Drive unit

Abstract

The present invention relates to a drive unit (10) for a human-powered vehicle, in particular for a bicycle or EPAC. The drive unit (10) comprises a housing (12), an electric motor (18) having a stator (44) and a rotor (46), a stator carrier (48), and an electronic unit (50). The stator carrier (48), the stator (44), the rotor (46), and the electronic unit (50) are designed as a pre-assembled unit (56), so that the pre-assembled unit (56) can be attached to the housing (12).

Description

[Technical field]

[0001] The present invention relates to a drive unit for a human-powered vehicle having the features according to the preamble of claim 1. Furthermore, the present invention relates to an assembly consisting of a wire harness for a human-powered vehicle and a drive unit having the features of the dependent claims. [Background technology]

[0002] DE 102015100676 A1 discloses a drive assembly having a human drive, an electric auxiliary drive, a strain wave gearing and a common output element, the drive having a complex structure with many individual components and bearing points.

[0003] EP 2 724 926 A1 discloses a central drive unit with a bottom bracket shaft for a human drive and an auxiliary drive with a motor and a planetary gear set downstream of the motor, which drive unit also has a relatively complex structure with many individual components.

[0004] DE102014108611A1 discloses a bicycle drive having a drive housing for receiving a bottom bracket shaft and a strain wave gear device arranged inside the drive housing and capable of drivingly connecting with a traction means carrier. This bicycle drive also has a complicated structure. The assembly is cumbersome. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] DE102015100676A1 No. [Patent Document 2] EP2724926A1 issue [Patent Document 3] DE102014108611A1 No. Summary of the Invention [Problem to be solved by the invention]

[0006] The object of the present invention is to provide an improved drive unit compared to the above-mentioned prior art, in particular with respect to a reduced number of components, integration of functions and optimized packaging. [Means for solving the problem]

[0007] The present invention solves this problem by a drive unit having the features of claim 1. The drive unit is designed for a human-powered vehicle (actuated by muscle power), in particular for a bicycle or an EPAC (Electrically Power Assisted Cycle). The drive unit can be a bicycle drive.

[0008] The drive unit comprises a housing, an electric motor with a stator and a rotor, a stator carrier and an electronic unit. The electronic unit may comprise or be designed as an electronic circuit board. The stator carrier, the stator, the rotor and the electronic unit are formed as a preassembled unit (assembly). The preassembled unit can thus be mounted as a whole in the housing of the drive unit, i.e. placed and fixed in the housing.

[0009] Combining the aforementioned components to form an assembly allows for easier handling during installation. Thus, when assembling the drive unit, the combined components are mounted as an assembly, not individually, in the housing of the drive unit. As a result, the final mounting of the assembly can be optimized. Furthermore, combining the components provides a pre-assembled and functionally testable assembly. The stator carrier does not only fix the stator to the drive housing, but also further components to the drive housing. Thus, the stator carrier serves multiple functions, which allows for greater integration of functions and a reduction in the number of components to be achieved.

[0010] The drive unit may comprise a bottom bracket shaft for the human drive, which is rotatably mounted on the housing of the drive unit. Furthermore, the drive unit may comprise an auxiliary drive, which comprises an electric motor and a strain wave gear as essential components. The electric motor is mechanically coupled to the strain wave gear. The human drive and the auxiliary drive may be coupled to a common output element, to which, for example, a chain ring or a chain ring carrier is fixed.

[0011] The output element can be designed as a hollow shaft, which partially surrounds the bottom bracket shaft radially outward in the axial direction. A number of freewheel clutches can be arranged radially between the bottom bracket shaft and the output element. One of the freewheel clutches connects the auxiliary drive or the strain wave gear to the output element. A further freewheel clutch connects the bottom bracket shaft to the output element. The freewheel clutches can be arranged adjacent to one another in the axial direction. And / or the freewheel clutch can interact with an inner surface, in particular with the inner circumferential surface of the output shaft.

[0012] The wave gearing can be coupled on the input side to an electric motor and on the output side to an output element. The wave gearing can have a wave generator, a deformable cylindrical bush or inner bush with external teeth (Flexspline), and a cylindrical outer ring or outer bush with internal teeth. The wave generator can be formed as an elliptical disk. The disk has a rolling bearing arranged thereon and an optionally deformable raceway. The flexspline can be designed in an annular or cup-shaped manner. The flexspline usually serves as the output of the wave gearing.

[0013] The stator carrier may comprise a particularly annular or sleeve-shaped carrying part and a particularly disk-shaped fixing part. The two parts may be formed as separate elements and fixed to one another, or the two parts may be formed as a common structural element in a one-piece design. The carrying part may, for example, have a stator fixed thereto, and / or the rotor may be rotatably attached to the end part. Via the fixing part, the stator carrier may be connected with a housing of the drive unit, i.e. fixed to or in the drive unit.

[0014] One or more ducts for electrical signal lines and / or power lines can advantageously be formed in the stator carrier, in particular in the fixed part, so that short cable lengths can be routed, for example from the electronic unit to the electric motor, via the stator carrier, thus allowing simple contacting over short cable lengths.

[0015] Optionally, the stator, the electronic unit and / or the rotor can be fixed to the stator carrier. The rotor can be mounted to the stator carrier by means of rolling bearings. The stator carrier is the central element of a structural unit. This structural unit accommodates at least the stator with the coils, the rolling bearings of the rotor and the electronic unit. The electronic unit, e.g. an electronic circuit board, can be arranged on one side of the stator carrier or its fixed part, e.g. on the outside. The electric motor can be arranged on the other side, e.g. on the inside. The electronic unit is therefore arranged separately from the electric auxiliary drive.

[0016] The stator carrier can advantageously comprise a fixing part that protrudes radially outward. With this fixing part the stator carrier can be attached or fixed to the housing of the drive unit, in particular by press-fit. This allows for a compact and stable fixing, for example without the use of separate fixing elements. The external geometry (e.g. outer circumference) of the stator carrier can correspond to the internal geometry (e.g. inner circumference) of the housing. An oil-tight connection between the fixing part and the housing can be produced by press-fit, for example with the aid of a sealing compound. In this way the drive components can be lubricated on one side of the fixing part without affecting the electronic unit on the other side of the fixing part.

[0017] The electric motor is advantageously designed as an external rotor motor, i.e. the rotor of the electric motor can be designed as an external rotor, the rotor radially surrounding the stator, with this construction an advantageous power density and a relatively compact size can be achieved.

[0018] The rotor can advantageously be provided on the output side with a sleeve-like coupling part for coupling with a wave gearing arranged in the housing. The coupling part can have an elliptical outer contour. The coupling part is therefore the output-side interface for the wave gearing. The wave generator is integrated as a coupling part directly into the rotor of the electric motor. The coupling part is configured to receive a rolling bearing (Flexlager) of the wave generator.

[0019] The stator of the electric motor can be advantageously potted on the stator carrier. The potting compound can extend at least partially over the radially outwardly projecting fixing part and / or sleeve-like carrying part of the stator carrier. The coil windings of the stator are fixed by the potting compound, which can result in a rigid connection between the stator and the stator carrier. Furthermore, it can be thermally connected to the housing via the stator carrier. Electrical signal lines, power lines or their ducts can also be sealed by the potting compound. The potting compound can, for example, be thermally conductive and / or electrically insulating.

[0020] The rotor can advantageously be mounted on the stator carrier at the first bearing point by only one rolling bearing. This allows for a structurally advantageous mounting with a small number of components and little space. The magnetic field of the electric motor can form the second bearing point as a dynamic magnetic bearing as soon as the magnetic field is applied via the stator coil. In this way, mounting of the rotor by rolling bearing (first bearing point) and magnetic bearing (second bearing point) occurs.

[0021] Advantageously, an electrical flexible conductor can be provided, which has two layers and is designed as a double-layer flexible conductor, which is connected at one end to an electronic unit, e.g. an electronic circuit board, and at the other end has an electrical interface with a number of contact surfaces for connection to a vehicle plug. This allows a particularly compact routing of the power lines. One layer of the flexible conductor can be designed for power transmission as an electrical power transmission layer. The second layer can be designed for signal transmission as an electrical signal transmission layer.

[0022] The grooves in which the flexible conductors and the electrical interface are arranged can advantageously be formed on the outside of the housing. By designing them as flexible conductors, it is possible to have a small groove depth for guiding the lines without affecting the internal geometry of the housing of the drive unit. Parts of the flexible conductors, for example contact tabs for connecting the flexible conductors to the electronic unit, can be guided from the radially outside to the radially inside through slots formed in the housing.

[0023] Optionally, the layer of flexible conductor can be covered by a potting compound or coating. Through openings are formed in the potting compound or coating at the electrical interface. In this way, mechanical fixing and sealing of the flexible conductor in the housing is possible. The potting compound or coating can close a groove formed on the outside of the housing, preferably so as to be flush on the radial outside.

[0024] The electrical contact surfaces can advantageously be formed as flat contacts for transmitting power and electrical signals. The flat contacts do not protrude or only slightly protrude from the flexible conductor or from the layer of the flexible conductor. Thus, there is no risk of the protruding plug elements being sheared off during installation. This can facilitate the installation of the drive unit in the vehicle.

[0025] The electronic unit advantageously comprises a position sensor system for detecting the rotational position of the bottom bracket shaft of the drive unit. The position sensor system comprises one or more proximity sensors fixed to the housing and an eccentric element, in particular an eccentric ring, which is fixed non-rotatably on the bottom bracket shaft and interacts with the one or more proximity sensors. In this way, a radial detection of the rotational position of the bottom bracket shaft is performed. The one or more proximity sensors have a detection area in which the eccentric element is located. The one or more proximity sensors can be arranged on the electronic unit or on an electronic circuit board. And / or the proximity sensors can each be designed as a Hall effect sensor, an infrared sensor, an inductively operated sensor, etc. As the arrangement of the eccentric element relative to the bottom bracket shaft is known, the proximity sensors allow the rotational position of the bottom bracket shaft to be determined based on the distance. The change in angle, the angular velocity and / or the first derivative of the angular velocity can be determined by the position sensor system.

[0026] The problem stated at the outset is also solved by an assembly having the features of the dependent claims.

[0027] The assembly includes a wire harness for a human-powered vehicle, in particular a bicycle or EPAC, and a drive unit. The wire harness may comprise a connector plug for connecting to an electrical interface of the flexible conductor. The connector plug comprises spring-loaded contact pins for electrically contacting contact surfaces of the flexible conductor. A retention clamp may be provided. The retention clamp may be used to secure the connector plug to the drive unit. The retention clamp grips the connector plug and engages (at one or both ends) in a recess formed in the exterior, in particular shell surface, of the housing of the drive unit. The wire harness may form part of a vehicle wire harness.

[0028] With regard to the advantages which can be achieved hereby reference is made to the relevant embodiments of the drive unit, the measures described in relation to the drive unit being applicable to further embodiments of the assembly.

[0029] The invention will now be described with reference to the drawings, in which the same elements or elements having the same function are given the same reference numbers. [Brief description of the drawings]

[0030] [Figure 1] 1 is a schematic cross-sectional view of an exemplary embodiment of a drive unit according to the present invention; [Diagram 2] FIG. 2 shows a stator carrier and a housing of the drive unit of FIG. 1. [Figure 3a] FIG. 2 is a side view of the rotor of the electric motor of the drive unit of FIG. 1; [Figure 3b] FIG. 2 is a perspective view of the rotor of the electric motor of the drive unit of FIG. 1; [Figure 4] FIG. 2 is a view of a stator carrier with a stator of the drive unit of FIG. 1; [Diagram 5] FIG. 2 is a diagram of a stator carrier with a stator and a rotor of the drive unit of FIG. 1; [Figure 6a] FIG. 2 is a perspective view of the housing of the drive unit of FIG. 1 with a flexible conductor and a plug of the vehicle-side wiring harness. [Figure 6b] FIG. 2 is a cross-sectional view of the housing of the drive unit of FIG. 1, including a flexible conductor and a plug of the vehicle-side wire harness. [Figure 7] FIG. 6c is a bottom perspective view of the flexible conductor and plug of FIGS. 6a and 6b. [Figure 8a] FIG. 8 is an exploded view of the flexible conductor of FIGS. 6a, 6b and 7. [Figure 8b] FIG. 8 shows the flexible conductor of FIGS. 6a, 6b and 7 in an assembled state. [Figure 9a] FIG. 2 is a cross-sectional view of a position sensor system of the drive unit of FIG. [Figure 9b] FIG. 2 is a side view of the position sensor system of the drive unit of FIG. 1; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] 1 shows a drive unit for a human-powered vehicle, such as a bicycle, the drive unit being generally designated by the reference numeral 10.

[0032] The drive unit 10 comprises a housing 12 in or within which the components of the drive unit 10 are arranged. The drive unit 10 comprises a bottom bracket shaft 14 for human drive, i.e. drive by muscle power. The bottom bracket shaft 14 is rotatably mounted in the housing 12 of the drive unit 10. Furthermore, the drive unit 10 comprises an electric auxiliary drive 16 comprising an electric motor 18 and a strain wave gear 20. The electric motor 18 is mechanically coupled to the strain wave gear 20. The bottom bracket shaft 14 and the auxiliary drive 16 are coupled to a common output shaft 22, to which a chain ring carrier or chain rings can be fixed (not shown).

[0033] The bottom bracket shaft 14 is mounted by means of a first rolling bearing 24 to a housing cover 26 which closes the housing 12 of the drive unit 10 on one side (the left side in FIG. 1 ). Furthermore, the bottom bracket shaft 14 is rotatably mounted by means of a second rolling bearing 28 to an output element 22. The output element 22 is rotatably mounted to the housing 12 by means of a third rolling bearing 30 and a fourth rolling bearing 32.

[0034] The wave gearing 20 comprises a wave generator 34, a deformable cylindrical bushing or inner bushing 36 with external teeth (flexspline) and a cylindrical outer ring 38 with internal teeth. The wave gearing 20 is coupled to the electric motor 18 on the input side and to the output element 22 on the output side, precisely by means of a first freewheel clutch 40. The bottom bracket shaft 14 is coupled to the output element 22 by means of a further second freewheel clutch 42.

[0035] The electric motor 18 comprises a stator 44 with stator coils 45 and a rotor 46. The drive unit 10 further comprises a stator carrier 48 and an electronic unit 50 formed as an electronic circuit board. The stator carrier 48 (Figures 1, 2, 4 and 5) comprises, for example, a sleeve-shaped carrying part 52 and, for example, a disk-shaped fixed part 54. The carrying part 52 and the fixed part 54 are designed in one piece in this embodiment.

[0036] The stator carrier 48, the stator 44, the rotor 46, and the electronics unit 50 are formed as a pre-assembled unit 56 (FIGS. 2 and 5) such that the pre-assembled unit 56 can be mounted as a whole in the housing 12 of the drive unit 10.

[0037] The stator 44 is fixed to a carrying part 52 (FIG. 5). The rotor 46 is rotatably mounted on the carrying part 52 by means of rolling bearings 58. The stator carrier 48 can be connected with the housing 12 of the drive unit 10 via a fixing part 54.

[0038] Ducts for electrical signal lines 60 and for power lines 62 are formed in the stator carrier 48 (FIG. 2), in particular in the fixed part 54. The stator 44, the electronic unit 50 and the rotor 46 are fixed to the stator carrier 48. The rotor 46 is mounted on the stator carrier 48 by means of rolling bearings 58. The electronic unit or electronic circuit board 50 is arranged on one side of the stator carrier 48 or the fixed part 54 and the electric motor 18 on the other side.

[0039] As already explained, the stator carrier 48 comprises a fixing part 54 which projects radially outwards, by means of which the stator carrier 48 can be attached to the housing 12 of the drive unit 10, which is achieved in this embodiment by means of a press fit. The outer geometry 49 of the stator carrier 48 or the fixing part 54 corresponds to the inner geometry 13 of the housing 12 (FIG. 2). An oil-tight connection between the fixing part 54 and the housing 12 can be produced by means of a press fit, for example using a sealing compound (not shown).

[0040] The electric motor 18 (FIGS. 1 and 5) is designed as an external rotor motor, i.e. the rotor 46 of the electric motor 18 is designed as an external rotor and surrounds the stator 44 radially outwardly.

[0041] The rotor 46 (Figures 1, 2, 3a, 3b) has, on the output side, a sleeve-like coupling part 64 for coupling with the strain wave gear device 20 arranged in the housing 12. The coupling part 64 has an elliptical outer contour 65. The coupling part 64 is therefore the output side interface for the strain wave gear device 20. The coupling part 64 is configured to receive a rolling bearing 66 as a flex bearing of the wave generator 20.

[0042] In this embodiment, the stator 44 (FIG. 4) of the electric motor 18 is fixed to the stator carrier 48 by a potting compound 68. The potting compound 68 extends partially over the fixed portion 54 and the carrying portion 52 of the stator carrier 48. The potting compound 68 mechanically fixes the coil windings 45 of the stator 44. In addition, the potting compound 68 seals the signal and power lines or their ducts 60, 62.

[0043] The rotor 46 (FIG. 5) is attached to the stator carrier 48 only by one rolling bearing 58 as a first bearing point. The magnetic field of the electric motor 18 forms a second bearing point 70 as a "dynamic magnetic bearing" as soon as a magnetic field is applied through the stator coils.

[0044] Furthermore, a flexible conductor 72 (Flexleiter) (Figures 6a, 6b, 7, 8a, 8b) is provided. The flexible conductor is designed as a double-layer flexible conductor and comprises two layers 74, 76. The flexible conductor is connected at one end to the electronic unit 50, i.e. to an electronic circuit board, and at the other end comprises an electrical interface 78 with a number of flat contact surfaces 79 for connection to a vehicle-side plug 204. The first layer 74 of the flexible conductor 72 is designed as a power transmission layer 74. The second layer 76 is designed as an electrical signal transmission layer 76.

[0045] A groove 82 in which the flexible conductor 72 and the electrical interface 78 are disposed is formed on the exterior 80 of the housing 12 (FIGS. 6a, 6b). Portions of the flexible conductor 72, such as contact tabs 84 for connecting the flexible conductor 72 to the electronic unit 50, may be led (from radially outward to radially inward) through slots 86 formed in the housing 12.

[0046] The layers 74, 76 (FIGS. 7, 8a, 8b) of the flexible conductor 72 may be covered by a potting compound or coating 88. A through opening 89 is formed (in the potting compound or coating 88) at the electrical interface 78. The potting compound or coating 88 may close the groove, preferably flush radially outward.

[0047] The contact surfaces 79 are designed as flat contacts 79 and do not protrude, or only very slightly, from the flexible conductor 72 or from the layers 74, 76 of the flexible conductor 72 (FIGS. 8a, 8b).

[0048] 6a, 6b, 7, 8a, and 8b show an assembly 200 including a wire harness 202, only a portion of which is shown, for a human-powered vehicle and drive unit 10. The wire harness 202 has a plug 204 at one end for connecting to the electrical interface 78 of the flexible conductor 72. The connector plug 204 has spring-loaded contact pins 206 for electrically contacting corresponding contact surfaces 79 of the flexible conductor 72.

[0049] Furthermore, a retaining clamp 208 is provided (FIG. 6a). The retaining clamp 208 can be used to secure the connector plug 204 to the drive unit 10. The retaining clamp 208 is designed to grip the connector plug 204 and engage at one or both ends with recesses 91 formed in the exterior 80 of the housing 12 of the drive unit 10. This secures the connector plug 204 to the housing 12.

[0050] The electronic unit (Figures 9a, 9b) comprises a position sensor system 90 for detecting the rotational position of the bottom bracket shaft 14 of the drive unit 10. The position sensor system 90 comprises a number of proximity sensors 92 distributed around the circumference, in this example four proximity sensors 92, and an eccentric element, for example an eccentric ring 94, which is non-rotatably fixed to the bottom bracket shaft 14 and interacts with the proximity sensors 92.

[0051] The proximity sensors 92 are arranged in the electronic unit 50 or on an electronic circuit board. The proximity sensors 92 can each be designed as a Hall effect sensor, an infrared sensor or as an inductively operated sensor, etc. [Explanation of symbols]

[0052] 10 Drive unit 12. Housing 13 Internal Geometry 14 Bottom bracket shaft 16 Auxiliary drives, electrical 18 Electric Motor 20 Strain Wave Gearing 22 Output elements 24 First rolling bearing 26 Housing cover 28 Second rolling bearing 30 Third rolling bearing 32 No. 4 rolling bearing 34 Wave Generator 36 Inner bush, flexspline 38 Outer Ring 40 First freewheel clutch 42 Second freewheel clutch 44 Stator 45 Coil 46 Rotor 48 Stator carrier 49 External Geometry 50 Electronic unit, electronic circuit board 52 Supporting part 54 Fixed part 56 Pre-assembled Units 58 First bearing point, rolling bearing 60 Duct for signal lines 62 Tact for power lines 64 Joining part 65 Oval Outer Shape 66 Rolling bearing (flex bearing) 68 Potting Compound 70 Second bearing point 72 Flexible Conductor 74 1st layer 76 2nd layer 78 Electrical Interface 79 Contact surface 80 outside 82 Groove 84 Contact Tab 86 Slots 88 Potting Compounds, Coatings 89 Through opening 90 Position Sensor System 91 Recess 92 Proximity Sensor 94 Eccentric elements, eccentric rings 200 Assembly 202 Wire harness 204 Plug 206 Contact pin 208 Retaining Clamp

Claims

1. A drive unit (10) for a human-powered vehicle, in particular a bicycle or an EPAC, comprising a housing (12), an electric motor (18) having a stator (44) and a rotor (46), a stator carrier (48) and an electronic unit (50), said stator carrier (48), said stator (44), said rotor (46) and said electronic unit (50) being formed as a pre-assembled unit (56) so that said pre-assembled unit (56) can be attached to said housing (12), A drive unit (10) is provided with a flexible conductor (72), the flexible conductor (72) having two layers (74, 76), connected to the electronic unit (50) at one end and having an electrical interface (78) at the other end having a plurality of contact surfaces (79) for connecting to a vehicle-side plug (204).

2. 2. The drive unit (10) of claim 1, characterized in that one or more ducts (60, 62) for electrical signal lines and power lines are formed in the stator carrier (48), the stator (44), the electronic unit (50) and the rotor (46) are fixed to the stator carrier (48), and the rotor (46) is mounted to the stator carrier (48) by means of rolling bearings (58).

3. 3. The drive unit (10) according to claim 1 or 2, characterized in that the stator carrier (48) has a fixing portion (54) protruding radially outward, by means of which the stator carrier (48) can be attached or fixed to the housing (12) of the drive unit (10), in particular by press-fit.

4. The drive unit (10) according to any one of the preceding claims, characterized in that the electric motor (18) is designed as an external rotor motor.

5. The drive unit (10) according to any one of claims 1 to 4, characterized in that the rotor (46) has a sleeve-shaped coupling portion (64) for coupling with a strain wave gear device (20) arranged in the housing (12), the coupling portion (64) having an elliptical outer contour (65).

6. A drive unit (10) according to any one of the preceding claims, characterized in that the stator (44) of the electric motor (18) is potted onto the stator carrier (48).

7. A drive unit (10) according to any one of claims 1 to 6, characterized in that the rotor (46) is mounted on the stator carrier (48) only by one rolling bearing (58).

8. 2. The drive unit (10) of claim 1, characterized in that a groove (82) in which the flexible conductor (72) and the electrical interface (78) are arranged is formed on the outside (80) of the housing (12), the layers (74, 76) of the flexible conductor (72) are covered by a potting compound or coating (88), and a through opening (89) is formed in the electrical interface (78).

9. The drive unit (10) according to any one of claims 1 to 8, characterized in that the electronic unit (50) comprises a position sensor system (90) for detecting a rotational position of a bottom bracket shaft (14) of the drive unit (10), the position sensor system (90) comprising one or more proximity sensors (92) and an eccentric element (94), in particular an eccentric ring (94), fixed non-rotatably on the bottom bracket shaft (14) and interacting with the one or more proximity sensors (92).

10. 10. An assembly (200) comprising a wire harness (202) for a human-powered vehicle, in particular a bicycle or an EPAC, and a drive unit (10) according to any one of claims 1, 8 or 9, wherein the wire harness (202) comprises a connector plug (204) for connecting to an electrical interface (78) of a flexible conductor (72), the connector plug (204) comprising spring-loaded contact pins (206) for contacting contact surfaces (79) and / or a retaining clamp (208) for securing the connector plug (204) to the drive unit (10), the retaining clamp (208) being adapted to grip the connector plug (204) and engage a recess (91) formed in the outer side (80) of the housing (12) of the drive unit (10).

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