drive unit of an e-bike or pedelec as well as e-bike or pedelec

Abstract

Drive unit (15) of an e-bike or pedelec, comprising an output shaft (19), a pedal crank shaft (16) operatively connected to the output shaft (16) to apply a rider-side torque to the output shaft (19), an electric machine (26) wherein a motor shaft (29) of the same is operatively connected to the output shaft (19) via at least one gear stage (30, 31) such that a motor-side torque can be applied to the output shaft (19) via the electric machine (26), a torque sensor (34) for detecting the rider-side torque, and a control device (36) coupled to the torque sensor (34) via a data transmission device (35) extending through a cavity or channel (38) in the at least one gear stage (30, 31) and through a cavity or channel (37) of the motor shaft (29) extends from the torque sensor (34) to the control device (36),and wherein the data transmission device (35) is designed as a rigid, rod-like projection of a printed circuit board (39) of the torque sensor (34), which is connected at one end of the printed circuit board (39) via a plug connection (40) to the control device (36), which on the one hand provides the signal-side coupling of the data transmission device (35) and thus of the torque sensor (34) with the control device (36) and on the other hand provides mechanical positioning in the axial direction of the motor shaft (29) and torque support of the data transmission device (35) and thus of the torque sensor (34).

Description

[0001] The invention relates to a drive unit of an e-bike or pedelec and to an e-bike or pedelec.

[0002] EP 2 731 858 B1 discloses a bicycle designed as an e-bike or pedelec with a drive system. The drive system of the e-bike or pedelec has a pedal crankshaft to which pedal cranks engage. A rider-side torque can be provided to a sprocket via the pedal crankshaft. Furthermore, the drive system has an electric motor that can provide a motor-side torque to the sprocket for drive support. A motor shaft of the electric motor extends perpendicular to the pedal crankshaft. The electric motor can thus be installed in a space-saving manner in the down tube of a bicycle frame.

[0003] The electric motor of a drive unit of an e-bike or pedelec assists the rider by providing the motor-side torque to the sprocket in addition to the rider-side torque. The motor-side torque provided by the electric motor typically depends on the rider-side torque. It is known that the rider-side torque can be measured using a torque sensor.

[0004] DE 10 2021 213 062 A1 discloses a drive unit of an e-bike or pedelec with a torque sensor. The torque sensor is connected to an evaluation device or control device via a cable. The cable, which serves to connect the torque sensor to the evaluation device or control device, runs in a cable duct. The cable duct is either arranged on a radial outer side of the electric machine or is provided by a motor shaft of the electric machine designed as a hollow shaft and also by a transmission shaft designed as a hollow shaft. The cable, which extends through the cable duct, is flexible.

[0005] DE 10 2020 129 083 B3 discloses another drive unit of an e-bike or pedelec with a torque sensor.

[0006] US 2017 / 0 254 671 A1 discloses a shaft-integrated angle sensing device for an electric bicycle. A sensor assembly includes a sensor element and a magnet module. The sensor element is configured to measure a magnetic field and is positioned within a shaft. The shaft is configured to shield the magnet module and the sensor element. The magnet module is configured to generate the magnetic field.

[0007] CN 1 10 293 828 A discloses further prior art.

[0008] Connecting the torque sensor to the control unit via a cable requires at least two plug connections: one between the cable and the torque sensor, and the other between the cable and the control unit. This complicates automated assembly of the drive unit. Furthermore, simple torque support for the torque sensor in the drive unit of an e-bike or pedelec has been challenging to date. Therefore, there is a need for a drive unit for an e-bike or pedelec that can be assembled automatically and that features simple torque support for the torque sensor. Furthermore, there is a need for an e-bike or pedelec with such a drive unit.

[0009] The object of the invention is to provide a corresponding drive unit of an e-bike or pedelec as well as an e-bike or pedelec with such a drive unit.

[0010] This object is achieved by a drive unit of an e-bike or pedelec according to claim 1 and by an e-bike or pedelec according to claim 12.

[0011] According to the invention, the data transmission device is designed as a rigid or rigid, rod-like or cylinder-like projection of a circuit board of the torque sensor, which is connected to the control device at an end applied by the circuit board via a plug connection, wherein the plug connection on the one hand provides the signal-side coupling of the data transmission device and thus of the torque sensor with the control device and on the other hand provides a mechanical positioning in the axial direction of the motor shaft and a torque support of the data transmission device and thus of the torque sensor.

[0012] In the drive unit according to the invention, the torque sensor is connected to the control device not via a flexible cable, but rather via the rigid or rigid, rod-like or cylindrical data transmission device, which is designed as a projection of a circuit board of the torque sensor and extends through the cavity or channel of the motor shaft and the at least one gear stage. The number of plug connections is thus reduced, since no plug connection is required between the data transmission device and the torque sensor. Furthermore, automated assembly of the drive unit is possible.

[0013] The data transmission device, which is designed as a projection of the circuit board, is connected to the control device via a plug connection at the end facing away from the circuit board, both on the signal side and mechanically. The mechanical connection provides the mechanical positioning of the data transmission device and thus of the torque sensor in the axial direction of the motor shaft and torque support for the torque sensor. The data transmission device, which connects the torque sensor to the control device in the drive unit according to the invention, therefore performs a dual function, namely both the function of data transmission between the torque sensor and the control device and the function of torque support for the torque sensor.

[0014] Preferably, the data transmission device is positioned and mounted in the cavity or channel of the motor shaft and / or in the cavity or channel of at least one gear stage, in particular via a respective plain bearing bush in the radial direction of the motor shaft. This is particularly preferred for precise positioning of the data transmission device and thus of the torque sensor, as well as for torque support of the torque sensor.

[0015] Preferred developments of the invention will become apparent from the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail, without being limited thereto, with reference to the drawings. Herein: Fig. 1 an e-bike or pedelec, Fig. 2 a cross section of a first drive unit according to the invention, Fig. 3 one opposite Fig. 2 cross-section offset by 90° through the first drive unit according to the invention, Fig. 4 a cross-section analogous to the cross-section of the Fig. 2 by a second drive unit according to the invention, Fig. 5 a cross-section analogous to the cross-section of the Fig. 2 by a third drive unit according to the invention.

[0016] Fig. 1 shows an e-bike or pedelec 10. The e-bike or pedelec 10 has a frame 11, with a saddle 12 and a handlebar 13 attached to the frame 11. Furthermore, Fig. 1 Wheels 14 of the e-bike or pedelec 10 are shown.

[0017] The e-bike or pedelec 10 has a drive unit 15. The drive unit 15 has a crankshaft 16, with cranks 17 and pedals 18 engaging the crankshaft 16. The drive unit 15 also has an output shaft 19. A sprocket 20, on which a drive chain 21 is guided, engages the output shaft 19. Alternatively, a belt pulley, on which a drive belt is guided, can engage the output shaft 19.

[0018] The output shaft 19 is preferably designed as a hollow shaft, which the pedal crankshaft 16, which according to Fig. 3 is also preferably designed as a hollow shaft, surrounds it in sections in the axial direction and concentrically in the radial direction. The output shaft 19 is mounted on the pedal crankshaft 16 via a freewheel 22 and is operatively connected to the pedal crankshaft 16. The freewheel 22 is preferably a sprag freewheel.

[0019] A driver can apply a driver-side torque to the pedal crankshaft 16 of the drive unit 15 via the pedals 18 and pedal cranks 17 in order to drive the pedal crankshaft 16 and, via the pedal crankshaft 16, the output shaft 19 and, via the output shaft 19, the chain wheel 20 or belt wheel with the driver-side torque.

[0020] The pedal crank shaft 16 and the output shaft 19 of the drive unit 15 are rotatably mounted via bearings 23, 24 in a first housing 25 of the drive unit 15.

[0021] This shows Fig. 3 a bearing 23 between the pedal crank shaft 16 and the first housing 25 and a bearing 24 between the output shaft 19 and the first housing 25 of the drive unit 15.

[0022] The drive unit 15 further comprises an electric machine 26, which serves as the drive motor of the drive unit 15. The electric machine 26 is configured to apply a motor-side torque to the output shaft 19 and, via the output shaft 19, to the sprocket 20 or belt pulley, in addition to the rider-side torque applied via the pedals 18, pedal cranks 17, and pedal crankshaft 16, in particular to assist the rider of the e-bike or pedelec 10.

[0023] The electric machine 26 of the drive unit 15 can be arranged together with the pedal crankshaft 16 and the output shaft 19 in the first housing 25, alternatively, as shown in the Fig. 2 to 5, the electric machine 26 may be arranged in a separate second housing 46, which is then connected to the first housing 25.

[0024] A stator 27, a rotor 28, and a motor shaft 29 of the electric machine 26 are shown. The rotor 28 of the electric machine 26 is also referred to as the rotor and rotates together with the motor shaft 29. The stator 27 of the electric machine 26 is also referred to as the stator.

[0025] The motor shaft 29 of the electric machine 26 extends perpendicular to the pedal crankshaft 16 and perpendicular to the output shaft 19. The electric machine 26, namely the motor shaft 29 thereof, is operatively connected to the output shaft 19 via at least one gear stage 30, 31 and a further freewheel 32. According to Fig. 3, the gear stage 30 is designed as a planetary gear stage and the gear stage 31 as a bevel gear stage.

[0026] The bevel gear stage 31 is in engagement with a ring gear 33, wherein the ring gear 33 is mounted on the output shaft 19 via the further freewheel 32 and is operatively connected to the output shaft 19.

[0027] The further freewheel 32 preferably has a spring element and preferably an axial toothing.

[0028] As already explained, a torque can therefore be applied to the chain wheel 20 or belt pulley connected to the output shaft 19, on the one hand by the rider and on the other hand by the electric motor 26. The rider-side torque applied by the rider is transferred via the pedal crankshaft 16 to the output shaft 19 in the area of ​​the freewheel 22. The torque applied by the electric motor 26 is transferred via the two gear stages 30 and 31 and the freewheel 32 between the ring gear 33 and the output shaft 19 to the output shaft 19. In an axial section 19a of the output shaft 19 located between the two freewheels 22, 32, the rider-side torque is initially applied exclusively to the output shaft. Only at section 19b of the output shaft 19, on which the chain wheel 20 or belt pulley engages, does the total torque of the rider-side torque and the motor-side torque apply.

[0029] The engine-side torque provided by the electric motor 26 serves to assist the driver. The engine-side torque provided by the electric motor 26 at the output shaft 19 depends on the driver-side torque.

[0030] The drive unit 15 according to the invention has a torque sensor 34 configured to detect the driver-side torque applied by the driver in the region of a measuring shaft, in particular at section 19a of the output shaft 19 serving as the measuring shaft. The torque sensor 34 is coupled to a control device 36 via a data transmission device 35 in order to provide the signals detected by the torque sensor 34 for evaluation and further processing by the control device 36. The data transmission device 35 extends through a cavity or channel 37 of the motor shaft 29 and through a cavity or channel 38 of the gear stages 30, 31.

[0031] In the drive unit 15 of an e-bike or pedelec 10 according to the invention, the data transmission device 35 is designed as a rigid or rigid, rod-like or cylindrical projection of a circuit board 39 of the torque sensor 34. The data transmission device 35 is therefore an integral component of a circuit board 39 of the torque sensor 34 and is made of the same material as this circuit board 39 of the torque sensor 34.

[0032] On the side facing the circuit board 39 of the torque sensor 34, the data transmission device 35 merges into the circuit board 39 in one piece or monolithically, i.e., without a plug connection. At the end facing away from the circuit board 39, the data transmission device 35 is connected to the control device 36 via a plug connection 40.

[0033] The plug connection 40 provides, on the one hand, the signal-side coupling of the data transmission device 35 and thus of the torque sensor 34 to the control device 36; on the other hand, this plug connection 40 also provides a mechanical positioning of the data transmission device 35 and thus of the torque sensor 34 in the axial direction of the motor shaft 29 and thus in the radial direction of the output shaft 19, as well as a torque support of the data transmission device 35 and thus of the torque sensor 34.

[0034] Two functions are therefore provided via the rigid or flexurally stiff data transmission device 35, which is designed as a rod-like or cylindrical projection of the printed circuit board 39, and the interaction of the same with the plug connection 40 at the end of the data transmission device 35 facing away from the printed circuit board 39: on the one hand, the signal-side coupling of the torque sensor 34 to the control device 36 and, on the other hand, the torque support and mechanical positioning of the torque sensor 34.

[0035] While the pedal crankshaft 16, the output shaft 19 and the motor shaft 29 as well as the ring gear 33 and assemblies of the gear stages 30, 31 rotate during operation, the torque sensor 34, the data transmission device 35 and the control device 36 are stationary.

[0036] The data transmission device 35 is positioned and mounted in the cavity or channel 37 of the motor shaft 29 in the radial direction of the motor shaft 29, preferably via a plain bearing bush 41.

[0037] Furthermore, the data transmission device 35 is positioned and mounted in the cavity or channel 38 of the at least one gear stage 30, 31 as seen in the radial direction of the motor shaft 29, in particular by providing a clearance fit between the data transmission device 35 and Fig. 3 the bevel gear 42 of the bevel gear stage 31 or via another plain bearing bush.

[0038] The printed circuit board 39, like the data transmission device 35, is rigid and flexurally stiff. Fig. 2 and Fig. In the embodiment shown in Figure 3, the torque sensor 34 has a single circuit board 39, which carries components 43 for torque detection. The circuit board 39 with the components 43 for torque detection is connected radially to the outside of the measuring shaft, on which the driver-side torque is to be detected.

[0039] As already explained, in the embodiment shown, the torque sensor 34 detects the driver-side torque at the section 19a of the output shaft 19. While in Fig. 5 the section 19a of the output shaft 19 together with the pedal crankshaft 16 is shown in cross section, namely at the axial position of the section 19a, is in Fig. 2 and Fig. 4, the output shaft 19, or rather section 19a thereof, is shown only schematically. This is intended to emphasize that torque measurement can also be performed on a different measuring shaft. Thus, it is also possible to use the pedal crankshaft 16 as the measuring shaft.

[0040] Fig. 4 and Fig. 5 shows exemplary embodiments of a drive unit 15 according to the invention, in which the torque sensor 34, in addition to the circuit board 39 on which the data transmission device 35 is formed as an integral projection, further comprises circuit boards 44, 45 that carry the torque detection modules 43. These circuit boards 44, 45 are connected to the circuit board 39.

[0041] In the illustrated embodiment, the electric machine 26, together with the control device 36, is arranged in the second housing 46, whereas the pedal crankshaft 16 and the output shaft 19 are arranged in the first housing 25. These two housings 25, 46 are then connected to one another, with the respective housings 25, 46 and the assemblies accommodated therein then forming subunits of the drive unit 15 according to the invention. The gear stages 30, 31 can be arranged exclusively in the first housing 25 or exclusively in the second housing 46, or partially in one of the housings 25, 46 and partially in another of the two housings 25, 46.

Claims

[1] Drive unit (15) of an e-bike or pedelec, with an output shaft (19), with a pedal crankshaft (16) which is operatively connected to the output shaft (19) in order to apply a driver-side torque to the output shaft (19), with an electric machine (26), wherein a motor shaft (29) of the electric machine (26) runs perpendicular to the pedal crankshaft (16) and output shaft (19), wherein the motor shaft (29) is operatively connected to the output shaft (19) via at least one gear stage (30, 31) such that a motor-side torque can be applied to the output shaft (19) via the electric machine (26), with a torque sensor (34) for detecting the driver-side torque, with a control device (36) which is coupled to the torque sensor (34) via a data transmission device (35), wherein the data transmission device (35) extends through a cavity or a channel (38) in the at least one gear stage (30, 31) and through a cavity or a channel (37) of the motor shaft (29) from the torque sensor (34) to the control device (36), characterized by , that the data transmission device (35) is designed as a rigid or flexurally rigid, rod-like or cylinder-like projection of a printed circuit board (39) of the torque sensor (34), which is connected to the control device (36) at an end applied by the printed circuit board (39) via a plug connection (40), wherein the plug connection (40) on the one hand provides the signal-side coupling of the data transmission device (35) and thus of the torque sensor (34) to the control device (36) and on the other hand provides mechanical positioning in the axial direction of the motor shaft (29) and torque support of the data transmission device (35) and thus of the torque sensor (34). [2] Drive unit (15) according to claim 1, characterized by that the data transmission device (35) is positioned and mounted in the cavity or channel (27) of the motor shaft (39) in the radial direction of the motor shaft (39). [3] Drive unit (1) according to claim 2, characterized bya plain bearing bush (41) for radially supporting the data transmission device (35) in the cavity or channel (37) of the motor shaft (29). [4] Drive unit (15) according to one of claims 1 to 3, characterized by that the data transmission device (35) is positioned and mounted in the cavity or channel (30) of the at least one gear stage (30, 31) in the radial direction of the motor shaft (29). [5] Drive unit (15) according to claim 4, characterized by a plain bearing bush for the radial mounting of the data transmission device in the cavity or channel (38) of the at least one gear stage (30, 31). [6] Drive unit (15) according to one of claims 1 to 5, the circuit board (39) of the torque sensor (34), on which the data transmission device (35) is formed as an integral or monolithic projection, is designed as a rigid circuit board. [7] Drive unit (15) according to one of claims 1 to 6, the circuit board (39) of the torque sensor (34), on which the data transmission device (35) is formed, carries modules (43) for torque detection. [8] Drive unit (15) according to one of claims 1 to 6, the circuit board (39) of the torque sensor (34), on which the data transmission device (35) is formed, is connected to further circuit boards (44, 45) of the torque sensor (34), which carry assemblies (43) for torque detection. [9] Drive unit (15) according to one of claims 1 to 8, characterized by , that the output shaft (19) is designed as a hollow shaft through which the pedal crank shaft (16) extends, the output shaft (19) is operatively connected to the pedal crank shaft (16) via a first freewheel (22), the output shaft (29) is operatively connected to the at least one gear stage (30, 31) via a second freewheel (32) and to the electric machine (26) via the at least one gear stage (30, 31). [10] Drive unit (15) according to one of claims 1 to 9, characterized by that the output shaft (33) is designed for the rotationally fixed connection of a chain wheel (20) or belt wheel. [11] Drive unit (15) according to one of claims 1 to 10, characterized by that the torque sensor (34) detects the driver-side torque on a measuring shaft, in particular on a section (19a) of the output shaft (19) serving as a measuring shaft, on which only the driver-side torque is effective. [12] E-bike or pedelec (10) with a drive unit (15) according to one of claims 1 to 11.

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