Drive unit and electric assist bicycle

Abstract

To enhance freedom in laying out components in a drive unit.SOLUTION: A drive unit (20) according to an embodiment is employed in a power-assisted bicycle (10). The drive unit (20) includes an electric motor (25), a housing (21) accommodating a part or the whole of the electric motor (25), a pedal crank shaft (22) that pierces the housing (21) and is rotatively supported by the housing (21), a transmission mechanism (40) that transmits a torque of the electric motor (25) to the pedal crank shaft (22), a rigid substrate (110) including an electric circuit (111) for use in activating the electric motor (25), and a flexible printed board (120) that electrically connects the rigid substrate (110) to predetermined components (110 and 130) other than the rigid substrate (110).SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a drive unit and an electrically assisted bicycle. [Background technology]

[0002] Bicycles are widely used by people of all ages and genders as an easily accessible means of transportation. In recent years, electrically assisted bicycles, which use an electric motor to assist the user's pedaling force, have become increasingly popular (see, for example, Patent Document 1). With electrically assisted bicycles, the electric motor generates driving force corresponding to the human force applied to the pedals by the user, reducing the burden on the user when, for example, riding uphill or carrying luggage.

[0003] Electrically assisted bicycles are equipped with a drive unit that includes an electric motor. Known drive units include those that are located inside the rear wheel hub and those that are attached to the bottom end of the frame (around the bottom bracket). In recent years, the latter type of drive unit has become more common.

[0004] The electrically assisted bicycle disclosed in Patent Document 1 includes a drive unit attached to the lower end of the body frame. This drive unit includes a housing, an electric motor, a pedal crankshaft, etc. The electric motor is housed in the housing and generates a drive force to assist the rider's pedaling force. The pedal crankshaft is disposed to penetrate the housing in the left-right direction of the vehicle. Pedals are attached to the pedal crankshaft via arms. The rotation of the pedal crankshaft is transmitted to the rear wheel via a drive sprocket, a chain, a driven sprocket, etc. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-196080 Summary of the Invention [Problem to be solved by the invention]

[0006] Electrically assisted bicycles require various components to be placed within the limited space of the vehicle body. If the drive unit is large, the placement of the components around the drive unit is restricted. This also restricts the placement of the drive unit itself. For this reason, there is a demand for smaller drive units.

[0007] In order to reduce the size of the drive unit, it is necessary to increase the degree of freedom in arranging the components inside the drive unit. [Means for solving the problem]

[0008] This specification discloses a drive unit and an electrically assisted bicycle as described in the following items.

[0009] [Item 1] A drive unit for use in an electric assisted bicycle, An electric motor; a housing that accommodates a part or all of the electric motor; a pedal crankshaft extending through the housing and rotatably supported by the housing; a transmission mechanism that transmits torque of the electric motor to the pedal crankshaft; a rigid substrate provided with an electric circuit for operating the electric motor; a flexible printed circuit board that electrically connects the rigid board to a predetermined component separate from the rigid board; A drive unit comprising:

[0010] According to one embodiment of the present invention, a rigid board having an electrical circuit for operating an electric motor is electrically connected to a predetermined component using a flexible printed circuit board. Generally, flexible printed circuit boards are thinner and have a greater degree of bending freedom than round electric wires. By electrically connecting the rigid board and the predetermined component using a flexible printed circuit board, the rigid board and the predetermined component can be positioned more freely within the housing. This also allows for a greater degree of freedom in the positioning of other components within the housing.

[0011] By using a flexible printed circuit board as wiring, twisting and bending that occur with round electric wires, which have large dimensional tolerances, do not occur, so the space required for wiring can be reduced and the drive unit can be made smaller.

[0012] [Item 2] the predetermined component includes an external connector for electrically connecting to an external device; Item 2. The drive unit according to item 1, wherein the flexible printed circuit board electrically connects the rigid board and the external connection connector.

[0013] This allows greater freedom in arranging the rigid board and the external connector within the housing.

[0014] [Item 3] the predetermined component includes a rigid board separate from the rigid board, Item 2. The drive unit according to item 1, wherein the flexible printed circuit board electrically connects the rigid board and the other rigid board.

[0015] This allows for greater freedom in arranging multiple rigid boards within the housing.

[0016] [Item 4] Item 4. A drive unit as described in item 3, wherein one of the rigid board and the other rigid board is a power supply circuit board provided with a power supply circuit that outputs power to drive the electric motor, and the other is a control circuit board provided with a control circuit that controls the operation of the power supply circuit.

[0017] The control circuit can be located away from the power supply circuit, which generates a large amount of heat, thereby improving the stability of control over the operation of the electric motor and increasing the heat tolerance of the power supply circuit.

[0018] By electrically connecting the power supply circuit board and the control circuit board using a flexible printed circuit board, the degree of freedom in arranging the power supply circuit board and the control circuit board within the housing can be increased.

[0019] [Item 5] Item 5. The drive unit according to item 4, wherein the control circuit board is smaller in size than the power supply circuit board.

[0020] The control circuit board can be placed in a relatively small space within the housing. By separating the power supply circuit and the control circuit onto separate boards, the relatively small free space within the housing can be used effectively.

[0021] [Item 6] the predetermined component includes an external connector for electrically connecting to an external device; The drive unit is a rigid substrate separate from the rigid substrate; an external connector different from the external connector; a flexible printed circuit board different from the flexible printed circuit board; Furthermore, the flexible printed circuit board electrically connects the rigid board and the external connector; Item 2. The drive unit according to item 1, wherein the other flexible printed circuit board electrically connects the other rigid board and the other external connection connector.

[0022] By separating the external connector and the flexible printed circuit board, which would otherwise become large when combined, the external connector and the flexible printed circuit board can be made smaller and can be placed in a smaller space within the housing.

[0023] [Item 7] Item 7. A drive unit as described in item 6, wherein one of the rigid board and the other rigid board is a power supply circuit board provided with a power supply circuit that outputs power to drive the electric motor, and the other is a control circuit board provided with a control circuit that controls the operation of the power supply circuit.

[0024] The external connector for the control circuit board and the flexible printed circuit board can be easily miniaturized and can be disposed in a relatively small space within the housing, making it possible to effectively utilize the relatively small free space within the housing.

[0025] [Item 8] The drive unit described in item 2 further comprises a reinforcing plate arranged between the flexible printed circuit board and the external connection connector in the thickness direction of the flexible printed circuit board at a position where the flexible printed circuit board and the external connection connector overlap.

[0026] By not using a connector for connecting the flexible printed circuit board and the external connector, the thickness of the connection portion between the flexible printed circuit board and the external connector can be reduced.

[0027] By using the reinforcing plate, the strength of the connection portion between the flexible printed circuit board and the external connector can be increased.

[0028] [Item 9] The drive unit described in item 2 further comprises a reinforcing plate provided on the surface of the flexible printed circuit board opposite to the surface to which the external connection connector is connected, in the thickness direction of the flexible printed circuit board at a position where the flexible printed circuit board and the external connection connector overlap.

[0029] By using the reinforcing plate, the strength of the connection portion between the flexible printed circuit board and the external connector can be increased.

[0030] [Item 10] 10. The drive unit according to item 8 or 9, wherein the pins of the external connector pass through the reinforcing plate.

[0031] This allows the flexible printed circuit board and the external connector to be electrically connected without providing wiring that detours around the reinforcing plate.

[0032] The pins of the external connector penetrate the reinforcing plate, thereby preventing the reinforcing plate from shifting in position.

[0033] [Item 11] 10. The drive unit according to item 2, 8 or 9, wherein the flexible printed circuit board and the external connection connector are electrically connected using at least one of solder, an anisotropic conductive film and an anisotropic conductive paste.

[0034] By directly attaching the flexible printed circuit board to the external connector without using a connector to connect the flexible printed circuit board to the external connector, the thickness of the connection portion between the flexible printed circuit board and the external connector can be reduced.

[0035] [Item 12] 12. The drive unit according to any one of items 1 to 11, further comprising a noise suppression component provided on the flexible printed circuit board.

[0036] By using a flexible printed circuit board as wiring, it is easy to place noise suppression components in positions on the wiring that are effective for noise suppression, and the number of noise suppression components required on a rigid board can be reduced, allowing the rigid board to be made smaller.

[0037] [Item 13] 11. The drive unit according to any one of items 8 to 10, wherein the reinforcing plate is a rigid board provided with anti-noise components.

[0038] This makes it possible to increase the strength of the connection between the flexible printed circuit board and the external connector, and also to increase the resistance to noise.

[0039] [Item 14] An electrically assisted bicycle equipped with a drive unit according to any one of items 1 to 13.

[0040] The ability to reduce the size of the drive unit allows for greater freedom in arranging parts around the drive unit of an electrically assisted bicycle. [Effects of the Invention]

[0041] According to one embodiment of the present invention, a rigid board having an electrical circuit for operating an electric motor is electrically connected to a predetermined component using a flexible printed circuit board. Generally, flexible printed circuit boards are thinner and have a greater degree of bending freedom than round electric wires. By electrically connecting the rigid board and the predetermined component using a flexible printed circuit board, the rigid board and the predetermined component can be positioned more freely within the housing. This also allows for a greater degree of freedom in the positioning of other components within the housing.

[0042] By using a flexible printed circuit board as wiring, twisting and bending that occur with round electric wires, which have large dimensional tolerances, do not occur, so the space required for wiring can be reduced and the drive unit can be made smaller. [Brief explanation of the drawings]

[0043] [Figure 1] 1 is a right side view showing an electrically assisted bicycle 10 according to an embodiment of the present invention. [Figure 2] 1 is a cross-sectional view showing the internal structure of a drive unit 20 provided in an electrically assisted bicycle 10 according to an embodiment of the present invention. [Figure 3] 1A and 1B are diagrams illustrating examples of a substrate and wiring according to an embodiment of the present invention. [Figure 4] 2 is a diagram showing an example of the inside of a drive unit 20 in which a substrate and wiring are arranged according to an embodiment of the present invention. FIG. [Figure 5] (a) shows an external connection connector 130, a reinforcing plate 150, and a flexible printed circuit board 120a according to an embodiment of the present invention, and (b) shows the external connection connector 130 and the flexible printed circuit board 120a connected with the reinforcing plate 150 sandwiched between them. [Figure 6] (a) shows an external connection connector 130, a flexible printed circuit board 120a, and a reinforcing plate 150 according to an embodiment of the present invention, and (b) shows the reinforcing plate 150 arranged on the side of the flexible printed circuit board 120a opposite to the side to which the external connection connector 130 is connected. [Figure 7] 10A and 10B are diagrams illustrating another example of a method for connecting an external connector 130 and a flexible printed circuit board 120a according to an embodiment of the present invention. [Figure 8] 1 is a diagram showing a reinforcing plate 150 provided with a noise suppression component 125 according to an embodiment of the present invention. [Figure 9] 10A and 10B are diagrams illustrating another example of a flexible printed circuit board 120 and a connector 130 according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0044] A drive unit and an electrically assisted vehicle equipped with a drive unit according to embodiments of the present invention will be described below with reference to the drawings. In the description of the embodiments, like components will be given like reference symbols, and redundant descriptions will be omitted. In the embodiments of the present invention, the terms "front, rear, left, right, top, bottom" refer to the front, rear, left, right, top, bottom, and bottom, relative to a position where a rider is seated on the saddle (seat) of the electrically assisted vehicle and facing the handlebars. The symbols F, Re, L, R, U, and D in the drawings represent front, rear, left, right, top, and bottom, respectively. The following embodiments are merely examples, and the present invention is not limited to the following embodiments.

[0045] [Electric assisted bicycle] An electrically assisted bicycle 10, which is an example of an electrically assisted vehicle according to an embodiment of the present invention, will be described with reference to Fig. 1. Fig. 1 is a right side view showing the schematic configuration of the electrically assisted bicycle 10.

[0046] The electrically assisted bicycle 10 includes a body frame 60, a front wheel 14F, a rear wheel 14R, a handlebar 16, and a saddle 18. The electrically assisted bicycle 10 further includes a drive unit 20 and a battery unit 26.

[0047] The vehicle frame 60 includes a head tube 61 , a top tube 62 , a down tube 63 , a seat tube 64 and a bracket 65 .

[0048] The head tube 61 is disposed at the front of the body frame 60 and extends vertically. A stem 27 is rotatably inserted into the head tube 61. The handlebars 16 are fixed to the upper end of the stem 27. A front fork 28 is fixed to the lower end of the stem 27. A front wheel 14F is rotatably attached to the lower end of the front fork 28. In other words, the front wheel 14F is supported by the body frame 60 via the stem 27 and the front fork 28.

[0049] The top tube 62 is disposed rearward of the head tube 61 and extends in the front-to-rear direction. The front end of the top tube 62 is connected to the head tube 61. The rear end of the top tube 62 is connected to the seat tube 64.

[0050] The down tube 63 is disposed rearward of the head tube 61 and extends in the front-to-rear direction. The down tube 63 is disposed below the top tube 62. The front end of the down tube 63 is connected to the head tube 61. In the example shown in FIG. 1 , the front end of the down tube 63 is also connected to the front end of the top tube 62. The rear end of the down tube 63 is connected to a bracket 65.

[0051] A battery unit 26 is attached to the down tube 63. In the example shown in FIG. 1, the battery unit 26 is attached inside the down tube 63. The battery unit 26 supplies power to the drive unit 20. The battery unit 26 has a battery and a control circuit. The battery is a rechargeable battery that can be charged and discharged. The control circuit controls the charging and discharging of the battery, and monitors the battery's output current, remaining capacity, etc.

[0052] The seat tube 64 is disposed rearward of the top tube 62 and the down tube 63, and extends in the vertical direction. The lower end of the seat tube 64 is connected to a bracket 65. In other words, the seat tube 64 extends upward from the bracket 65.

[0053] 1, the seat tube 64 is bent in the vertical middle section, so that the lower part of the seat tube 64 extends vertically, but the upper part of the seat tube 64 extends in a direction inclined relative to the vertical direction.

[0054] The seat post 29 is inserted into the seat tube 64. The saddle 18 is attached to the upper end of the seat post 29.

[0055] Bracket 65 is located at the lower end of body frame 60. Bracket 65 supports drive unit 20. Drive unit 20 attached to body frame 60 generates a driving force that is transmitted to a wheel (here, rear wheel 14R). Details of drive unit 20 will be described later.

[0056] The vehicle body frame 60 further includes a swing arm 30, a pair of connecting arms 303, and a suspension 304. The swing arm 30 includes a pair of chain stays 301 and a pair of seat stays 302.

[0057] The pair of chain stays 301 each extend in the front-to-rear direction. The pair of chain stays 301 are arranged side by side in the left-to-right direction. The rear wheel 14R is disposed between the pair of chain stays 301. The pair of chain stays 301 are arranged symmetrically. Therefore, only the right chain stay 301 is shown in Figure 1.

[0058] The front end of each chain stay 301 is attached to the bracket 65. In other words, each chain stay 301 extends rearward from the bracket 65. Each chain stay 301 is disposed relative to the bracket 65 so as to be able to swing about an axis extending in the left-right direction.

[0059] An axle 341 of the rear wheel 14R is non-rotatably attached to the rear end of each chain stay 301. In other words, the rear wheel 14R is supported by the pair of chain stays 301 so that it can rotate around the axle 341. In other words, the rear wheel 14R is supported by the body frame 60. A multi-stage driven sprocket 32 ​​is fixed to the rear wheel 14R.

[0060] The pair of seat stays 302 each extend in the front-to-rear direction. The pair of seat stays 302 are arranged side by side in the left-to-right direction. The rear wheel 14R is disposed between the pair of seat stays 302. The pair of seat stays 302 are arranged symmetrically. Therefore, only the right seat stay 302 is shown in Figure 1.

[0061] The rear end of the left seat stay 302 is connected to the rear end of the left chain stay 301. The rear end of the right seat stay 302 is connected to the rear end of the right chain stay 301.

[0062] The pair of connecting arms 303 each extend in the front-to-rear direction. The pair of connecting arms 303 are arranged side by side in the left-to-right direction. The seat tube 64 is disposed between the pair of connecting arms 303. The pair of connecting arms 303 are arranged symmetrically. Therefore, only the right connecting arm 303 is shown in Figure 1.

[0063] Each connecting arm 303 is attached to the seat tube 64. Each connecting arm 303 is disposed so as to be swingable relative to the seat tube 64 around an axis extending in the left-right direction.

[0064] When viewed from the side of the vehicle, the front end of each connecting arm 303 is located forward of the seat tube 64. When viewed from the side of the vehicle, the rear end of each connecting arm 303 is located rearward of the seat tube 64.

[0065] The rear end of the right connecting arm 303 is attached to the front end of the right seat stay 302. The right connecting arm 303 is disposed so as to be swingable relative to the right seat stay 302 about an axis extending in the left-right direction.

[0066] The rear end of the left connecting arm 303 is attached to the front end of the left seat stay 302. The left connecting arm 303 is disposed so as to be swingable relative to the left seat stay 302 about an axis extending in the left-right direction.

[0067] The suspension 304 is disposed in front of the seat tube 64 and behind the down tube 63. The upper end of the suspension 304 is attached to a pair of connecting arms 303. The suspension 304 is disposed so as to be able to swing relative to the pair of connecting arms 303 around an axis extending in the left-right direction. The lower end of the suspension 304 is attached to a bracket 65. The suspension 304 is disposed so as to be able to swing relative to the bracket 65 around an axis extending in the left-right direction. The attachment position of the suspension 304 to the bracket 65 is forward of the attachment position of the seat tube 64 to the bracket 65.

[0068] A drive sprocket 34 is attached to the drive unit 20 via a support member 33. A chain 36 is wound around the drive sprocket 34 and the driven sprocket 32.

[0069] [Drive unit] An example of the configuration of the drive unit 20 will be described with reference to Fig. 2. Fig. 2 is a cross-sectional view showing an example of the internal structure of the drive unit 20.

[0070] As shown in FIG. 2, the drive unit 20 includes a housing 21, a pedal crankshaft 22, a rotating shaft 23, a transmission mechanism 40, and an electric motor 25.

[0071] First, the configuration of the housing 21 according to this embodiment will be described.

[0072] The housing 21 is fixed to a bracket 65 (FIG. 1) by a plurality of fasteners. The housing 21 includes a first case 211, a second case 212, and a cover 213. The first case 211, the second case 212, and the cover 213 are each formed of a metal material (e.g., an aluminum alloy).

[0073] The first case 211 is placed on the second case 212 from the left side in the left-right direction. The first case 211 and the second case 212 are fixed together with a plurality of fasteners. As a result, a space 214 is formed between the first case 211 and the second case 212.

[0074] The cover 213 is placed on the first case 211 from the left side in the left-right direction. The cover 213 and the first case 211 are fixed together with a plurality of fasteners. As a result, a space 215 covered by the cover 213 is formed on the left side of the first case 211. The electric motor 25 is housed in this space 215.

[0075] Next, the configuration of the pedal crankshaft 22 according to this embodiment will be described.

[0076] The pedal crankshaft 22 is disposed to penetrate the housing 21 in the left-right direction of the vehicle and is rotatably supported by the housing 21. A central axis CL4 of the pedal crankshaft 22 extends in the left-right direction. When viewed from the axial direction (thrust direction) of the pedal crankshaft 22, the central axis CL4 serves as a rotation central axis RC4 (fourth central axis) of the pedal crankshaft 22. The pedal crankshaft 22 rotates relative to the housing 21 around the central axis CL4.

[0077] The pedal crankshaft 22 passes through the housing 21 along a fourth central axis RC4 and is rotatably supported by the housing 21 about the fourth central axis RC4. The pedal crankshaft 22 is rotatably supported within the housing 21 by a pair of bearings 38L and 38R. The bearing 38L is located on the left side in the axial direction and is fixed to the first case 211. The bearing 38R is located on the right side in the axial direction and is fixed to the second case 212.

[0078] The pedal crankshaft 22 is disposed so as to pass through the rotating shaft 23. The rotating shaft 23 is housed in the housing 21. Details of the rotating shaft 23 will be described later. A pair of left and right crank arms 35 (Fig. 1) are attached to the pedal crankshaft 22. A pedal 37 (Fig. 1) is attached to each of the crank arms 35.

[0079] Next, the configurations of the electric motor 25 and the transmission mechanism 40 according to this embodiment will be described.

[0080] The electric motor 25 is accommodated in the housing 21 and fixed to the housing 21. The electric motor 25 generates a driving force for assisting the traveling of the electrically assisted bicycle 10. The electric motor 25 has a stator 251 and a rotor 252.

[0081] Stator 251 has a plurality of bobbins 2512 around which coils 2511 are wound. An iron core 2513 is inserted into each bobbin 2512. Stator 251 is disposed in space 215. In this state, stator 251 is fixed to first case 211.

[0082] The rotor 252 is disposed inside the stator 251. The central axis CL1 of the rotor 252 is parallel to the central axis CL4 of the pedal crankshaft 22. In other words, the rotor 252 is disposed parallel to the pedal crankshaft 22. When viewed from the axial direction of the pedal crankshaft 22, the central axis CL1 becomes the rotation central axis RC1 (first central axis) of the rotor 252.

[0083] The rotor 252 includes a rotor body 2521 and an output shaft 2522. The outer peripheral surface of the rotor body 2521 is magnetized with N poles and S poles alternately arranged in the circumferential direction.

[0084] The output shaft 2522 is disposed to pass through the rotor body 2521. The output shaft 2522 is fixed to the rotor body 2521. That is, the output shaft 2522 rotates together with the rotor body 2521.

[0085] The output shaft 2522 is supported by the housing 21 so as to be rotatable around a first central axis RC1 inside the housing 21. The output shaft 2522 is rotatably supported by two bearings 42L and 42R relative to the housing 21 around a central axis CL1. The bearing 42L is fixed to the cover 213. The bearing 42R is disposed to the right of the rotor body 2521 and is fixed to the first case 211. The output shaft 2522 is disposed to penetrate the first case 211. An output gear 252A is formed on a portion of the output shaft 2522 that is located within the space 214. The output gear 252A is, for example, a helical gear.

[0086] The transmission mechanism 40 is accommodated in the housing 21. Specifically, the transmission mechanism 40 is disposed in the space 214. The transmission mechanism 40 has a reducer 24, an idle gear 41, and a rotating shaft 43. The transmission mechanism 40 transmits the torque of the electric motor 25 to the pedal crankshaft 22.

[0087] The reducer 24 is rotatably supported by the housing 21 and increases the torque of the output gear 252A of the electric motor 25. The reducer 24 has a first transmission gear 241, a second transmission gear 242, and a transmission shaft 243. A central axis CL2 of the transmission shaft 243 is parallel to a central axis CL4 of the pedal crankshaft 22. In other words, the transmission shaft 243 extends parallel to the central axis CL4 of the pedal crankshaft 22. The central axis CL2 is a rotation central axis RC2 (second central axis) of the transmission shaft 243 when viewed in the axial direction of the transmission shaft 243, i.e., when viewed from the axial direction of the pedal crankshaft 22. The reducer 24 is supported by the housing 21 inside the housing 21 so as to be rotatable about the second central axis RC2.

[0088] The first transmission gear 241 is disposed on the right portion of the transmission shaft 243 in the axial direction. The left portion of the transmission shaft 243 is rotatably supported by a bearing 44L. The first transmission gear 241 disposed on the right portion of the transmission shaft 243 is rotatably supported by a bearing 44R. The transmission shaft 243 and the first transmission gear 241 are rotatably supported around the central axis line CL2 by two bearings 44L and 44R. The bearing 44L is fixed to the first case 211. The bearing 44R is fixed to the second case 212.

[0089] The first transmission gear 241 meshes with an output gear 252A of the electric motor 25. As a result, the driving force generated by the electric motor 25 is transmitted to the first transmission gear 241 from the output gear 252A.

[0090] A one-way clutch 244 is disposed between the first transmission gear 241 and the transmission shaft 243. The one-way clutch 244 connects the transmission shaft 243 and the first transmission gear 241. The one-way clutch 244 restricts the rotation of the first transmission gear 241 relative to the transmission shaft 243 in one direction. The rotational force of the output gear 252A in the direction that rotates the rear wheel 14R (FIG. 1) of the electrically assisted bicycle 10 forward is transmitted to the transmission shaft 243 via the first transmission gear 241, but the rotational force of the output gear 252A in the direction that rotates the rear wheel 14R backward is not transmitted to the transmission shaft 243. The one-way clutch 244 also prevents the rotational force of the pedal crankshaft 22 in the forward rotation direction, which is generated by the rider's manual power, from being transmitted to the electric motor 25.

[0091] The first transmission gear 241 has a larger diameter than the output gear 252A of the electric motor 25 and has more teeth than the output gear 252A. In other words, the first transmission gear 241 is slower than the output gear 252A.

[0092] The second transmission gear 242 is made of a metal material (e.g., iron). The second transmission gear 242 is disposed on the transmission shaft 243. The second transmission gear 242 is disposed at a different position from the first transmission gear 241 in the axial direction of the transmission shaft 243. The second transmission gear 242 has a smaller diameter than the first transmission gear 241 and fewer teeth than the first transmission gear 241. In this embodiment, the transmission shaft 243 and the second transmission gear 242 are formed integrally, but this is not limiting. The second transmission gear 242 may be fixed to the transmission shaft 243 by serration coupling (or press fitting). The second transmission gear 242 rotates together with the transmission shaft 243. The transmission shaft 243 transmits the rotation of the first transmission gear 241 to the second transmission gear 242.

[0093] The idle gear 41 is made of a metal material (for example, iron). The idle gear 41 is disposed on the rotary shaft 43. The idle gear 41 is fixed to the rotary shaft 43 by, for example, but not limited to, a fastener. The idle gear 41 may be fixed to the rotary shaft 43 by serration coupling (or press fitting). Alternatively, the idle gear 41 and the rotary shaft 43 may be formed integrally. The idle gear 41 rotates together with the rotary shaft 43.

[0094] The central axis CL3 of the rotary shaft 43 is parallel to the central axis CL4 of the pedal crankshaft 22. That is, the rotary shaft 43 extends parallel to the central axis CL4 of the pedal crankshaft 22. The central axis CL3 becomes the rotation central axis RC3 (third central axis) of the rotary shaft 43 when viewed in the axial direction of the rotary shaft 43, that is, the axial direction of the pedal crankshaft 22. The idle gear 41 fixed to the rotary shaft 43 is supported by the housing 21 inside the housing 21 so as to be rotatable around the third central axis RC3.

[0095] The rotating shaft 43 is supported by two bearings 46L and 46R so as to be rotatable about the central axis CL3. The bearings 46L and 46R are fixed to the first case 211. The idle gear 41 is disposed closer to the bearing 46R than to the bearing 46L in the axial direction of the rotating shaft 43. The idle gear 41 meshes with the second transmission gear 242 of the reducer 24. As a result, the output torque of the electric motor 25, which has been increased by the reducer 24, is transmitted to the idle gear 41.

[0096] Next, the configuration around the pedal crankshaft 22 will be described.

[0097] The rotating shaft 23 is disposed coaxially with the pedal crankshaft 22 and is rotatable together with the pedal crankshaft 22. The rotating shaft 23 includes a connecting shaft 231 and a one-way clutch 50.

[0098] The connecting shaft 231 has a cylindrical shape. The pedal crankshaft 22 is inserted into the connecting shaft 231. The connecting shaft 231 and the pedal crankshaft 22 are disposed coaxially.

[0099] The left end of the connecting shaft 231 is connected to the pedal crankshaft 22 by a serration connection or the like. As a result, the connecting shaft 231 rotates together with the pedal crankshaft 22 whether the pedal crankshaft 22 rotates forward or backward.

[0100] A torque detector 232 is disposed around the connecting shaft 231. The torque detector 232 is supported by the connecting shaft 231 and is unable to rotate relative to the first case 211. The torque detector 232 detects the torque generated in the connecting shaft 231 when the rider pedals. The torque detector 232 is, for example, a magnetostrictive torque sensor. The torque detector 232 outputs a signal corresponding to the detected torque to a control circuit mounted on a board described later. The control circuit refers to the torque detected by the torque detector 232 to determine the pedaling state of the rider and controls the electric motor 25.

[0101] The one-way clutch 50 is disposed to the right of the torque detection device 232 in the axial direction of the pedal crankshaft 22. The one-way clutch 50 is provided on the pedal crankshaft 22 via a connecting shaft 231. The one-way clutch 50 is disposed coaxially with the pedal crankshaft 22. The one-way clutch 50 includes an inner member 51 and an outer member 52.

[0102] The inner member 51 of the one-way clutch 50 has a cylindrical shape. The right portion of the connecting shaft 231 is inserted into the inner member 51. The inner member 51 is disposed coaxially with the connecting shaft 231. In this state, the right portion of the connecting shaft 231 is connected to the inner member 51 by a serration connection or the like. As a result, whether the connecting shaft 231 rotates forward or backward, the inner member 51 rotates together with the connecting shaft 231. In other words, whether the pedal crankshaft 22 rotates forward or backward, the inner member 51 rotates together with the pedal crankshaft 22. The connecting shaft 231 and the inner member 51 function as a crank rotation input shaft that rotates integrally with the pedal crankshaft 22.

[0103] The outer member 52 of the one-way clutch 50 has a cylindrical shape. The pedal crankshaft 22 is inserted into the outer member 52. A plain bearing 49 is disposed between the outer member 52 and the pedal crankshaft 22. As a result, the outer member 52 is disposed so as to be rotatable coaxially with the pedal crankshaft 22.

[0104] A ratchet mechanism serving as a one-way clutch mechanism is formed between the outer member 52 and the inner member 51. As a result, the rotational force of the inner member 51 in the forward rotation direction is transmitted to the outer member 52, but the rotational force of the inner member 51 in the backward rotation direction is not transmitted to the outer member 52. In addition, the rotational force of the outer member 52 in the forward rotation direction generated by the rotation of the electric motor 25 is not transmitted to the inner member 51.

[0105] The outer member 52 is supported by a bearing 38R so as to be rotatable relative to the housing 21 around the central axis CL4 of the pedal crankshaft 22. The outer member 52 is disposed to penetrate the second case 212. The drive sprocket 34 is attached to a portion of the outer member 52 located outside (on the right side) of the housing 21.

[0106] The outer member 52 has a driven gear 233. The driven gear 233 is attached to the pedal crankshaft 22 via the one-way clutch 50 and the connecting shaft 231. The driven gear 233 meshes with the idle gear 41. The driven gear 233 has a larger diameter than the second transmission gear 242 and the idle gear 41 and has more teeth than the second transmission gear 242 and the idle gear 41. In other words, the rotation speed of the driven gear 233 is slower than the rotation speeds of the second transmission gear 242 and the idle gear 41, respectively. By meshing the idle gear 41 with the second transmission gear 242 and the driven gear 233, the output torque of the electric motor 25, which has been increased by the reducer 24, can be transmitted to the driven gear 233 via the single idle gear 41.

[0107] The outer member 52 transmits the resultant force of the human power (pedal force) transmitted to the connecting shaft 231 and the auxiliary driving force of the electric motor 25 to the driving sprocket 34. The outer member 52 realizes a resultant force output shaft 235 that combines and outputs the human power input via the one-way clutch 50 and the auxiliary driving force input via the driven gear 233. The resultant force output shaft 235 rotates coaxially with the pedal crankshaft 22. The resultant force output shaft 235 is included in the rotating shaft 23.

[0108] [Board and wiring] Next, the boards and wiring arranged in the drive unit 20 of this embodiment will be described.

[0109] As described above, many components are arranged inside the drive unit 20. Therefore, the boards and wiring on which the electric circuits for operating the electric motor 25 are mounted are subject to layout restrictions, just like other components. In this embodiment, by configuring these boards and wiring to increase the degree of freedom in layout within the drive unit 20, it is possible to increase the degree of freedom in layout of other components and also to reduce the size of the drive unit 20.

[0110] Fig. 3 is a diagram showing an example of the substrate and wiring of this embodiment. Fig. 4 is a diagram showing an example of the inside of the drive unit 20 in which the substrate and wiring of this embodiment are arranged. Fig. 4 shows the inside of the drive unit 20 as seen from the right side. In this embodiment, flexible printed circuits (FPC) are used as at least part of the wiring that electrically connects components together.

[0111] In this example, the drive unit 20 includes a power supply circuit board 110a, a control circuit board 110b, flexible printed circuit boards 120a-120d, and an external connection connector .

[0112] The power supply circuit board 110a and the control circuit board 110b are rigid boards. The power supply circuit board 110a is provided with a power supply circuit 111a that outputs power to drive the electric motor 25. The power supply circuit 111a includes, for example, a smoothing circuit that smoothes the DC voltage output from the battery unit 26 (FIG. 1) and an inverter circuit that generates a motor drive current. The power supply circuit 111a generates, for example, a three-phase AC motor drive current. The control circuit board 110b is provided with a control circuit 111b that controls the operation of the power supply circuit 111a. The external connection connector 130 is a connector for electrically connecting the drive unit 20 to an external device (for example, the battery unit 26 and an operation panel, etc.).

[0113] The control circuit board 110b and the external connector 130 are electrically connected via a flexible printed circuit board 120a.

[0114] The control circuit board 110b and the flexible printed circuit board 120a are electrically connected via, for example, a connector 140a. The connector 140a is, for example, a board-to-board connector or an FPC connector. Using a board-to-board connector can reduce the thickness of the connection portion. The connectors 140b-140e, which will be described later, can also be board-to-board connectors or FPC connectors.

[0115] The flexible printed circuit board 120a extends to cover the rear surface of the external connector 130, from which a plurality of pins extend, and the external connector 130 may be directly attached to the flexible printed circuit board 120a. The external connector 130 may be electrically connected to the flexible printed circuit board 120a via a connector.

[0116] The control circuit board 110b and the power supply circuit board 110a are electrically connected via a flexible printed circuit board 120b. The control circuit board 110b and the flexible printed circuit board 120b are electrically connected via, for example, a connector 140b. The power supply circuit board 110a and the flexible printed circuit board 120b are electrically connected via, for example, a connector 140c. The power supply circuit 111a and the control circuit 111b can transmit and receive signals via the flexible printed circuit board 120b.

[0117] The control circuit 111b can transmit and receive signals to and from external devices via the external connector 130 and the flexible printed circuit board 120a. The output current of the battery unit 26 is supplied to the power supply circuit 111a via the external connector 130, the flexible printed circuit board 120a, the control circuit board 110b, and the flexible printed circuit board 120b. The power supply circuit 111a generates and outputs a motor drive current for driving the electric motor 25.

[0118] The power supply circuit board 110a and the electric motor 25 are electrically connected via a flexible printed circuit board 120c. The power supply circuit board 110a and the flexible printed circuit board 120c are electrically connected via, for example, a connector 140d. A bus bar is electrically connected to the stator 251 of the electric motor 25. The flexible printed circuit board 120c is electrically connected to the bus bar via a connector 142. The motor drive current output by the power supply circuit 111a is supplied to the stator 251 via the flexible printed circuit board 120c and the bus bar, and can cause the stator 251 to generate a magnetic force.

[0119] The control circuit board 110b and the torque detection device 232 are electrically connected via a flexible printed circuit board 120d. The control circuit board 110b and the flexible printed circuit board 120d are electrically connected via a connector 140e, for example. A connector 145 is provided on the flexible printed circuit board 120d. The flexible printed circuit board 120d is electrically connected to the torque detection device 232 via the connector 145. The connector 145 may be directly attached to the flexible printed circuit board 120d. The connector 145 may also be electrically connected to the flexible printed circuit board 120d via a connector. The control circuit board 110b can receive an output signal from the torque detection device 232 via the flexible printed circuit board 120d. If the drive unit 20 is equipped with a rotation detection device that detects rotation of the pedal crankshaft 22, the control circuit board 110b can receive an output signal from the rotation detection device via the flexible printed circuit board 120d.

[0120] 4, the control circuit board 110b and the flexible printed circuit board 120a are mainly arranged in the gap at the top inside the housing 21. The power supply circuit board 110a and the flexible printed circuit board 120c are mainly arranged in the gap at the right side inside the housing 21. Because the flexible printed circuit board has a large degree of bending freedom, as shown in FIG. 4, the flexible printed circuit board 120b can be bent with a large curvature in a narrow space.

[0121] Flexible printed circuit board 120a extending from control circuit board 110b is bent approximately 90 degrees at the rear lower portion inside housing 21 and connected to external connector 130. In this example, as shown in Fig. 2, external connector 130 is exposed to the outside from an opening provided in the left wall of housing 21. A connector extending from an external device is connected to external connector 130.

[0122] In this embodiment, the control circuit board 110b and the external connector 130 are electrically connected using a flexible printed circuit board 120a. Generally, a flexible printed circuit board is thinner than a round electric wire and has a greater degree of bending freedom. By electrically connecting the control circuit board 110b and the external connector 130 using the flexible printed circuit board 120a, the control circuit board 110b and the external connector 130 can be arranged more freely within the housing 21. Furthermore, the degree of freedom in arranging other components within the housing 21 can be increased.

[0123] In this embodiment, by using a flexible printed circuit board as wiring, twisting and bending that occur with round electric wires with large dimensional tolerances do not occur, so it is possible to reduce the space required for wiring and make it possible to miniaturize the drive unit 20. By making the drive unit 20 smaller, it is possible to increase the degree of freedom in arranging the components around the drive unit 20 of the electrically assisted bicycle 10.

[0124] In this embodiment, the power supply circuit board 110a and the control circuit board 110b are provided separately, which allows the control circuit 111b to be located away from the power supply circuit 111a, which generates a large amount of heat, thereby improving the stability of control over the operation of the electric motor 25 and increasing the heat tolerance of the power supply circuit 111a.

[0125] By electrically connecting the power supply circuit board 110a and the control circuit board 110b using the flexible printed circuit board 120b, the degree of freedom in arranging the power supply circuit board 110a and the control circuit board 110b within the housing 21 can be increased.

[0126] 3, the control circuit board 110b can be made smaller in size than the power supply circuit board 110a. Therefore, the control circuit board 110b can be placed in a relatively small space within the housing 21. By separating the power supply circuit 111a and the control circuit 111b onto separate boards, the relatively small free space within the housing 21 can be used effectively.

[0127] 3, a noise suppression component 125 is provided on a flexible printed circuit board 120a. The noise suppression component 125 includes, for example, a capacitor and / or an inductor. Using a flexible printed circuit board as wiring makes it easy to arrange the noise suppression component 125 at a position on the wiring that is effective for noise suppression. This makes it possible to reduce the number of noise suppression components provided on a rigid board such as the control circuit board 110b, thereby enabling the rigid board to be made smaller.

[0128] Next, an example of a method for connecting the external connector 130 and the flexible printed circuit board 120a will be described.

[0129] FIG. 5 is a diagram illustrating an example of a method for connecting the external connector 130 and the flexible printed circuit board 120a. FIG. 5(a) shows the external connector 130, a reinforcing plate 150, and the flexible printed circuit board 120a. FIG. 5(b) shows the external connector 130 and the flexible printed circuit board 120a connected with the reinforcing plate 150 sandwiched therebetween. In this example, the reinforcing plate 150 is disposed between the flexible printed circuit board 120a and the external connector 130 in the thickness direction Dt of the flexible printed circuit board 120a at a position where the flexible printed circuit board 120a and the external connector 130 overlap. The reinforcing plate 150 is, for example, a rigid board, but is not limited thereto. The reinforcing plate 150 may be adhered to the flexible printed circuit board 120a and / or the external connector 130.

[0130] A plurality of pins 135 extending from the external connector 130 penetrate the reinforcing plate 150 and the flexible printed circuit board 120a. The flexible printed circuit board 120a and the pins 135 of the external connector 130 are electrically connected using, for example, solder 161. Instead of the solder 161, an anisotropic conductive film or an anisotropic conductive paste may be used.

[0131] By directly attaching external connector 130 to flexible printed circuit board 120a without using a connector to connect external connector 130 and flexible printed circuit board 120a, it is possible to reduce the thickness of the connection portion between external connector 130 and flexible printed circuit board 120a. By using reinforcing plate 150, it is possible to increase the strength of the connection portion between external connector 130 and flexible printed circuit board 120a.

[0132] 6A and 6B are diagrams showing another example of a method for connecting the external connector 130 and the flexible printed circuit board 120a. Fig. 6A shows the external connector 130, the flexible printed circuit board 120a, and the reinforcing plate 150. Fig. 6B shows the reinforcing plate 150 arranged on the surface of the flexible printed circuit board 120a opposite to the surface to which the external connector 130 is connected, in the thickness direction Dt of the flexible printed circuit board 120a at a position where the flexible printed circuit board 120a and the external connector 130 overlap.

[0133] Pins 135 of external connector 130 penetrate flexible printed circuit board 120a and reinforcing plate 150. Flexible printed circuit board 120a and pins 135 of external connector 130 are electrically connected using, for example, solder 161. An anisotropic conductive film or an anisotropic conductive paste may be used instead of solder 161. For example, flexible printed circuit board 120a and pins 135 may be electrically connected by an anisotropic conductive film or anisotropic conductive paste disposed between external connector 130 and flexible printed circuit board 120a.

[0134] FIG. 7 is a diagram showing another example of a method for connecting the external connector 130 and the flexible printed circuit board 120a. In the example shown in FIG. 7, the external connector 130 is electrically connected to the flexible printed circuit board 120a by surface mounting. For the connection, solder 161, an anisotropic conductive film, or an anisotropic conductive paste may be used. The reinforcing plate 150 is placed on the surface of the flexible printed circuit board 120a opposite to the surface to which the external connector 130 is connected. In this example, the reinforcing plate 150 does not have to be a rigid board, and any plate that can obtain the required strength can be used as the reinforcing plate 150.

[0135] In the example shown in FIG. 3, the noise suppression component 125 is provided on the flexible printed circuit board 120a. However, the noise suppression component 125 may also be provided on the reinforcing plate 150. FIG. 8 is a diagram showing the noise suppression component 125 provided on the reinforcing plate 150. In the example shown in FIG. 8, the reinforcing plate 150 is a rigid board, and the reinforcing plate 150 is electrically connected to the flexible printed circuit board 120a via a connector 140g. The connector 140g is, for example, a board-to-board connector or an FPC connector. The noise suppression component 125 is disposed, for example, near the connector 140g. Using the rigid board 110 provided with the noise suppression component 125 can increase the strength of the connection between the flexible printed circuit board 120a and the external connector 130 and improve noise resistance. The noise suppression component 125 may also be provided on the reinforcing plate 150 shown in FIGS. 5 to 7.

[0136] Next, a description will be given of another example of the flexible printed circuit board 120 and the connector 130. FIG.

[0137] 9, a connector 130a that receives the output current of the battery unit 26 and a connector 130b that transmits and receives control signals between the control circuit board 110b and an external device are provided separately. The connector 130b is electrically connected to the flexible printed circuit board 120a. The control circuit board 110b is electrically connected to the external device via the flexible printed circuit board 120a and the connector 130b.

[0138] The connector 130a is electrically connected to the flexible printed circuit board 120e. The flexible printed circuit board 120e and the power supply circuit board 110a are electrically connected via a connector 140f. The connector 140f is, for example, a board-to-board connector or an FPC connector. The output current of the battery unit 26 is supplied to the power supply circuit 111a via the external connection connector 130a and the flexible printed circuit board 120e.

[0139] External connector 130 tends to become larger when its functions are consolidated. Similarly, flexible printed circuit board 120 tends to become larger when its functions are consolidated. By dividing external connector 130 and flexible printed circuit board 120, which tend to become larger when consolidated, external connector 130 and flexible printed circuit board 120 can be made smaller and can be placed in a smaller space within housing 21.

[0140] The external connector 130b for the control circuit board 110b and the flexible printed circuit board 120a can be easily miniaturized and can be placed in a relatively small space within the housing 21. The relatively small free space within the housing 21 can be effectively utilized.

[0141] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, although the above-described embodiments illustrate electrically assisted bicycles with suspensions, the present invention can also be suitably used in electrically assisted bicycles without suspensions.

[0142] In the above-described embodiment, the drive unit 20 (FIG. 2) has four shafts: the output shaft 2522, the transmission shaft 243, the rotating shaft 43, and the pedal crankshaft 22. However, the number of shafts is not limited to four. The present invention is also applicable to drive units having five or more shafts. For example, the present invention is also applicable to a drive unit in which a gear is disposed between the output gear 252A of the electric motor 25 and the first transmission gear 241 of the reducer 24, and torque is transmitted from the output gear 252A to the first transmission gear 241 via the gear.

[0143] In the above-described embodiment, the drive unit 20 is provided with the idle gear 41, but the present invention is also applicable to a drive unit 20 that does not have the idle gear 41.

[0144] In the above-described embodiment, the entire electric motor 25 is housed in the housing 21, but the structure of the housing 21 is not limited to this. Only a portion of the electric motor 25 may be housed in the housing 21. For example, the left portion of the first case 211 may have an opening through which the electric motor 25 can pass, and the electric motor 25 may be attached so that a portion of the electric motor 25 is positioned inside the housing 21 through the opening. In this case, the opening may be covered with a cover to protect against dust and water.

[0145] The cover 213 (FIG. 2) may be a part of the housing 21 and may be included in the housing 21. The cover 213 may have a shape that covers the side of the electric motor 25, and the electric motor 25 may be supported by the cover 213. A form in which the electric motor 25 is supported by the cover 213 is also included in a form in which the electric motor 25 is supported by the housing 21.

[0146] In the above-described embodiment, a two-wheeled electrically assisted bicycle is used as the electrically assisted bicycle 10, but the present invention is not limited to this. For example, the electrically assisted bicycle 10 may be a three- or more-wheeled electrically assisted bicycle.

[0147] In the above-described embodiment, the human power generated by the rider pedaling and the assisting force generated by the electric motor are transmitted to the rear wheels as drive wheels, but the present invention is not limited to this. Depending on the configuration of the electrically assisted bicycle, the human power and the assisting force may be transmitted to the front wheels, or to both the front and rear wheels.

[0148] In the above-described embodiment, the vehicle is an electrically assisted bicycle, but the present invention may be applied to vehicles other than electrically assisted bicycles. The present invention can be suitably used in vehicles where a compact drive unit is required.

[0149] The present specification discloses a drive unit and an electrically assisted bicycle as described in the following items.

[0150] [Item 1] A drive unit 20 used in an electrically assisted bicycle 10, an electric motor 25; a housing 21 that accommodates a part or all of an electric motor 25; a pedal crankshaft 22 that passes through the housing 21 and is rotatably supported by the housing 21; a transmission mechanism 40 that transmits the torque of the electric motor 25 to the pedal crankshaft 22; a rigid substrate 110 provided with an electric circuit 111 for operating the electric motor 25; a flexible printed circuit board (120) that electrically connects the rigid substrate (110) and predetermined components (110, 130) that are separate from the rigid substrate (110); A drive unit 20 comprising:

[0151] According to one embodiment of the present invention, a rigid substrate 110, on which an electric circuit 111 for operating the electric motor 25 is provided, is electrically connected to predetermined components 110 and 130 using a flexible printed circuit board 120. Generally, a flexible printed circuit board 120 has a thinner shape and a greater degree of bending freedom compared to a round electric wire. By electrically connecting the rigid substrate 110 and the predetermined components 110 and 130 using the flexible printed circuit board 120, the degree of freedom in arranging the rigid substrate 110 and the predetermined components 110 and 130 within the housing 21 can be increased. In addition, the degree of freedom in arranging other components within the housing 21 can be increased.

[0152] By using the flexible printed circuit board 120 as wiring, twisting and bending that occur with round electric wires with large dimensional tolerances do not occur, so the space required for wiring can be reduced and the drive unit 20 can be made smaller.

[0153] [Item 2] The predetermined components 110 and 130 include an external connector 130 for electrically connecting with an external device, Item 1. The drive unit (20) according to item 1, wherein the flexible printed circuit board (120) electrically connects the rigid circuit board (110) and the external connection connector (130).

[0154] This allows greater freedom in arranging the rigid board 110 and the external connector 130 within the housing 21.

[0155] [Item 3] The predetermined component 110, 130 includes a rigid substrate 110 separate from the rigid substrate 110; Item 1. The drive unit (20) according to item 1, wherein the flexible printed circuit board (120) electrically connects the rigid circuit board (110) to another rigid circuit board (110).

[0156] This allows for greater freedom in arranging multiple rigid boards 110 within housing 21.

[0157] [Item 4] A drive unit 20 as described in item 3, wherein one of the rigid substrate 110 and the other rigid substrate 110 is a power supply circuit substrate 110a provided with a power supply circuit 111a that outputs power for driving the electric motor 25, and the other is a control circuit substrate 110b provided with a control circuit 111b that controls the operation of the power supply circuit 111a.

[0158] The control circuit 111b can be located away from the power supply circuit 111a, which generates a large amount of heat, thereby improving the stability of control over the operation of the electric motor 25 and increasing the heat tolerance of the power supply circuit 111a.

[0159] By electrically connecting the power supply circuit board 110a and the control circuit board 110b using the flexible printed circuit board 120, the degree of freedom in arranging the power supply circuit board 110a and the control circuit board 110b within the housing 21 can be increased.

[0160] [Item 5] Item 5. The drive unit 20 according to item 4, wherein the size of the control circuit board 110b is smaller than the size of the power supply circuit board 110a.

[0161] The control circuit board 110b can be placed in a relatively small space within the housing 21. By separating the power supply circuit 111a and the control circuit 111b onto separate boards, the relatively small free space within the housing 21 can be used effectively.

[0162] [Item 6] The predetermined components 110 and 130 include an external connector 130 for electrically connecting with an external device, The drive unit 20 is a rigid substrate 110 different from the rigid substrate 110; an external connector 130 different from the external connector 130; a flexible printed circuit board 120 different from the flexible printed circuit board 120; Furthermore, The flexible printed circuit board 120 electrically connects the rigid circuit board 110 and the external connector 130, Item 1. The drive unit (20) according to item 1, wherein the separate flexible printed circuit board (120) electrically connects the separate rigid circuit board (110) and the separate external connection connector (130).

[0163] By separating the external connection connector 130 and the flexible printed circuit board 120, which would otherwise become large when combined, the external connection connector 130 and the flexible printed circuit board 120 can be made smaller and can be placed in a smaller space within the housing 21.

[0164] [Item 7] A drive unit 20 as described in item 6, wherein one of the rigid substrate 110 and the other rigid substrate 110 is a power supply circuit substrate 110a provided with a power supply circuit 111a that outputs power for driving the electric motor 25, and the other is a control circuit substrate 110b provided with a control circuit 111b that controls the operation of the power supply circuit 111a.

[0165] The external connector 130 for the control circuit board 110b and the flexible printed circuit board 120 can be easily miniaturized and can be placed in a relatively small space within the housing 21. The relatively small free space within the housing 21 can be effectively utilized.

[0166] [Item 8] The drive unit 20 described in item 2 further comprises a reinforcing plate 150 arranged between the flexible printed circuit board 120 and the external connection connector 130 in the thickness direction Dt of the flexible printed circuit board 120 at a position where the flexible printed circuit board 120 and the external connection connector 130 overlap.

[0167] By not using a connector for connecting the flexible printed circuit board 120 and the external connector 130, the thickness of the connection portion between the flexible printed circuit board 120 and the external connector 130 can be reduced.

[0168] By using the reinforcing plate 150, the strength of the connection portion between the flexible printed circuit board 120 and the external connector 130 can be increased.

[0169] [Item 9] The drive unit 20 described in item 2 further comprises a reinforcing plate 150 provided on the surface of the flexible printed circuit board 120 opposite to the surface to which the external connection connector 130 is connected, in the thickness direction Dt of the flexible printed circuit board 120 at a position where the flexible printed circuit board 120 and the external connection connector 130 overlap.

[0170] By using the reinforcing plate 150, the strength of the connection portion between the flexible printed circuit board 120 and the external connector 130 can be increased.

[0171] [Item 10] The drive unit (20) according to item 8 or 9, wherein the pins (135) of the external connection connector (130) pass through the reinforcing plate (150).

[0172] This allows the flexible printed circuit board 120 and the external connector 130 to be electrically connected without providing wiring that detours around the reinforcing plate 150 .

[0173] The pins 135 of the external connector 130 penetrate the reinforcing plate 150, thereby preventing the reinforcing plate 150 from shifting in position.

[0174] [Item 11] The drive unit 20 according to item 2, 8 or 9, wherein the flexible printed circuit board 120 and the external connector 130 are electrically connected using at least one of solder 161, an anisotropic conductive film and an anisotropic conductive paste.

[0175] By directly attaching the flexible printed circuit board 120 and the external connection connector 130 without using a connector to connect the flexible printed circuit board 120 and the external connection connector 130, the thickness of the connection portion between the flexible printed circuit board 120 and the external connection connector 130 can be reduced.

[0176] [Item 12] 12. The drive unit (20) according to any one of items 1 to 11, further comprising a noise suppression component (125) provided on the flexible printed circuit board (120).

[0177] By using flexible printed circuit board 120 as wiring, it is easy to arrange noise suppression components 125 at positions on the wiring that are effective for noise suppression. This allows a reduction in the number of noise suppression components 125 provided on rigid substrate 110, thereby enabling the rigid substrate 110 to be made smaller.

[0178] [Item 13] The drive unit (20) according to any one of items (8) to (10), wherein the reinforcing plate (150) is a rigid substrate (110) on which the noise suppression component (125) is provided.

[0179] This makes it possible to increase the strength of the connection between the flexible printed circuit board 120 and the external connector 130, and also to increase the resistance to noise.

[0180] [Item 14] An electrically assisted bicycle 10 equipped with a drive unit 20 according to any one of items 1 to 13.

[0181] By making the drive unit 20 smaller, the degree of freedom in arranging the components around the drive unit 20 of the electrically assisted bicycle 10 can be increased. [Industrial Applicability]

[0182] The present invention is particularly useful in the field of electrically assisted vehicles and drive units mounted on electrically assisted vehicles. [Explanation of symbols]

[0183] 10: Electrically assisted vehicle (electrically assisted bicycle), 20: Drive unit, 21: Housing, 22: Pedal crankshaft, 24: Reducer, 25: Electric motor, 26: Battery unit, 34: Drive sprocket, 35: Crank arm, 37: Pedal, 40: Transmission mechanism, 41: Idle gear, 50: One-way clutch, 51: Inner member, 52: Outer member, 60: Body frame, 61: Head tube, 62: Top tube, 63: Down tube, 64: Seat tube, 65: Bracket, 233: Driven gear, 235: Resultant force output shaft, 241: First transmission gear, 242: Second transmission gear, 243: Transmission shaft, 252A: Output gear, 2522: Output shaft, 110: Rigid circuit board (power supply circuit board, control circuit board), 111: Electric circuit (power supply circuit, control circuit), 120: Flexible printed circuit board, 125: Noise suppression component, 130: External connection connector, 135: Pin, 140: Connector, 142: Connector, 145: Connector, 150: Reinforcing plate, 161: Solder

Claims

1. A drive unit for use in an electric assisted bicycle, An electric motor; a housing that accommodates a part or all of the electric motor; a pedal crankshaft extending through the housing and rotatably supported by the housing; a transmission mechanism that transmits torque of the electric motor to the pedal crankshaft; a rigid substrate provided with an electric circuit for operating the electric motor; a rigid substrate separate from the rigid substrate; Equipped with one of the rigid board and the other rigid board is a power supply circuit board provided with a power supply circuit that outputs power to drive the electric motor, and the other is a control circuit board provided with a control circuit that controls the operation of the power supply circuit; further comprising a flexible printed circuit board that electrically connects the rigid board and the other rigid board; one of the component surface of the rigid substrate and the component surface of the other rigid substrate extends along a direction closer to the up-down direction of the drive unit than to the left-right direction of the drive unit, A drive unit, wherein the other of the component surface of the rigid substrate and the component surface of the other rigid substrate extends along a direction closer to the left-right direction of the drive unit than to the up-down direction of the drive unit.

2. The component surface of the power supply circuit board extends along a direction closer to the up-down direction of the drive unit than to the left-right direction of the drive unit, The drive unit according to claim 1 , wherein the component surface of the control circuit board extends in a direction closer to the left-right direction of the drive unit than to the up-down direction of the drive unit.

3. The drive unit according to claim 1 , wherein the control circuit board is smaller in size than the power supply circuit board.

4. an external connector for electrically connecting to an external device; a flexible printed circuit board different from the flexible printed circuit board; Furthermore, The drive unit according to claim 1 , wherein the other flexible printed circuit board electrically connects the rigid circuit board and the external connector.

5. The drive unit according to claim 4, further comprising a reinforcing plate arranged between the other flexible printed circuit board and the external connection connector in the thickness direction of the other flexible printed circuit board at a position where the other flexible printed circuit board and the external connection connector overlap.

6. The drive unit according to claim 4, further comprising a reinforcing plate provided on the surface of the other flexible printed circuit board opposite to the surface to which the external connection connector is connected in the thickness direction of the other flexible printed circuit board at a position where the other flexible printed circuit board and the external connection connector overlap.

7. 7. The drive unit according to claim 5, wherein a pin of the external connector passes through the reinforcing plate.

8. 6. The drive unit according to claim 4, wherein the other flexible printed circuit board and the external connector are electrically connected using at least one of solder, an anisotropic conductive film, and an anisotropic conductive paste.

9. 6. The drive unit according to claim 4, further comprising a noise suppression component provided on said another flexible printed circuit board.

10. 7. The drive unit according to claim 5, wherein the reinforcing plate is a rigid board provided with anti-noise components.

11. An electrically assisted bicycle comprising the drive unit according to claim 1 or 2.

Images