Method for controlling a gear shift in a transmission

Abstract

Method for controlling a gear shift in a transmission (4), wherein the transmission (4) is part of a micromobility vehicle (6) and the micromobility vehicle (6) further comprises a crank (10) and wherein the gear shift is carried out with an electric actuator (8), the method comprising the steps: - Detection (S1.1) of a user's switching request, - Detecting (S1.2) a crank position, - Determining (S2) a maximum current value depending on the detection (S1.2) of the crank position, - controlling (S3) the electric actuator (8) with a control current depending on the switching request, wherein in the control step (S3) the control current is controllable up to the maximum current value, - Holding (S4) the control current to carry out the switching operation and - Switching off (S5) the control current.

Description

Technical area

[0001] The technical field relates to a method for controlling a gearshift in a transmission, as well as a control unit configured to execute the method for controlling a gearshift. Furthermore, the technical field relates to a micromobility vehicle with such a control unit. State of the art

[0002] Manual or partially automated methods for controlling a gearshift in a transmission are known from the prior art. Description of the invention

[0003] The invention relates to a method for controlling a gear shift in a transmission. The transmission can be part of a micromobility vehicle, for example an e-bicycle with a drive motor, such as a pedelec, S-pedelec, e-bike, cargo bike, velomobile, etc., as well as part of an e-scooter, e-scooter, e-light vehicle, or similar. The transmission can be a powershift transmission, for example a derailleur gear system, a planetary gear system, a hub gear system, or alternatively or additionally a bottom bracket gear system. A gear shift can comprise shifting between two different gears of the transmission. Controlling the gear shift in the transmission can comprise performing or not performing the gear shift at a specific time in the transmission.

[0004] The gear shift is performed using an electric actuator. The electric actuator can be an electric motor, for example. To perform the gear shift using the electric actuator, the electric actuator can be connected to an energy storage device, such as a battery, and receive electrical energy from this energy storage device. The electric actuator can be configured to perform gear shifts to higher gears and, alternatively or additionally, to lower gears of the transmission.

[0005] The method includes a step of detecting a user's gearshift request. The gearshift request can be detected via a user interface. The user interface can be a gearshift lever, for example. For example, the gearshift request can contain information about whether the user wants to shift up or down a gear.

[0006] The method further comprises a step of controlling the electric actuator with a control current depending on the gear shift request. The control can occur independently of other states. For example, the control can occur independently of the state of the transmission. The control of the electric actuator with the control current can occur independently of a torque of the transmission and alternatively or additionally independently of a rotational speed of parts of the transmission. The control of the electric actuator can occur when a gear shift request is present. In other words, the control of the electric actuator can occur directly after the gear shift request is detected. The electric actuator can be supplied with electrical energy from the battery by means of the control current immediately upon the presence and detection of the gear shift request.

[0007] During the control step, the control current can be controlled up to a maximum current value. In other words, the electric actuator can be controlled and thus energized with a predefined target current value, which is between 0 and the maximum current value. The control current can be a maximum of the maximum current value. The control current can also be lower than the maximum current value, at least temporarily.

[0008] The method further comprises a step of holding the drive current to perform the switching operation. The holding step may comprise holding the drive current at the predefinable target current value up to the maximum current value. The holding step may comprise controlling the drive current, which is controllable by the predefinable target current value, which is between 0 and the maximum current value. In other words, the holding step may comprise regulating the drive current by the predefinable target current value. During the step of holding the drive current, the switching operation may be successfully performed. Alternatively, the switching operation may not be performed while the drive current is being held. The holding of the drive current may continue until the switching operation has been successfully performed.

[0009] The method further includes a step of switching off the control current. This switching off step can occur after the switching operation has been successfully performed. The step of switching off the control current can interrupt the supply of electrical energy from the battery to the electric actuator. In other words, after the control current has been switched off, the switching operation with the electric actuator can no longer be performed.

[0010] Advantageously, a method is thus shown with which the gearshift process can be controlled directly as a function of the gearshift request by means of a simple implementation. This simple implementation occurs by controlling the electric actuator with the control current. In particular, further processing of the gearshift request and more complex control of the electric actuator can be avoided. The force required to carry out the gearshift process in the transmission and, alternatively or additionally, the required torque depends on the current load on the transmission. For example, when the transmission is under load, a greater force may be required to shift than when the transmission is not under load. The force applied by the electric actuator to carry out the gearshift process depends on the control current.Thus, with a higher control current, the electric actuator can exert a higher torque and, alternatively or additionally, a higher force on parts of the manual transmission to perform the gear shift. By controlling the electric actuator with the control current up to the maximum current value, a clear definition of the maximum permissible load on the transmission during the gear shift is established. Thus, if the transmission is in a high-load state, the electric actuator can be controlled with a control current based on the user's detected gear shift request, although the control current is insufficient to successfully complete the gear shift.If a state transition now occurs from the transmission in the loaded state to a less loaded state, the constant torque applied by the electric actuator and, alternatively or additionally, the constant force applied due to the constant control current may be sufficient to execute the gearshift in the transmission. This method allows for a reproducible gearshift, since the gearshift can be executed at comparable load conditions of the transmission with the same forces or torques from the electric actuator due to the maximum current value.

[0011] According to a further embodiment, if in the holding step the gearshift of the transmission has been carried out by the electric actuator before the expiration of a maximum time period, the switching off step can take place directly after the gearshift has been carried out and before the expiration of the maximum time period since the start of the holding. The maximum time period can be adjustable; for example, the maximum time period can be adjustable by the user and dependent on a user input. The maximum time period can describe the time period for which the control current is held. In other words, the maximum time period can describe a time window in which the gearshift can be carried out. In a virtually load-free state of the transmission, the gearshift can be carried out immediately after the electric actuator has been controlled with the control current, and the switching off step can take place directly after the gearshift has been carried out.With an initially higher load condition, if the load condition transitions to a sufficiently reduced load condition within the maximum time period since the start of the hold, the gear shift can occur before the shutdown step. The sufficiently reduced load condition can describe the load condition of the transmission at which a gear shift can just be performed with the control current.

[0012] Advantageously, the method can thus be used to avoid unnecessary energization of the electrical actuator with the control current when the switching process has already been successfully carried out.

[0013] According to a further embodiment, if the gear shift has not been performed by the electric actuator after the maximum time period has elapsed in the holding step, the switching-off step can be performed after the maximum time period has elapsed since the start of the holding step. Thus, if the transmission is in a high-load state and the electric actuator cannot perform the gear shift due to the control current being limited by the maximum current value, the supply of the control current to the electric actuator can be interrupted. This means that the gear shift can no longer be performed based on the underlying gear shift request.

[0014] Advantageously, the method can thus be used to utilize the user's actual switching request to control the switching process. In other words, after a maximum period of time since the start of the hold, i.e., at least after the same maximum period of time since the detection of the switching request, it can be assumed that the past switching request no longer necessarily corresponds to the user's current switching request after the maximum period has elapsed. Furthermore, the method advantageously allows the electrical actuator to be supplied with the control current without thermally overloading it by switching off the control current again after the maximum period has elapsed.

[0015] The method further comprises a step of determining the maximum current value. The step of controlling the electric actuator with the control current can occur depending on the determination of the maximum current value. Determining the maximum current value can comprise setting the maximum current value. The current value can, for example, be set differently for different transmission materials. For example, for high-quality transmission materials, the maximum current value can be set higher than for cheaper materials. This allows the gear shifting process to be carried out by the electric actuator even with higher forces and torques. This can occur depending on the material properties of the transmission. Wear of the materials and gear shifting performance, i.e. up to which load gear shifting is possible in the transmission, can be influenced by determining the maximum current value.

[0016] Advantageously, the method can thus be applied to different gears and different materials by only determining the maximum current value.

[0017] The transmission is part of a micromobility vehicle, and the micromobility vehicle further comprises a crank. The transmission can be a hub gear in the rear axle of the micromobility vehicle and, alternatively or additionally, a bottom bracket gear in the bottom bracket of the micromobility vehicle. The method further comprises a step of detecting a crank position. Furthermore, the method can comprise a step of detecting a torque applied to the crank and, alternatively or additionally, a step of detecting a cadence of the crank. The maximum current value is determined as a function of detecting the crank position. Alternatively or additionally, the maximum current value can be determined as a function of detecting the torque on the crank and, alternatively or additionally, as a function of detecting the cadence of the crank.The control of the electric actuator with the control current can be directly dependent on the determined maximum current value and only indirectly dependent on the detected crank position. In other words, the dependence on the crank position, torque, and cadence can influence the control of the electric actuator solely by determining the maximum current value.

[0018] The method can advantageously be used to control a gearshift of a micromobility vehicle. For example, in a crank position where the crank is almost horizontal, a high torque can be applied to the crank. In this position, the maximum current value can be set to a relatively low value. Thus, the successful execution of the gearshift with the electric actuator in a horizontal crank position can be prevented or at least made more difficult by the relatively low maximum current value. This can lead to reduced wear on the transmission by avoiding the gearshift in crank positions in which a high torque can act on the crank by setting the maximum current value to a relatively low value.

[0019] According to a further embodiment, the actuation step can be carried out as a function of the detection of the crank position. Alternatively or additionally, the actuation step can be carried out as a function of the detection of the torque on the crank and alternatively or additionally as a function of the detection of the cadence of the crank. Thus, in addition to the actuation current, the electrical actuator can be controlled by means of a further signal as a function of the detected crank position such that the switching process is not carried out in horizontal positions of the crank and the switching process is carried out in almost vertical positions of the crank. This additional actuation dependency can occur independently of the maximum current value. For example, the actuation current can also be switched off as a function of the detected crank position when the crank position is in the horizontal position.Alternatively or additionally, the control can be based on a temporal change in the crank position. This way, the control current can be switched off if the temporal change in the crank position shows that the crank position has not changed for a certain period of time. This can prevent a gear change from being performed when the transmission is stationary. Alternatively, gear changes can be performed deliberately while the transmission is stationary, if the transmission's technical capabilities allow this. This can lead to less wear on the transmission.

[0020] Advantageously, the method can be used to perform the gear shift in direct dependence on the crank position, allowing the system to react to transmission conditions, such as a crank stop. This can reduce transmission wear.

[0021] According to a further embodiment, the transmission can have at least three gears, wherein in the step of determining the maximum current value for a first shift operation between a first and a second gear, a first maximum current value is determined, and wherein in the step of determining for a second shift operation between the second and a third gear, a second maximum current value is determined. For example, the transmission can have three gears. A first maximum current value can be determined for the shift operation between the first and the second gear. Furthermore, a second maximum current value can be determined for a shift operation between the second and the third gear.

[0022] The second maximum current value can be greater in absolute terms than the first maximum current value. This allows the electric actuator to be controlled with the control current up to different maximum current values. This allows the electric actuator to exert a different force or torque on the transmission to perform the gear shift.

[0023] The method can advantageously be used when different relative gear ratio changes occur between first and second gear, and between second and third gear. Different maximum current values ​​for the different gear shifts can be used to accommodate the fact that different torques or forces applied to the manual transmission by the electric actuator may be necessary to achieve a smooth gear shifting experience for the user. Thus, the method can be used to implement smooth gear shifting with the electric actuator.

[0024] According to a further embodiment, the step of determining the maximum current value can be performed depending on a shift direction. Thus, a lower maximum current value can be determined for shifting from second to first gear, and a higher maximum current value can be determined for shifting from first to second gear.

[0025] Advantageously, a higher maximum current value can be determined when shifting to a higher gear, where a higher torque may be necessary for this shifting process. This allows the shifting process to be carried out successfully. At the same time, the maximum current value when downshifting can be determined to a lower value due to the lower torque or force required by the electric actuator. This allows the shifting process from second to first gear to be carried out successfully, with the control current being limited to the lower maximum current value relative to the maximum current value for shifting to the higher gear. This avoids unnecessary energization of the electric actuator, which can contribute to energy efficiency and prevent thermal overload of the actuator.

[0026] According to a further embodiment, the method can comprise a step of detecting an additional user input. The additional user input can be entered via a user interface, for example, by means of a switch. The additional user input, or user input, can be detected via the user interface in addition to the actual gearshift request, which can also represent user input. The step of determining the maximum current value can be dependent on the step of detecting the user input. For example, the driver can input that they wish to operate the transmission and thus shift gears in a comfort mode or in a sport mode. In a comfort mode, the maximum current value can be set to a lower value than in sport mode. A higher determined current value can result in the gearshift being possible even under higher loads on the transmission.

[0027] Advantageously, the method can thus be used for various transmission operating modes. User preferences can be addressed, whether priority should be given to reduced shifting performance, reduced wear, and improved acoustics during gear shifting, or to increased shifting performance with increased transmission wear.

[0028] A further aspect of the invention relates to a control unit which is configured to carry out the method for controlling the gearshift process in a transmission according to an embodiment of the preceding aspect of the invention. The control unit can have a microprocessor and interfaces. Furthermore, the control unit can have a storage medium, wherein commands for carrying out the method according to an embodiment of the preceding aspect of the invention can be stored on the storage medium. The processor can be configured to read and execute the commands stored on the storage medium. The user's gearshift request can be detected via the interfaces, and the electrical actuator can be controlled, held, and switched off. Information on the detected crank position, the torque on the crank, and the cadence of the crank can be read in via the interface.Further user input, such as inputs regarding different modes, can be read via the interface. The processor can be configured to regulate the drive current during the step of holding the drive current so that it remains nearly constant during the holding period.

[0029] A further aspect relates to a micromobility vehicle with a transmission, an electric actuator, and a control unit according to the previous aspect of the invention. Furthermore, the micromobility vehicle can have a user interface for detecting the gear shift request and, alternatively or additionally, for detecting the user input. Furthermore, the micromobility vehicle can have an energy storage device, such as a battery. The electric actuator, the control unit, and the battery can be connected to one another so that the control unit can be powered by the battery, and the control unit can control the electric actuator such that the electric actuator is powered by electrical energy from the battery. The control unit can be configured to carry out gear shifts in the transmission using the electric actuator. Short description of the characters Fig. 1 schematically shows steps of a method for controlling a switching operation according to an embodiment. Fig. 2 schematically shows components of a micromobility vehicle with a control unit according to an embodiment. Detailed description of embodiments

[0030] Fig. 1 schematically shows steps of a method for controlling a gear shift according to an embodiment. According to the embodiment, a gear shift is controlled in a transmission 4 of a micromobility vehicle 6, wherein Fig. 2 schematically shows components of the micromobility vehicle 6. In a step of detecting a shift request from the user (S1.1), a user interface 12 of the micromobility vehicle 6 detects that the user has a shift request. In other words, the user wishes to perform a shift in the transmission 4. The user interface 12 is designed as a gearshift lever. In the detection step S1.1, according to the embodiment, it is detected that the user wishes to shift up a gear.

[0031] The method further comprises a step S1.2 of detecting a crank position. The crank position describes the position of a crank 10 of the micromobility vehicle 6. The crank position is detected by means of a sensor. Furthermore, the method comprises a step S1.3 of detecting an additional user input from the user. The additional user input is made via the user interface 12. The additional user input comprises information regarding the mode in which the user wishes to use the micromobility vehicle 6. The additional user input does not comprise the gearshift request as such, but rather additional information from the user. In the embodiment shown, the user wishes to use the micromobility vehicle 6 in sport mode.

[0032] The method further comprises a step S2 of determining a maximum current value. The step of determining S2 takes place in a control unit 2 of the micromobility vehicle 6. For this purpose, the control unit 2 is connected to the user interface 12 and to the sensor for detecting the crank position S1.2. In the step of determining S2, the control unit 2 determines the maximum current value as a function of the detected crank position and as a function of the detected user input. The maximum current value is determined independently of the gear shift request. According to the embodiment, the detected crank position indicates that the crank 10 is in a vertical position. The maximum current value is therefore determined to be relatively high because the user wishes to use the micromobility vehicle 6 in sport mode, and the crank 10 is in a position in which no or only a small torque can be transmitted by the driver.

[0033] The method further comprises a step S3 of controlling an electric actuator 8 with a control current. The electric actuator 8 is connected to a battery 19 of the micromobility vehicle 6 and to the control unit 2. The control unit 2 is configured to control the electric actuator 8. In doing so, the control unit 2 controls the supply of electrical energy from the battery 19 to the electric actuator 8. The control current is the current with which the electric actuator 8 is energized. The step of controlling S3 occurs as a function of the step of detecting S1.1 the switching request. In other words, the control S3 occurs when the step of detecting S1.1 the switching request has occurred. Furthermore, the step of controlling S3 the electric actuator 8 occurs as a function of the step of determining S2 the maximum current value. Thus, in the control step S3, the control current can be controlled up to the specific maximum current value.Furthermore, the control step S3 is directly dependent on the crank position detection step S1.2. In the crank position detection step S1.2, both the absolute crank position and the temporal progression of the crank position are detected. Thus, the control S3 of the electric actuator 8 is interrupted with the control current or specifically controlled / changed when the user stops pedaling and the crank position remains unchanged over time.

[0034] The method further comprises a step S4 of holding the control current. In step S4, the control unit 2 regulates the control current such that it is in a range between 0 and the maximum current value. If the transmission 4 is under high load, the gear shift is not carried out because the control current is not sufficient for the electric actuator 8 to apply a sufficiently high torque to the transmission 4 to carry out the gear shift. When the control current is held S4, a timer begins to run. The timer runs for a maximum period of time. If the transmission 4 reaches a state of lower load within the maximum period of time during the holding S4, the gear shift is carried out with the electric actuator 8 if the torque due to the control current is sufficient to carry out the gear shift.If the switching operation takes place before the maximum time has elapsed, a step of switching off S5 of the control current takes place directly, shown via path A in . Fig. 1, after the switching operation has been performed. In other words, the control current is not maintained until the maximum time period has elapsed once the switching operation has been performed. This saves energy and protects against excessive thermal stress on the electrical actuator 8. The control unit 2 is therefore configured to detect the successful completion of the switching operation and to switch off the control current. If the switching operation has not been successfully performed after the maximum time period has elapsed since the start of the holding S4, the switching-off step S5 takes place after the maximum time period has elapsed since the start of the holding S4, shown via path B in Fig.1. The control unit 2 is configured to detect the elapse of the maximum time period and, if this has not already happened, to switch off the control current. Reference symbol 2 control unit 4 gearboxes 6 Micromobility vehicle 8 electric actuator 10 crank 12 User interface 19 Battery S1.1 (Step) Detecting a switching request S1.2 (Step) Detecting a crank position S1.3 (Step) Capturing an (additional) user input S2 (step) Determining a maximum current value S3 (step) Controlling an electrical actuator with a control current S4 (Step) Hold the control current S5 (step) Switching off the control current A (Way) The switching off step takes place directly after a switching operation has been carried out B (Distance) The switching off step takes place after a maximum time has elapsed since the start of the hold

Claims

[1] Method for controlling a gear shift in a transmission (4), wherein the transmission (4) is part of a micromobility vehicle (6) and the micromobility vehicle (6) further comprises a crank (10) and wherein the gear shift is carried out with an electric actuator (8), the method comprising the steps: - Detection (S1.1) of a user's switching request, - Detecting (S1.2) a crank position, - Determining (S2) a maximum current value depending on the detection (S1.2) of the crank position, - controlling (S3) the electric actuator (8) with a control current depending on the switching request, wherein in the control step (S3) the control current is controllable up to the maximum current value, - Holding (S4) the control current to carry out the switching operation and - Switching off (S5) the control current. [2] Method according to claim 1, wherein, if in the step of holding (S4) the switching operation of the transmission (4) by the electric actuator (8) has been carried out before the expiration of a maximum time period, the step of switching off (S5) takes place directly (A) after the switching operation has been carried out and before the expiration of the maximum time period since the start of the holding (S4). [3] Method according to claim 1 or 2, wherein, if in the step of holding (S4) the switching operation by the electrical actuator (8) has not been carried out after the expiration of the maximum time period, the step of switching off (S5) takes place after the expiration of the maximum time period since the beginning of the holding (S4) (B). [4] Method according to one of the preceding claims, wherein the step of controlling (S3) is carried out in dependence on the detection (S1.2) of the crank position. [5] Method according to one of the preceding claims, wherein the transmission (4) has at least three gears, and wherein in the step of determining (S2) the maximum current value for a first shift operation between a first and a second gear, a first maximum current value is determined, and wherein in the step of determining (S3) for a second shift operation between the second and a third gear, a second maximum current value is determined. [6] Method according to one of the preceding claims, wherein the step of determining (S2) the maximum current value is carried out as a function of a switching direction. [7] Method according to one of the preceding claims, further comprising a step of detecting (S1.3) an additional user input, wherein the step of determining (S2) the maximum current value is performed in dependence on the step of detecting (S1.3) the user input. [8] Control unit (2) which is configured to carry out the method for controlling the gear shifting operation in a transmission (4) according to one of the preceding claims. [9] Micromobility vehicle (6) with a transmission (4), an electric actuator (8) and a control unit (2) according to claim 8, which is designed to carry out switching operations in the transmission (4) with the electric actuator (8).

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