Assembly for arrangement on an electric bicycle, and method for an electric bicycle

Abstract

Assembly for an electric bicycle (F), comprising a detection device (2) for determining a speed of the electric bicycle and a drive system (3) that has a bottom bracket shaft (31), which is available for generating a pedal power for muscle-power-operated movement of the electric bicycle, at least one drive motor (32) for providing a drive power generated by extraneous force in addition to the pedal power and an electronic control unit (33) configured to use the detection device to determine the speed of the electric bicycle and to operate the drive system in an emergency mode if said electronic control unit cannot determine the speed of the electric bicycle using the detection device. The electronic control unit is configured and intended to limit the drive power in the emergency mode.

Description

[0001] Assembly for arrangement on an electric bicycle and method for an electric bicycle

[0002] Description

[0003] The proposed solution relates to an assembly according to the preamble of claim 1 and a method according to claim 10.

[0004] As is well known, electric bicycles have at least one drive motor, which is used to provide additional drive power to assist the rider in addition to the pedaling power provided by the electric bicycle rider. The electric bicycle is then driven jointly by the pedaling power and the additional drive power. In principle, this would allow the electric bicycle to reach any desired speed, provided the drive motor can provide a sufficiently high drive power.

[0005] For the rider's safety, the drive power is therefore limited depending on the speed of the electric bike. A detection device is usually provided to limit the speed of the electric bike. Once a predetermined maximum speed is reached, the electric bike cannot be accelerated further using the at least one drive motor (acceleration by increasing pedaling power is possible regardless).

[0006] If the detection device fails, preventing the bicycle's speed from being determined, the drive power is no longer provided for safety reasons (the electric bicycle can then only be propelled by pedaling power). This prevents a reduction in rider safety, which may be deliberately accepted by a user removing the detection device or part of it. Against this background, the proposed solution is based on the task of providing an assembly for an electric bicycle that enables a rider to use the electric bicycle safely and comfortably when the detection device cannot determine the electric bicycle's speed.

[0007] According to a first aspect of the proposed solution, the problem is solved by an assembly for an electric bicycle. The proposed assembly comprises at least

[0008] - a detection device for determining a speed of the electric bicycle and

[0009] - a drive system that

[0010] - a bottom bracket shaft, which is available to generate pedal power for muscle-powered propulsion of the electric bicycle,

[0011] - at least one drive motor for providing an externally powered drive power in addition to the pedal power and

[0012] - an electronic control unit configured to determine the speed of the electric bicycle using the detection device and to operate the drive system in an emergency mode if it cannot determine the speed of the electric bicycle using the detection device.

[0013] In addition, the electronic control unit is designed and intended to limit the drive power in emergency operation.

[0014] A basic idea of ​​the proposed solution is to be able to provide at least a minimum of drive power (e.g. a drive power greater than zero or greater than 10% of the available drive power in normal operation of the drive system) if the electronic control unit cannot determine the speed of the electric bicycle using the detection device. By limiting the drive power, the rider's safety can be protected even if the speed of the electric bicycle cannot be determined. Furthermore, the rider can potentially maintain a minimum level of comfort when using the electric bicycle by not having to propel it exclusively using pedal power, but rather being able to continue to propel it in a type of "degraded mode" in terms of drive power. The rider can therefore, if necessary,not require the full drive power that the at least one drive motor is designed to provide during normal operation. However, the rider can be provided with at least a drive power that is different from zero, for example, to drive the electric bicycle to a repair shop if the electric bicycle's detection device has a technical defect.

[0015] The electronic control unit cannot determine the speed of the electric bicycle using the detection device if, among other things, the detection device has a technical defect, has been lost, damaged, stolen, and / or is unable to communicate with the electronic control unit. It may also happen that a user of the electric bicycle decides to remove the detection device or parts of it in order to bypass a safety check of the electric bicycle's speed. To prevent the electric bicycle from being ridden at arbitrarily high speeds in such a situation, it may be advisable to operate it in emergency mode until the detection device can determine the electric bicycle's speed again.Such an approach can protect the rider's safety and ensure that the electric bicycle complies with legal requirements applicable to electric bicycles in some countries, which stipulate that an electric bicycle must not be designed to exceed a certain maximum speed, such as 25 km / h, based on the motor power.

[0016] In one embodiment, the electronic control unit is configured and provided to limit the drive power in emergency operation in terms of time and location, at least based on a rotational speed of the at least one drive motor and / or at least based on a torque of the at least one drive motor. Limiting the drive power in emergency operation can generally comprise limiting the value of the drive power (calculable as the product of the factors torque and rotational speed). However, limiting the drive power can also be understood as a limitation in the broader sense, which can extend to time, space, and / or at least one of the factors from which the drive power can be calculated.

[0017] In one embodiment, the time limit comprises a shutdown or at least a (quantitative) reduction of the drive power after the end of an emergency operation interval. The emergency operation interval can, for example, cover a period of one day or three hours. The electronic control unit can have a timer to measure the expiration of the emergency operation interval. The emergency operation interval can be made available so that the electric bicycle can be ridden, for example, to a workshop or to a destination, without the operation of the electric bicycle being immediately restricted and with an unacceptable loss of comfort for the rider.

[0018] In one embodiment, the local limitation comprises switching off or at least reducing the drive power after covering an emergency distance and / or after leaving a movement area around a location at which the speed of the electric bicycle was last determined. In order to determine the emergency distance and / or the location at which the speed of the electric bicycle was last determined, the electronic control unit can have a limitation module. The limitation module can in particular comprise a GPS module. The emergency distance can, for example, comprise a distance that the electric bicycle can cover from the location at which the speed of the electric bicycle was last determined to a workshop or a location frequently visited by the rider of the electric bicycle, such as their home.The movement area can be used to enable the rider to at least find a safe place or to abort a tour with the electric bike without having to accept significant disadvantages.

[0019] Alternatively or additionally, the limiting module can be configured and provided to count revolutions of the bottom bracket spindle (e.g., based on the rider's cadence) and / or revolutions of the at least one drive motor during a subsequent ride during which the speed of the electric bicycle cannot be determined. The respective revolutions can be compared by the limiting module with a limit value. Reaching the limit value can correspond to reaching the local limit.

[0020] In principle, the drive power can be made available during the emergency running interval, on the emergency running distance and / or within the movement range as in normal operation. The electric bike can then move forward using the pedal power and the (additional) drive power as assistance. After the emergency running interval has expired, the emergency running distance has been covered and / or the movement range has been left, the drive power can then be reduced (in terms of amount), for example, to a fraction of the drive power in normal operation. Alternatively, the drive power can be switched off after the emergency running interval has expired, the emergency running distance has been covered and / or the movement range has been left, i.e. permanently set to zero. In this case, the electric bike can still move forward using the pedal power, so that the electric bike can only move more slowly and / or with more effort for the rider.

[0021] In one embodiment, the limitation of the drive power at least on the basis of the speed comprises a specification of an emergency speed for the speed which the speed must not exceed, and / or the limitation of the drive power at least on the basis of the torque comprises a specification of an emergency torque for the torque which the torque must not exceed. In principle, the drive power, as the product of speed and torque, can be limited by limiting one or both of the individual factors. The emergency speed and the emergency torque can be understood as upper limits for the speed and the torque, respectively, which specify a value which must not be exceeded. In particular, the emergency torque and / or the emergency speed can be specified in such a way that a certain speed cannot be exceeded in emergency operation.It is also conceivable and possible to specify an emergency drive power level whose value must not be exceeded by the drive power. This specification can be based on design features of the assembly. Such a design feature could, for example, include a gear ratio with which the drive power (and pedaling power) is applied to a wheel of the electric bicycle.

[0022] In one embodiment, the assembly comprises a transmission device via which the bottom bracket shaft can be coupled to an output shaft, via which the pedaling power and the drive power can be applied to a wheel of the electric bicycle, wherein the transmission ratio of the transmission device is adjustable. The transmission device can thus be used to specify the transmission ratio with which the drive power can be applied to the wheel. With a high transmission ratio, even a relatively low rotational speed can result in a high speed of the electric bicycle, whereas with a low transmission ratio, the same rotational speed can result in a lower speed of the electric bicycle. The transmission device can, for example, have at least one drive wheel, at least one output pinion, and a power transmission element such as a bicycle chain or a drive belt.The drive power (and the pedaling power) can be transmitted from the at least one drive wheel to the at least one drive pinion via the power transmission element. With a high gear ratio, one revolution of the at least one drive wheel can be converted into more revolutions of the at least one drive pinion than with a lower gear ratio. Different gear ratios can be provided, for example, by providing at least two output pinions of different sizes. Depending on which output pinion the power transmission element is guided over, a different gear ratio can then be obtained (e.g. 1:3 and 1:5). In principle, it is conceivable and possible to provide a plurality of n drive wheels and m output pinions, each of different sizes, with which any number of n times m gear ratios can be realized.

[0023] In one embodiment, the emergency speed and / or the emergency torque are based on a highest adjustable gear ratio, on a highest possible gear ratio for which the transmission device is suitable, or on a current gear ratio. Such an embodiment is based on the consideration that the speed of the electric bicycle, with a constant torque of the at least one drive motor, can be determined by its speed. Based on the highest adjustable gear ratio, a maximum speed of the electric bicycle can thus be specified with the emergency speed.

[0024] In principle, it is conceivable and possible for a user of an electric bicycle with this assembly to modify the transmission device in such a way that it enables even higher transmission ratios than the highest (originally) adjustable transmission ratio. Such a modification can be achieved, for example, by replacing a drive pinion with a smaller output pinion. A minimum size of the drive pinion, in turn, can be specified by a design of the transmission device, in particular its derailleur. For example, in such a case, the emergency speed and / or the emergency torque can be based on the highest possible transmission ratio for which the transmission device is fundamentally suitable (i.e., even after modification).This ensures that the electric bicycle cannot move at too high a speed with the assistance of the drive power if the detection device cannot determine the speed of the electric bicycle.

[0025] Basing the emergency speed and / or torque on the current gear ratio can enable dynamic adjustment of the emergency speed and / or torque. This option can be provided particularly with electronically controlled transmissions, because the current gear ratio is known – this is not necessarily the case with a purely mechanical transmission.

[0026] In one embodiment, the detection device has at least one sensor element for arrangement on one of the frame and wheel of the electric bicycle and optionally at least one counter element for arrangement on the other of the frame and wheel. For example, the detection device can have a wheel speed sensor. With the wheel speed sensor, the speed of the electric bicycle can be determined via a speed of a wheel of the electric bicycle, for example in the form of a rear wheel or a front wheel. For this purpose, the detection device can, for example, have a magnetic sensor on one of the frame and wheel of the electric bicycle and a magnet on the other of the frame and wheel of the electric bicycle. The detection device can be coupled to the electronic control unit so that it can receive a signal from the detection device in order to determine the speed of the electric bicycle via the signal. If the electronic control unit, for example,If the signal is not received, it cannot determine the speed of the electric bicycle via the detection device. The electronic control unit can be configured and provided, among other things, to subsequently operate the drive system in emergency mode.

[0027] According to a second aspect, the proposed solution also relates to an electric bicycle with an assembly according to the first aspect.

[0028] According to a third aspect, the proposed solution also relates to a method for an electric bicycle with a detection device for determining the speed of the electric bicycle. The method serves to operate the electric bicycle in emergency mode when the speed of the electric bicycle cannot be determined via the detection device. The method comprises the following steps:

[0029] - Generation of pedal power for muscle-powered propulsion of the electric bicycle via a bottom bracket shaft,

[0030] - Providing a power-driven drive power in addition to the pedal power via at least one drive motor of a drive system,

[0031] - Operating the drive system in emergency mode at the instigation of an electronic control unit if the electronic control unit cannot determine the speed of the electric bicycle via the detection device, whereby the drive power in emergency mode is limited by the electronic control unit.

[0032] The method can have the features and advantages described in connection with the first aspect of the proposed solution. In particular, the electronic control unit can limit the drive power at least in terms of its value and, in particular, also temporally and spatially, at least based on a rotational speed of the at least one drive motor and / or at least based on a torque of the at least one drive motor.

[0033] According to a fourth aspect, the proposed solution relates to a computer program product comprising instructions which, when executed by at least one processor of an electronic control unit of a drive system of an electric bicycle, cause the at least one processor to execute a method according to the third aspect.

[0034] The attached figures illustrate exemplary embodiments of the proposed solution.

[0035] Here,

[0036] Figure 1 a view of an electric bicycle and

[0037] Figure 2 is a schematic view of an assembly.

[0038] Figure 1 shows an electric bicycle F with a frame R on which two wheels (a front wheel V and a rear wheel H) are arranged. A detection device 2 is configured and provided to determine a speed of the electric bicycle F via a rotational speed of the rear wheel H. For this purpose, the detection device 2 is arranged on the frame R. In principle, the detection device 2 can also determine the speed of the electric bicycle F at the front wheel V.

[0039] The electric bicycle F is drivable via a bottom bracket shaft 31 of a drive system 3 by a rider N of the electric bicycle F actuating two crank elements K with pedals P arranged thereon. This allows the rider N to apply pedaling power for muscle-powered propulsion of the electric bicycle F to the bottom bracket shaft 31. The pedaling power and additional drive power generated by at least one drive motor 32 are transmitted via a transmission device 34 to an output shaft A, which is coupled to the rear wheel H, so that the rear wheel H is driven by the pedaling power and the drive power. In principle, propulsion of the electric bicycle F based solely on pedaling power is conceivable and possible.

[0040] Figure 2 shows a schematic view of the assembly 1. The detection device 2 has a sensor element 21 for attachment to the frame R of the electric bicycle F and a counter element 22 for attachment to the rear wheel H of the electric bicycle F. The sensor element 21 detects a movement of the counter element 22 caused by the rear wheel H of the electric bicycle F in order to detect the speed of the electric bicycle F.

[0041] The bottom bracket shaft 31 of the drive system 3 of the assembly 1 is equipped with a drive motor

[0042] 32. In this way, the externally generated drive power can be added to the pedaling power at the bottom bracket shaft 31 to enable assistance to the rider N in propelling the electric bicycle F. The drive system 3 also has an electronic control unit 33 configured to determine the speed of the electric bicycle F using the detection device 2. If the electronic control unit 33 cannot determine the speed of the electric bicycle F using the detection device 2, it operates the drive system 3 in emergency mode. In emergency mode, the drive power is limited by the electronic control unit 33, so that the electric bicycle F can only be propelled at a limited speed.

[0043] To limit the drive power for a certain period of time, the electronic control unit

[0044] 33 has a timer 331. The timer 331 is configured and intended to measure the expiration of an emergency operation interval, after which the electronic control unit 33 shuts down or at least reduces the drive power (in terms of amount). Thus, a drive power comparable to normal operation (if at all) is only available for a limited period of time. In this way, the drive power is limited in time. In principle, a drive power that is reduced (in terms of amount) compared to normal operation can also be available during the emergency operation interval.

[0045] For locally limiting the drive power, the electronic control unit 33 has a limiting module 332. The limiting module comprises a GPS module with which the electronic control unit 33 can locally limit the drive power by switching it off or at least reducing it (in terms of amount) after traveling an emergency route and / or after leaving a movement area around a location at which the speed of the electric bicycle was last determined. In this way, the drive power is locally limited. Thus, a drive power comparable to normal operation is only available to a locally limited extent. In principle, a drive power reduced compared to normal operation can also be available while moving along the emergency route and / or within the movement area.The emergency stop and / or leaving the range of motion can be determined by the limiting module 332 alternatively or additionally via a number of revolutions of the bottom bracket shaft 31 and / or the drive motor 32.

[0046] The drive motor 32 has a speed detection unit 321, which is configured and provided to determine a speed of the drive motor 32. For this purpose, the speed detection unit 321 can use a commutation frequency in the case of a drive motor 32 with a BLDC motor. Furthermore, the drive motor 32 has a torque detection unit 322, which is configured and provided to determine a torque of the drive motor 32. This can be done, for example, via a motor current of the drive motor 32. Based on the speed, the electronic control unit 33 can limit the drive power by specifying an emergency speed that the speed of the drive motor 32 must not exceed in emergency operation.Likewise, the drive power can be alternatively or additionally limited based on the torque by the electronic control unit 33, in which the electronic control unit 33 specifies an emergency torque that the torque of the drive motor 32 may not exceed in emergency operation. This allows the speed of the electric bicycle to be limited (depending on a gear ratio) if a suitable emergency speed and / or a suitable emergency torque are specified by the electronic control unit 33.

[0047] The bottom bracket spindle is coupled to an output shaft A via a transmission device 34, via which the pedaling power and the drive power can be applied to a wheel of the electric bicycle F. The transmission ratio of the transmission device 34 is adjustable. In principle, it is also conceivable and possible for the transmission ratio of the transmission device 34 to be non-adjustable, for example, because only one transmission ratio is available. The speed at which the electric bicycle F travels depends, among other things, on the transmission ratio provided by the transmission device 34 for transmitting the drive power.

[0048] One way to limit the speed is to determine the emergency speed and / or the emergency torque so that at the highest adjustable

[0049] A gear ratio is used to ensure that a specific speed (e.g., 25 km / h) cannot be exceeded with the drive power resulting from the emergency speed and / or the emergency torque. A gear ratio cannot then be set that would result in a speed higher than the specified speed being achieved with the support of the drive power at a given emergency speed and / or given emergency torque.

[0050] In principle, the speed can also be limited based on which gear ratio is theoretically feasible on the electric bicycle F or on the gear transmission device 34 (without the gear transmission device 34 being designed and intended to actually provide this gear ratio; a mere suitability for making it available is sufficient).

[0051] List of reference symbols

[0052] 1 assembly

[0053] 2 Detection device

[0054] 21 Sensor element

[0055] 22 Counter element

[0056] 3 Drive system

[0057] 31 bottom bracket spindle

[0058] 32 drive motor

[0059] 321 Speed ​​detection unit

[0060] 322 Torque detection unit

[0061] 33 electronic control unit

[0062] 331 timers

[0063] 332 Limiting module

[0064] 34 Translation device

[0065] A output shaft

[0066] F Electric bike

[0067] H rear wheel

[0068] KT retkurbel

[0069] N driver

[0070] P Pedal

[0071] R frame

[0072] V front wheel

Claims

Claims 1. Assembly (1) for an electric bicycle (F), with - a detection device (2) for determining a speed of the electric bicycle (F), - a drive system (3) which - a bottom bracket shaft (31) which is available for generating pedal power for muscle-powered movement of the electric bicycle (F), - at least one drive motor (32) for providing an externally powered drive power in addition to the pedal power and - an electronic control unit (33) which is configured to determine the speed of the electric bicycle (F) with the detection device (2) and to operate the drive system (3) in an emergency mode if it cannot determine the speed of the electric bicycle (F) via the detection device (2), characterized in that the electronic control unit (33) is designed and provided to limit the drive power in the emergency mode.

2. Assembly (1) according to claim 1, characterized in that the electronic control unit (33) is designed and provided to limit the drive power in emergency operation temporally, locally, at least on the basis of a rotational speed of the at least one drive motor (32) and / or at least on the basis of a torque of the at least one drive motor (32).

3. Assembly (1) according to claim 2, characterized in that the time limitation comprises a shutdown or at least reduction of the drive power after expiry of an emergency running interval.

4. Assembly (1) according to one of claims 2 or 3, characterized in that the local limitation involves a shutdown or at least a reduction of the Drive power after covering an emergency running distance and / or after leaving a movement area around a location where the speed of the electric bicycle (F) was last determined.

5. Assembly (1) according to one of claims 2 to 4, characterized in that the limitation of the drive power at least on the basis of the speed comprises a specification of an emergency speed for the speed which must not exceed the speed, and / or the limitation of the drive power at least on the basis of the torque comprises a specification of an emergency torque for the torque which must not exceed the torque.

6. Assembly (1) according to one of the preceding claims, characterized by a transmission device (34) via which the bottom bracket shaft (31) can be coupled to an output shaft (A), via which the pedaling power and the drive power can be applied to a wheel of the electric bicycle (F), wherein the transmission ratio of the transmission device (34) is adjustable.

7. Assembly (1) according to claim 5 and claim 6, characterized in that the emergency speed and / or the emergency torque are based on a highest adjustable gear ratio, on a highest possible gear ratio for which the transmission device (34) is suitable, or on a current gear ratio.

8. Assembly (1) according to one of the preceding claims, characterized in that the detection device (2) has at least one sensor element (21) for arrangement on one of the frame (R) and wheel (V, H) of the electric bicycle (F) and optionally at least one counter element (22) for arrangement on the other of the frame (R) and wheel (V, H).

9. Electric bicycle (F) with an assembly (1) according to one of claims 1 to 8.

10. Method for an electric bicycle (F) with a detection device (2) for determining a speed of the electric bicycle (F) for operating the electric bicycle (F) in an emergency mode when the speed of the electric bicycle (F) cannot be determined via the detection device (2), comprising the steps: - generation of pedal power for muscle-powered movement of the electric bicycle (F) via a bottom bracket shaft (31), - Providing an externally powered drive power in addition to the pedal power via at least one drive motor (32) of a drive system (3), - Operating, at the instigation of an electronic control unit (33), the drive system (3) in an emergency mode if the electronic control unit (33) cannot determine the speed of the electric bicycle (F) via the detection device (2), wherein the drive power in the emergency mode is limited by the electronic control unit (33).

11. A computer program product comprising instructions which, when executed by at least one processor of an electronic control unit (33) of a drive system (3) of an electric bicycle (F), cause the at least one processor to execute a method according to claim 10.

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