Method for operating a gearing of a bicycle

Abstract

The present invention relates to a method for operating a gearing of a bicycle, in particular of an electric bicycle, the gearing comprising a derailleur having a shifting device which is designed to move a bicycle chain between various sprockets, the method comprising the steps of: detecting a shifting movement performed by the shifting device, determining a number of revolutions of the sprockets in response to detecting the shifting movement performed by the shifting device, and generating a target gear signal when the determined number of revolutions reaches a predetermined shifting number of revolutions.

Description

[0001] Description

[0002] title

[0003] Method for operating a bicycle gear system

[0004] State of the art

[0005] The present invention relates to a method for operating a gearshift of a bicycle, and a bicycle.

[0006] Bicycle gear systems are commonly known as derailleur gears. In this system, the bicycle chain is moved between the sprockets by a shifting mechanism. Before the new gear is actually engaged after a shift, the chain typically has to complete a certain number of revolutions. Electronic gear systems are also known, in which a shift signal is transmitted electrically from a shift lever to the derailleur. Usually, the newly engaged gear or gear change is transmitted as soon as the electrical shift signal is generated.

[0007] Disclosure of the invention

[0008] The method according to the invention, with the features of claim 1, is characterized in that a particularly precise and reliable transmission of a target gear after a shifting operation can be achieved using simple and cost-effective means. This is achieved according to the invention by a method for operating the gear shifting system of a bicycle, preferably an electric bicycle, wherein the gear shifting system comprises a derailleur system with a shifting device. The shifting device is configured to move a bicycle chain onto different sprockets. The method comprises the following steps:

[0009] - Detecting movement of the switching device, - Determining the number of revolutions of the pinions in response to the detection of the switching movement of the switching device, and

[0010] - Generating a target gear signal when the determined number of revolutions reaches a predetermined switching revolution number.

[0011] In particular, the gearshift has several different discrete gears, which are provided by the different sprockets.

[0012] A derailleur and / or a front derailleur can preferably be considered the switching device.

[0013] A switching movement of the switching device is considered in particular to be a movement which effects a switching process, i.e. a gear change, by changing the chain to a different sprocket.

[0014] The target gear signal represents the newly engaged gear after the shift or gear change. The target gear signal can, in particular, comprise an electrical signal and / or information representing the new gear after the shift or gear change. The target gear signal specifically represents the point in time at which the shift or gear change is complete.

[0015] The predetermined shift revolution count specifies the number of revolutions of a sprocket required to complete a gear shift. This predetermined shift revolution count is unique for each gear change. Each gear change requires a specific number of sprocket revolutions (predetermined shift revolution count).

[0016] In other words, the method detects a shifting movement of the shifting device and, in particular from the moment the shifting movement is detected, determines the number of revolutions of the sprockets, i.e., tracks them. When the determined number of revolutions reaches a predetermined value, namely the predetermined number of shift revolutions, the target gear signal is generated. This target gear signal can then be used, for example, to transmit information about the gear selected after the shifting process. The method thus offers the advantage that the target gear signal, which preferably represents the new gear and / or a completed gear change, is only reliably provided once the chain has been securely moved onto the sprocket of the new target gear. Therefore, information about the current gear ratio can be provided with exceptional reliability and precision at all times while the bicycle is in operation.In particular, additional bicycle functions that use information about the current gear ratio and / or gear changes can be performed with exceptional reliability and are optimally coordinated with the drivetrain. This also ensures a particularly high level of user comfort for the cyclist.

[0017] The dependent claims describe preferred embodiments of the invention.

[0018] Preferably, the number of shift revolutions is defined individually for each gear change. This means that for each shift from one sprocket to an adjacent sprocket, a separately adjusted number of shift revolutions is defined. This takes into account the different diameters and mechanical properties during the respective gear changes between the various sprockets, allowing for a particularly precise generation of the target gear signal. Thus, the exact moment of the fully completed gear change can be specified with exceptional accuracy.

[0019] Preferably, all different shift revolution counts are stored in a lookup table. This means that all shift revolution counts are predefined values ​​stored in the lookup table. Specifically, after each detected shift movement, the corresponding shift revolution count for the currently executed gear change is retrieved from the lookup table and used for subsequent monitoring of the pinion revolutions. This allows for particularly simple and cost-effective monitoring of gear changes.

[0020] Particularly preferably, the detection of the shifting movement includes detecting the end point of the shifting movement of the switching device. Determining the number of revolutions of the pinions begins at the end point of the detected shifting movement. That is, tracking the number of revolutions of the pinions begins at the moment when the movement of the switching device ends. This ensures, with particular reliability, that the mechanical gear change to the new pinion occurs before the target gear signal is generated, by subsequently determining the number of revolutions and generating the target gear signal only after the predetermined number of shifting revolutions has been reached. Thus, the method can be carried out in a particularly simple and precise manner. Preferably, the end point of the shifting movement of the switching device can be detected by means of sensors.Alternatively, preferably, the endpoint can be determined starting from a starting point of the switching movement, whereby a predetermined time period for the movement of the switching device is assumed for each switching operation.

[0021] Preferably, the detection of the shifting movement of the shifting device is based on a manually and / or automatically generated shift signal. A manually generated shift signal can preferably be considered to be one generated manually by a bicycle rider, in particular by means of a shift lever. The shift lever can preferably be configured for mechanical actuation, for example by means of a cable, or for electronic actuation of the shifting device, wherein, in particular, an electrical signal is generated by the shift lever when it is actuated. An automatically generated shift signal can, in particular, be considered to be one generated by means of a control unit, which is preferably generated automatically based on one or more parameters.By using the switching signal to determine the movement of the switching device, a particularly simple and cost-effective way of carrying out the procedure can be provided.

[0022] Preferably, the target gear signal includes information about the gear ratio engaged after the shifting process is complete. This means that the target gear signal can simultaneously transmit information about the current gear ratio after the shift to, for example, other components or functions of the bicycle. This allows for optimized operation of these other bicycle components and functions. In particular, it can provide a high level of user comfort for the cyclist. Preferably, the method further includes the step of determining the bicycle speed and / or the rear wheel rotational speed after generating the target gear signal and based on the gear ratio. Preferably, the bicycle speed and rear wheel rotational speed can be converted into each other using a known rear wheel circumference.In particular, the new gear ratio transmitted as part of the target gear signal is used, that is, the gear ratio updated after the gear change. Preferably, in addition to the gear ratio, the rear wheel circumference of the bicycle and the instantaneous cadence and / or motor speed of a drive unit of the bicycle, especially if the bicycle is an e-bike, are used to determine the bicycle speed and / or the rear wheel speed. This allows the instantaneous bicycle speed and / or the rear wheel speed to be determined with particularly high accuracy and high temporal resolution.

[0023] Preferably, the bicycle speed and / or rear wheel speed are determined after a predetermined time interval has elapsed following the generation of the target gear signal. That is, after the target gear signal has been generated, the system waits for the predetermined time interval before determining the current bicycle speed. This ensures with particular reliability that the chain is fully engaged with the new sprocket after the gear change. This allows the bicycle speed to be determined with exceptional accuracy.

[0024] Preferably, the method further comprises, particularly when the bicycle is an e-bike, controlling a walk assist function based on the target gear signal. A walk assist function is defined in particular as the operation of a drive unit to generate motor torque, which occurs when the rider pushes the bicycle, i.e., without pedaling. Specifically, the operation of the walk assist function can utilize a target rotational speed at a chainring that can be driven by the motor torque of the drive unit, the circumference of the rear wheel, and the determined current gear ratio to provide a predefined target walking speed for the bicycle through controlled operation of the drive unit. Precise determination of the gear shift point and the gear ratio enables particularly reliable and comfortable operation of the walk assist function.Alternatively or additionally, the method preferably includes actuating the drive unit of the electric bicycle based on the target gear signal. This means that the controlled operation of the drive unit to generate motor torque while the electric bicycle is in motion can be based on the target gear signal. For example, this allows the current gear position of the gear system to be reliably and with high resolution taken into account, enabling particularly targeted, efficient, and wear-free operation of the electric bicycle.

[0025] Particularly preferably, the number of revolutions of the sprockets is determined based on recording a temporal rotational speed profile of the sprockets. That is, the rotational speed of the sprockets is determined and tracked over time. In particular, the distance traveled per revolution can be integrated over time to track the number of revolutions. Preferably, the rotational speed of the sprockets can be determined, in particular, from the rotational speed of the chainring and the gear ratio of the last gear engaged, i.e., the previously engaged gear (before the shifting process or gear change). The rotational speed of the chainring is determined based on a maximum of a motor speed of the drive unit, for example, at the chainring connected to the drive unit, and a cadence. This allows the number of revolutions to be determined in a particularly simple and cost-effective manner using simple sensors.The resulting rotational speed of the pinions is integrated over time, which determines the number of revolutions of the pinions.

[0026] Preferably, the method further comprises the step of delaying a subsequent gear change until the target gear signal is received. In particular, a gear change is thus delayed or prevented between the detection of the shifting movement and the generation of the target gear signal. That is, if, for example, a further gear change is requested by means of a shift signal before the previous gear change is completely finished, the execution of the subsequent gear change is deliberately delayed until the selected gear has been reliably detected based on the target gear signal. This enables particularly reliable and comfortable operation of the bicycle's gear system. Furthermore, the invention leads to a bicycle, in particular an e-bike, comprising a gear system that includes a derailleur system with a shifting device. The shifting device is designed to move a bicycle chain between different sprockets.Furthermore, the bicycle includes a control unit configured to carry out the described method. In particular, the bicycle can be an electric bicycle that includes a drive unit. Preferably, the control unit for carrying out the method can correspond to the control unit of the drive unit.

[0027] Preferably, the sprockets of the gear shift are part of a cassette, which is arranged on a rear wheel hub of the bicycle.

[0028] Brief description of the drawings

[0029] An embodiment of the invention is described in detail below with reference to the accompanying drawings. The drawing shows:

[0030] Figure 1 shows a simplified schematic view of an electric bicycle in which a method for operating a gearshift according to a preferred embodiment of the invention is carried out, and

[0031] Figure 2 shows a highly simplified schematic view of the method according to the invention.

[0032] Embodiments of the invention

[0033] Preferably, all identical components, elements and / or units in all figures are provided with the same reference numerals.

[0034] Figure 1 shows a simplified schematic view of an electric bicycle 100, in which a method 10 for operating a gearshift 1 of the bicycle 100 is carried out according to a preferred embodiment of the invention. Figure 2 shows a highly simplified schematic view of the method according to the invention.

[0035] The bicycle 100 is an electric bicycle comprising a drive unit 110 with a motor, in particular an electric motor. The motor can be supplied with electrical energy by means of an electrical energy storage device 109 of the bicycle 100. The drive unit 110 is located in the area of ​​the bottom bracket of the bicycle 100.

[0036] The motor torque generated by the motor can provide motor assistance to the pedaling force generated by the rider of bicycle 100. The rider's muscle power can be applied via a crank mechanism with cranks 104.

[0037] The drive unit 110 further comprises a control unit 50, which is configured to actuate the motor in a controlled manner. For example, the control unit 50 can control an electrical actuation current to actuate the motor. Preferably, the control unit 50 is additionally configured to carry out the method 10 according to the invention.

[0038] The bicycle 100 comprises a gear system 1, which is designed as a derailleur system 2. The derailleur system 2 includes a cassette 101 on a rear hub of the bicycle 100. The cassette 101 comprises a number of sprockets 5, by means of which different gear ratios can be provided in the drivetrain of the bicycle 100.

[0039] The bicycle 100 is driven by the crank mechanism with the drive unit 110 via a chainring 107, which can be driven by the motor torque of the drive unit 110 as well as by the pedaling torque applied via the cranks 104. The resulting total torque is transmitted from the chainring 107 via a bicycle chain 4 to the cassette 101.

[0040] Furthermore, the derailleur system includes a shifting device 3, which can move the bicycle chain 4 between the different sprockets 5 of the cassette 101 in order to change the gear ratio. In particular, the shifting device 3 can also be referred to as a front derailleur or rear derailleur. The shifting device 3 can be actuated by means of a shift signal. The shift signal can either be generated automatically by the control unit 50, for example, depending on various riding parameters such as bicycle speed and / or cadence. Alternatively, and preferably, the shift signal can be generated by means of a manual shifting device 8, which, for example, includes a shift lever.

[0041] Method 10 allows for precise monitoring of the switching processes, as described below with reference to Figure 2.

[0042] In method 10, the switching signal 15 is first detected. Upon detection of the switching signal 15, a switching movement of the switching device 3 is detected 11. In detail, the end time of the switching movement of the switching device 3 is determined. This can be done, in particular, by considering the end time of the movement as a time that lies a predefined time interval after the time of the switching signal 15.

[0043] Immediately after the detection 11 of the switching movement of the switching device 3, that is, immediately from the end time of the switching movement, a determination 12 of the number of revolutions of the pinion 5 takes place.

[0044] Determining the number of revolutions of pinion 5 is done by recording a time-dependent rotational speed profile of pinion 5. That is, for example, based on the rotational speed of pinion 5 recorded by a speed sensor, the number of revolutions of pinion 5 is tracked, in other words, counted.

[0045] When the number of revolutions of the pinion 5 determined in step 12 reaches a predetermined number of shift revolutions, a target gear signal 13 is generated immediately in response.

[0046] The number of shift revolutions is a fixed parameter individually defined for each specific gear change, which is stored in a lookup table. This means that the lookup table contains a corresponding predefined number of shift revolutions for every possible gear change on the 101-speed cassette. In particular, the gear changes are differentiated according to the direction of shifting (up or down) and the specific sprocket before and after the shift.

[0047] The target gear signal is understood to be information that represents a fully completed gear shift. That is, if a target gear signal is generated in step 13, it is assumed that the bicycle chain 4 has completely shifted to the desired gear, i.e., the desired sprocket 5.

[0048] Additionally, the target gear signal includes information about the gear ratio engaged after the switching operation, that is, for example, the numerical value of the newly engaged gear ratio. Preferably, this information can be obtained based on a tracking of the switching operations or gear ratio changes.

[0049] Method 20 thus offers the advantage that the exact time at which the shifting process is reliably completed, i.e., at which the bicycle chain 4 has reliably shifted onto the desired next sprocket 5, can be determined with particular reliability and temporal precision. In particular, situations can be avoided in which a gear change is assumed to have already taken place based on the shift signal 15, but the chain 4 is not yet fully positioned on the corresponding sprocket due to the mechanical characteristics of the chain movement during the gear change, in order to reliably allow torque transmission.

[0050] Furthermore, by reliably and precisely generating 13 the target gear signal at the time when the new gear is safely engaged, additional advantageous functions can be provided, as described below by way of example.

[0051] The procedure 10 can include determining 16 a bicycle speed after generating 13 the target gear signal and based on the new gear ratio. The determination 16 of the bicycle speed can additionally take place after a predetermined time interval has elapsed following the generation 13 of the target gear signal.

[0052] The predetermined time interval can have a predefined value, for example at least 10 ms, preferably a maximum of 50 ms. This ensures, in particular, that the drivetrain is properly tensioned after a gear change, thus enabling particularly precise and reliable speed measurement.

[0053] Preferably, the determination of the bicycle speed can additionally be based on a known rear wheel circumference of a rear wheel of the bicycle 100 and on a motor speed and / or a cadence.

[0054] Furthermore, the method 10 can include controlling a push assist 17 based on the target gear signal. In particular, this allows for optimal timing of the push assist, which involves activating the drive unit 110 while the rider is pushing the bicycle 100. Moreover, if the current gear ratio is known, the target pushing speed of the bicycle 100 can be set particularly precisely and reliably by operating the drive unit 110 accordingly.

[0055] Furthermore, in method 10, the drive unit 110 of the electric bicycle 100 can be actuated based on the generated target gear signal. This means that the controlled provision of motor torque by means of the drive unit 110 can be specifically dependent on the target gear signal and, in particular, based on the gear ratios provided by method 10. This allows for particularly flexible and comfortable operation of the bicycle 100 for the rider.

Claims

Claims 1. Method for operating a gearshift (1) of a bicycle (100), in particular an electric bicycle, wherein the gearshift (1) comprises a derailleur gear (2) with a shifting device (3) which is configured to move a bicycle chain (4) between different sprockets (5), comprising the steps: Detecting (11) a switching movement of the switching device (3), determining (12) a number of revolutions of the pinions (5) in response to the detection (11) of the switching movement of the switching device (3), and Generating (13) a target speed signal when the determined number of revolutions reaches a predetermined switching revolution number.

2. Method according to claim 1, wherein the number of shift revolutions is individually defined for each gear change.

3. Method according to claim 2, wherein all switching revolution numbers are stored in a lookup table.

4. Method according to one of the preceding claims, wherein the detection (11) of the switching movement comprises a detection of an end time of the switching movement of the switching device (3), and wherein the determination (12) of the number of revolutions of the pinions (5) begins at the end time of the detected switching movement.

5. Method according to one of the preceding claims, wherein the detection (11) of the switching movement of the switching device (3) is based on a manually and / or automatically generated switching signal (15).

6. Method according to one of the preceding claims, wherein the target signal includes information about the gear ratio applied after the switching operation.

7. The method of claim 6, further comprising the step of: Determining (16) a bicycle speed and / or a rear wheel rotational speed after generating (13) the target gear signal and based on the gear ratio.

8. Method according to claim 7, wherein the determination (16) of the bicycle speed and / or the rear wheel rotation speed takes place after a predetermined time interval has elapsed following the generation (13) of the target gear signal.

9. Method according to any of the preceding claims, further comprising: controlling (17) a push assist based on the target speed signal, and / or Actuation (18) of a drive unit (110) based on the target gear signal.

10. Method according to one of the preceding claims, wherein the determination (12) of the number of revolutions is based on a detection of a time-dependent rotational speed profile of the pinions (5).

11. Method according to any of the preceding claims, further comprising the step of: Delaying a further gear change until the target gear signal.

12. Bicycle, in particular electric bicycle, comprising: a gear shift (1) comprising a derailleur gear (2) with a shifting device (3) which is configured to move a bicycle chain (4) between different sprockets (5), and a control unit (50) which is configured to carry out the method (10) according to one of the preceding claims.

13. Bicycle according to claim 12, wherein the sprockets (5) are part of a cassette (101) on a rear wheel hub (102) of the bicycle (100).

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