includes a housing 30, bearings 40, a motor 50, a reducer 60, a substrate 70, a heat transfer body 80, and a cover 90. The housing 30 is formed in a hollow shape. The housing 30 is made of, for example, magnesium. As shown in Figure 2, the housing 30 is attached to the human-powered vehicle 1 by being fixed to a support 3d of the frame 3. In this specification, the state in which the drive unit 20 is attached to the human-powered vehicle 1 and all the wheels of the human-powered vehicle 1 are in contact with the horizontal ground is described as the horizontal mounting state. The drawings show the drive unit 20 in the horizontal mounting state. In this embodiment, the wheels include front wheels 7 and rear wheels 8.
[0037] As shown in Figures 5 to 7, the housing 30 includes a first housing 31 and a second housing 32. The first housing 31 constitutes the right side of the housing 30 when horizontally mounted. The first housing 31 is formed in a box shape with an opening on the left side when horizontally mounted. The first housing 31 includes a first side surface 31a, a first through hole 31b, and a first connecting portion 31c.
[0038] The first side surface 31a shown in Figure 6 forms the right side surface of the housing 30 when it is mounted horizontally. The first through hole 31b penetrates the first housing 31 along the left-right direction when it is mounted horizontally. The crankshaft 2a and the output shaft 14 are inserted through the first through hole 31b.
[0039] The output shaft 14 is configured to transmit the rotation of the crankshaft 2a to the first rotating body 9a when the crankshaft 2a rotates in a first rotational direction. The output shaft 14 has a substantially cylindrical shape. The output shaft 14 and the crankshaft 2a are arranged coaxially. The output shaft 14 has a rotational axis. The output shaft 14 is positioned radially outward from the crankshaft 2a in the radial direction with respect to the rotational axis of the output shaft 14. A portion of the output shaft 14 protrudes into the external space of the housing 30 through a first through hole 31b. The first rotating body 9a is attached to a portion of the output shaft 14. In Figure 6, the description of the first rotating body 9a is omitted.
[0040] In this embodiment, the crankshaft 2a and the output shaft 14 are indirectly connected via a transmission shaft 12 and a one-way clutch 13. The transmission shaft 12 is positioned between the crankshaft 2a and the one-way clutch 13 in the transmission path for human-powered driving force. The transmission shaft 12 is configured to transmit human-powered driving force from the crankshaft 2a to the one-way clutch 13. For example, the transmission shaft 12 is formed by a hollow shaft and is positioned coaxially with the crankshaft 2a.
[0041] The one-way clutch 13 is positioned between the transmission shaft 12 and the output shaft 14 in the transmission path of human-powered drive force. The one-way clutch 13 includes, for example, a roller clutch, a sprag clutch, a pawl ratchet clutch, or a face ratchet clutch. The one-way clutch 13 is configured to rotate the output shaft 14 when the crankshaft 2a rotates in a first rotational direction, and to allow relative rotation between the crankshaft 2a and the output shaft 14 when the crankshaft 2a rotates in a second rotational direction. The crankshaft 2a and the output shaft 14 may be directly connected without the transmission shaft 12 and the one-way clutch 13.
[0042] The first connecting portion 31c shown in Figure 7 is a portion that can be attached to the support portion 3d of the frame 3. When the vehicle is mounted horizontally, the first connecting portion 31c extends away from the outer edge of the first side surface 31a when viewed from the left and right directions of the human-powered vehicle 1. When the vehicle is mounted horizontally, the first connecting portion 31c is formed at the front, the front and rear intermediate portions, and the rear of the housing 30.
[0043] The first connecting portion 31c formed at the front of the housing 30 is positioned closer to the down tube 3a than the first connecting portion 31c formed at the front-rear and rear of the housing 30 when it is mounted horizontally. The first connecting portion 31c formed at the front-rear and rear of the housing 30 is positioned closer to the seat tube 3b than the first connecting portion 31c formed at the front and rear of the housing 30 when it is mounted horizontally. The first connecting portion 31c formed at the rear of the housing 30 is positioned closer to the pair of chainstays 3c than the first connecting portion 31c formed at the front and rear of the housing 30 when it is mounted horizontally.
[0044] The first connecting portion 31c includes a first connecting hole 31d configured to connect to a fastener. The fastener includes, for example, at least one of a bolt and a rivet. In the drawings, the fastener is not shown.
[0045] The first connecting hole 31d penetrates the first connecting portion 31c in the left-right direction when horizontally mounted. When horizontally mounted, the first connecting hole 31d is formed in a circular shape when viewed from the left-right direction of the human-powered vehicle 1. If the fastener includes a bolt, for example, the first connecting hole 31d is configured to be connected to the fastener by attaching a cylindrical inner member, for example, a cylindrical inner member with a female thread formed on its inner surface, to the first connecting hole 31d.
[0046] In this specification, the first connecting hole 31d of the first connecting portion 31c formed at the front of the first housing 31 is described as the front first connecting hole 31d. In this specification, the first connecting hole 31d of the first connecting portion 31c formed at the rear of the first housing 31 is described as the rear first connecting hole 31d.
[0047] The second housing 32, shown in Figures 5 and 6, constitutes the left side of the housing 30 when horizontally mounted. The second housing 32 is formed to close the opening formed on the left side of the first housing 31 when horizontally mounted. When the second housing 32 closes the opening of the first housing 31, the first housing 31 and the second housing 32 are connected to each other. When the second housing 32 closes the opening of the first housing 31, the housing 30 defines the internal space S30 by the first housing 31 and the second housing 32. In this embodiment, the internal space S30 of the housing 30 is the space between the inner surface of the first housing 31 and the inner surface of the second housing 32.
[0048] As shown in Figures 5 and 6, the second housing 32 includes a second side surface 32a, a second through-hole 32b, a second connecting portion 32c, and a heat dissipation fin 32d. The second side surface 32a forms the left side of the housing 30 when horizontally mounted. The second through-hole 32b is formed to allow the crankshaft 2a to pass through. The second through-hole 32b penetrates the second housing 32 along the left-right direction when horizontally mounted. As shown in Figure 6, the crankshaft 2a is inserted through the second through-hole 32b.
[0049] The second connecting portion 32c shown in Figure 5 is a portion that can be attached to the support portion 3d of the frame 3. When horizontally mounted, the second connecting portion 32c extends away from the outer edge of the second side surface 32a when viewed from the left and right directions of the human-powered vehicle 1. The second connecting portion 32c is formed at the front, front and rear intermediate, and rear of the housing 30, similar to the first connecting portion 31c of the first housing 31. The second connecting portion 32c includes a second connecting hole 32e, which is configured similarly to the first connecting hole 31d of the first housing 31.
[0050] The heat dissipation fins 32d are formed on the second side surface 32a of the second housing 32. In this embodiment, the heat dissipation fins 32d are formed on the front lower part of the second side surface 32a when horizontally mounted. In the horizontal mounting state, the heat dissipation fins 32d are formed in front of the second through hole 32b. The arrangement of the heat dissipation fins 32d is not limited to this embodiment.
[0051] As shown in Figure 9, the heat dissipation fin 32d protrudes from the second side surface 32a. In this embodiment, when horizontally mounted, the heat dissipation fin 32d protrudes to the left from the second side surface 32a. As shown in Figure 5, when horizontally mounted, the heat dissipation fin 32d is formed to extend in the front-rear direction. When horizontally mounted, the heat dissipation fin 32d is formed in a plate shape with its plate surface oriented in the up-down direction. When horizontally mounted, multiple heat dissipation fins 32d are formed in the up-down direction.
[0052] The housing 30 is fitted from below onto the support portion 3d of the frame 3 shown in Figure 2. In the horizontal mounting state, the front upper part to the rear part of the outer edge of the housing 30 is positioned inside the support part 3d and is sandwiched between the support part 3d from both sides. With the housing 30 sandwiched between the support part 3d, the first housing 31 is fixed to the support part 3d by connecting a fastener inserted through the support part 3d to the first connecting hole 31d. With the housing 30 sandwiched between the support part 3d, the second housing 32 is fixed to the support part 3d by connecting a fastener inserted through the support part 3d to the second connecting hole 32e.
[0053] The bearing 40 shown in Figures 6 and 7 is configured to support members inserted through the first through-hole 31b and the second through-hole 32b. In this embodiment, the bearing 40 is configured to support the crankshaft 2a and the output shaft 14. The bearing 40 includes a first bearing 41, a second bearing 42, and a third bearing 43. The first bearing 41 is configured to rotatably support the output shaft 14 relative to the first housing 31. The first bearing 41 is located in at least one of the internal space S30 of the housing 30 and the first through-hole 31b. The output shaft 14 is mounted on the first bearing 41. The crankshaft 2a is mounted on the first bearing 41 via the output shaft 14 and the third bearing 43.
[0054] The second bearing 42 is configured to rotatably support the crankshaft 2a relative to the second housing 32. The second bearing 42 is located in at least one of the internal space S30 of the housing 30 and the second through hole 32b. The crankshaft 2a is mounted on the second bearing 42.
[0055] The third bearing 43 is positioned between the inner circumference of the output shaft 14 and the outer circumference of the crankshaft 2a. The output shaft 14 rotatably supports the crankshaft 2a via the third bearing 43. The first bearing 41, the second bearing 42, and the third bearing 43 may each be ball bearings, roller bearings, or sliding bearings. In this embodiment, the first bearing 41 and the second bearing 42 are radial bearings, and the third bearing 43 is a needle bearing.
[0056] In this specification, the bearing 40 may be described as a crankshaft mounting portion. The bearing 40 includes the central axis CA40 of the crankshaft mounting portion. The central axis CA40 of the crankshaft mounting portion is the axis of the bearing 40. The central axis CA40 of the crankshaft mounting portion coincides with the rotational axis of the crankshaft 2a. In this specification, the direction in which the rotational axis of the crankshaft 2a extends may be described as the axial direction AD. In a horizontal mounting configuration, the axial direction AD is the left-right direction.
[0057] The motor 50 shown in Figure 6 is configured to provide propulsion to the human-powered vehicle 1. The motor 50 is configured to transmit rotational force to the rear wheels 8 of the human-powered vehicle 1, for example, via a motor output shaft 51. The motor 50 is mounted in either the first housing 31 or the second housing 32. In this embodiment, the motor 50 is mounted in the first housing 31. The motor 50 has a motor output shaft 51, a rotor 52, and a stator 53. The rotor 52 is fixed to the motor output shaft 51. The stator 53 faces the rotor 52.
[0058] The motor output shaft 51 is formed of, for example, a metallic material. The motor output shaft 51 is rotatably supported in the housing 30 via a pair of sixth bearings 46. The sixth bearings 46 may be ball bearings, roller bearings, or sliding bearings. The motor output shaft central axis CA 51 is located at a different position from the crankshaft mounting central axis CA 40. The direction in which the motor output shaft central axis CA 51 extends is substantially parallel to the axial direction AD. As shown in Figure 8, in the horizontal mounting configuration, the motor output shaft 51 is located in front of the crankshaft mounting.
[0059] The gearbox 60 shown in Figure 6 is configured to connect the motor 50 and the output shaft 14 to each other. The gearbox 60 is housed in the housing 30. The gearbox 60 is located in the internal space S30 of the housing 30. The gearbox 60 includes a first rotating body 61, a first reduction rotating shaft 62, a second rotating body 63, a third rotating body 64, a second reduction rotating shaft 65, a fourth rotating body 66, a fifth rotating body 67, and a sixth rotating body 68.
[0060] The first rotating body 61 is mounted on the output shaft 14 so as to rotate integrally with the output shaft 14. The first rotating body 61 and the output shaft 14 are formed from, for example, the same metal material. The first rotating body 61 and the output shaft 14 are formed integrally as, for example, a one-piece member. The first rotating body 61 and the output shaft 14 may be formed as separate parts and fixed so as not to rotate relative to each other. The first rotating body 61 may be formed from, for example, a resin material.
[0061] The first reduction rotating shaft 62 shown in Figures 6 and 7 has a rotational axis C62 located at a different position from the crankshaft mounting axis CA40 and the motor output shaft axis CA51. The direction in which the rotational axis C62 of the first reduction rotating shaft 62 extends is substantially parallel to the axial direction AD. The first reduction rotating shaft 62 is rotatably supported in the housing 30 via a pair of fourth bearings 44. The first reduction rotating shaft 62 is formed of, for example, a metallic material. The pair of fourth bearings 44 support the axial ends of the first reduction rotating shaft 62 in the axial direction with respect to the rotational axis C62 of the first reduction rotating shaft 62. The pair of fourth bearings 44 may be ball bearings, roller bearings, or sliding bearings.
[0062] The second rotating body 63 is mounted on the first reduction rotating shaft 62 via a one-way clutch 63a. The second rotating body 63 is connected to the first rotating body 61 directly or via a ring member. In this embodiment, the first rotating body 61 and the second rotating body 63 include gears with gear teeth on their outer circumference. The gear teeth of the first rotating body 61 and the gear teeth of the second rotating body 63 mesh together, thereby directly connecting the first rotating body 61 and the second rotating body 63.
[0063] The one-way clutch 63a includes, for example, a roller clutch, a sprag clutch, a pawl ratchet clutch, or a face ratchet clutch. The one-way clutch 63a is configured to rotate the second rotating body 63 when the first reduction rotating shaft 62 rotates in a first rotational direction, and to allow relative rotation between the first reduction rotating shaft 62 and the second rotating body 63 when the first reduction rotating shaft 62 rotates in a second rotational direction opposite to the first rotational direction. The one-way clutch 63a may be provided between the first reduction rotating shaft 62 and the third rotating body 64, rather than between the first reduction rotating shaft 62 and the second rotating body 63.
[0064] The third rotating body 64 is configured to rotate integrally with the first reduction shaft 62. The third rotating body 64 is formed from, for example, a resin material or a metal material. The third rotating body 64 and the first reduction shaft 62 are formed separately and fixed so as not to rotate relative to each other. The third rotating body 64 and the first reduction shaft 62 may be formed integrally as a one-piece member. The second rotating body 63 and the third rotating body 64 are positioned between a pair of fourth bearings 44 in the axial direction of the first reduction shaft 62.
[0065] The second reduction rotating shaft 65 has a rotational axis C65 located at a different position from the crankshaft mounting axis CA40 and the motor output shaft axis CA51. The direction in which the rotational axis C65 of the second reduction rotating shaft 65 extends is substantially parallel to the axial direction AD. The second reduction rotating shaft 65 is rotatably supported in the housing 30 via a pair of fifth bearings 45. The pair of fifth bearings 45 support the axial ends of the second reduction rotating shaft 65 in the axial direction with respect to the rotational axis C65 of the second reduction rotating shaft 65. The fifth bearings 45 may be ball bearings, roller bearings, or sliding bearings.
[0066] The fourth rotating body 66 is mounted on the second reduction shaft 65 so as to rotate integrally with the second reduction shaft 65. The fourth rotating body 66 and the second reduction shaft 65 are integrally formed, for example, as a one-piece member. The fourth rotating body 66 is connected to the third rotating body 64 directly or via a ring member. In this embodiment, the third rotating body 64 and the fourth rotating body 66 include gears with gear teeth on their outer circumference. The gear teeth of the third rotating body 64 and the gear teeth of the fourth rotating body 66 mesh together to directly connect the third rotating body 64 and the fourth rotating body 66.
[0067] The fifth rotating body 67 is configured to rotate integrally with the second reduction shaft 65. The fifth rotating body 67 is formed from, for example, a resin material or a metal material. The fifth rotating body 67 and the second reduction shaft 65 are formed separately and fixed so as not to rotate relative to each other. The fifth rotating body 67 and the second reduction shaft 65 may be formed integrally as a one-piece member. The fourth rotating body 66 and the fifth rotating body 67 are positioned between a pair of fifth bearings 45 in the axial direction of the second reduction shaft 65.
[0068] The sixth rotating body 68 is mounted on the motor output shaft 51 of the motor 50 so as to rotate integrally with the motor output shaft 51. The sixth rotating body 68 is formed of, for example, a metal material. The sixth rotating body 68 and the motor output shaft 51 are formed integrally as, for example, a one-piece member. The sixth rotating body 68 and the motor output shaft 51 may be formed as separate parts and fixed so as not to rotate relative to each other. The sixth rotating body 68 may be formed of, for example, a resin material.
[0069] The sixth rotating body 68 is connected to the fifth rotating body 67 either directly or via a ring member. In this embodiment, the fifth rotating body 67 and the sixth rotating body 68 include gears with gear teeth on their outer circumference. The gear teeth of the fifth rotating body 67 and the gear teeth of the sixth rotating body 68 mesh together, thereby directly connecting the fifth rotating body 67 and the sixth rotating body 68.
[0070] When the motor 50 is driven, the rotational force of the motor 50 is transmitted to the output shaft 14 via the reduction gear 60, so that the rotational speed of the output shaft 14 decreases relative to the rotational speed of the motor output shaft 51. The configuration of the reduction gear 60 is not limited to this embodiment. The reduction gear 60 may be configured to indirectly connect two rotating bodies by, for example, pulleys, ring members, and chains. Ring members include, for example, chains and belts. The reduction gear 60 may be configured to include, for example, only one pair of rotating bodies, only two pairs of rotating bodies, or a planetary gear mechanism.
[0071] The substrate 70 shown in Figures 6 and 7 is configured to control the motor 50. The thickness direction of the substrate 70 is substantially parallel to the axial direction AD. As shown in Figure 6, when viewed from a direction perpendicular to the axial direction AD, the substrate 70 extends in a direction intersecting the direction in which the central axis CA40 of the crankshaft mounting portion extends. In this embodiment, the substrate 70 extends in a direction perpendicular to the axial direction AD. By extending the substrate 70 in a direction intersecting the axial direction AD, the substrate 70 can be suitably positioned. For example, the motor 50 and the substrate 70 can be easily arranged side by side in the axial direction AD.
[0072] In this embodiment, the substrate 70 includes two printed circuit boards. In this specification, one of the two printed circuit boards is referred to as the first substrate 71. In this specification, the other of the two printed circuit boards is referred to as the second substrate 72. As shown in Figure 7, the first substrate 71 is positioned midway between the front and rear of the housing 30 in the horizontal mounting position. In the horizontal mounting position, the rear of the first substrate 71 overlaps with the output shaft 14 when viewed from the axial direction AD. In the horizontal mounting position, the front of the first substrate 71 overlaps with the motor output shaft 51 when viewed from the axial direction AD.
[0073] In the horizontal mounting state, the second substrate 72 is positioned to the right of the first substrate 71. As shown in Figure 8, in the horizontal mounting state, the second substrate 72 is positioned to extend from the front to the middle of the housing 30. The second substrate 72 is positioned so as not to overlap with the motor output shaft 51 and the fifth rotating body 67 when viewed from the axial direction AD. As shown in Figure 7, a portion of the second substrate 72 is positioned to overlap with the first substrate 71 when viewed from the axial direction AD.
[0074] At least a portion of the substrate 70 is positioned in front of the crankshaft mounting portion when the drive unit 20 is attached to the human-powered vehicle 1 and all the wheels of the human-powered vehicle 1 are in contact with the horizontal ground. For example, as shown in Figures 7 and 8, in the horizontal mounting state, at least a portion of the first substrate 71 and the entirety of the second substrate 72 are positioned in front of the second bearing 42 when viewed from the axial direction AD. The positional relationship between the substrate 70 and the crankshaft mounting portion is not limited to this embodiment. For example, a portion of the second substrate 72 may be positioned in front of the second bearing 42 when viewed from the axial direction AD in the horizontal mounting state.
[0075] At least a portion of the circuit board 70 is positioned in front of the motor output shaft 51 when horizontally mounted. For example, when horizontally mounted, the front end of the first circuit board 71 and the front portion of the second circuit board 72 are positioned in front of the motor output shaft 51. At least a portion of the circuit board 70 is positioned to overlap with at least a portion of the motor 50 when viewed from the direction in which the central axis CA40 of the crankshaft mounting portion extends. As shown in Figure 7, for example, a portion of the first circuit board 71 and a portion of the second circuit board 72 are positioned to overlap with the stator 53 when viewed from the axial direction AD.
[0076] The positional relationship between the substrate 70 and the motor output shaft 51 is not limited to this embodiment. For example, the entire second substrate 72 may be positioned in front of the motor output shaft 51 when viewed from the axial direction AD in a horizontally mounted state. For example, the entire second substrate 72 may be positioned so as to overlap with the stator 53 when viewed from the axial direction AD in a horizontally mounted state.
[0077] The substrate 70 is attached to either the first housing 31 or the second housing 32. For example, the substrate 70 is attached to the first housing 31. In this embodiment, both the first substrate 71 and the second substrate 72 are attached to the first housing 31. The second substrate 72 is attached to the first housing 31 by bolts 72a schematically shown in Figures 7 and 8. In the drawings, the bolts used to attach the first substrate 71 to the first housing 31 are not shown.
[0078] In this embodiment, at least a portion of the substrate 70 is positioned below the line L1 passing through the central axis CA40 of the crankshaft mounting portion and the central axis CA51 of the motor output shaft, when viewed from the direction in which the central axis CA40 of the crankshaft mounting portion extends, in a horizontal mounting state in which the drive unit 20 is attached to the human-powered vehicle 1 and all the wheels of the human-powered vehicle 1 are in contact with the horizontal ground. As shown in Figure 8, for example, a portion of the second substrate 72 is positioned below the line L1 when viewed from the axial direction AD in a horizontal mounting state. The positional relationship between the substrate 70 and the line L1 is not limited to this embodiment. For example, the entire second substrate 72 may be positioned below the line L1 when viewed from the axial direction AD in a horizontal mounting state.
[0079] As shown in Figure 6, an electronic component 73 for controlling the motor 50 is provided on at least one side of the substrate 70 in the thickness direction, and on at least one of the other side. The electronic component 73 includes, for example, a microprocessor, a capacitor, a resistor, a FET (Field effect transistor), and a current sensor. In this specification, the electronic component 73 provided on the first substrate 71 is described as the first electronic component 73a. In this specification, the electronic component 73 provided on the second substrate 72 is described as the second electronic component 73b. In Figure 7, the descriptions of the first electronic component 73a and the second electronic component 73b are omitted. Figure 8 schematically shows the second electronic component 73b superimposed on the heat transfer body 80.
[0080] The control unit of the drive unit 20 is formed by providing electronic components 73 on the substrate 70. The control unit controls the motor 50 to impart propulsion to the human-powered vehicle 1 according to predetermined parameters, for example. The predetermined parameters include, for example, the human-powered driving force input to the human-powered vehicle 1 and at least one of the vehicle speed. The control unit controls the motor 50 to output a first driving force calculated according to the human-powered driving force when the vehicle speed is below a predetermined threshold, for example. When the control unit controls the motor 50, heat is generated from the electronic components 73. In this embodiment, the temperature of the second substrate 72 is more likely to rise than the temperature of the first substrate 71 due to the heat generated from the electronic components 73. The temperatures of the second substrate 72 and the second electronic component 73b are more likely to rise as the driving force of the motor 50 increases.
[0081] The control unit is configured to reduce the driving force of the motor 50 when the temperature of the electronic component 73 exceeds a predetermined threshold while the motor 50 is being driven. The temperature of the electronic component 73 is obtained, for example, from a temperature change unit whose temperature changes in accordance with the temperature of the electronic component 73. The temperature change unit may be, for example, a part of the drive unit 20 whose temperature is easily changed in accordance with the temperature change of the second electronic component 73b. The temperature change unit may be, for example, a part that is in contact with the second electronic component 73b, and at least one of the second electronic component 73b. The predetermined threshold may be set, for example, according to the upper limit of the temperature range in which the second electronic component 73b operates normally.
[0082] For example, when the motor 50 is being driven, the control unit controls the motor 50 to output a second driving force lower than the first driving force when the temperature of the temperature change section is above a threshold. By outputting the second driving force, the output of the motor 50 is reduced, and the rise in temperature of the second electronic component 73b can be suppressed, making the second electronic component 73b less likely to be damaged.
[0083] If the output of the motor 50 is reduced, the propulsive force applied to the human-powered vehicle 1 decreases. The drive unit 20 of this embodiment is configured to make it difficult to reduce the output of the motor 50 by suppressing the temperature rise of the second electronic component 72b with the heat transfer body 80. Because it is difficult to reduce the output of the motor 50, the rider can easily and comfortably ride the human-powered vehicle 1. For example, the rider can continuously ride the human-powered vehicle 1 at the maximum output torque of the motor 50.
[0084] The heat transfer body 80 shown in Figures 8 and 9 is configured to diffuse the heat generated from the electronic component 73 and transfer it to at least one of the first housing 31 and the second housing 32. The heat transfer body 80 in this embodiment is configured to diffuse the heat generated from the second electronic component 73b and transfer it to the second housing 32. The heat transfer body 80 includes a copper plate and at least one of a vapor chamber 81. In this embodiment, the heat transfer body 80 includes a vapor chamber 81. The heat transfer body 80 further includes a heat dissipation sheet 82.
[0085] The vapor chamber 81 is constructed by sealing a working fluid and a wick in a hollow, sealed metal container. The working fluid includes, for example, water. The vapor chamber 81 is formed in a plate shape. The thickness direction of the vapor chamber 81 is substantially parallel to the thickness direction of the second substrate 72. The area of the vapor chamber 81 is larger than the area of one second electronic component 73b when viewed from the axial direction AD.
[0086] The vapor chamber 81 is positioned between the second housing 32 and the second substrate 72 in the axial direction AD. The vapor chamber 81 is positioned so as to overlap a portion of the second substrate 72 when viewed from the axial direction AD. The vapor chamber 81 is positioned so as to overlap a portion of the second electronic components 73b among the plurality of second electronic components 73b when viewed from the axial direction AD. In this embodiment, in the horizontal mounting state, the vapor chamber 81 is positioned so as to overlap a portion of the second substrate 72 that is located in front of the third rotating body 64 when viewed from the axial direction AD. In the horizontal mounting state, the vapor chamber 81 is positioned so as to overlap a portion of the second electronic components 73b that are located in front of the third rotating body 64 when viewed from the axial direction AD.
[0087] The heat dissipation sheet 82 has excellent thermal conductivity. For example, the heat dissipation sheet 82 has better thermal conductivity than the substrate 70 and the housing 30. In Figures 7 and 8, the heat dissipation sheet 82 is not shown. As shown in Figure 9, the heat dissipation sheet 82 includes a first thermal sheet 82a and a second thermal sheet 82b.
[0088] The first thermal sheet 82a is configured to transfer heat from the vapor chamber 81 to the second housing 32. The first thermal sheet 82a is positioned between the vapor chamber 81 and the second housing 32 in the axial direction AD. The second thermal sheet 82b is configured to transfer heat from the second substrate 72 to the vapor chamber 81. The second thermal sheet 82b is positioned between the second substrate 72 and the vapor chamber 81 in the axial direction AD.
[0089] The vapor chamber 81 is attached to at least one of the substrate 70 and the housing 30 via a heat dissipation sheet 82. For example, the vapor chamber 81 is attached to both the second substrate 72 and the second housing 32 via the heat dissipation sheet 82. As shown in Figure 8, a stopper 83 that supports the vapor chamber 81 is attached to the second substrate 72. The stopper 83 is made of, for example, resin. The stopper 83 is formed to follow at least a portion of the outer edge of the vapor chamber 81. The stopper 83 is attached to the first housing 31 together with the second substrate 72 by bolts 72a. In the horizontal mounting position, the stopper 83 supports the lower part of the outer edge of the vapor chamber 81. The stopper 83 supporting the lower part of the outer edge of the vapor chamber 81 makes it difficult for the vapor chamber 81 to fall even if the drive unit 20 vibrates.
[0090] The first thermal sheet 82a and the second thermal sheet 82b may be made of a material with lower hardness than the sealed container of the vapor chamber 81, the substrate 70, and the housing 30. By making the first thermal sheet 82a and the second thermal sheet 82b from a material with lower hardness, the first thermal sheet 82a and the second thermal sheet 82b can be made more elastically deformable.
[0091] By making the first thermal sheet 82a easily elastically deformable, a compressible portion of the first thermal sheet 82a is provided between the second housing 32 and the vapor chamber 81. By making the second thermal sheet 82b easily elastically deformable, a compressible portion of the second thermal sheet 82b is provided between the vapor chamber 81 and the second substrate 72. By providing compressible portions for the first thermal sheet 82a and the second thermal sheet 82b, dimensional variations of the second substrate 72, the vapor chamber 81, and the second housing 32 can be absorbed.
[0092] By providing the first thermal sheet 82a and the second thermal sheet 82b with a compressible portion, the adhesion between the second housing 32, the vapor chamber 81, and the second substrate 72 is increased, and the contact thermal resistance is reduced. By reducing the contact thermal resistance, heat can be efficiently transferred from the second substrate 72 to the second housing 32.
[0093] As shown in Figure 8, at least a portion of the heat transfer body 80 is positioned in front of the motor output shaft 51 when horizontally mounted. At least a portion of the heat transfer body 80 is positioned below the straight line L1 passing through the crankshaft mounting center axis CA40 and the motor output shaft center axis CA51 when viewed from the direction in which the crankshaft mounting center axis CA40 extends when horizontally mounted. For example, the portion of the vapor chamber 81 other than the upper end is positioned below the straight line L1 when viewed from the axial direction AD when horizontally mounted. The positional relationship between the heat transfer body 80 and the straight line L1 is not limited to this embodiment. For example, the entire vapor chamber 81 may be positioned below the straight line L1 when viewed from the axial direction AD when horizontally mounted.
[0094] The heat generated from the second electronic component 73b is transferred to the vapor chamber 81 via the second substrate 72 and the second thermal sheet 82b shown in Figure 9. The working fluid in the vapor chamber 81 evaporates due to the heat transferred to the vapor chamber 81. As the working fluid evaporates, vapor is generated in the internal space of the vapor chamber 81. The vapor diffuses within the internal space of the vapor chamber 81. The heat of the diffused vapor is transferred to the second housing 32 via the first thermal sheet 82a. As the heat of the vapor is transferred to the second housing 32, the heat generated from the electronic component 73 is transferred to the second housing 32 by the heat transfer body 80. In this embodiment, the heat generated from the second electronic component 73b is diffused in the vapor chamber 81 and transferred to the second housing 32.
[0095] The heat from the steam is transferred to the second housing 32, which cools the steam and liquefies the working fluid. The liquefied working fluid is then moved by the wick to the portion of the vapor chamber 81 that is in contact with the part of the second substrate 72 where the temperature is likely to rise. For example, the working fluid is moved to the portion of the vapor chamber 81 that overlaps with the second electronic component 73b when viewed from the axial direction AD. In the vapor chamber 81, the repeated evaporation and liquefaction of the working fluid efficiently transfers the heat generated from the second electronic component 72b to the housing 30, thereby suppressing the temperature rise of the second electronic component 72b and the second substrate 72.
[0096] By suppressing the temperature rise of the second electronic component 73b and the second substrate 72, the output of the motor 50 can be made less likely to decrease. Because the output of the motor 50 can be made less likely to decrease, the propulsion force on the human-powered vehicle 1 is less likely to decrease, making it easier for the rider to comfortably ride the human-powered vehicle 1.
[0097] The second housing 32 is less susceptible to heat generated by the motor 50 than the first housing 31 to which the motor 50 is mounted. Because the second housing 32 is less susceptible to heat generated by the motor 50, the temperature of the second housing 32 is lower than that of the first housing 31 when the motor 50 is running. In this embodiment, heat generated from the second electronic component 73b is transferred to the lower-temperature second housing 32, allowing for efficient heat transfer to the housing 30. By efficiently transferring heat to the housing 30, the temperature rise of the second electronic component 73b and the second substrate 72 can be suppressed.
[0098] In this embodiment, the substrate 70 is attached to the first housing 31. With the substrate 70 attached to the first housing 31, and the heat transfer body 80 transferring heat generated from the second electronic component 73b to the second housing 32, the heat generated from the second electronic component 73b is transferred to both the first housing 31 and the second housing 32, thereby suppressing the temperature rise of the second electronic component 73b.
[0099] As shown in Figures 5 and 9, the heat transfer body 80 of this embodiment is positioned so as to overlap the front lower part of the second housing 32 when viewed from the axial direction AD in a horizontally mounted state. Heat generated from the second electronic component 73b is transferred to the front lower part of the second housing 32 via the heat transfer body 80. The heat dissipation fins 32d are formed on the front lower part of the second side surface 32a of the second housing 32, and are provided on the outer surface of the portion of the second housing 32 to which heat generated from the electronic component 73 is transferred by the heat transfer body 80. When the heat dissipation fins 32d are positioned as to overlap at least a portion of the heat transfer body 80 when viewed from the axial direction AD in a horizontally mounted state. In this embodiment, when the heat dissipation fins 32d are positioned as to overlap the portion of the heat transfer body 80 excluding the upper end when viewed from the axial direction AD in a horizontally mounted state.
[0100] By providing heat dissipation fins 32d on the outer surface of the portion of the second housing 32 to which heat generated from the electronic component 73 is transferred, the heat transferred to the housing 30 can be easily dissipated to the space outside the housing 30 via the heat dissipation fins 32d. By making it easier to dissipate heat to the space outside the housing 30, the temperature rise of the second housing 32 can be suppressed, and thus the heat generated from the second electronic component 73b can be efficiently transferred to the housing 30.
[0101] As shown in Figure 7, in this embodiment, at least a portion of the second substrate 72 and at least a portion of the heat transfer body 80 are positioned in front of the first bearing 41 and the motor output shaft 51 when viewed from the axial direction AD in the horizontal mounting state. By positioning at least a portion of the second substrate 72 and at least a portion of the heat transfer body 80 in front of the first bearing 41 and the motor output shaft 51, heat generated from the second electronic component 73b is easily transferred to the front side of the second housing 32.
[0102] Because the front of the second housing 32 is easily exposed to airflow, the heat transferred from the second electronic component 73b to the front of the second housing 32 is easily dissipated into the external space of the housing 30 by the airflow. As the heat transferred to the front of the second housing 32 is easily dissipated into the external space of the housing 30, the temperature of the front of the second housing 32 can be kept low even when heat generated from the second electronic component 73b is transferred. By keeping the temperature of the front of the second housing 32 low, the heat generated from the second electronic component 73b can be efficiently transferred to the housing 30, thereby suppressing the temperature rise of the second electronic component 73b and the second substrate 72.
[0103] As shown in Figure 2, since the upper part of the housing 30 is located inside the support portion 3d of the frame 3, heat may be difficult to dissipate when heat is transferred to the upper part of the housing 30. The heat transfer body 80 of this embodiment is configured to transfer heat generated from the second electronic component 73b to the portion of the second housing 32 shown in Figure 5 that is exposed from the support portion 3d. For example, the heat transfer body 80 is configured to transfer heat generated from the second electronic component 73b to the lower part of the second housing 32.
[0104] As shown in Figure 8, in this embodiment, at least a portion of the second substrate 72 and at least a portion of the heat transfer body 80 are positioned below the straight line L1 when viewed from the axial direction AD in a horizontal mounting state, thereby transferring heat generated from the second electronic component 73b to the lower part of the second housing 32. Because the heat generated from the second electronic component 73b is transferred to the lower part of the second housing 32, the heat generated from the second electronic component 73b can be easily dissipated into the external space of the housing 30, thereby suppressing the temperature rise of the housing 30, the second electronic component 73b, and the second substrate 72.
[0105] In this embodiment, at least a portion of the second substrate 72 and at least a portion of the heat transfer body 80 are positioned below a straight line L31 passing through the center C31 of the front first connecting hole 31d and the center C31 of the rear first connecting hole 31d, when viewed from the axial direction AD, in a horizontal mounting state. By positioning at least a portion of the second substrate 72 and at least a portion of the heat transfer body 80 below the straight line L31, heat generated from the second electronic component 73b is easily transferred to the portion of the housing 30 exposed from the support portion 3d, thereby suppressing the temperature rise of the housing 30, the second electronic component 73b, and the second substrate 72.
[0106] The cover 90 shown in Figures 2 to 4 is configured to cover the housing 30. The cover 90 is fixed to the housing 30. In this embodiment, the cover 90 is formed to follow a portion of the outer edge of the housing 30. When horizontally mounted, the cover 90 is positioned to cover the lower part of the housing 30. In this embodiment, the right portion of the cover 90 covers the lower part of the first housing 31. The left portion of the cover 90 covers the lower part of the second housing 32. In this specification, the portion of the cover 90 that covers the lower part of the first housing 31 may be referred to as the first cover portion 91. In this specification, the portion of the cover 90 that covers the lower part of the second housing 32 may be referred to as the second cover portion 92.
[0107] The cover 90 includes an intake section 93 for introducing air into the cover space S90 defined by the cover 90 and the housing 30, and an exhaust section 94 provided behind the intake section 93 for discharging air from the cover space S90 when the drive unit 20 is attached to the human-powered vehicle 1 and all the wheels of the human-powered vehicle 1 are in contact with the ground.
[0108] The cover space S90 shown in Figure 4 is formed between the inner surface of the cover 90 and the outer surface of the housing 30. When the housing is mounted horizontally, the cover space S90 is formed to extend along the shape of the lower part of the housing 30.
[0109] The intake section 93 penetrates the cover 90 and is formed to communicate with the cover space S90 and the external space of the drive unit 20. As shown in Figure 3, two intake sections 93 are formed along the left-right direction when the unit is mounted horizontally. Of the left and right intake sections 93, at least a portion of the right intake section 93 is formed in the first cover section 91. Of the left and right intake sections 93, at least a portion of the left intake section 93 is formed in the second cover section 92.
[0110] In this embodiment, at least a portion of the right intake portion 93 is formed in the first cover portion 91, and at least a portion of the left intake portion 93 is formed in the second cover portion 92, so that the intake portions 93 are formed in both the portion of the cover 90 that covers the first housing 31 and the portion that covers the second housing 32. Multiple left and right intake portions 93 are formed along the front-rear direction when the unit is horizontally mounted. The configuration of the intake portions 93 is not limited to this embodiment. For example, only one intake portion 93 may be formed in the cover 90.
[0111] As shown in Figure 4, the exhaust section 94 penetrates the cover 90 and is formed to communicate with the cover space S90 and the external space of the drive unit 20. As shown in Figure 3, two exhaust sections 94 are formed along the left-right direction when the unit is mounted horizontally. Of the left and right exhaust sections 94, at least a portion of the right exhaust section 94 is formed in the first cover section 91. Of the left and right exhaust sections 94, at least a portion of the left exhaust section 94 is formed in the second cover section 92.
[0112] In this embodiment, at least a portion of the right-side exhaust section 94 is formed in the first cover section 91, and at least a portion of the left-side exhaust section 94 is formed in the second cover section 92, so that the exhaust sections 94 are formed in both the portion of the cover 90 that covers the first housing 31 and the portion that covers the second housing 32. The configuration of the exhaust section 94 is not limited to this embodiment. For example, only one exhaust section 94 may be formed in the cover 90.
[0113] As shown in Figure 4, in the horizontal mounting state, the front end of the heat dissipation fin 32d faces the left intake section 93. In this embodiment, by having the front end of the heat dissipation fin 32d face the left intake section 93, the heat dissipation fin 32d is provided on the air flow path C90 from the intake section 93 to the exhaust section 94. The left intake section 93 is formed to guide the airflow towards the heat dissipation fin 32d. In this embodiment, the left intake section 93 is formed to protrude from the inner surface of the cover 90 toward the heat dissipation fin 32d, thereby guiding the airflow towards the heat dissipation fin 32d.
[0114] When the human-powered vehicle 1 is in motion, the airflow directed at the human-powered vehicle 1 flows through the intake section 93 into the cover space S90. The airflow flows through the cover space S90 towards the rear. In this embodiment, since the heat dissipation fins 32d are provided on the airflow path C90 from the intake section 93 to the exhaust section 94, a portion of the airflow hits the heat dissipation fins 32d, and heat is removed from the second housing 32 via the heat dissipation fins 32d. In this embodiment, the intake section 93 on the left side is formed to guide the airflow to the heat dissipation fins 32d, making it easier to direct the airflow to the heat dissipation fins 32d.
[0115] In this configuration, where the housing 30 is protected by the cover 90, a portion of the airflow absorbs heat from the second housing 32 via the heat dissipation fins 32d, heat generated from the second electronic component 73b can be efficiently transferred to the second housing 32, thereby suppressing the temperature rise of the second electronic component 73b. The airflow circulates to the outside of the cover space S90 via the exhaust section 94.
[0116] In this embodiment, since the right intake section 93 and the right exhaust section 94 are formed in the first cover section 91 that covers the first housing 31, the airflow circulating through the cover space S90 via the right intake section 93 easily hits the first housing 31. By allowing the airflow to easily hit the first housing 31, the temperature rise of the first housing 31 and the motor 50 can be suppressed.
[0117] As shown in Figure 2, a portion of the heat dissipation fins 32d in this embodiment is positioned to be exposed from both the support portion 3d and the cover 90. Because the heat dissipation fins 32d are exposed from both the support portion 3d and the cover 90, heat can be easily dissipated to the external space of the housing 30 via the heat dissipation fins 32d. This efficiently transfers the heat generated from the second electronic component 73b to the housing 30, thereby suppressing the temperature rise of the second electronic component 73b.
[0118] As shown in Figure 5, the upper end of the heat transfer element 80 does not overlap with the heat dissipation fin 32d when viewed from the axial direction AD. The portion of the second housing 32 that overlaps with the upper end of the heat transfer element 80 when viewed from the axial direction AD is exposed from the support portion 3d shown in Figure 2 and the cover 90, so even if heat is transferred from the heat transfer element 80, it is easy for the heat to escape into the external space of the housing 30.
[0119] (modified version) The description relating to this embodiment is illustrative of possible forms of the present invention and is not intended to limit it. The present invention may take the form of, for example, the following modifications of this embodiment, and at least two non-contradictory modifications combined.
[0120] For example, the configuration of the drive unit 20 in this embodiment is just one example, and the drive unit 20 may include various devices not shown in this embodiment, or it may have a configuration that does not include some of the various devices shown in this embodiment.
[0121] For example, the heat transfer element 80 may be configured to transfer heat generated from the first electronic component 73a to the housing 30. The heat transfer element 80 may be configured to transfer both heat generated from the first electronic component 73a and heat generated from the second electronic component 73b to the housing 30.
[0122] For example, as schematically shown in Figure 10, the substrate 70 may include one printed circuit board 75. By including one printed circuit board 75 in the substrate 70, the contact area between one vapor chamber 81 and the substrate 70 when one vapor chamber 81 is in contact with the substrate 70 can be made larger than the contact area between one vapor chamber 81 and the substrate 70 when the substrate 70 includes multiple printed circuit boards. By making the contact area between one vapor chamber 81 and the substrate 70 larger, the area over which heat is diffused by the heat transfer body 80 can be expanded, so that the heat generated from the electronic components 73 can be efficiently transferred to the housing 30.
[0123] For example, as shown in Figure 11, the vapor chamber 81 may be fixed to the housing 30 by bolts 85. When the vapor chamber 81 is fixed to the housing 30 by bolts 85, thermal grease 84 may be applied to the surface of the vapor chamber 81 that faces the inner surface of the housing 30. The thermal grease 84 fills the gap between the vapor chamber 81 and the housing 30. Fixing the vapor chamber 81 to the housing 30 reduces the contact thermal resistance between the vapor chamber 81 and the housing 30.
[0124] For example, as schematically shown in Figure 12, the shape of the heat dissipation fins 32d may be formed in a pincushion shape. By forming the heat dissipation fins 32d in a pincushion shape, the total surface area of the multiple heat dissipation fins 32d can be increased, thereby improving heat dissipation.
[0125] As schematically shown in Figure 12, the heat transfer body 80 may include a copper plate 86. The heat transfer body 80 may include a copper plate 86 when the heat dissipation fins 32d are formed in a plate shape, as in this embodiment. The heat transfer body 80 may include both the copper plate 86 and the vapor chamber 81.
[0126] As used herein, the expression "at least one" means "one or more" of the desired options. For example, as used herein, the expression "at least one" means "only one option" or "both of the two options" if there are two options. As another example, as used herein, the expression "at least one" means "only one option" or "a combination of two or more any options" if there are three or more options. For example, the expression "at least one of A and B" means (1) A only, and (2) B only, and (3) both A and B. For example, the expression "at least one of A, B, and C" means (1) A only, and (2) B only, (3) C only, (4) both A and B, (5) both B and C, (6) both A and C, and (7) all of A, B, and C. In other words, the expression “at least one of A and B” as used herein does not mean “at least one A and at least one B.” [Explanation of Symbols]
[0127] 1...Human-powered vehicle, 2a...Crankshaft, 7...Front wheel, 8...Rear wheel, 20...Drive unit, 30...Housing, 31...First housing, 32...Second housing, 40...Bearing, 50...Motor, 51...Motor output shaft, 73...Electronic component, 70...Circuit board, 80...Heat transfer element, 81...Vapor chamber, 86...Copper plate, 90...Cover, 91...First cover section, 92...Second cover section, 93...Intake section, 94...Exhaust section, AD...Axial direction, CA40...Crank mounting section center axis, CA51...Motor output shaft center axis, C90...Flow path, L1...Straight line, S30...Internal space
Claims
1. A drive unit for a human-powered vehicle, Housing that defines the interior space, A motor provided in the aforementioned internal space, having a motor output shaft that includes the central axis of the motor output shaft, It is configured to mount a crankshaft that is inserted into the housing, and includes a crankshaft mounting portion that includes the central axis of the crankshaft mounting portion, A substrate is provided in the internal space, on which electronic components for controlling the motor are provided, The system includes a heat transfer body provided to transfer heat generated from the electronic component to the housing, The heat transfer body is a drive unit comprising a copper plate and at least one vapor chamber.
2. The drive unit according to claim 1, wherein the heat transfer element includes the vapor chamber.
3. The drive unit according to claim 1, wherein at least a portion of the substrate is positioned in front of the crankshaft mounting portion when the drive unit is mounted on the human-powered vehicle and all the wheels of the human-powered vehicle are in contact with the horizontal ground.
4. The motor output shaft is positioned in front of the crankshaft mounting portion in the horizontal mounting state. The drive unit according to claim 3, wherein at least a portion of the circuit board is positioned in front of the motor output shaft in the horizontal mounting state.
5. The drive unit according to claim 4, wherein at least a portion of the heat transfer element is positioned in front of the motor output shaft in the horizontal mounting state.
6. The housing is configured such that the internal space is defined by the first housing and the second housing. The motor is mounted on the first housing. The drive unit according to claim 1, wherein the heat generated from the electronic component is transferred to the second housing by the heat transfer body.
7. The drive unit according to claim 6, wherein the circuit board is attached to the first housing.
8. The drive unit according to claim 6, wherein heat dissipation fins are provided on the outer surface of the portion of the second housing to which heat generated from the electronic components is transferred by the heat transfer body.
9. The housing further comprises a cover that covers the housing, The cover includes an intake section for introducing air into the cover space defined by the cover and the housing, and an exhaust section located behind the intake section for discharging air from the cover space when the drive unit is mounted on the human-powered vehicle and all the wheels of the human-powered vehicle are in contact with the ground. The drive unit according to claim 8, wherein the heat dissipation fins are provided on the air flow path from the intake section to the exhaust section.
10. The drive unit according to claim 9, wherein the intake portion and the exhaust portion are formed in both the portion of the cover that covers the first housing and the portion that covers the second housing.
11. The drive unit according to claim 1, wherein at least a portion of the substrate is positioned below the straight line passing through the central axis of the crankshaft mounting portion and the central axis of the motor output shaft, when viewed from the direction in which the central axis of the crankshaft mounting portion extends, in a horizontal mounting state in which the drive unit is attached to the human-powered vehicle and all the wheels of the human-powered vehicle are in contact with a horizontal ground.
12. The drive unit according to claim 11, wherein at least a portion of the heat transfer body is positioned below the line passing through the central axis of the crankshaft mounting portion and the central axis of the motor output shaft, when viewed from the direction in which the central axis of the crankshaft mounting portion extends.
13. The drive unit according to claim 1, wherein the substrate extends in a direction intersecting the direction in which the central axis of the crankshaft mounting portion extends.
14. The drive unit according to claim 1, wherein at least a portion of the substrate is arranged to overlap with at least a portion of the motor when viewed from the direction in which the central axis of the crankshaft mounting portion extends.