Method for operating bicycle transmission and bicycle

Abstract

To provide a method for operating an electric bicycle transmission that can provide particularly accurate and reliable switching of a chain shifting device by using a simple and cost-effective means.SOLUTION: The invention is related to a method for operating a transmission for a bicycle, in particular an electric bicycle. The transmission is provided with a chain shifting device that includes a shifting device set to be able to controllably move a bicycle chain between different sprockets. Only after the end of a gear change is detected and the end of the previous gear change is detected, the shifting device is controlled and actuated to perform gear changes only to adjacent gears and sequentially such that a new gear change can be performed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method of operating a bicycle transmission and to a bicycle. [Background technology]

[0002] Bicycle transmissions with chain shifting devices are known. In these cases, the bicycle chain is moved between sprockets by a shifting device. After a shifting process, the sprockets usually first have to rotate a certain number of times before the new gear is actually engaged. Therefore, when shifting processes are performed in rapid succession, there is a possibility that the next gear will already be preselected before the previous gear change has been fully effected. If the shifting mechanism or front derailleur is moved accordingly, the chain may run diagonally across several sprockets, which may increase wear, among other things. Summary of the Invention

[0003] In contrast, the method according to the present invention, having the features of claim 1, is characterized by the fact that it provides particularly accurate and reliable shifting of a chain shifting device using simple and cost-effective means. According to the present invention, this is achieved by a method for operating a transmission for a bicycle, in particular an electric bicycle, which includes a chain shifting device with a controllably actuable shifting device. The shifting device is configured to move the bicycle chain to a different sprocket. In this method, the end of a gear change is detected. The shifting device is then controlled and activated to perform gear changes, in particular all gear changes, only to adjacent gears and sequentially, so that a new gear change can only be performed once the end of the previous gear change has been detected.

[0004] Preferably, the shifting mechanism and / or the front derailleur can be considered a shifting device.

[0005] In particular, a gear change is defined as a shifting of a bicycle chain from one sprocket to another by a shifting device. In this case, a gear change specifically includes a state immediately between two sprockets, each of which is immediately before and after a full engagement. In this case, for example, full engagement can be defined as engagement with a predetermined number of sprocket teeth. Therefore, in particular, the end of a gear change defines a state in which the shifting device holds the bicycle chain on the sprocket of the target gear and the bicycle chain is in a predetermined target engagement state with the sprocket of the target gear.

[0006] In other words, in this method, the end of a gear change is precisely detected, and a new gear change is only permitted once the end of the previous gear change has been reliably recognized. This means, in particular, that a new gear change is precisely prevented before the previous gear change has been completely completed. Furthermore, only adjacent gears are shifted to sequentially. Therefore, in particular, only adjacent sprockets with a bicycle chain are engaged as adjacent gears during a gear change. That is, only one of the directly adjacent gears is shifted to during the shifting process.

[0007] This method therefore offers the advantage that a new shifting operation can only be performed once the completion of the previous shifting operation has been reliably recognized. This results in numerous advantages, particularly from a mechanical standpoint. Specifically, it ensures that a relatively large portion of the bicycle chain always engages with at least one of the corresponding sprockets of the two gears before and after the gear change during a precise shifting operation from one gear to the next, ensuring that the bicycle chain can always transmit sufficient force. This may further prevent chain slippage as much as possible. This may also significantly reduce wear and tear on the shifting system, particularly compared to situations in which the bicycle chain may be tilted across more than two sprockets simultaneously. Furthermore, this method always allows for rapid processing of shift commands with as precise chain movement as possible. This means that particularly rapid switching of multiple gears in succession is possible, particularly when the shifting device initiates the next gear change immediately after the completion of the previous gear change has been recognized.

[0008] The dependent claims show preferred developments of the invention.

[0009] Preferably, the end of the gear change is recognized based on the lapse of a predetermined period of time after the start of the gear change is recognized. In this case, this recognition is performed, in particular, only during chain movement of the bicycle chain. In other words, the gear change is considered complete after the lapse of a predetermined period of time after the start of the gear change, especially if the bicycle chain is constantly moving during that time. The predetermined period of time can be, for example, at least 0.5 seconds, preferably at most 2 seconds. This makes the method particularly simple and cost-effective to implement.

[0010] Preferably, the completion of the gear change is recognized in response to detecting a predetermined number of chainring rotations of the bicycle chainring after the start of the gear change has been recognized. In other words, the number of chainring rotations is detected and, in particular, recorded since the start of the gear change has been recognized. The gear change is considered to be completed when this predetermined number of chainring rotations is reached. In particular, a chainring is considered to be a transmission element that is non-rotatably connected to the bicycle crankshaft and / or crank and engages with the bicycle chain. Preferably, the number of chainring rotations can be determined based on cadence detection. For example, the predetermined number of chainring rotations can be at least 0.5 revolutions, preferably at most 3 revolutions. This allows for particularly reliable monitoring of the completion of the gear change.

[0011] More preferably, the end of the gear change is recognized in response to detecting a predetermined chainring angle of the bicycle chainring after the start of the gear change is recognized. In other words, the angle through which the bicycle chainring rotates since the start of the gear change is detected and recorded. The gear change is considered complete when the detected angle reaches the predetermined chainring angle. For example, the predetermined chainring angle can be at least 180 degrees, preferably up to 1080 degrees. For example, the chainring angle can be detected using an angle sensor on the chainring and / or a component connected thereto.

[0012] Preferably, the end of the gear change is recognized in response to detecting a predetermined number of sprocket revolutions of the sprocket after the start of the gear change is recognized. In other words, the number of sprocket revolutions is detected and recorded since the start of the gear change. The gear change is considered complete when the detected number of sprocket revolutions reaches the predetermined number of sprocket revolutions. For example, the number of sprocket revolutions can be detected directly by detecting the rotational movement of the sprocket, for example, by a rotational speed sensor and / or an angle sensor. Alternatively, the number of sprocket revolutions can be detected indirectly, for example, by an element, such as a chain or chainring, that engages with the sprocket. This allows for particularly reliable and accurate detection of sufficient rotational movement of the sprocket to recognize the end of the gear change.

[0013] More preferably, the end of the gear change is recognized in response to detecting a predetermined sprocket rotation angle of the sprocket after the start of the gear change is recognized. In other words, the sprocket rotation angle is detected and recorded after the start of the gear change is recognized. The gear change is considered complete when the total rotation angle reaches the predetermined sprocket rotation angle. In particular, the predetermined sprocket rotation angle is at least 360 degrees, preferably up to 1080 degrees. For example, the sprocket rotation angle can be detected directly, for example, by a rotation angle sensor, or alternatively, indirectly, preferably via a component such as a bicycle chain or chainring that engages with the sprocket. This allows particularly reliable and accurate monitoring of the sprocket movement to ensure that sufficient rotational movement for a complete gear change has occurred.

[0014] Preferably, the sprocket rotation speed and / or sprocket rotation angle are detected based on the detected cadence and / or motor rotation speed and the instantaneous gear ratio. That is, the sprocket rotation speed is detected indirectly based on the cadence and / or motor rotation speed and the mechanical relationship between the corresponding drive train and the instantaneous gear ratio. In particular, the motor rotation speed is considered to be the rotation speed of the motor of the drive unit of the electric bicycle. The cadence can be detected by a cadence sensor, in particular in the area of ​​the chainring and / or crank. The motor rotation speed can be detected, for example, by a motor rotation speed sensor. Thus, the rotation speed of the sprocket can be easily and accurately monitored with a simple and cost-effective structure based on existing components of the electric bicycle to ensure that a sufficient rotational movement reference is obtained to achieve a complete gear change before the next gear change.

[0015] Preferably, the shifting device is controlled and operated so that gear changes are initiated in response to manually and / or automatically generated shift signals. Preferably, a shift signal generated manually by the bicycle rider, in particular by a shift lever, can be considered a manually generated shift signal. The shift lever can preferably be configured to mechanically activate the shifting device, for example by a cable, or electronically, in which case an electrical signal is generated by the shift lever upon activation as the shift signal. A shift signal generated, in particular by a control unit, preferably automatically based on one or more parameters, can be considered an automatically generated shift signal. That is, a gear change is initiated by movement of the shifting device when the shift signal is present. In that case, the shift signal can also be used, for example, to simply detect movement of the shifting device, i.e., to detect the completion of a gear change based thereon.

[0016] Preferably, the start of a gear change is recognized in response to the generation of a shift signal and / or in response to the recognition of a chain change time. In particular, the chain change time is considered to be the time when the shifting device is in a position where the bicycle chain is ready to move to the next sprocket. For example, by this chain change time, the shifting device may have already moved at least partially. In particular, the chain change time corresponds to a state where the bicycle chain can change to a new target gear. That is, for example, when the shift signal and / or the chain change time are recognized, tracking of the number of rotations to recognize the completion of the gear change is initiated. This makes it possible to provide a particularly simple and cost-effective method of reliably monitoring the completeness of a gear change.

[0017] It is further preferred to control and operate the shifting device so that gear changes are only performed while the rotation of the sprocket, particularly at least one predetermined number of shift revolutions, is detected, preferably sensor-based. That is, the method allows the shifting device to shift only when it is reliably recognized that the sprocket rotates at least at this predetermined number of shift revolutions. Preferably, the method can reliably prevent gear changes if the sprocket does not rotate or rotates at a number of revolutions lower than the predetermined number of shift revolutions. This further ensures that the bicycle chain moves during the shifting process. This allows the shifting process to be performed particularly quickly, reliably, and with low wear.

[0018] The present invention further provides a bicycle, particularly an electric bicycle, with a transmission having a chain shifting device including a shifting device configured to shift a bicycle chain between different sprockets. The bicycle further includes a control unit configured to perform the above-described method. In particular, the bicycle may be an electric bicycle with a drive unit. Preferably, the control unit for performing the method corresponds to the control unit of the drive unit.

[0019] Preferably, the derailleur sprockets are part of a cassette located on the rear wheel hub of the bicycle. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a simplified schematic diagram of an electric bicycle on which a method for operating a transmission according to a preferred exemplary embodiment of the present invention is performed; [Figure 2] 1 is a highly simplified schematic diagram of a method according to the invention; DETAILED DESCRIPTION OF THE INVENTION

[0021] Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0022] Preferably, the same parts, elements and / or units are provided with the same reference signs in all figures.

[0023] FIG. 1 shows a simplified schematic diagram of an electric bicycle 100 on which a method 10 of operating a transmission 1 of a bicycle 100 according to a preferred exemplary embodiment of the present invention is performed.

[0024] FIG. 2 shows a highly simplified schematic diagram of the method according to the invention.

[0025] Bicycle 100 is an electric bicycle equipped with a drive unit 110 having a motor, in particular an electric motor, which can be supplied with electrical energy by an electrical energy store 109 of bicycle 100. Drive unit 110 is arranged in the area of ​​the bottom bracket of bicycle 100.

[0026] The motor torque generated by the motor can supplement the pedaling force generated by the muscles of the rider of the bicycle 100. In this case, the rider's muscles can be applied via a crank mechanism having a crank 104.

[0027] The drive unit 110 further comprises a control unit 50 configured to control and operate the motor. For example, the control unit 50 may control an operating current for operating the motor. Preferably, the control unit 50 is further configured to perform the method 10 according to the present invention.

[0028] Bicycle 100 includes a transmission 1 configured as a chain shifting device 2. Chain shifting device 2 includes a cassette 101 on the rear wheel hub of bicycle 100. Cassette 101 includes a number of sprockets 5 that can provide different gear ratios in the drive train of bicycle 100.

[0029] Bicycle 100 is driven by a crank mechanism using drive unit 110 via chainrings 107, which can be driven by motor torque from drive unit 110 and pedal torque provided via cranks 104. The total resulting torque is transmitted by chainrings 107 to cassette 101 via bicycle chain 4.

[0030] Furthermore, the chain shifting device includes a shifting device 3 that can move the bicycle chain 4 between different sprockets 5 of the cassette 101, thereby changing the gear ratio. In particular, the shifting device 3 can also be referred to as a front derailleur or a shifting mechanism.

[0031] In that case, the shifting device 3 can be activated by a shift signal. The shift signal can be generated automatically by the control unit 50 depending on various riding parameters, such as bicycle speed and / or cadence. Preferably, alternatively, the shift signal can be generated by a manual shifting device 8, including, for example, a shift lever.

[0032] Method 10, as described below with reference to FIG. 2, can allow for particularly accurate, efficient, and low-friction gear changes.

[0033] The method 10 begins with recognition of the shift signal 15 .

[0034] In response to recognition of the shift signal 15, an actuation 11 of the shifting device 3 occurs, in particular, the shifting device 3 is moved so that the bicycle chain 4 is moved to the sprocket 5 currently located next to the sprocket 5 in order to change to the adjacent gear.

[0035] That is, in that case, the bicycle chain 4 is moved only between adjacent gears.

[0036] Subsequently, in response to the recognition of the shift signal 15 and / or in response to the additional recognition of the start of the movement of the shift device 3, a recognition 11 of the shift movement of the shift device 3 takes place. In particular, the end time of the shift movement of the shift device 3 is detected. This can be done in particular by considering a time point that is situated a predetermined period after the time point of the shift signal 15 as the end time of the shift movement.

[0037] Immediately after the recognition 12 of the shifting movement of the shifting device 3, i.e. immediately after the end of the shifting movement, a detection 13 of the rotational speed of the sprocket 5 is carried out.

[0038] In this case, the detection 13 of the number of revolutions of the sprocket 5 is performed by detecting the time profile of the number of revolutions of the sprocket 5. That is, the number of revolutions of the sprocket is tracked, in other words counted, based on the detection of the time profile of the number of revolutions of the sprocket 5.

[0039] For example, in this case, the rotation speed of the sprocket 5 can be detected by a rotation speed sensor.

[0040] Alternatively, and preferably, the sprocket rotation speed is sensed based on the detected cadence and / or motor rotation speed of drive unit 110 and the known instantaneous gear ratio.

[0041] When the number of revolutions of the sprocket 5 sensed in step 13 reaches a predetermined number of revolutions of the sprocket, a target gear signal 14 is generated in response thereto.

[0042] In this case, the predetermined number of sprocket revolutions is a characteristic number individually defined for each specific gear change and stored in a look-up table, i.e., the look-up table stores predetermined numbers of sprocket revolutions corresponding to each possible gear change of the cassette 101.

[0043] In this case, the gear changes are differentiated in particular according to the direction of the shift, i.e. up or down, and according to the respective sprockets before and after the shifting process.

[0044] In particular, the information representing the completed shifting process is considered to be the target gear signal, i.e., when the target gear signal is generated in step 14, it is assumed that the bicycle chain 4 has been completely changed to the desired gear, i.e., the desired sprocket 5.

[0045] In that case, method 10 is configured in such a way that a new actuation of the shifting device according to step 11 is only possible once target gear signal 14 has been detected, so that gear changes can only be performed between adjacent gears and only sequentially, i.e., in such a way that a new gear change can only be performed once the end of the previous gear change has been detected, in particular based on target gear signal 14.

[0046] Thus, method 10 offers the advantage of particularly reliable and precise shifting. By allowing a new shift to only one of the adjacent gears and only after the target gear signal has reliably confirmed that the previous gear change has been completed, it is possible to ensure that the bicycle chain 4 always engages with as many teeth as possible on at least one sprocket 5. This is also achieved by preventing the bicycle chain 4 from running diagonally across multiple sprockets 5. This allows for optimal force transmission at all times while also enabling low wear on drivetrain components. [Explanation of symbols]

[0047] 1. Transmission 2 Chain shift device 3 Shift device 4. Bicycle chain 5 sprockets 50 Control Unit 8 Shift Equipment 10 ways 11 Operation 12 Recognition 13 Detection 15 Shift signal 100 bicycles, electric bicycles 104 Crank 107 chainring 109 Energy Reservoir 110 Drive Unit

Claims

1. A method for operating a transmission (1) for a bicycle (100), in particular an electric bicycle, comprising: - said transmission (1) comprises a chain shifting device (2) having a controllably actuable shifting device (3) configured to shift a bicycle chain (4) between different sprockets; - The end of the gear change is detected, - controlling and operating said shifting device (3) to carry out gear changes only to adjacent gears and sequentially, such that a new gear change can only be carried out when the end of the previous gear change has been detected.

2. 2. The method according to claim 1, wherein the end of the gear change is recognized based on the lapse of a predetermined period of time after the start of the gear change has been recognized, in particular during chain movement.

3. 3. The method of claim 1, wherein the end of the gear change is recognized in response to detecting a predetermined number of chainring revolutions of a chainring of the bicycle after the start of the gear change is recognized.

4. 4. The method of claim 1, wherein the end of the gear change is recognized in response to detecting a predetermined chainring angle of a chainring of the bicycle after the start of the gear change has been recognized.

5. 5. A method according to any one of claims 1 to 4, wherein the end of the gear change is recognised in response to detecting a predetermined number of sprocket revolutions of the sprocket after the start of the gear change is recognised.

6. 6. A method according to any one of claims 1 to 5, wherein the end of the gear change is recognised in response to detecting a predetermined sprocket rotation angle of the sprocket after the start of the gear change has been recognised.

7. 7. The method according to claim 5, wherein the sprocket rotation speed and / or the sprocket rotation angle are detected based on a detected cadence and / or motor rotation speed and an instantaneous gear ratio.

8. 8. The method according to any one of claims 1 to 7, wherein the shifting device (3) is controlled and operated so that the gear change is recognized in response to a manually and / or automatically generated shift signal (15).

9. 9. The method of claim 8, wherein the initiation of the gear change is recognized in response to the generation of the shift signal (15) and / or in response to recognition of a chain change instant.

10. 10. The method according to claim 1, wherein the shifting device (3) is controlled and operated in such a way that the gear change is carried out only while a rotation of the sprocket with at least one predetermined number of shift revolutions is detected.

11. A bicycle, particularly an electric bicycle, a transmission (1) having a chain shifting device (2) including a shifting device (3) configured to shift a bicycle chain (4) between different sprockets; - a control unit (50) configured to carry out the method (10) according to any one of claims 1 to 10.

12. 12. The bicycle of claim 11, wherein the sprocket is part of a cassette (101) of a rear wheel hub (102) of the bicycle (100).

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