Processor and method, in particular a computer-implemented method, for controlling a bottom bracket gearbox of a bicycle with an auxiliary motor and bottom bracket shifting system with a processor of this type

Abstract

The invention relates to a processor (30) and a computer-implemented method for controlling a bottom bracket gearbox (18, 20) of a bicycle (1) with an auxiliary motor (2). The bottom bracket gearbox (18, 20) comprises an input shaft (64) and an actuator (50), wherein the actuator (50) functions to drive the gear change of the bottom bracket gearbox (18, 20). The objective is to allow for a gear change even under load. This is achieved in that the processor (30) is designed to receive a gear change signal (92) that is representative of a gear change triggered by the user of the bicycle (1). The processor (30) is also designed to receive a drive parameter signal (96) that is representative of a torque (68) being applied at the input shaft. Finally, the processor (30) is designed such that, after receipt of the gear change signal (92), according to the drive parameter signal (96), it generates the shift signal (106) and outputs same. The computer-implemented method is designed correspondingly. Via the output of the shift signal (106), according to the drive parameter signal (96), it is possible to perform the shifting process according to the torque at the input shaft (64), which determines the friction in the bottom bracket gearbox (18, 20) and thereby the force required for shifting.

Description

[0001] Processor and method, in particular computer-implemented method, for controlling a bottom bracket gearshift of a bicycle with auxiliary motor and bottom bracket gearshift with such a processor

[0002] The invention relates to a processor and a method, in particular a computer-implemented method for controlling a bottom bracket transmission of a bicycle with an auxiliary motor, said transmission being provided with an input shaft and an actuator for changing gears in response to a shift signal. The invention further relates to a bottom bracket transmission for a bicycle with an auxiliary motor, comprising such a processor.

[0003] On bicycles with an auxiliary motor, so-called pedelecs, gear shifts ensure that a user can pedal at a roughly constant cadence at various speeds. The most common type currently is derailleur gears, which feature multiple pinions on the rear wheel hub and one or more chainrings on the bottom bracket spindle. By shifting the chain onto the various chainrings and pinions, the different gears or gear steps can be engaged. While derailleur gears are lightweight, they are also very maintenance-intensive and wear out quickly. The rapid wear of derailleur gears is primarily due to their unprotected exposure to the environment.

[0004] These disadvantages are avoided by using manual transmissions, such as those used in hub gears and bottom bracket gears. Hub gears and bottom bracket gears have a housing in which the actual hub or bottom bracket gear is encapsulated and protected from environmental influences. They are therefore significantly less susceptible to wear. Unlike derailleur gears, a hub gear or bottom bracket gear can be used with a toothed belt instead of a chain. A toothed belt is largely maintenance-free and, while running more smoothly, has a longer service life than a chain.

[0005] Hub gears result in unfavorable weight distribution, with the majority of the bike's weight being on the rear wheel. Bikes with hub gears are unwieldy to carry and have poor cornering characteristics. Bottom bracket gears, on the other hand, result in a very favorable weight distribution.

[0006] One problem with bottom bracket gears, however, is that they are difficult or impossible to shift under load. Just before shifting between different gears on the bottom bracket gear system, the user must release their pedal force to shift. If this is not done, the desired gear may not be engaged. This disrupts the flow of the bike and impairs the riding experience. Shifting may become impossible, especially when riding uphill.

[0007] In view of this, the invention is based on the object of providing bottom bracket gearshifts that can be shifted better under load.

[0008] This object is achieved for the processor mentioned at the outset in that the processor is designed to receive a gear change signal that is representative of a gear change initiated by a user of the bicycle, and a drive parameter signal that is representative of at least a torque applied to the input shaft, wherein the processor is further designed to output the switching signal as a function of the drive parameter signal after receiving the gear change signal.

[0009] The object is further achieved by a method for switching between the gears of a multi-speed bottom bracket gearshift, actuated by an actuator, of a bicycle with an auxiliary motor, wherein, in response to a gear change signal generated by a user, the actuator is automatically actuated, in particular only, when a torque applied to an input shaft of the bottom bracket gearshift is less than a predetermined limit value.

[0010] Accordingly, for example, a gear change signal is first received, which the user generates, for example, via a gear lever or a gear button on the bicycle handlebar. By generating the gear change signal, the user gives the command to change the gear of the bottom bracket shift transmission. The actual gear change is carried out by the output of the shift signal to the actuator or the reception of the shift signal by the actuator. However, this only occurs after the gear change signal has been received and depends on the drive parameter signal, i.e., depending on the torque applied to the input shaft, which is represented by the drive parameter signal.

[0011] The torque applied to the input shaft determines the friction generated in the bottom bracket transmission. If this torque is high, a high frictional force is generated, and the parts that move relative to each other, such as the gears or clutch pawls, can only be moved with considerable effort.

[0012] However, the actuator, for example a magnetic or electric motor drive with, if necessary, a gearbox, that drives the shifting movement, can only exert a limited shifting force. By generating and outputting the shift signal depending on the drive parameter signal, the shifting process can now take place when the torque applied to the input shaft is large enough for the actuator to overcome the friction present in the gearbox.

[0013] The term "receive" encompasses both actively retrieving the signal, for example, by querying a memory location, and passively receiving it, for example, through an input interface of the processor or by writing from outside to a memory location of the processor. The term "output" generally encompasses making a signal available for external access, for example, by providing a memory location for reading from outside the processor or by applying a signal to an output interface.

[0014] The invention can be improved by the following optional, individually advantageous, and freely combinable further features. The features specified below can be used indiscriminately for both a device and a method, regardless of whether they are described in connection with a device or a method.

[0015] For example, the shift signal can be an incremental signal or an absolute signal. If the shift signal is an incremental signal, the shift signal represents the upshift or downshift by one gear or a predetermined number of gears, based on the currently engaged gear. The shift signal can be a shift pulse or a sequence of shift pulses, with each shift pulse or its duration representing or triggering an upshift or downshift by a predetermined number of gears in conjunction with the actuator.

[0016] If the shift signal is an absolute signal, it can represent a specific gear that the actuator must engage. In this case, the shift signal indicates which gear the actuator should engage, regardless of the currently engaged gear. This gear is referred to below as the target gear. The currently engaged gear is referred to as the actual gear.

[0017] The drive parameter signal does not necessarily have to directly represent the torque applied to the input shaft, as would be provided, for example, by a power sensor or a torque sensor arranged on the input shaft and directly detecting the torque applied there. The drive parameter signal can also be a combination of several individual signals which together allow the calculation or estimation of the torque applied to the input shaft. In this case, the processor is preferably designed to determine the torque applied to the input shaft from the individual signals of the drive parameter signal. For example, the drive parameter signal comprises at least one individual signal which is representative of a characteristic value from the group of angular position, torque, speed, power and / or acceleration.The individual signal can represent the characteristic value of a location from the group comprising a motor shaft of the auxiliary motor, the bottom bracket shaft, at least one pedal crank, the input shaft of the bottom bracket transmission, and an output shaft of the bottom bracket transmission, for example, because the sensor generating the respective individual signal is mounted or measures at this location. The term "drive parameter signal" refers to any individual signal contained in the drive parameter signal and required to determine the torque applied to the input shaft.

[0018] The drive parameter signal can be representative of the torque currently applied to the input shaft, or a moving time average of the torque at the input shaft over a time window ending at the current time. Such a time window can be, for example, one second, three seconds, or ten seconds.

[0019] The processor can further be configured to receive, store, and / or process a temporal profile of the drive parameter signal. For example, the processor can be configured to determine a mean value representative of the torque applied to the input shaft from a temporal profile of the drive parameter signal. This allows short-term fluctuations that are irrelevant to the gearshift process to be filtered out.

[0020] As already mentioned, the drive parameter signal does not necessarily have to be determined directly at the input shaft of the bottom bracket transmission. For example, the drive parameter signal can also be determined at the bottom bracket shaft, for example by one or more sensors arranged there. The torque determined or measured there can represent a first approximation of the torque applied to the input shaft if friction losses on the way to the input shaft are neglected. The processor can be designed to take these losses into account, for example by calculating a predetermined correction of the drive parameter signal, for example by applying a predetermined correction factor, a predetermined correction function, or a lookup table with predetermined correction factors or correction functions to the drive parameter signal.This correction, in the form of computational loss compensation, can take friction losses into account and be dependent on speed, torque, and / or power, for example. A correction is preferably only necessary if the drive parameter signal is not recorded directly at the input shaft.

[0021] The processor is preferably configured to output the switching signal, in particular, only when the drive parameter signal or, equivalently, the torque represented by the drive parameter signal is less than a predetermined value. The predetermined value represents a torque on the input shaft at which the actuator can still shift safely. If the torque represented by the drive parameter signal or the drive parameter signal itself is greater than the predetermined value, no switching signal is output in this configuration. In this case, the actuator would not be able to perform the shifting process safely. The greatest torque applied to the input shaft at which the actuator can still shift safely is referred to below as the powershift maximum.

[0022] In some bottom bracket transmissions, the powershift maximum can have a different value for downshifting than for upshifting. The processor can therefore be designed to receive a shift direction signal that is representative of a shift direction towards a higher or lower gear, i.e. representative of upshifting or downshifting. The processor is preferably designed to output the shift signal depending on the shift direction signal and drive parameter signal. This design is advantageous because, in a bottom bracket transmission, the powershift maximum can be dependent on the shift direction. For example, a lower force may be required for changing gears for downshifting than for upshifting. By generating orBy outputting the switching signal (also) as a function of the switching direction signal, the switching direction dependence of the load switching maximum can be taken into account when performing the switching process. In this embodiment, the processor can be configured to determine the load switching maximum as a function of the switching direction or to assign a load switching maximum to a switching direction.

[0023] In one embodiment, the shift direction signal can be part of the gear change signal. If the gear change signal is, for example, an incremental signal, then the shift direction signal is contained in the gear change signal. If the gear change signal is an absolute signal, then it is advantageous if the processor is configured to calculate the shift direction signal from the shift signal. This can be done, for example, by calculating the difference between the gear represented in the shift signal, the target gear, and the currently engaged actual gear from a shift signal generated as an absolute signal. To determine the actual gear, the processor can be configured to receive a gear signal representative of the currently engaged gear.

[0024] The actuator is preferably operated when a predetermined crank position is reached by the pedal cranks of the bicycle. For this purpose, it can be provided that the processor is designed to receive a crank position signal that is representative of the angular position of one or both pedal cranks of the bicycle. In other words, the crank position signal is representative of the crank position of the bicycle. The processor is in particular designed to output the switching signal (also) depending on the crank position signal or the angular position of the pedal cranks. The crank position signal can be an incremental signal that merely represents a change in the angular position of the pedal cranks. Alternatively, the crank position signal can be an absolute signal that represents an angular value of the angular position of the pedal cranks between, for example, 0° and 360°. The crank position signal can be included in the drive parameter signal or be a separate signal.

[0025] The output of the switching signal depending on the crank position signal makes it possible to carry out a switching process when the user is least aware of it due to the pedaling movement and / or when they are exerting the least force on the cranks. For example, the pedal force generated by the user is at its lowest when the pedal cranks are at their dead centers, i.e. aligned vertically or around the vertical. The vertical alignment of the cranks is referred to below as the dead center position. In one development, the processor can be designed to output the switching signal when the angular position of the pedal crank represented by the crank position signal corresponds to a predetermined limit angle before the vertical or perpendicular pedal position. Such a limit angle can, for example, be approximately 25° to 10° before the dead center position.

[0026] In a further embodiment, the processor can be configured to calculate, depending on the drive parameter signal and the crank position signal, the angular position at which the pedaling force or torque generated by the user is minimal, and to determine this value as the dead center position. This can be achieved, for example, by the processor being configured to receive a time profile of the crank position signal and a time profile of the drive parameter signal, and to assign the drive parameter to at least some of the angular positions represented in the crank position signal and to average the individual angular positions over several pedal revolutions. A curve fit can be used to calculate an estimate of the future course.The processor can further be configured to receive a power signal representative of the user's pedaling power and / or the assist power of the auxiliary motor, particularly at the input shaft of the bottom bracket transmission. The processor is preferably configured to determine the three power levels: pedaling power, assist power, and total power, depending on the power signal. Furthermore, the processor can be configured to determine the portion of the torque applied to the input shaft generated by the user and / or the portion generated by the auxiliary motor, depending on the drive parameter signal and the power signal.

[0027] Receiving the power signal and determining the pedaling power is advantageous in that it enables the processor to control the auxiliary motor more precisely. In particular, the power signal enables the processor to control the auxiliary motor or its assistance power depending on the gear shift signal. This will be discussed in more detail below.

[0028] According to a further advantageous embodiment, the processor can be configured to generate and output a motor control signal representative of the assistance power to be delivered by the auxiliary motor, wherein the processor is configured to generate the motor control signal as a function of the gear change signal and the drive parameter signal. With this embodiment, it is possible to adjust the assistance power generated by the auxiliary motor, which increases the pedaling power generated by the user, such that a gear change is possible.

[0029] It is further preferred if the assistance power of the auxiliary motor is reduced, especially temporarily, during operation of the actuator. In particular, the assistance power can be reduced during operation of the actuator to a value at which the torque at the input shaft of the bottom bracket transmission is less than the maximum power shift. For example, the processor can be configured to determine the user's pedaling power depending on the drive parameter signal and / or the power signal and to generate the motor control signal depending on the determined pedaling power.

[0030] The processor can, in particular, be configured to adjust or control the assistance power of the auxiliary motor depending on the drive parameter signal and the gear change signal. Additionally, the processor can be configured to adjust or control the assistance power depending on the power signal or the pedaling power. It is advantageous if the processor is configured to adjust the assistance torque of the auxiliary motor such that the torque at the input shaft is less than the powershift maximum when the pedaling power generates a torque at the input shaft that is less than the powershift maximum.If the torque applied to the input shaft of the bottom bracket transmission is greater than the powershift maximum because the assist power of the auxiliary motor is added to the pedaling power, then in this design the assist power is reduced so that the sum of the torque resulting from the pedaling power and the torque resulting from the assist power at the input shaft of the bottom bracket transmission is less than the powershift maximum.

[0031] During operation, it may happen that the user generates multiple shift commands and thus gear change signals in a shorter sequence than the bottom bracket transmission can shift. This can be particularly the case if the powershift maximum is only undershot at certain crank positions and / or shifting only occurs at certain crank positions, because in this case the conditions necessary for shifting are only met at certain times. Furthermore, it may happen that individual shift commands in such a sequence cancel each other out, for example, because the user triggers a gear increase twice and a gear decrease once in quick succession. Consequently, in an advantageous embodiment, the processor should be able to store the gear change signals that have not yet been processed.Furthermore, it is advantageous if the processor is designed to summarize the gear change signals which follow one another in time and which have not yet been processed, and to output the shift signal depending on the summary. If, for example, two commands to shift up by one gear each and one command to shift down by one gear each are given in quick succession, the summary results in a shift signal which only shifts up one gear. If, according to another example, three commands to shift down by one gear each and one command to shift up by one gear are given, the processor summarizes the gear change signals based on them so that the shift signal represents the downshift by two gears. In another case, a single upshift and an immediate downshift, or vice versa, may not trigger a gear change at all.

[0032] For a precise shifting process, it is advantageous if the processor is configured to receive a gear signal representative of the gear currently engaged on the bottom bracket transmission. The processor can be configured to generate the shift signal depending on the gear signal. In this configuration, it is possible for the processor not to output a shift signal if, with the smallest gear engaged, the gear change signal and / or the shift direction signal represents a downshift, or if, with the largest gear engaged, the gear change signal and / or the shift direction signal represents an upshift.

[0033] The gear signal does not necessarily have to be supplied to the processor from outside. It can also be determined within the processor itself by continuously adding the successive gear-change signals or starting from a reference gear if they are incremental signals, or by adding the last gear-change signal in each case, in the case of an absolute signal, to the gear signal. However, this solution is disadvantageous compared to determining the gear signal directly at the transmission because it does not allow for gear position control.

[0034] In a further embodiment, the gear signal can be determined from the drive parameter signal if, for example, the drive parameter signal or the gear signal contains two individual signals that are representative of the speed of the input shaft and the speed of the output shaft of the bottom bracket shift transmission. In this way, the actual gear can be determined using the ratio of these two speeds and, for example, a lookup table stored in the processor that represents the gear ratios of the gear steps of the bottom bracket shift transmission. The processor can therefore be configured to determine the currently engaged gear based on the drive parameter signal. Furthermore, the processor can be configured to determine a target gear, i.e. the gear to be engaged, depending on at least one received gear change signal, and an actual gear, i.e. the currently engaged gear, depending on the gear signal.The processor is preferably designed to output the shift signal until an actual gear corresponding to the target gear is represented in the gear signal.

[0035] The processor can also be configured to determine the shift direction signal from the gear change signal and the gear signal. This is particularly advantageous when the gear change signal is an absolute signal, i.e., represents the target gear and not, like an incremental signal, a number of gears to be shifted.

[0036] In one embodiment, the gear signal can be composed of individual signals, with each individual signal of the gear signal representing the shifting state of a clutch of the bottom bracket transmission. The processor can be configured to assign the shifting states represented by the individual signals to an actual gear.

[0037] The processor can further be configured to receive a partial transmission speed signal representative of a speed between two partial transmissions of the bottom bracket shift transmission. The partial transmission speed signal can be part of the drive parameter signal. The processor can be configured to determine the actual gear depending on the drive parameter signal and the transmission speed signal. According to a further configuration, based on the speed between two partial transmissions, the processor can determine the gear ratio and, from this, the currently engaged gear. The partial transmission speed signal can also be a rotation angle signal. In this case, the processor should be configured to determine the speed by time-deriving the rotation angle signal.

[0038] The shifting force required for a gear change can depend not only on the shift direction, but also on the currently engaged gear, i.e., the actual gear. To account for this dependency, the processor can be configured to calculate the powershift maximum based on the gear signal or to calculate the shift signal based on the gear signal. For example, the processor can be configured to determine the powershift maximum using a lookup table based on the gear signal. Different powershift maximums can be assigned to different gears in the lookup table.

[0039] It may happen that the powershift maximum on the input shaft of the manual transmission is exceeded during the gearshift process, even though it had not yet been exceeded when the gearshift process was initiated or the gearshift signal was output. In this case, there is a risk that the actuator or shifting element will remain in a position between two gears. To avoid this, the processor can be designed to compare the actual gear with the target gear after a gearshift process has been completed and, if the actual gear does not correspond to the target gear, to set the target gear equal to the actual gear and to output a gearshift command that represents a gearshift to the target gear. This moves the actuator or shifting element back to the position that corresponds to the last fully engaged gear, as represented in the gear signal.

[0040] A gear shifting system for a bicycle with an auxiliary motor, which has a processor in one of the above embodiments, is preferably provided with the bottom bracket gear shifting system having the input shaft, the actuator and with a sensor device which is designed to generate the drive parameter signal.

[0041] The auxiliary motor can be a hub motor. If the bicycle uses a hub motor, there is sufficient space around the bottom bracket for almost any type of bottom bracket gear.

[0042] However, the auxiliary motor can also be located in the area of ​​the bottom bracket. With such a configuration, both the auxiliary motor and the bottom bracket transmission are located in the area of ​​the bottom bracket, leaving less space for the bottom bracket transmission. In particular, the auxiliary motor and bottom bracket transmission can be structurally combined. An example of a bottom bracket transmission that also allows the auxiliary motor to be located in the bottom bracket area is shown and described in German patent application DE 102021101415.8.

[0043] The sensor arrangement can comprise one or more drive parameter sensors, wherein in the case of several drive parameter sensors each sensor can generate an individual signal of the drive parameter signal.

[0044] For example, a drive parameter sensor of the sensor arrangement can be located directly on the input shaft of the bottom bracket transmission. The drive parameter sensor on the input shaft can be a torque sensor, so that the drive parameter signal it generates directly represents the torque applied to the input shaft. However, in a further embodiment, the drive parameter sensor on the input shaft can also comprise a speed sensor and / or angle sensor and / or be a power sensor.

[0045] Such a drive parameter sensor or another drive parameter sensor can alternatively or additionally be located at a location other than the input shaft of the bottom bracket transmission, for example, on the bottom bracket spindle and / or the rear wheel hub. As described above, the drive parameter signal generated by such a positioned drive parameter sensor can be used, with or without correction, as a signal representing the torque at the input shaft of the bottom bracket transmission, since it sufficiently accurately reflects the torque applied to the input shaft.

[0046] In a further advantageous embodiment, the sensor arrangement can comprise a crank position sensor configured to output the crank position signal. The crank position sensor can be arranged on the bottom bracket spindle or a crank.

[0047] Furthermore, the sensor arrangement can comprise a gear sensor designed to generate the gear signal. The gear sensor can be integrated into the bottom bracket transmission or arranged within a housing of the bottom bracket transmission. The gear sensor can comprise one or more speed sensors and / or rotation angle sensors, which are arranged, for example, on the input shaft of the bottom bracket transmission, the output shaft of the bottom bracket transmission, and / or an output shaft or transmission shaft (if present) of the actuator. The gear sensors on the input shaft and / or the output shaft of the transmission can simultaneously serve as drive parameter sensors. Furthermore, the gear sensor can comprise a position sensor, for example a rotation angle sensor or a position sensor, on a shifting element of the transmission driven by the actuator, for example a shift drum.The gear sensor may further comprise one or more rotation angle sensors and / or rotation position sensors between sub-gears of the bottom bracket transmission. Finally, the gear sensor may comprise one or more position sensors designed to detect the position of clutch elements of the bottom bracket transmission and output them as a gear signal, as already explained above.

[0048] The sensor arrangement may further comprise a power sensor configured to determine at least two power values ​​from the group consisting of pedaling power, assist power, and total power and output them as a power signal. The power sensor may comprise one or more individual sensors that, for example, detect the power at an output of the auxiliary motor, at the bottom bracket shaft, at the output shaft of the transmission, and / or at the input shaft of the transmission, and / or the motor current, the motor voltage, and / or the electrical power currently being consumed by the auxiliary motor.

[0049] According to a further embodiment, the gearshift system can comprise a manually operable gearshift switch, which is designed to generate the gearshift signal when actuated. The gearshift switch can be integrated into the handlebars, frame, brake lever of the bicycle, and / or another component ergonomically accessible to the user.

[0050] The transmission shifting system may further comprise the auxiliary motor configured to generate an assist power in response to the motor control signal.

[0051] The actuator of the transmission shift system is preferably an electric motor or a magnetic drive. The actuator is preferably an electric motor with a reduction gear to achieve the highest possible shifting force or torque.

[0052] The actuator is designed to drive a gear shift depending on the shift signal. The actuator moves one or more shifting elements, the movement of which engages and disengages clutches of the bottom bracket transmission in a predetermined sequence, thus engaging and disengaging the gear stages assigned to the clutches. The movement driven by the actuator can be a rotary or translatory movement, or a combination of a translatory and rotary movement. For example, the shifting element can be a shift drum or shift shaft, the angular position of which determines the shift state of the clutches and thus the currently engaged gear. The clutches can have engageable and disengageable toothed clutches or pawls. The bottom bracket transmission is preferably designed to be able to be shifted even when stationary.

[0053] The gear change signal, the drive parameter signal, the shift signal, the power signal, the shift direction signal, the crank position signal, and / or the gear signal are preferably electrical signals. These can be analog or digital electrical signals. The individual signals can be transmitted independently of one another, either wired or wirelessly.

[0054] The processor is preferably an electronic component, such as an ASIC or a suitably programmed control unit for the auxiliary motor. The processor can also be a smartphone running an application with the functionality described above.

[0055] The processor can have an input interface designed to receive the above-mentioned signals. The input interface can be configured for wired and / or wireless reception of these signals. For example, the input interface can have a Bluetooth, ANT, and / or WLAN receiver. Furthermore, the processor can have a wired and / or wireless output interface to which the switching signal and / or the motor control signal can be retrieved, sent, and / or applied from outside the processor. The output interface can, in particular, have a Bluetooth, ANT, and / or WLAN transmitter. Of course, the Bluetooth, ANT, and / or WLAN transmitter and Bluetooth, ANT, and / or WLAN receiver can be integrated into one electronic component.

[0056] The invention is explained below using an exemplary embodiment with reference to the accompanying drawings. In accordance with the above description, features whose technical effect is not important for a specific application may be omitted from the described exemplary embodiment. Conversely, features described above that are not present in the described exemplary embodiment may be added if the technical effect associated with these features is important for a specific application.

[0057] In the following description, features that correspond to one another in terms of function and / or structure are given the same reference numerals.

[0058] Shown are: Fig. 1 a schematic representation of a bicycle with auxiliary motor, processor and gear shift system;

[0059] Fig. 2 is a schematic representation of the structure of a transmission shift system;

[0060] Fig. 3 is a schematic representation of the course of a pedaling moment generated by a user;

[0061] Fig. 4 is a schematic representation of a method for processing a gear change signal;

[0062] Fig. 5 is a schematic representation of a method for determining a torque at an input shaft of a bottom bracket transmission;

[0063] Fig. 6 is a schematic representation of a method for determining the gear currently engaged;

[0064] Fig. 7 is a schematic representation of a method for determining a crank position; and

[0065] Fig. 8 is a schematic representation of a method for switching under load.

[0066] Fig. 1 shows, by way of example, a bicycle 1 with an auxiliary motor 2, particularly in the form of an electric motor. The auxiliary motor 2 is arranged here in the area of ​​a bottom bracket 4. The auxiliary motor 2 serves to assist a pedaling movement performed by a user (not shown), for which the bicycle is equipped with pedals 6 arranged at the end of pedal cranks 8.

[0067] The bicycle 1 further comprises an accumulator 10, which serves as an energy source for the auxiliary motor 2.

[0068] The auxiliary motor 2 adds support power to the pedaling power generated by the user. A traction drive 12, such as a belt drive or a chain drive, serves to transmit the drive power, which is composed of the pedaling power and the support power, to the rear wheel 14. A bottom bracket gearshift 18 with a bottom bracket shift transmission 20 is also located in the area of ​​the bottom bracket 4. The auxiliary motor 2 and bottom bracket gearshift 18 can be structurally combined.

[0069] As an alternative to the configuration shown in Fig. 1, the auxiliary motor 2 can also be configured as a hub motor (not shown) and arranged on a rear wheel hub 16. The bottom bracket shifting mechanism 20 provides a plurality of gears. In the embodiment described here, the bottom bracket shifting mechanism 20 is shifted electrically by the user initiating a gear change by actuating a gear switch 22, which can be attached to a handlebar 24 or to a brake (not shown) attached to the handlebar. The gear switch 22 is preferably electronic, but can also be mechanical.

[0070] The bicycle 1 further includes a control unit 26, which can be used to control the auxiliary motor 2 and, if necessary, other functions of the bicycle 1. This control unit provides the user with various information such as speed, cadence, distance traveled, and / or navigation functions via a display 28. The gear shifter 22 and the control unit 26 can be two separate devices or structurally combined.

[0071] A processor 30 serves to control the bottom bracket transmission, in particular to control the shifting process of the bottom bracket transmission 20. The processor 30 can be part of the gear shifter 22 or the control unit 26 or can be a separate part located somewhere on the bicycle, for example in the auxiliary motor 2 or in the bottom bracket gearshift 18 or in the vicinity of the auxiliary motor 2 or the bottom bracket transmission 20.

[0072] The processor 30 can be implemented as hardware and / or software. For example, the processor 30 can be formed by an application running on one or more electronic components. An example of such an electronic component is an ASIC. The processor 30 can be connected to the gearshift 22 and / or the control unit 26, if not integrated into these devices, via a bidirectional data connection, which can be wired or wireless.

[0073] The control unit 26 can, for example, be a device provided by the manufacturer of the auxiliary motor 2 or an application for controlling the auxiliary motor 2 that is executed on a smartphone.

[0074] The bicycle also has a frame 32, which supports the battery, the bottom bracket gearshift 18, and the auxiliary motor 2. The auxiliary motor 2 and the bottom bracket gearshift 20 can be housed in a common housing 34 of the bottom bracket gearshift 18. The frame 32 can have any shape and size. A diamond frame is shown in Fig. 1 for exemplary purposes only.

[0075] Fig. 2 shows the schematic structure of a gearshift system 52 with a bottom bracket shift gear 20. An actuator 50, for example, an electric motor or a magnetic drive, serves to drive a gear change through the bottom bracket shift gear. In this illustration, the actuator 48 and the auxiliary motor 2 are merely exemplary parts of the gearshift system 52.

[0076] During operation, the user (not shown) pedals the pedals 6 with a pedal force 54. This causes a pedaling torque 58 to act on a bottom bracket shaft 56. The pedaling power generated by the user is the product of the pedaling torque 58 and the speed of the bottom bracket shaft 56.

[0077] The auxiliary motor 2 is connected to the bottom bracket shaft 56 via a motor gear 60, a hollow shaft 61, and optionally a freewheel 62, transmitting torque in at least one direction of rotation. The auxiliary motor 2 supports the user's pedaling performance by adding an assist power or assist torque 63.

[0078] In the illustrated embodiment, the hollow shaft 61 is simultaneously the input shaft 64 of the bottom bracket transmission 20. Of course, in another variant, the input shaft 64 can also be formed by a further shaft which, for example, runs parallel to the bottom bracket shaft 56.

[0079] In the illustrated embodiment, the pedaling power and the assist power at input shaft 64 add up to a total power output. When using a hub motor (not shown), this power superposition only occurs at the rear wheel.

[0080] The total power is transmitted through the bottom bracket transmission 20 to its output shaft 65, here also a hollow shaft 61, merely by way of example. A gear 66, for example a chainring or a pulley, can be attached directly to the output shaft as part of the traction drive 12. The traction drive also has a toothed belt pulley 67 on the rear wheel hub 16, or, if a chain drive is used, a pinion, via which the total power is transmitted to the rear wheel 14 (Fig. 1). The total torque resulting from the total power is designated by reference numeral 68 in Fig. 2.

[0081] If the auxiliary motor 2 is a hub motor, the assistance power is only added to the pedal power at the rear wheel hub 16.

[0082] The bottom bracket transmission 20 has one or more gear stages 69, for example, a first gear stage 69a, a second gear stage 69b, a third gear stage 69c, and a fourth gear stage 69d. The number of gear stages 69 essentially determines the number of gears provided by the bottom bracket transmission 20. Each gear stage 69 can have a spur gear 70, as shown in Fig. 2 merely as an example. However, instead of a spur gear 70, a planetary gear can also be provided as the gear stage. An intermediate shaft 71 is part of the bottom bracket transmission.

[0083] Each gear stage 69 has at least one clutch 72 that can be engaged and disengaged to shift a gear. A freewheel may be integrated into the clutch 72.

[0084] The respective combination of the engaged and disengaged clutches 72 of all gear stages 69 determines the power or torque flow through the bottom bracket transmission 20 and thus which gear is currently engaged in the bottom bracket transmission 20. The currently engaged gear is referred to as the actual gear.

[0085] The clutches 72 can, for example, include switchable toothed clutches or movable pawls. The clutches of the bottom bracket transmission 20 are synchronized or moved jointly by at least one movable shifting element 74, for example, a rotating shift drum, which engages and disengages the clutches 72 via gate controls 76 and shift fingers 77 extending through the intermediate shaft 71. The shifting element 74 can be arranged in the intermediate shaft 71, in particular coaxially in the intermediate shaft 74 if the intermediate shaft 71 is a hollow shaft as shown.

[0086] Instead of a shift drum, another method can of course be provided for engaging and disengaging the clutches 72. For example, a camshaft can be used instead of the shift drum 74 to shift the clutches 72. Furthermore, instead of a rotary movement, a translatory movement along a shaft axis 78 can be used, so that the shift element 74 is moved like a tappet or a draw key. Each position of the shift element 74, or in the case of a rotating shift element, each angular position of the shift element 74, is assigned a different gear. For this purpose, the shift element 74 can assume discrete positions in which it can be locked or inhibited. Each different discrete position corresponds to a different gear.

[0087] The shifting element 74, which effects the shifting process in the bottom bracket transmission 20, is driven by the actuator 50. An actuator gear 80 can be located between the actuator 50 and the shifting element 74, which is particularly useful when a small, high-speed electric motor 50 is used as the actuator 50, whose high speed must be reduced to a low speed at the shifting element 74. The actuator gear 80 can also contain a speed superposition gear (not shown here) if the shifting element 74 rotates and the actuator 50 is fixedly arranged on the housing. Control via such a speed superposition gear is known, for example, from EP1982913A1.

[0088] The torque applied to the input shaft 64 of the bottom bracket transmission is transmitted through the torque-transmitting components of the bottom bracket transmission 20. The currently engaged clutches 72 represent a portion of these torque-transmitting components. When changing gear under load, some or all of the engaged clutches 72 must be disengaged and some or all of the disengaged clutches 72 must be engaged while the total torque 68 is transmitted.

[0089] If the clutches 72 have engaging and disengaging gear teeth 84 for torque transmission, these are pressed against each other by the torque 68 on the input shaft 64, which creates friction. To counteract this friction, the gear teeth 84 of the engaged clutches 72 must be disengaged from each other. The higher the torque 68 on the input shaft 64, the more force is required to disengage the gear teeth, because with the torque 68, the surface pressure in the gear teeth 84 increases, and thus the friction between the engaged gear teeth 84 to be disengaged.

[0090] Friction increasing with the torque 68 can also occur on guides 86, for example splines, which guide the parts of the clutches that move during switching.

[0091] The greater the torque 68 on the input shaft 64 of the bottom bracket transmission 20, the more power is required for the gear shifting process.

[0092] The drive power of actuator 50 is limited, so that the shifting element 74 can only be moved with a specific maximum force. If this force is insufficient to release a torque-transmitting clutch 72, a gear change cannot occur. The actuator 50 can therefore only reliably shift the bottom bracket transmission 20 up to a specific maximum torque 68 on the input shaft 64. This maximum torque is referred to as the powershift maximum. As long as the torque 68 is below the powershift maximum, shifting between the gears of the bottom bracket transmission 20 is unproblematic.

[0093] A gear change is initiated by the user by actuating the gear switch 22, for example, by pressing a button 88 to shift up one gear or a button 90 to shift down one gear. If the torque 68 at the input shaft 64 is below the powershift maximum at the time the gear switch 22 is actuated, the gear can be changed immediately. However, if the torque 68 exceeds the powershift maximum at the time the gear switch 22 is actuated, the actuator 50 cannot effect a gear change, at least not temporarily.

[0094] The following describes how a gear shift operation is enabled by the transmission shift system 52 under load.

[0095] Actuation of the gear switch 22 or the buttons 88, 90 generates a gear change signal 92, which is received by the processor 30. The gear change signal 92 is representative of a gear change initiated by the user.

[0096] The gear change signal 92 can be an incremental signal or an absolute signal. As an incremental signal, it simply represents the upshift or downshift by one or a different number of gears. As an absolute signal, the gear change signal represents the gear to be engaged.

[0097] The transmission shift system 52 has a sensor arrangement comprising one or more sensor elements, which are designated S in Fig. 2.

[0098] One or more of these sensors S form a drive parameter sensor 94, which generates a drive parameter signal 96 representative of at least the torque 68 on the input shaft 64, which is received by the processor 30.

[0099] For example, a torque and / or power sensor 100 may be arranged on the input shaft 64, which directly measures the torque 68 and outputs it in the form of the drive parameter signal 96.

[0100] In addition to the torque, the sensor 100 can also detect the speed of the input shaft 64 and output it as part of the drive parameter signal 96.

[0101] The drive parameter signal 96 itself does not have to directly contain the torque 68 in coded form. The torque 68 must only be able to be determined with sufficient accuracy based on the drive parameter signal 96.

[0102] In particular, the processor 30 can be configured to calculate the torque 68 using the drive parameter signal 96. The drive parameter signal 96 can, for example, contain a speed and a power as individual signals, so that the processor can calculate the torque from these two individual signals, for example, by dividing the power contained in the drive parameter signal by the speed contained in the drive parameter signal. Furthermore, the torque, speed, and / or power do not have to be measured at the same location or on the input shaft 64.

[0103] Alternatively or additionally, a torque sensor 102 can also be arranged on the bottom bracket shaft 56 as a drive parameter sensor 94 or as part thereof. The torque sensor 102 detects the pedaling torque 58 exerted by the user on the bottom bracket shaft 56.

[0104] The torque sensor 102 can be part of a power sensor on the bottom bracket spindle 56, which, in addition to the torque acting on the bottom bracket spindle 56, also detects the speed and / or power at the bottom bracket spindle 56. Alternatively, the torque sensor 102 can also be just a power sensor.

[0105] As a drive parameter sensor 94 or part thereof, a torque and / or power sensor 104 can be arranged on the output shaft 65 of the bottom bracket transmission 20 as an alternative or in addition to the above-mentioned sensors.

[0106] The processor 30 may also be configured to correct the torque detected by the drive parameter sensor 94 and / or to calculate a torque from a power.

[0107] For example, processor 30 may apply a correction factor, correction function, or lookup table to the torque or power sensed by sensor 104 to calculate a value representative of the torque 68 at the input shaft. Thus, the correction may represent a transfer function from the output shaft to the input shaft, for example, the power losses occurring along this transfer path.

[0108] The drive parameter signal 96 can be representative of the torque 68 currently applied to the input shaft 64 or representative of a time average of the torque 68 applied to the input shaft 64. In particular, however, the processor 30 can be configured to calculate a time average, for example over 3 or 10 seconds or any other time period, of the torque 68 applied to the input shaft 64 from a time profile of the drive parameter signal 96 as the value representing the torque 68. The processor 30 is configured to generate and output a switching signal 106 as a function of the drive parameter signal 96 and the gear change signal 92. The generation of the switching signal 106 by the processor 30 can be dependent on an instantaneous value or an average value of the drive parameter signal 96 or the torque 68 represented by it.

[0109] Actuator 50 is actuated by switching signal 106. When actuator 50 receives the switching signal, it executes a predetermined drive movement or one determined by switching signal 106. The switching signal 106 can be output by processor 30 either wired or wirelessly. Wireless output can be achieved, for example, via Bluetooth or ANT. Output can also be achieved by remote query or by reading a memory location by another electronic component or another functional unit.

[0110] The switching signal 106 can be an incremental signal, in response to which the actuator 50 moves over a predetermined distance or a distance dependent on the switching signal 106 in a direction dependent on the switching signal 106. This distance is dimensioned such that the switching element 74 shifts forward from the current gear by exactly a predetermined number of gears or a number dependent on the switching signal 106.

[0111] Alternatively, the switching signal 106 can also be an absolute signal, in response to which the actuator 50 moves to a specific location, for example to the gear represented in the switching signal 106.

[0112] By generating or outputting the switching signal 106 as a function of the drive parameter signal 96 representing at least the torque 68 and after receiving the gear change signal 92, the processor 30 is fundamentally enabled to have a switching operation carried out by the actuator 50 only when the load switching maximum is undershot at the input shaft 64.

[0113] The maximum load switching value or, synonymously, a value representative thereof can be stored in processor 30. For example, processor 30 can be configured to compare the stored maximum load switching value with drive parameter signal 96 and output switching signal 106 based on this comparison.

[0114] The pedaling force 54 applied by the user and its direction, and thus also the pedaling torque 58, change at least approximately cyclically during one complete revolution of a crank 8. This is explained below with reference to Fig. 3, which schematically shows the course of the pedaling torque 58 on the bottom bracket shaft 56 as a function of the crank position 8 during one complete revolution of one of the two cranks 8. The angular position 0° designates the crank 8 pointing vertically upwards, while at the angular positions 90° and 270° the crank is aligned horizontally in the opposite direction. It can be seen that the pedaling torque 58 is maximum at certain angular positions 108 of the pedal cranks 8 and minimum at certain other angular positions. The pedaling torque 58 is therefore always maximum when the pedal cranks are at least approximately horizontal.In the at least approximately vertical position of the pedal cranks 8 there are dead center positions 110 at which the pedal torque 58 is minimal.

[0115] The sum of pedal torque 58 and assist torque 62, less any losses, is applied to the input shaft 64.

[0116] If the assistance torque 62 is always in a certain ratio to the pedaling torque 58 or if the assistance torque is constant over time, the curve of the torque 68 on the input shaft 64 follows the curve of the pedaling torque 58. In such a case, the curve of the torque 68 is also cyclical; the curve of the torque 68 has a minimum at the dead center positions 110. It is therefore possible that, although the powershift maximum at the input shaft 64 is exceeded at the time the gear change signal 92 is received, the powershift maximum is undershot at one point during a crank revolution. In such a case, the gearshift process can be carried out with a short delay as soon as the powershift maximum is undershot. Since the processor 30 can determine the instantaneous value of the torque 68 based on the drive parameter signal 96, the gearshift signal 10 is only output orthe switching operation is only carried out if the torque 68 is at least temporarily below the powershift maximum.

[0117] The transmission shifting system 52 may include a crank position sensor 112 that outputs a crank position signal 114 representative of the angular position of one or both pedal cranks 8. The processor 30 is configured to detect the crank position signal 114 and to output the shift signal 106 as a function of the crank position signal 114.

[0118] For example, the switching signal 106 is only output when the angular position 108 of a pedal crank 8 is in a predetermined range 116 (Fig. 3). The range 116 preferably extends around the dead center position 110. The range 116 can begin 10° or 20° before the dead center position 110, i.e., at a crank position of approximately 160° or approximately 170°. The range 116 can further extend to approximately 10° or approximately 20° past the dead center position 110, i.e., to approximately 190° or approximately 200°. The range 116 does not have to be determined by the angular position 108 of a pedal crank 8, but can alternatively or cumulatively be determined by the powershift maximum 117, for example, in that in the range 116 the torque 58 is below the powershift maximum 117.

[0119] Shifting at the bottom dead center position 110 or in the area 116 is also sensible if the torque 68 is always or over a larger range of a crank revolution below the power shift maximum, because when shifting in the area 116 the natural pedaling movement of the user is least disturbed by the shifting process.

[0120] Thus, in one embodiment, the processor 30 can be designed to generate or output the switching signal 106 independently of the drive parameter signal 96 when the crank position or angular position of the crank 8 represented by the crank position signal 114 is in the range 116.

[0121] In an alternative embodiment, the crank position sensor 112 can be omitted. Thus, the processor 30 can be configured to determine the dead center position 110 based on the drive parameter signal 96. In this case, the drive parameter signal 96 also represents the crank position. Thus, the processor 30 can be configured to determine the crank position using the torque and / or power sensor 102 based on the time profile of the drive parameter signal 96, here in particular the torque or power.

[0122] For example, the processor can be configured to adapt a sine function to the curve of the drive parameter signal 96, i.e., to the curve of the torque 68 or the pedaling torque 58. From such an adaptation, the dead center position results from the minimum of the adapted sine function. The term sine function here refers not only to a trigonometric function, but also to an essentially sinusoidal function calculated in another way, for example, using polynomials or a spline curve. This calculation offers the advantage that the future curve of the torque 68 or the crank position 108 can be estimated and the switching signal 106 can be output before the range 116 is reached or the torque 68 has dropped below the powershift maximum 117, in order to take into account reaction times resulting from the inertia of the actuator 50 and the mechanics of the bottom bracket shift gear 20.

[0123] Such a curve fit can, of course, also be performed when a crank position signal 114 is present. It may happen that the torque 68 at the input shaft 64 of the bottom bracket transmission 20 does not fall below the powershift maximum 117 during one or more pedal revolutions. This can have two causes.

[0124] First, the user's pedaling power may be below the powershift maximum, so that the torque 68 at the input shaft 64 does not fall below the powershift maximum only because the support power of the auxiliary motor 2 is added to the pedaling power. Second, the user's pedaling power alone may result in a torque 68 that is greater than the powershift maximum.

[0125] In the former case, it is useful if the processor 30 is configured to determine the proportion of pedaling power in the torque 68 and / or the proportion of assist power in the torque 68. Furthermore, the processor 30 should be configured to reduce the assist power generated by the auxiliary motor 2 in the region 116 and / or at another angular position 108 of the pedal crank 8 such that the torque 68 drops below the powershift maximum 117. This is described in detail below.

[0126] In the second case, a gear change cannot be performed even if the assistance power is temporarily reduced because the switching force required by the actuator 50 is still insufficient to move the switching element 63 against the internal friction. In this case, it is expedient for the processor 30 to be configured to output an alarm signal 118, which can be output, for example, in the form of a visual warning signal 120 and / or an acoustic warning signal 122 on the gearshift 22 or the control unit 26.

[0127] The processor 30 may have a memory 124 in which gear change signals 92 that have not yet been processed are stored. For example, if a gear change is not possible at the time the gear change signal 92 is received because the torque 68 does not fall below the powershift maximum 117 during a full crank revolution, the gear change signal 96 may be stored in the memory 124 to be processed immediately when the torque 68 falls below the powershift maximum 117. Other parameters, such as the powershift maximum, look-up tables, and / or conversion and / or correction functions, may also be stored in the memory 124.

[0128] The alarm signal 118 may alternatively or cumulatively be representative of the fact that one or more unprocessed gear change signals 92 are contained in the memory 124. The gear shifter 22 and / or the control unit 96 can display an indication signal 126 in the display 28 depending on the alarm signal 118 or on the gear change signals 92 stored in the memory 124. In Fig. 1, for example, a "plus" sign is shown in the display 28 as an indication that a gear change signal 92 representative of an upshift is still stored, i.e., the user-initiated gear change is still pending.

[0129] The processor 30 can also be configured to combine gear change signals 92 that have not yet been processed in order to avoid unnecessary gear shifts. For example, if the user presses the downshift button 90 in the previously described situation in which the gearshift has not yet shifted up, this would cancel the previously issued upshift command. In the processor 30, such a combination can be achieved by simply adding the gear change signals 92 or the gear changes they represent if they are incremental signals. If the gear change signal 92 is an absolute signal, the processor should be configured to calculate and add the resulting gear steps from the absolute signals located in the memory 124.

[0130] The processor 30 may be configured to delete a gear change signal 92 stored in the memory 124 if a gear change was not possible over a predetermined time or number of crank revolutions.

[0131] To enable processor 30 to determine the proportion of pedaling power or assistance power to torque 68, transmission shifting system 52 may include a sensor 128 configured to detect the assistance power of auxiliary motor 2. Sensor 128 may be a torque and / or power sensor arranged on a motor shaft of the auxiliary motor or at another location between auxiliary motor 2 and freewheel 62. Sensor 128 may also be configured to determine the motor current and / or motor voltage of auxiliary motor 2 and / or the electrical power consumed by auxiliary motor 2. Alternatively or additionally, the transmission shifting system may include a sensor 129 configured to detect the user's pedaling power. Such a sensor 129 can be arranged, for example, on the pedals 6 or on the cranks 8 in order to detect the pedal force 54 applied by the user and a rotational speed of the cranks 8.Furthermore, the sensor 102 can be used as sensor 129.

[0132] Sensors 100, 102, 128, 129 are each configured to generate a power signal 130 representative of the power and speed measured by the respective sensor, or the torque measured by the respective sensor. The power signal 130 can include, as individual signals, an angular position signal, a speed signal, a torque signal, and / or a force signal, which represents, for example, the force on the pedals. The power signal 130 can be part of the drive parameter signal 96.

[0133] With the power signal 130, the processor 30 is able to calculate the proportion of the pedaling power and / or the assist power in the torque 68 at the input shaft 64. It can be assumed that the proportion of the pedaling power and / or the assist power in the respective total torque remains unchanged along the torque flow.

[0134] If it turns out that the portion of torque 68 based solely on the user's pedaling power is below the powershift maximum, the assistance power of auxiliary motor 2 can be reduced to such an extent that torque 68 actually drops below the powershift maximum. In principle, the assistance power can be reduced at any point in the crank position 108. However, the assistance power is preferably reduced in the range 116.

[0135] For this purpose, the processor 30 is designed to generate a motor control signal 132 depending at least on the drive parameter signal 96, but preferably also on the crank position signal 114 and / or the power signal 130. The motor control signal 132 is output to the auxiliary motor 2 or its control system (not shown) and can be representative of a target value for the assistance power. The assistance power is then regulated to this target value. The motor control signal 132 can be generated by the processor 30 at regular intervals or continuously, for example, if the assistance power of the auxiliary motor 2 is generally regulated by the processor 30. The motor control signal 132 can be a digital or analog signal. With an analog motor control signal 132, for example, a current and / or voltage of the motor control signal 132 can be proportional to the assistance power.

[0136] Immediately after the pedal cranks 8 have passed the area 116 around the dead center position or the gear shifting process has ended, the assistance power is increased again to the previous value.

[0137] A gear sensor 134 of the transmission shift system 52 generates a gear signal 136 representative of the actual gear. Using the gear signal 136, the processor 30 can determine the currently engaged gear. The at least one gear sensor 134 can be constructed in various ways and can also have different individual sensors. For example, the gear sensor 134 can detect a position, for example, the angular position, of an actuator output shaft 138. Alternatively, the gear sensor 134 can detect the position, for example, the angular position, of the shift element 74. Both the position of the actuator output shaft 138 and the position of the shift element 74 are representative of the currently engaged gear.

[0138] Alternatively, the gear sensor 134 can comprise two individual sensors, for example, sensors 100 and 104, each outputting a value representative of the rotational speed of the input shaft 64 and the rotational speed of the output shaft 38 of the bottom bracket transmission 20. The ratio of the rotational speeds of the input shaft 64 and the output shaft 38 of the bottom bracket transmission 20 is representative of the currently engaged gear. A transfer function can be stored in the memory 124 of the processor 30, for example, in the form of an analytical function that assigns the gear corresponding to different ratios of the rotational speeds of the input shaft 64 and the output shaft 38. A transfer function or a lookup table can also be used in the processor 30 to assign a value representative of the currently engaged gear to the positions of the actuator output shaft 138 or the shifting element 74.

[0139] Alternatively or additionally, the gear sensor 134 can also monitor the position of the clutches 72, for example, by arranging a position sensor 134a, 134b, 134c, 134d on each clutch 72, which outputs a signal representative of the position of the clutch 72. The individual signals from the sensors 134a-d indicate the shifting state of the bottom bracket transmission 20 and thus also represent the currently engaged gear. Here, too, the processor 30 is preferably configured to assign a currently engaged gear to a combination of clutch positions represented in the gear signal using a transfer function or look-up table.

[0140] Instead of monitoring the clutch positions, the speeds of the partial transmissions can also be monitored.

[0141] The processor 30 is configured to output the shift signal 106 depending on the gear signal 136. For example, the processor 30 does not output a shift signal 106 to the actuator 50 if the gear signal 136 determines that the lowest gear is already engaged and the user still wants to downshift. The same applies if the actual gear determined by the processor 30 is the highest gear of the bottom bracket transmission 20 and the user wants to upshift. In such a case, the processor 30 can be configured to delete the gear change signal.

[0142] Processor 30 can further be configured to determine the target gear resulting from the gear change signals 92 that have not yet been processed and compare it with the actual gear. If the comparison shows that the target gear does not yet correspond to the actual gear, the shift signal 136 can be output—again dependent at least on the drive parameter signal 96.

[0143] A gear indicator 140, for example, in the display 28, can be provided in the gear shifter 22 or the control unit 26, which indicates the current gear. The current gear can be included in the alarm signal 118.

[0144] Depending on the design of the bottom bracket transmission 20, the shifting force required by the actuator 50 to shift between two gears may also depend on the currently engaged gear. For example, fewer clutches 72 need to be moved for certain gear changes than for other gear changes, or due to the gear ratios of the sub-transmissions, the torque generating friction at the clutches 72 to be moved is smaller for certain gears than for other gears. The powershift maximum may therefore be gear-dependent. To account for this dependency, the processor may be configured to output the shifting signal 136 as a function of the gear signal 136. The processor 30 may have a conversion function or lookup table in the memory 124 that assigns a powershift maximum to an actual gear. In this case, the switching signal 136 is output depending on the actual gear only when the torque 68 falls below the gear-dependent powershift maximum.

[0145] Furthermore, the processor 30 can be configured to output the motor control signal 132 depending on the gear signal 136. For example, when shifting between some gears, the assistance power must be reduced more than when shifting between other gears in order to reduce the torque 68 at the input shaft 64 below the powershift maximum.

[0146] With reference to Figs. 4 to 8, examples of methods for switching under load are described below. The methods are particularly intended to be executed on a processor, for example, processor 30 of Fig. 2.

[0147] Fig. 4 shows that a user triggers a gear change signal 92, i.e., generates a shift command, in a step 200. The gear change signal 92 is stored in a memory, for example, the memory 124, in a step 202. In step 204, the gear change signal 92 stored in the memory is updated and / or consecutive and stored gear change signals 92 are combined, so that mutually canceling gear change signals are deleted.

[0148] Furthermore, in step 204, the gearshift signal in memory can be corrected if the gearshift signal intends to initiate a gearshift beyond the lowest or highest gear. In this case, the gearshift signal in memory can be set to a value that represents the lowest or highest gear, respectively.

[0149] In step 204, the shift status can also be taken into account, which results after a gear change has been carried out completely, only partially, or not at all after the shift signal has been issued. The result of the shift process is provided in step 206. If, for example, all gear change signals have been processed by successfully executing a shift process - the actual gear corresponds to the target gear - the gear change signal can be deleted, unless the user has generated another gear change signal in the meantime in step 200. If, on the other hand, the shift process could only be carried out incompletely, the actual gear engaged is transmitted in step 206, for example, and the gear change signal in the memory is updated accordingly in step 204: There are still gears that need to be shifted. If the gear change could not be carried out at all, as shown below in Fig.8 is executed, then the gear change signal remains unchanged.

[0150] Finally, in step 204, the shift direction resulting from the gear change signal and, if applicable, by comparing the gear change signal and the gear signal can be determined and also stored in step 202.

[0151] The method illustrated in Fig. 4 can be executed at a fixed rate. Alternatively or additionally, the method illustrated in Fig. 3 can be executed, for example, in an interrupt-controlled manner whenever the user generates a gear change signal 92 or a gear shift is completed.

[0152] Using the method illustrated in Fig. 5, the torque 68 at the input shaft 64 can be recorded and continuously updated. Additionally, the proportion of pedaling power or assist power to the torque 68 can be continuously determined. Furthermore, the powershift maximum can be determined using the method illustrated in Fig. 5. The method illustrated in Fig. 5 can be performed in parallel or alternately with the method illustrated in Fig. 4.

[0153] In step 300, a signal representative of the torque 68 is detected, for example, the drive parameter signal 96. Additionally, a signal representative of the pedaling power and / or the assist power at the input shaft 64, for example, the power signal 130, which may also be part of the drive parameter signal 96, may be detected. This value is stored in step 302 and updated and, if necessary, corrected in step 304, as described above in Fig. 2.

[0154] In step 304, the respective powershift maximum can also be calculated as a function of the shift direction and / or the actual gear engaged and also stored. This is illustrated in Fig. 5 by the schematically illustrated reading of the gearshift signal updated in step 202. Alternatively, the powershift torque can be calculated in step 204 as a function of the shift direction and / or the actual gear engaged and updated in step 202 together with the gearshift signal. In step 304, a predetermined powershift maximum can be assigned to an actual gear and / or a shift direction, for example, using a lookup table.

[0155] The method according to Fig. 5 can be carried out by the processor at a fixed, preferably as short a time interval as possible, so that the values ​​updated in step 302 reflect the current state as accurately as possible.

[0156] Fig. 6 illustrates a further method which can be executed, for example, by the processor 30 of Fig. 2, in parallel or alternately with the methods of Figs. 4 and 6. In a step 400, a gear signal representative of the currently engaged gear, the actual gear, is received and stored in step 402.

[0157] Fig. 7 shows a further method that can be carried out in parallel or sequentially to the methods of Fig. 4 to 7. In step 500, a value representative of the crank position of the cranks 8 is received, for example the crank position signal 114. In step 502, this value is stored, for example in memory 124. In optional step 504, the value received in step 500 can be processed, for example by storing not only the current but also the time profile of the crank position in step 502 and calculating a curve fit to the time profile. The curve fit can be carried out, for example, by means of a spline fit or a fit of a sinusoidal curve, for example a sine function or a polynomial. In calculation step 504, for example, the time that will elapse until the range 116 is reached at the current cadence can also be calculated.

[0158] Fig. 8 shows, by way of example, the sequence of a method by which the bottom bracket transmission 20 can be shifted under load. The method illustrated in Fig. 8 can be executed in parallel or sequentially to the methods illustrated in Figs. 4 to 7. It can be executed at predetermined time intervals or interrupt-controlled, for example, upon receipt of a gear change signal 92. The methods of Figs. 4 to 8 can also be part of the method according to Fig. 8.

[0159] In step 600, the value representative of the instantaneous torque 68 on the input shaft 64 is read out, which is continuously updated after step 302 of Fig. 5.

[0160] In addition, the load switching maximum 117 can also be read out in step 600, which is continuously updated in step 302. Alternatively, the load switching maximum 117 can also be a value stored in memory 124 as a constant value.

[0161] In step 602, the torque at input shaft 64 is compared with the powershift maximum 117. If torque 68 is less than the powershift maximum, this means that actuator 50 is capable of performing a gear change. In this case, the gearshift can be performed immediately, and the process continues with step 604.

[0162] In step 604, the target gear to be engaged is first read out, which is continuously updated and stored, for example, in step 202 according to the method of Fig. 4.

[0163] In step 606, the target gear is compared with the actual gear stored in step 402.

[0164] If this comparison shows that the target gear cannot be engaged, for example because the lowest gear is already engaged when shifting down or the highest gear is already engaged when shifting up, the gear change process ends without a gear change with step 206. The gear change signal can be deleted beforehand.

[0165] If the comparison in step 606 determines that the target gear can be engaged, the shifting process is performed in step 608. In the embodiment shown in Fig. 2, for example, this means that the shift signal 106 is output to the actuator 50, and the actuator 50 actuates the shifting element 74. In step 608, a waiting loop can be implemented that suspends the execution of the next step for a predetermined period of time. This period of time is preferably greater than a predetermined period of time, which, for example, corresponds to the length of the time period for the gear change.

[0166] Step 606 can also be omitted if the target gear is continuously updated in the method according to Fig. 4 and the comparison made in step 606 and the resetting of the gear shift signal in step 612 already takes place continuously in step 204.

[0167] After the gear shift 608, the actual gear now engaged is compared in step 610 with the target gear read in step 604.

[0168] If the comparison between the actual and target gear in step 610 shows that the gear to be engaged is actually engaged, i.e., the target gear corresponds to the actual gear, the gear change process is terminated with step 206. The gear change signal is then automatically updated according to the method of Fig. 4 or can be reset or deleted at this point.

[0169] If, however, it emerges in step 610 that the requested gear change could not be fully executed, i.e. the actual gear does not correspond to the target gear, the target gear is set to the actual gear in step 612 and another gear change 608 is carried out before the gear change process is ended with step 206. This situation can occur, for example, if the powershift maximum is exceeded during the execution of step 608, so that the actuator 50 or the switching element 74 cannot complete the switching movement. In this case, setting the target gear to the current actual gear in step 612 and the subsequent execution of the switching process in step 608 causes the actuator 50 or the switching element 74 to move back to the position corresponding to the actual gear. Such a move back is possible at any time due to the freewheel functions in the clutches 72.

[0170] If it is determined in step 602 that the torque 68 at the input shaft 64 of the bottom bracket transmission 20 is greater than the powershift maximum, the current crank position, which can be updated, for example, according to the method of Fig. 7, can be queried in a step 618. As long as the crank position is not in the range 116, i.e., in a predetermined angular range around the dead center position 110, the next method step is not executed.

[0171] In step 620, the portion of torque 68 attributable to pedaling power is compared with the powershift maximum. The portion of torque 68 attributable to pedaling power is continuously updated according to the method of Fig. 5 and stored in step 302. If the portion of the input shaft torque attributable to pedaling power is above the powershift maximum, this means that even if the assistance power of auxiliary motor 2 is reduced, actuator 50 will not be able to perform a gearshift. The method is therefore terminated after comparison 620 without performing a gearshift with step 206.

[0172] Alternatively, step 620 can be omitted and instead the process simply continues with step 604. This is particularly possible if steps 610, 612, and 608 are used to check again whether the gear could be fully engaged and to ensure that the actuator 50 or the shift element is moved to a position corresponding to the actual gear.

[0173] If it is determined in step 620 that the portion of torque 68 attributable to pedaling power is smaller than the powershift torque, the process continues with step 604.

[0174] In step 604, the current target gear from step 202 is read and compared with the actual gear in step 606. If the requested gear shift is not possible, the gear shift is terminated with step 206, although the gear shift signal can be reset beforehand.

[0175] If the target gear can be engaged starting from the actual gear, the assist power of the auxiliary motor is reduced in step 622 until the torque at the input shaft of the manual transmission is less than or equal to the powershift maximum. For this purpose, processor 30 can calculate and output the motor control signal accordingly.

[0176] Subsequently, the shifting process 608 is executed, and in step 624, the assistance power is increased back to the level it had before the shifting process 608. Step 624 can be performed within a specific time after the shifting signal is output or depending on the crank position and / or a change in the actual gear. For example, the assistance power can be restored when the actual gear corresponds to the target gear. Otherwise, the time required by the actuator 50 and the bottom bracket transmission 20 to shift from the actual gear to the target gear can simply be waited for.

[0177] The system then continues with step 610 and checks the engaged gear.

[0178] 1 Bicycle 2 Auxiliary motor

[0179] 4 bottom brackets

[0180] 6 Pedal

[0181] 8 pedal crank

[0182] 10 Accumulator 12 Traction drive

[0183] 14 Rear wheel

[0184] 16 Hub 18 Bottom bracket gears

[0185] 20 bottom bracket gearbox 22 gear shifter

[0186] 24 handlebars

[0187] 26 Control unit 28 Display 30 Processor 32 Frame

[0188] 34 housings

[0189] 50 Actuator 52 Gearshift system

[0190] 54 pedal power

[0191] 56 Bottom bracket spindle 58 Pedal torque

[0192] 60 Motor gear 61 Hollow shaft 62 Freewheel

[0193] 63 Assistance torque 64 Input shaft 65 Output shaft

[0194] 66 Chainring or toothed belt pulley 67 Pinion or toothed belt pulley

[0195] 68 Torque at the input shaft 69 Gear stage 69a First gear stage 69b Second gear stage 69c Third gear stage

[0196] 70 Spur gear 71 Intermediate shaft

[0197] 72 Clutch 74 Switching element

[0198] 76 Gate control 77 Shift finger

[0199] 78 Shaft axis 80 Actuator gear

[0200] 84 Gearing 86 Guide

[0201] 88 Gear up button 90 Gear down button 92 Gear change signal

[0202] 94 Drive parameter sensor 96 Drive parameter signal 100 Torque and / or power sensor on the input shaft

[0203] 102 Torque and / or power sensor on the bottom bracket spindle

[0204] 104 Torque and / or power sensor on the output shaft

[0205] 106 switching signal

[0206] 108 Angular position of a pedal crank

[0207] 110 Dead center position

[0208] 112 Crank position sensor

[0209] 114 Crank position signal

[0210] 116 Area around dead center position

[0211] 117 Powershift maximum

[0212] 118 Alarm signal

[0213] 120 optical warning signal

[0214] 122 acoustic warning signal

[0215] 124 memory

[0216] 126 Information signal

[0217] 128 Sensor for recording the support power

[0218] 129 Sensor for recording pedal power

[0219] 130 power signal

[0220] 132 Motor control signal

[0221] 134 Gear sensor

[0222] 134a-d Position sensors

[0223] 136 Gear signal

[0224] 138 Actuator output shaft

[0225] 140 gear indicator

[0226] 200 Triggering a gear change signal

[0227] 202 Storing the gear change signal

[0228] 204 Updating the gear change signal

[0229] 206 Detecting the actual gear to update the gear change signal

[0230] 300 Recording a value representative of the torque at the input shaft of the bottom bracket transmission and optionally of the proportion of pedaling power and / or assistance power to the torque at the input shaft

[0231] 302 Saving the value

[0232] 304 Update and optionally correct and process the value

[0233] 400 Receiving a gear signal representative of the engaged gear 402, storing the gear signal

[0234] 500 Receiving a value representative of the crank position

[0235] 502 Saving the value

[0236] 504 Processing the value

[0237] 600 Recording the torque at the output shaft and the powershift maximum

[0238] 602 Comparison of torque and powershift maximum

[0239] 604 Recording the target gear

[0240] 606 Comparison of the target gear with the actual gear

[0241] 608 Command to execute the switching operation or execute the switching operation

[0242] 610 Comparison of the target gear with the actual gear

[0243] 612 Reset the target gear

[0244] 618 Comparison of the crank position with the dead center position

[0245] 620 Comparison of the proportion of pedal power to the torque at the input shaft with the powershift torque

[0246] 622 Reducing the support power

[0247] 624 Increasing the support performance

Claims

Claims 1. Processor (30) for controlling a bottom bracket gearbox (20) of a bicycle (1) with auxiliary motor (2), the gearbox being provided with an input shaft (64) and with an actuator (50) for gear changes depending on a switching signal (106), wherein the processor (30) is configured to: - receive a gear change signal (92) that is representative of a shift command triggered by a user of the bicycle (1), and - receive a drive parameter signal (96) that is representative of at least one torque (68) applied to the input shaft (64), - wherein the processor (30) is further configured to output the switching signal (106) depending on the drive parameter signal (96) after receiving the gear change signal (92). 2.Processor (30) according to claim 1, wherein the processor (30) is configured to receive a power signal (130) that is representative of the user's pedaling power and / or the auxiliary motor's (2) support power, and wherein the processor (30) is configured to determine, depending on the drive parameter signal (94) and the power signal (130), the user-generated portion of the torque (68) applied to the input shaft (64).

3. Processor (30) according to claim 1 or 2, wherein the processor (30) is configured to output the switching signal (106) when the torque (68) represented by the drive parameter signal (96) is less than a predetermined value (117). 4.Processor (30) according to any one of claims 1 to 3, wherein the processor (30) is configured to determine a switching direction that is representative of a switching direction towards a higher or lower gear, and wherein the processor (30) is configured to output the switching signal (106) depending on the determined switching direction.

5. Processor (30) according to any one of claims 1 to 4, wherein the processor (30) is configured to receive a crank position signal (114) that is representative of an angular position of a pedal crank (8) of the bicycle (1), and wherein the processor (30) is configured to output the switching signal (106) depending on the crank position signal (114).

6. Processor (30) according to claim 5, wherein the processor (30) is configured to determine a dead center position (110) at which the torque (68) on the input shaft (64) is minimal and / or less than a predetermined value (117), depending on the time course of the crank position signal (114) and the drive parameter signal (96).

7. Processor (30) according to any one of claims 1 to 6, wherein the processor (30) is configured to generate and output a motor control signal (132) that is representative of the support power to be delivered by the auxiliary motor (2), and wherein the processor (30) is configured to generate the motor control signal (132) depending on the gear shift signal (92) and the drive parameter signal (92).

8. Processor (30) according to claim 7, wherein the processor (30) is configured to generate the motor control signal (132) depending on the crank position sensor (112). 9.Processor (30) according to claim 7 or 8 and according to claim 2, wherein the processor (30) is configured to determine the pedaling power of the user of the bicycle (1) depending on the power signal (130).

10. Processor (30) according to any one of claims 1 to 9, wherein the processor (30) is configured to combine a plurality of temporally successive gear-change signals (92) and output them as a switching signal (106).

11. Processor (30) according to any one of claims 1 to 10, wherein the processor (30) is configured to receive a gear signal (136) that is representative of the gear currently engaged on the bottom bracket shift mechanism (18, 20), and wherein the processor (30) is configured to output the switching signal (106) depending on the gear signal (136). 12.Processor (30) according to claim 11, wherein the processor (30) is configured to determine a target gear to be engaged in the transmission depending on the gear shift signal (92) and an actual gear engaged in the bottom bracket shift mechanism (20) depending on the gear signal (136), and wherein the processor (30) is configured to output the shift signal (106) depending on the drive parameter signal (96) until the actual gear corresponds to the target gear.

13. Processor (30) according to claim 11 or 12, wherein the gear signal (130) contains a rotational speed of the input shaft (64) and a rotational speed of the output shaft (65) of the bottom bracket shift mechanism (18, 20) or the ratio of these two rotational speeds.

14. Processor (30) according to claim 3 and according to any one of claims 11 to 13, wherein the processor (30) is configured to determine the predetermined value (117) of the torque (68) at the input shaft (64) depending on the gear signal (130).

15. Computer-implemented method for controlling a bottom bracket gearbox (18, 20) of a bicycle (1) with auxiliary motor (2) provided with an input shaft (64) and with an actuator (50) for gear changes depending on a switching signal (106), wherein a gear change signal (92), which is representative of a shift command triggered by a user of the bicycle (1), and a drive parameter signal (96), which is representative of a torque (68) applied to the input shaft (64), are received, wherein after receiving the gear change signal (92), the switching signal (106) is output depending on the drive parameter signal (96). 16.Computer-implemented method according to claim 15, wherein the switching signal (106) is output when the torque (68) represented by the drive parameter signal (96) at the input shaft (64) is less than a predetermined value (117).

17. Computer program product or computer-readable storage medium comprising commands which, when the program is executed by a computer, cause it to perform the method according to claim 15 or 16.

18. Bottom bracket shifter (18) for a bicycle (1) with auxiliary motor (2), comprising a processor (30) according to any one of claims 1 to 14, the bottom bracket shifter (18, 20) having the input shaft (64), the actuator (50), and a drive parameter sensor (94) configured to generate the drive parameter signal (96). 19.Bottom bracket shifter (18) according to claim 18, wherein the drive parameter sensor (94) comprises at least one power sensor (100, 104) arranged on the bottom bracket axle (56) or the input shaft (64).

20. Bottom bracket shifter (18) according to claim 18 or 19, wherein the gear shifting system (52) comprises a crank position sensor (112) configured to output the crank position signal (114).

21. Bottom bracket shifter (18) according to any one of claims 18 to 20, wherein the gear shifting system (52) has a gear sensor (134) configured to generate the gear signal (136).

22. Bottom bracket shifter (18) according to claim 21, wherein the drive parameter sensor (94) is configured to detect at least two power values ​​from the group comprising the user's pedaling power, the assistance power of the auxiliary motor (2), and the total power.

23. Bottom bracket shifter (18) according to any one of claims 18 to 22, wherein the gear shifting system (52) has a manually operable gear switch (22) configured to generate the gear change signal (92) when actuated.

24. Bottom bracket shifter (18) according to any one of claims 18 to 23, wherein the gear shifting system (52) has an auxiliary motor (2). 25.Method for switching between the gears of a multi-speed bottom bracket gearbox (18, 20) of a bicycle (1) with an auxiliary motor (2), actuated by an actuator (50), wherein, upon a gear-shift signal (92) generated by a user of the bicycle (1), the actuator (50) is automatically actuated depending on a torque (68) at the input shaft (64).

26. Method according to claim 25, wherein the actuator (50) is operated when the torque (68) applied to the input shaft (64) of the bottom bracket gearbox (18, 20) is less than a predetermined value.

27. Method according to claim 25 or 26, wherein the actuator (50) is automatically operated when an angular position (108) of a pedal crank (8) of the bicycle (1) is within a predetermined range (116).

28. A method according to any one of claims 25 to 27, wherein the support power of the auxiliary motor (2) is automatically reduced during operation of the actuator (50). 29.A method according to claim 28, wherein the support power is automatically reduced to a value at which the torque (68) at the input shaft (64) is less than a predetermined limit. A method according to any one of claims 25 to 29, wherein the predetermined value of the torque (68) during a switchover depends on a switching direction.

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