Assembly of an electric bicycle with a drive system for setting a gear ratio based on a target pedal frequency value

Abstract

An assembly of an electric bicycle (F) comprises a drive system (A), which has a control device (2), a transmission (3) which can be adjusted for setting a gear ratio, and an electric drive motor (4) for providing an electromotive support torque at the transmission (3), wherein the control device (2) is designed to set the gear ratio of the transmission (3) based on a target pedal frequency value (Tsw, Tsw'). The control device (2) is also designed to change the target pedal frequency value (T sw, T sw') based on at least one driving situation parameter (FS) indicating a driving situation.

Description

[0001] Assembly of an electric bicycle with a drive system for adjusting a gear ratio based on a cadence target value

[0002] Description

[0003] The invention relates to an assembly of an electric bicycle according to the preamble of claim 1.

[0004] Such an assembly comprises a drive system having a control device, a transmission adjustable for setting a gear ratio, and an electric drive motor for providing an electric motor assist torque to the transmission. The control device is configured to adjust the gear ratio of the transmission based on a cadence setpoint.

[0005] Electric bicycles with an electric motor drive system enable the provision of an externally powered assistance torque to propel the electric bicycle, allowing the motor to support the drive force applied by muscle power via pedals connected to a bottom bracket spindle of the drive system. A control panel is typically provided to allow the user to control the drive system. This control panel is typically attached to the handlebars of the electric bicycle. Such a control panel can be used, for example, to control the level of assistance provided by at least one electric motor in the drive system.

[0006] Using such a control unit, an electric bicycle user can, for example, specify a cadence target value. The control unit then regulates the cadence during use of the electric bicycle, keeping the user's cadence essentially constant to power the electric bicycle. By controlling the cadence target value, the gear ratio of the transmission can be adjusted largely automatically in a manner controlled by the control unit. The user, for example, specifies the cadence target value via the electric bicycle's control unit, and the control unit then controls the transmission to adjust the gear ratio.The control commands to be given by a user can thus be reduced in that the user essentially only has to specify the cadence target value, but switching the transmission to adjust the gear ratio is then carried out in an automatically controlled manner by the control device.

[0007] The object of the present invention is to further simplify the user operability of an electric bicycle assembly.

[0008] This object is achieved by an article having the features of claim 1.

[0009] Accordingly, the control device is designed to change the cadence setpoint based on at least one driving situation parameter indicating a driving situation.

[0010] The control device is designed to adjust the gear ratio of the transmission based on a cadence target value. During operation, the cadence at which a user pedals to propel the electric bicycle is controlled based on the cadence target value, resulting in a cadence that at least approximately corresponds to the cadence target value.

[0011] Here, it is provided that the control device is designed to automatically change the cadence target value if this is indicated by at least one riding situation parameter that indicates a riding situation. Such a riding situation parameter can be, for example, the riding speed of the electric bicycle, an acceleration of the electric bicycle, the weight of the electric bicycle, or the pedaling force of the user. One or more riding situation parameters are evaluated by the control device in order to identify, based on the evaluation, whether an adjustment of the cadence target value is necessary. Depending on one or more riding situation parameters, the cadence target value is thus automatically adjusted by the control device, whereby after adjustment, the cadence is further regulated to the now adjusted cadence target value.

[0012] In one embodiment, the assembly comprises a first sensor device for detecting a current cadence value. The first sensor device can be mounted, for example, in the area of ​​a bottom bracket and can comprise one or more Hall sensors, for example, which can be used to detect a rotational movement of the pedals of the electric bicycle operated by a user. The control device is designed to regulate the gear ratio of the transmission based on the current cadence value and the target cadence value, such that a cadence is achieved that approximately corresponds to the target cadence value.

[0013] For example, if it is detected that the current cadence value measured by the first sensor device is higher than the target cadence value, the gear ratio can be increased, resulting in greater pedaling resistance, prompting a user to pedal more slowly. Conversely, if it is detected that the current cadence value measured by the first sensor device is lower than the target cadence value, the gear ratio can be decreased, resulting in reduced pedaling resistance, prompting a user to pedal faster.

[0014] In one version, the transmission is continuously variable. The gear ratio can thus be adjusted continuously.

[0015] The riding situation parameter can be a speed value indicating the riding speed of the electric bicycle, an acceleration value indicating the acceleration of the electric bicycle, a weight force value indicating the weight of the electric bicycle, a pedal force value indicating the pedal force of a user, or a gradient value indicating a positive or negative gradient. The control device can be configured to evaluate a riding situation parameter or a combination of multiple riding situation parameters to adjust the cadence target value. One or more riding situation parameters can, for example, define a specific riding situation that can be identified by evaluating the riding situation parameters, so that the cadence target value can be set and adjusted based on an identified riding situation.

[0016] If the riding situation parameter is the riding speed and the control device specifies that the cadence target value should be set to a predetermined value (e.g., 80 rpm) in a riding situation defined by a predetermined riding speed (e.g., a riding speed within a predetermined range, e.g., between 20 km / h and 25 km / h), then upon detection of the riding situation, the cadence target value to which the cadence is regulated can be automatically set to the value associated with the riding situation, e.g., 80 rpm. Additionally or alternatively, the acceleration of the bicycle can be taken into account, for example, to identify whether the bicycle is accelerating or moving at an approximately constant speed within the riding situation.

[0017] Additionally or alternatively, the weight of the bike (with a rider sitting on it) can be taken into account. For example, the cadence target value can be set to a different value for a lower weight than for a higher weight.

[0018] In one embodiment, the assembly comprises a sensor device for detecting the speed value and / or the acceleration value. Such a sensor device can, for example, be arranged in the region of a wheel of the electric bicycle and detect the rotational speed of the wheel. In another embodiment, such a sensor device can be configured, for example, as a GPS system, by means of which the speed and acceleration of the bicycle can be detected.

[0019] In one embodiment, the assembly includes a sensor device for detecting the weight force value. This sensor device can be used to measure the weight of the bicycle with the user sitting on it. The sensor device can be configured, for example, as a force sensor located in the area of ​​the frame, for example, near a bumper.

[0020] In one embodiment, the assembly includes a sensor device for detecting the pedaling force value. Such a sensor device can be arranged, for example, in the area of ​​the pedals of the electric bicycle and measure the pedaling force exerted by a user.

[0021] Output variables of the different sensor devices can be evaluated by the control device in order to determine, based on the evaluation, whether a predetermined driving situation exists and to adjust the cadence target value based on an identified driving situation.

[0022] In one embodiment, the assembly comprises a control unit operable by a user of the electric bicycle, via which the cadence target value can be manually set by the user. Such a control unit can be arranged, for example, on the handlebars of the electric bicycle and can be manually operated by the user to set the cadence target value. Based on the manually set cadence target value, the control device can control the transmission such that the cadence is regulated to the cadence target value manually set by the user.

[0023] For example, a cadence target value manually set by the user can be maintained as long as there is no (significant) change in the riding situation. If the control unit detects that a different riding situation exists based on one or more riding situation parameters, the cadence target value can be automatically set and adjusted by the control unit.

[0024] In one embodiment, the control device is designed to execute a learning algorithm that is configured to relate a setting of the cadence target value made by a user to a riding situation characterized by at least one riding situation parameter and to store this information. As part of the learning algorithm, the control device thus learns specific riding situations, which are then stored in the control device. If, for example, the control device recognizes that a user usually sets the cadence target value to a specific value at a riding speed between 20 and 25 km / h, this can be stored in the control device so that in later automatic operation, when a corresponding riding situation is recognized, the cadence target value can be automatically set to the stored value.

[0025] Riding situations can arise that are defined by one or more riding situation parameters. If, for example, the execution of the learning algorithm determines that a user sets a certain cadence target value for a certain bicycle weight and at a certain riding speed, this can be saved accordingly so that the corresponding cadence target value is automatically set when a corresponding riding situation is recognized. If, for example, a user typically pedals at a lower cadence with a heavier bicycle (e.g. because a child is sitting in a child seat on the bicycle) than with a lower bicycle weight (when no child is sitting in the child seat on the bicycle), corresponding riding situations with assigned cadence target values ​​can be saved so that the assigned cadence target value is automatically set during later operation when a corresponding riding situation is recognized.

[0026] In one embodiment, the control device is configured to detect whether the user changes their cadence in order to adjust the cadence target value based on such a change. The control device can thus detect that the user is changing their cadence through their pedaling behavior. This can be interpreted as a request for a changed (increased or decreased) cadence target value, so that the control device automatically adjusts the cadence target value and maintains the adjusted cadence target value during subsequent operation.

[0027] Because the cadence target value can be automatically set and adjusted by the control device, possibly after execution of a learning algorithm, the number of control commands to be entered by a user can be further reduced compared to control based on a cadence target value to be set by a user.

[0028] The concept underlying the invention will be explained in more detail below with reference to the exemplary embodiments illustrated in the figures. They show:

[0029] Fig. 1 is a schematic representation of an electric bicycle with a drive system arranged thereon;

[0030] Fig. 2 is a schematic representation of the drive system for driving the electric bicycle; and

[0031] Fig. 3 is a flowchart of setting a cadence target value for controlling the cadence of the electric bicycle.

[0032] Fig. 1 shows a perspective view of an electric bicycle F, in particular an e-bike or pedelec, which comprises a drive system A with at least one electric motor for driving the electric bicycle F at an intersection point of a down tube R1 and a seat tube R2 of a bicycle frame of the electric bicycle F. Via the at least one electric motor of the drive system A, an assistance torque can be generated by external power, which assists a user of the electric bicycle F in driving the electric bicycle F. The assistance torque and a corresponding assistance power of the drive system A can be adjusted in height at different assistance levels. For example, for selecting such an assistance level and thus for the electronic control of the drive system A, a control unit 1 is provided, which is mounted on a handlebar L of the electric bicycle F.

[0033] This control unit 1 is provided in the electric bicycle F shown in Fig. 1 in the area of ​​a left grip area of ​​the handlebar L. The control unit 1 here has, as an example, an operating area 10 for one-handed operation with a left hand. The operating area 10 is accordingly designed such that a user of the electric bicycle F can operate the control elements of the control unit 1 provided in the operating area 10 with the thumb of their left hand without having to release their left hand from the handlebar L.

[0034] For transmitting control and input signals, the control unit 1 is connected to the drive system A, for example, via at least one cable. In the illustrated embodiment, the control unit 1 is further equipped with an interface for wireless signal transmission, for example in the form of a Bluetooth interface, and is coupled to one or more display units D1, D2. Typically, only one of the display units D1, D2 is provided on the electric bicycle.

[0035] The respective display unit D1 or D2 has a display via which a user of the electric bicycle F can be shown information about the operating status of the drive system A, such as a currently selected support level or the range of a battery for the drive system A. In addition, speed information and / or information about a distance traveled can be made available via a display of the display unit D1 or D2. Due to the spatial separation between the control unit 1 and a display unit D1 and D2, the display unit D1 or D2 can be attached, for example, to a top tube R3 or to a position on the handlebar L that is different from the position of the control unit 1. The information provided by the respective display can thus be better and faster understood by a user of the electric bicycle F.At the same time, the control unit 1 with its operating area 10 can still be arranged in the immediate vicinity of a grip area of ​​the handlebar L for one-handed operation.

[0036] Fig. 2 shows a schematic diagram of the drive system A of the electric bicycle F, which has a control device 2, a transmission 3, and a drive motor 4. The drive motor 4 is operatively connected to the transmission 3, which in turn is operatively connected to the rear wheel H of the electric bicycle F, so that an electromotive assistance torque generated by the drive motor 4 is provided to the transmission 3 and transmitted via the transmission 3 to the rear wheel H to assist the pedaling force applied by the user.

[0037] In the illustrated embodiment, the drive system A is particularly designed to provide such a control that the cadence of the bicycle F is regulated based on a cadence target value, i.e., a user drives the bicycle F during operation at a cadence that at least approximately corresponds to the cadence target value. The transmission 3 is switchable, preferably continuously switchable, to set a gear ratio, so that the gear ratio of the transmission 3 is variable under the control of the control device 2 and can thus be adjusted to influence the cadence.

[0038] Accordingly, the electric bicycle F is to be controlled to a cadence target value, so that during operation, a cadence is achieved with which a user drives the bicycle F that at least approximately corresponds to the cadence target value. As shown schematically in Fig. 1, the electric bicycle F has a sensor device 5 for this purpose, which is designed to detect a current value of the cadence when the electric bicycle F is moving in order to control the gear ratio of the transmission 3 based on the current value of the cadence and the set cadence target value.

[0039] For example, if the cadence is decreasing, the gear ratio can be reduced based on the deviation of the current cadence from the target cadence, prompting the user to pedal faster and thus bringing the cadence closer to the target cadence. Conversely, if the cadence is increasing, the gear ratio can be increased based on the deviation of the current cadence from the target cadence, increasing the pedaling resistance and thus prompting the user to pedal more slowly, thus bringing the cadence closer to the target cadence.

[0040] Typically, such control can be achieved based on a cadence target value entered by a user, for example, via the control unit 1. The cadence target value can thus be manually specified by the user, whereby during operation, for example, during steady travel over a longer distance, the gear ratio of the transmission 3 is controlled based on the set cadence target value, thus maintaining the cadence at least approximately constant during the ride.

[0041] Because control is based on the specified cadence target value, the frequency of control commands required by a user can be reduced. During operation, a user may only need to specify the cadence target value, with the gear ratio being set automatically by the control device 2, regardless of any further user action.

[0042] To further reduce the frequency of control commands to be entered by a user, the present drive system A provides that the control device 2 is designed to change a currently set cadence target value depending on specific riding situations and thus adapt it automatically, independently of user intervention. If, based on the evaluation of specific riding situation parameters, it is detected that riding behavior is changing and a new riding situation is arising accordingly, the cadence target value can be adjusted based on the detection of the riding situation so that the cadence is now regulated to a value that is assigned to the new riding situation.

[0043] Driving situation parameters can be, for example, the driving speed of the electric bicycle F, the acceleration of the electric bicycle F, the weight of the electric bicycle F, a pedal force currently applied by a user or driving position information, in particular a gradient on the route of the electric bicycle F.

[0044] To record such driving situation parameters, different sensor devices 6, 7, 8 can be provided on the bicycle F, as shown schematically in Fig. 1.

[0045] For example, the traveling speed of the bicycle F can be measured via a sensor 6 on the front wheel of the bicycle F. Alternatively, a traveling speed of the bicycle F can be measured, for example, via a GPS unit, which is, for example, part of the display unit D2 or the display unit D1.

[0046] Another sensor device 7 can be designed, for example, to measure the weight of the bicycle F, i.e., the weight of the bicycle F including the user. Such a sensor device 7 can, for example, be arranged on a frame section of the bicycle F and be designed as a force sensor in order, for example, to infer a force acting on the frame section based on a deformation of the frame section. Such a sensor device 7 can, for example, be arranged on a bumper of the bicycle F in order to infer a weight on the bicycle F based on a load on the bumper, indicated by an adjustment path on the bumper.

[0047] A further sensor device 8 can, for example, be arranged in the area of ​​the pedals of the bicycle F and be designed as a force sensor in order to measure a pedal force applied by a user.

[0048] Further sensor devices may be provided, for example an inclination sensor to measure an inclination of the bicycle F.

[0049] During operation, it may be provided that a riding situation is identified based on one or more riding situation parameters, for example, the riding speed and / or the acceleration and / or a weight force of the bicycle F. If, for example, the riding speed is within a predetermined range, the acceleration is below a predefined limit, and the bicycle weight (including the user) is also within a predetermined range, a corresponding riding situation can be identified and the cadence target value can be set to a value associated with this riding situation.

[0050] Another driving situation may correspond to an acceleration process (for example, acceleration from a standstill, for example when changing a traffic light), in which case the cadence target value can be increased, for example, based on a predetermined target value curve.

[0051] If the riding situation changes, for example because the speed changes, or the bike weight is in a different range, a different riding situation can be identified and the cadence target value is set accordingly to a value that is assigned to this different riding situation.

[0052] The cadence target value can thus be automatically specified in a variable manner by the control device 2 and an evaluation of riding situation parameters by the control device 2, without requiring control commands from a user. Riding situations can be predefined in the control device 2 through programming. However, it is also conceivable and possible for the control device 2 to be designed to execute a learning algorithm and thus automatically learn riding situations based on user behavior.

[0053] Referring now to Fig. 3, in a control algorithm implemented in the control device 2, for example, a set cadence target value T Sw can be assumed (step S1). Based on the set cadence target value Tsw, the gear ratio of transmission 3 is controlled so that an at least approximately constant cadence at which the user moves the bicycle F results when riding.

[0054] The control algorithm checks whether, for example, a user has entered an operating command via the control unit 1 to change the cadence target value Tsw (step S2). If such a manual input by a user is present, the cadence target value Tsw is adjusted and set to a new value Tsw' based on the user input (step S6). Subsequently, the gear ratio of the transmission 3 is controlled based on this new, user-specified cadence target value Tsw'.

[0055] If such a manual adjustment of the cadence target value Tsw is detected by a user, this is evaluated by a learning algorithm LA (step S3). Within the framework of the learning algorithm LA, in particular, the modification of the cadence target value Tsw by the user and riding situation parameters FS, such as those detected by sensor devices 6, 7, 8 at the time of the change in the cadence target value T S w are measured, evaluated and assigned to each other in order to define a riding situation based on the assignment of the changed cadence target value Tsw' now set by the user and the one or more riding situation parameters FS.

[0056] Such an evaluation within the framework of the learning algorithm LA can be carried out during operation of the electric bicycle F whenever a currently set cadence target value Tsw is changed by a user and set to a new cadence target value Tsw', so that user behavior for setting the cadence target value Tsw, Tsw' is continuously analyzed during operation. If, during operation of the bicycle F, it is determined in the query according to step S2 that no operating command to change the cadence target value Tsw is present, the control algorithm checks whether, based on the currently recorded riding situation parameters FS, a change in the riding situation occurs, for example a (significant) change in speed, acceleration, pedaling force, gradient, or the like.If a different driving situation previously learned by the learning algorithm LA is identified, a control variable AB can be generated in step S4 which corresponds to the cadence target value T. S w is added (step S5) and based on which the cadence target value T S w is thus changed. In step S6, the cadence target value Tsw is again adjusted and thus the cadence target value Tsw is readjusted to a new value Tsw', based on which the gear ratio of transmission 3 is now controlled.

[0057] Within the framework of the LA learning algorithm, any and any number of riding situations can be learned and stored in the control unit 2. In particular, the LA learning algorithm can evaluate any manual operating procedure in which the cadence target value Tsw is manually changed by a user, for example, via an operating command on the control unit 1.

[0058] Because the frequency of the required operating commands to be entered by a user is thus further reduced and control of the cadence target value Tsw can be carried out at least partially automatically, this results in an increase in comfort for a user.

[0059] The idea underlying the invention is not limited to the embodiments described above, but can also be implemented in other ways.

[0060] Other parameters than those described here can also be evaluated as driving situation parameters, for example, environmental conditions such as ambient temperature, wind speed, or the like.

[0061] 1 control unit

[0062] 10 Operating area

[0063] 2 Control device

[0064] 3 gearboxes

[0065] 4 drive motor

[0066] 5-8 Sensor setup

[0067] A drive system

[0068] AB Control variable (deviation)

[0069] D1, D2 display unit

[0070] F Bicycle

[0071] FS driving situation parameters

[0072] H rear wheel

[0073] L handlebar

[0074] LA learning algorithm

[0075] R1 down tube

[0076] R2 seat tube

[0077] R3 top tube

[0078] S1-S6 steps

[0079] Tsw, Tsw' cadence setpoint

Claims

Claims 1. Assembly of an electric bicycle (F), with a drive system (A) which has a control device (2), a gear (3) which is adjustable for setting a gear ratio and an electric drive motor (4) for providing an electromotive assistance torque to the gear (3), wherein the control device (2) is designed to adjust the gear ratio of the gear (3) based on a cadence setpoint (Tsw, T S w'), characterized in that the control device (2) is designed to change the cadence target value (Tsw, Tsw') on the basis of at least one driving situation parameter (FS) indicating a driving situation.

2. Assembly according to claim 1, characterized by a first sensor device (5) for detecting a current cadence value, wherein the control device (2) is designed to regulate the gear ratio of the transmission (3) based on the current cadence value and the cadence target value (Tsw, Tsw').

3. Assembly according to claim 1 or 2, characterized in that the transmission (3) is continuously adjustable for setting a gear ratio.

4. Assembly according to one of claims 1 to 3, characterized in that the at least one driving situation parameter (FS) is a speed value indicating a driving speed of the electric bicycle (F), an acceleration value indicating an acceleration of the electric bicycle (F), a weight force value indicating the weight of the electric bicycle (F), a pedal force value indicating a pedal force of a user or a gradient value indicating a positive or negative gradient.

5. Assembly according to claim 4, characterized by a second sensor device (6) for detecting the speed value and / or the acceleration value.

6. Assembly according to claim 4 or 5, characterized by a third sensor device (7) for detecting the weight force value.

7. Assembly according to one of claims 4 to 6, characterized by a fourth sensor device (8) for detecting the pedal force value.

8. Assembly according to one of the preceding claims, characterized by an operating part (1) operable by a user of the electric bicycle (F), via which the cadence target value (Tsw, Tsw') can be set by a user.

9. Assembly according to claim 8, characterized in that the control device (2) is designed to execute a learning algorithm (LA) which is set up to learn a setting of the cadence setpoint (Tsw, T Sw') with a driving situation characterized by at least one driving situation parameter and to store it.

10. Assembly according to claim 9, characterized in that the control device (2) is designed to identify a driving situation stored during execution of the learning algorithm (LA) on the basis of at least one driving situation parameter and to adapt the cadence setpoint value (Tsw, Tsw') on the basis of the identified driving situation.

11. Electric bicycle (F) with an assembly according to one of the preceding claims.

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