Drive Device for a Bicycle and Method for the Open-Loop Control

Abstract

A drive device (1) for a bicycle (100) includes a transmission (2) having a sensor for detecting a crank angle and a rotational speed of a pedal crankshaft and generating appropriate sensor data, a sensor for detecting a rotational speed of a driven shaft and generating appropriate sensor data, a sensor for detecting a rotational speed of the rotor shaft and generating appropriate sensor data, and a control device (10) configured for processing the sensor data and controlling by way of an open-loop system, a downshift from a currently engaged gear into a next-smaller gear as a function of the sensor data by energizing an electric machine (7).

Claims

1-12. (canceled)

13. A drive device (1) for a bicycle (100), comprising: a transmission (2) with multiple gears and a driven shaft (3), the multiple gears are adjustable by a shifting device (4), the driven shaft (3) is configured to be operatively connected to a driving wheel (102) of the bicycle (100) via a flexible traction drive mechanism (101); a pedal crankshaft (5) with a pedal crank (6) for introducing drive power of a cyclist into the transmission (2), the pedal crankshaft (5) operatively connected to the driven shaft (3); an electric machine (7) with a rotor shaft (8) for introducing drive power of the electric machine (7) into the transmission (2), the rotor shaft (8) operatively connectable to the driven shaft (3) via a freewheel unit (9), the freewheel unit (9) configured to decouple the driven shaft (3) from the rotor shaft (8) when a rotational speed of the driven shaft is greater than a rotational speed of the rotor shaft; means for detecting a crank angle and a rotational speed of the pedal crankshaft and generating sensor data corresponding to the crank angle and the rotational speed of the pedal crankshaft; means for detecting a rotational speed of the driven shaft and generating sensor data corresponding to the rotational speed of the driven shaft; means for detecting a rotational speed of the rotor shaft and generating sensor data corresponding to the rotational speed of the rotor shaft; and a control device (10) configured to process the sensor data and control, by way of an open-loop system, a downshift from a currently engaged gear into a next-smaller gear as a function of the sensor data by energizing the electric machine (7).

14. The drive device (1) of claim 13, wherein the means for detecting the crank angle and the rotational speed of the pedal crankshaft comprises a first sensor (11) rotationally fixed to the pedal crankshaft (5).

15. The drive device (1) of claim 13, wherein the means for detecting the rotational speed of the driven shaft comprises at least a second sensor (12) rotationally fixed to the driven shaft (3).

16. The drive device (1) of claim 13, wherein the means for detecting the rotational speed of the rotor shaft comprises at least a third sensor (13) rotationally fixed to the rotor shaft (8).

17. A drive device (1) for a bicycle (100), comprising: a transmission (2) with multiple gears and a driven shaft (3), the multiple gears are adjustable by a shifting device (4), the driven shaft (3) is configured to be operatively connected to a driving wheel (102) of the bicycle (100) via a flexible traction drive mechanism (101); a pedal crankshaft (5) with a pedal crank (6) for introducing drive power of a cyclist into the transmission (2), the pedal crankshaft (5) operatively connected to the driven shaft (3); an electric machine (7) with a rotor shaft (8) for introducing drive power of the electric machine (7) into the transmission (2), the rotor shaft (8) operatively connectable to the driven shaft (3) via a freewheel unit (9), the freewheel unit (9) configured to decouple the driven shaft (3) from the rotor shaft (8) when a rotational speed of the driven shaft is greater than a rotational speed of the rotor shaft; a first sensor for detecting a crank angle and a rotational speed of the pedal crankshaft and generating sensor data corresponding to the crank angle and the rotational speed of the pedal crankshaft; a second sensor for detecting a rotational speed of the driven shaft and generating sensor data corresponding to the rotational speed of the driven shaft; a third sensor for detecting a rotational speed of the rotor shaft and generating sensor data corresponding to the rotational speed of the rotor shaft; and a control device (10) configured to process the sensor data from the first, second and third sensors and control, by way of an open-loop system, a downshift from a currently engaged gear into a next-smaller gear by energizing the electric machine (7) as a function of the sensor data from the first, second and third sensors.

18. A method for the open-loop control of the drive device (1) of claim 13, comprising: when the downshift from the currently engaged gear into the next-smaller gear is requested, reducing an energization of the electric machine (7) in a range from at least one degree to at most forty-five degrees prior to the pedal crank (6) reaching a dead center at least such that the rotational speed of the rotor shaft is less than the rotational speed of the driven shaft; disengaging the currently engaged gear when the rotational speed of the pedal crankshaft is less than the rotational speed of the driven shaft; after the dead center of the pedal crank (6) has been exceeded, energizing the electric machine (7) such that the rotational speed of the rotor shaft approaches a target rotational speed for the next-smaller gear; and engaging the next-smaller gear when the target rotational speed for the next-smaller gear is reached.

19. The method of claim 18, further comprising stopping the energization of the electric machine (7) in the range from at least one degree to at most forty-five degrees prior to the pedal crank (6) reaching the dead center.

20. The method of claim 18, wherein the energization of the electric machine (7) after the pedal crank (6) has exceeded the dead center essentially corresponds to the energization of the electric machine (7) prior to the reduction of the energization.

21. A control device (10), programmed to implement the method of claim 18.

22. A method for the open-loop control of the drive device (1) of claim 13, comprising: when the downshift from the currently engaged gear into the next-smaller gear is requested, reducing an energization of the electric machine (7) in a range from at least one degree to at most forty-five degrees prior to the pedal crank (6) reaching a dead center at least such that the rotational speed of the rotor shaft is lower than the rotational speed of the driven shaft; when the rotational speed of the pedal crankshaft is greater than the rotational speed of the driven shaft, energizing the electric machine (7) such that in a range from at least forty-five degrees up to at most ninety degrees prior to the pedal crank (6) reaching a next dead center the rotational speed of the driven shaft increases; again reducing the energization of the electric machine (7) in the range from at least one degree up to at most forty-five degrees prior to the pedal crank (6) reaching the dead center such that the rotational speed of the rotor shaft is less than the rotational speed of the driven shaft; disengaging the currently engaged gear when the rotational speed of the pedal crankshaft is less than the rotational speed of the driven shaft; after the dead center of the pedal crank (6) has been exceeded, energizing the electric machine (7) such that the rotational speed of the rotor shaft approaches a target rotational speed for the next-smaller gear; and engaging the next-smaller gear when the target rotational speed for the next-smaller gear is reached.

23. The method of claim 22, further comprising stopping the energization of the electric machine (7) in the range from at least one degree to at most forty-five degrees prior to the pedal crank (6) reaching the dead center.

24. The method of claim 22, wherein the energization of the electric machine (7) after the pedal crank (6) has exceeded the dead center essentially corresponds to the energization of the electric machine (7) prior to the reduction of the energization.

25. The method of claim 22, wherein the energization of the electric machine (7) is increased by at least twenty percent in the range from at least forty-five degrees to at most ninety degrees prior to the pedal crank (6) reaching the dead center.

26. A control device (10), programmed to implement the method of claim 22.

27. A method for the open-loop control of the drive device (1) of claim 13, comprising: when the downshift from the currently engaged gear into the next-smaller gear is requested, energizing the electric machine (7) in a range from at least forty-five degrees to at most ninety degrees prior to the pedal crank (6) reaching a dead center such that the rotational speed of the driven shaft increases; reducing the energization of the electric machine (7) in a range from at least one degree up to at most forty-five degrees prior to the pedal crank (6) reaching the dead center such that the rotational speed of the rotor shaft is less than the rotational speed of the driven shaft; disengaging the currently engaged gear when the rotational speed of the pedal crankshaft is less than the rotational speed of the driven shaft; after the dead center of the pedal crank (6) has been exceeded, energizing the electric machine (7) such that the rotational speed of the rotor shaft approaches a target rotational speed for the next-smaller gear; and engaging the next-smaller gear when the target rotational speed for the next-smaller gear is reached.

28. The method of claim 27, further comprising stopping the energization of the electric machine (7) in the range from at least one degree to at most forty-five degrees prior to the pedal crank (6) reaching the dead center.

29. The method of claim 27, wherein the energization of the electric machine (7) after the pedal crank (6) has exceeded the dead center essentially corresponds to the energization of the electric machine (7) prior to the reduction of the energization.

30. The method of claim 27, wherein the energization of the electric machine (7) is increased by at least twenty percent in the range from at least forty-five degrees to at most ninety degrees prior to the pedal crank (6) reaching the dead center.

31. A control device (10), programmed to implement the method of claim 27.

32. A bicycle (100), comprising the drive device (1) of claim 13, wherein the drive device (1) is operatively connected to the driving wheel (102) of the bicycle (100) via the flexible traction drive mechanism (101).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Exemplary embodiments of the invention are explained in greater detail in the following with reference to the schematic drawings, wherein identical elements are labeled with the same reference character, wherein

[0024] FIG. 1 shows a highly simplified schematic view of a bicycle that includes a drive device according to example aspects of the invention,

[0025] FIG. 2 shows a highly simplified schematic view of the drive device according to example aspects of the invention and according to FIG. 1,

[0026] FIG. 3 shows a diagram for illustrating an exemplary operating sequence of a first method according to example aspects of the invention,

[0027] FIG. 4 shows a diagram for illustrating an exemplary operating sequence of a second method according to example aspects of the invention, and

[0028] FIG. 5 shows a diagram for illustrating an exemplary operating sequence of a third method according to example aspects of the invention.

DETAILED DESCRIPTION

[0029] Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.

[0030] FIG. 1 shows a highly simplified view of a bicycle 100 according to example aspects of the invention. The bicycle 100 has a frame 104 on which a front wheel 103, a rear wheel designed as a driving wheel 102, bicycle handlebars 105, and a saddle 108 are arranged. Moreover, the bicycle 100 has a drive device 1, which is designed to drive the bicycle 100 at least with muscle power of a cyclist (not shown here). For this purpose, the cyclist, when riding, sits, for example, on the saddle 108 and applies drive power into the transmission 2 of the drive device 1 via respective pedals 109, which are connected to the drive device 1 via respective pedal cranks 6. The drive device 1 also includes an electric machine 7, which is shown only in FIG. 2 and is designed to also introduce, for its part, drive power into the transmission 2 in order to assist the cyclist. The drive powers of the electric machine 7 and of the cyclist are superimposed in the transmission 2 and transmitted onto the driving wheel 102 of the bicycle 100 via a driven shaft 3, which is shown only in FIG. 2. For this purpose, the driven shaft 3 is drivingly connected to the driving wheel 102 via a first chainring 110, which is rotationally fixed to the driven shaft 3, a second chainring 112, which is rotationally fixed to the driving wheel 102, and a chain 111 arranged therebetween. Consequently, the two chainrings 110, 112 and the chain 111 form a flexible traction drive mechanism 101 designed as a chain drive. Alternatively, the use of a belt drive is also conceivable for transmitting drive power from the drive device 1 onto the driving wheel 102 of the bicycle 100.

[0031] Moreover, inputs 106, which the cyclist can use for input, are arranged at the bicycle handlebars 105. For example, the inputs 106 are designed as actuating buttons, wherein a first actuating button is provided for downshifting a gear and a second actuating button is provided for upshifting a gear. The downshifting of a gear, i.e., a downshift, changes the ratio in the transmission 2 such that the rotational speed at the driven shaft 3 is increased and the torque at the driven shaft 3 is reduced. Moreover, a visual display device 107 is also arranged at the bicycle handlebars 105, which is designed to visualize at least drive-specific display data, more particularly a gear step and a speed of the bicycle 100, for the cyclist.

[0032] FIG. 2 shows a highly simplified view of the drive device 1 of the bicycle 100 from FIG. 1. The drive device 1 includes the transmission 2, which has multiple gears and the driven shaft 3. The gears are implemented by gearwheel pairs that are in mesh with one another and are not shown here. The particular gear is adjustable by a shifting device 4, wherein the shifting device 4 includes an actuator (not shown in greater detail) and a gear selector drum (not shown in greater detail) for selecting and actuating particular gearwheel pairs.

[0033] A pedal crankshaft 5 connects the pedal cranks 6 to each other for conjoint rotation, wherein the drive power of the cyclist is introduced into the transmission 2 via the pedals 109 at the pedal cranks 6. The pedal crankshaft 5 is operatively connected to the driven shaft 3 of the transmission 2. The electric machine 7 has a rotor shaft 8, which is operatively connectable to the driven shaft 3 via a freewheel unit 9 for introducing drive power of the electric machine 7 into the transmission 2. The freewheel unit 9 is designed such that the driven shaft 3 is decoupled from the rotor shaft 8 when a rotational speed of the driven shaft is greater than a rotational speed of the rotor shaft. As a result, the cyclist is prevented from entraining the rotor shaft 8 of the electric machine 7 when the energy accumulator is dead. Consequently, the freewheel unit 9 connects the driven shaft 3 and the rotor shaft 8 to each other for conjoint rotation only when the rotational speed of the rotor shaft is greater than the rotational speed of the driven shaft. The driven shaft 3 is drivingly connected to the driving wheel 102 of the bicycle 100 via the flexible traction drive mechanism 101 in order to transmit the drive power from the drive device 1 onto the driving wheel 102 of the bicycle 100.

[0034] Moreover, the drive device 1 has at least a first sensor 11, a second sensor 12, a third sensor 13, and a control unit 10. The first sensor 11 is arranged at the pedal crankshaft 5 and configured for detecting a crank angle and a rotational speed of the pedal crankshaft and generating appropriate sensor data. The second sensor 12 is arranged at the driven shaft 3 and configured for detecting a rotational speed of the driven shaft and generating appropriate sensor data. The third sensor 13 is arranged at the rotor shaft 8 and configured for detecting a rotational speed of the rotor shaft and generating appropriate sensor data. The control device 10 is connected to the sensors 11, 12, 13, wherein the sensor data are received and processed by the control device 10 in order to control, by way of an open-loop system, a downshift from a currently engaged gear into a next-smaller gear as a function of these sensor data by energizing the electric machine 7.

[0035] More particularly, the shift sequence is controlled by way of an open-loop system such that the electric machine 7 is energized in a targeted manner as a function of the sensor data in order to influence rotational speed and torque at certain points in time, more particularly at certain angular ranges of the pedal cranks 6, such that forces are reduced during the engagement and disengagement of the gears, i.e., during the gear ratio change, and, as a result, the wear of the drive device 1 is reduced.

[0036] In FIG. 1 and FIG. 2, the pedal cranks 6 are shown in a dead center, i.e., vertically aligned. In other words, one of the two pedal cranks 6 is aligned at an angle of zero (0) degrees or three hundred and sixty (360) degrees and the other of the two pedal cranks 6 is aligned at an angle of one hundred and eighty (180) degrees. In this position of the pedal cranks 6, the cyclist can introduce only minimal torque and, therefore, only minimal drive power into the drive device 1 via the pedals 109, because a lever arm is minimal. When the pedal cranks 6 are horizontally aligned, i.e., turned by ninety (90) degrees relative to the vertical position shown, the cyclist can introduce maximum torque and, therefore, maximum drive power into the drive device 1 via the pedals 109, because the lever arm has the maximum length. Therefore, the torque curve of the cyclist can be described by a sinusoidal function, wherein the highest points of the torque curve are always present when the pedal cranks are horizontally aligned, i.e., at ninety (90) degrees and two hundred and seventy (270) degrees, and the lowest points of the torque curve or dead centers of the pedal cranks 6 are always present when the pedal cranks 6 are vertically aligned, i.e., at zero (0) degrees or three hundred and sixty (360) degrees and one hundred and eighty (180) degrees.

[0037] According to FIG. 3, four diagrams are combined in one common diagram in order to illustrate a first method according to example aspects of the invention for the open-loop control of the drive device 1 according to FIG. 2. Time T is plotted on a particular abscissa of the four diagrams, wherein all four time axes are identical and, therefore, have the same time curve. By comparison, plotted on a particular ordinate, from bottom to top, are initially a rotational speed of the rotor shaft R, above that an energization B of the electric machine 7, above that the gear selection G, and above that the crank angle K. The crank angle K changes during the rotation of the pedal crankshaft 5 between zero (0) degrees and three hundred and sixty (360) degrees in accordance with the cadence. For example, the cadence is sixty (60), and so the cyclist operates the pedal crankshaft 5 with a rotational speed of sixty (60) revolutions per minute by his/her cadence. For the sake of simplicity, the cadence is constant in the present case.

[0038] At the point in time T1, a downshift from a currently engaged gear G2 into a next-smaller gear G1 is requested, for example, by the cyclist via the inputs 106.

[0039] At the point in time T2, the energization B of the electric machine is switched off, wherein the crank angle K at this point in time is, for example, ten (10) degrees prior to the pedal crank reaching a dead center. As a result, the rotational speed of the rotor shaft R decreases. As soon as the rotational speed of the rotor shaft R is less than the rotational speed of the driven shaft, the freewheel unit decouples the rotor shaft from the driven shaft.

[0040] At the point in time T3, the dead center of the pedal crank is reached. Moreover, at the point in time T3, the rotational speed of the pedal crankshaft is less than a rotational speed of the driven shaft, and so the currently engaged gear G2 is disengaged in a particularly low-wear manner, since no force is impressed upon the transmission via the pedal crankshaft and the rotor shaft. The disengagement of the currently engaged gear G2 is graphically represented by the shaded area at the gear selection G between the point in time T3 and the point in time T5.

[0041] At the point in time T4, the dead center of the pedal crank is exceeded, wherein the electric machine is now energized so strongly that a rotational speed of the rotor shaft R is moved closer to a higher target rotational speed for the next-smaller gear G1. More particularly, the energization of the electric machine at the point in time T4 essentially corresponds to the energization of the electric machine at the point in time T1, i.e., prior to the reduction of the energization, as a result of which a smooth transition is created.

[0042] At the point in time T5 the target rotational speed for the next-smaller gear G1 is reached, wherein the next-smaller gear G1 is engaged in a particularly low-wear manner. The downshifting operation is therefore concluded.

[0043] According to FIG. 4, four diagrams are combined in one common diagram in order to illustrate a second method according to the invention for the open-loop control of the drive device 1 according to FIG. 2. Time T is plotted on a particular abscissa of the four diagrams, wherein all four time axes are identical and, therefore, have the same time curve. By comparison, plotted on a particular ordinate, from bottom to top, are initially a rotational speed of the rotor shaft R, above that an energization B of the electric machine 7, above that the gear selection G, and above that the crank angle K. The crank angle K changes during the rotation of the pedal crankshaft 5 between zero (0) degrees and three hundred and sixty (360) degrees in accordance with the cadence. For example, the cadence is sixty (60), and so the cyclist operates the pedal crankshaft 5 with a rotational speed of sixty (60) revolutions per minute by his/her cadence. For the sake of simplicity, the cadence is constant in the present case.

[0044] At the point in time T1, a downshift from a currently engaged gear G2 into a next-smaller gear G1 is requested, for example, by the cyclist via the inputs 160.

[0045] At the point in time T2, the energization B of the electric machine is switched off, wherein the crank angle K at this point in time is, for example, ten (10) degrees prior to the pedal crank reaching a first dead center. As a result, the rotational speed of the rotor shaft R decreases. As soon as the rotational speed of the rotor shaft R is less than the rotational speed of the driven shaft, the freewheel unit decouples the rotor shaft from the driven shaft.

[0046] At the point in time T3, the first dead center of the pedal crank is reached. However, at the point in time T3, a rotational speed of the pedal crankshaft is greater than a rotational speed of the driven shaft. The electric machine is energized once again as the electric machine was prior to the current reduction.

[0047] At the point in time T4, the first dead center of the pedal crank is exceeded. At the point in time T4, the electric machine is energized by a twenty percent (20%) greater extent than the electric machine was previously energized, at fifty (50) degrees prior to the pedal crank reaching a second dead center, and so the rotational speed of the driven shaft increases.

[0048] At the point in time T5, the energization B of the electric machine is switched off, wherein the crank angle K at this point in time is, for example, ten (10) degrees prior to the pedal crank reaching a second dead center. As a result, the rotational speed of the rotor shaft R decreases. As soon as the rotational speed of the rotor shaft R is less than the rotational speed of the driven shaft, the freewheel unit decouples the rotor shaft from the driven shaft.

[0049] At the point in time T6, the second dead center of the pedal crank is reached. Moreover, at the point in time T6, the rotational speed of the pedal crankshaft is less than a rotational speed of the driven shaft, and so the currently engaged gear G2 is disengaged in a particularly low-wear manner, since no force is impressed upon the transmission via the pedal crankshaft and the rotor shaft. The disengagement of the currently engaged gear G2 is graphically represented by the shaded area at the gear selection G between the point in time T6 and the point in time T8. It is pointed out that the currently engaged gear G2 is disengaged only when a rotational speed of the pedal crankshaft is less than a rotational speed of the driven shaft. Otherwise, the method steps between T4 and T6 are repeated until this condition has been met.

[0050] At the point in time T7, the second dead center of the pedal crank is exceeded, wherein the electric machine is now energized so strongly that a rotational speed of the rotor shaft R is moved closer to a higher target rotational speed for the next-smaller gear G1. More particularly, the energization of the electric machine at the point in time T7 essentially corresponds to the energization of the electric machine at the point in time T1, i.e., prior to the reduction of the energization, as a result of which a smooth transition is created.

[0051] At the point in time T8 the target rotational speed for the next-smaller gear G1 is reached, wherein the next-smaller gear G1 is engaged in a particularly low-wear manner. The downshifting operation is therefore concluded.

[0052] According to FIG. 5, four diagrams are combined in one common diagram in order to illustrate a third method according to example aspects of the invention for the open-loop control of the drive device 1 according to FIG. 2. Time T is plotted on a particular abscissa of the four diagrams, wherein all four time axes are identical and, therefore, have the same time curve. By comparison, plotted on a particular ordinate, from bottom to top, are initially a rotational speed of the rotor shaft R, above that an energization B of the electric machine 7, above that the gear selection G, and above that the crank angle K. The crank angle K changes during the rotation of the pedal crankshaft 5 between zero (0) degrees and three hundred and sixty (360) degrees in accordance with the cadence. For example, the cadence is sixty (60), and so the cyclist operates the pedal crankshaft 5 with a rotational speed of sixty (60) revolutions per minute by his/her cadence. For the sake of simplicity, the cadence is constant in the present case.

[0053] At the point in time T1, a downshift from a currently engaged gear G2 into a next-smaller gear G1 is requested, for example, by the cyclist via the inputs 106.

[0054] At the point in time T2, the electric machine is energized by a twenty percent (20%) greater extent than the electric machine was previously energized, at fifty (50) degrees prior to the pedal crank reaching a dead center, and so the rotational speed of the driven shaft increases.

[0055] At the point in time T3, the energization B of the electric machine 7 is switched off, wherein the crank angle K at this point in time is, for example, ten (10) degrees prior to the pedal crank reaching a dead center. As a result, the rotational speed of the rotor shaft R decreases. As soon as the rotational speed of the rotor shaft R is lower than the rotational speed of the driven shaft, the freewheel unit decouples the rotor shaft from the driven shaft.

[0056] At the point in time T4, the dead center of the pedal crank is reached. Moreover, at the point in time T4, the rotational speed of the pedal crankshaft is lower than a rotational speed of the driven shaft, and so the currently engaged gear G2 is disengaged in a particularly low-wear manner, since no force is impressed upon the transmission via the pedal crankshaft and the rotor shaft. The disengagement of the currently engaged gear G2 is graphically represented by the shaded area at the gear selection G between the point in time T4 and the point in time T6. It is pointed out that the currently engaged gear G2 is disengaged only when a rotational speed of the pedal crankshaft is less than a rotational speed of the driven shaft. Otherwise, the method steps between T2 and T4 are repeated until this condition has been met.

[0057] At the point in time T5, the dead center of the pedal crank is exceeded, wherein the electric machine 7 is now energized so strongly that a rotational speed of the rotor shaft R is moved closer to a higher target rotational speed for the next-smaller gear G1. More particularly, the energization of the electric machine at the point in time T5 essentially corresponds to the energization of the electric machine at the point in time T1, i.e., prior to the reduction of the energization, as a result of which a smooth transition is created.

[0058] At the point in time T6 the target rotational speed for the next-smaller gear G1 is reached, wherein the next-smaller gear G1 is engaged in a particularly low-wear manner. The downshifting operation is therefore concluded.

[0059] Modifications and variations can be made to the embodiments illustrated or described herein without departing from the scope and spirit of the invention as set forth in the appended claims. In the claims, reference characters corresponding to elements recited in the detailed description and the drawings may be recited. Such reference characters are enclosed within parentheses and are provided as an aid for reference to example embodiments described in the detailed description and the drawings. Such reference characters are provided for convenience only and have no effect on the scope of the claims. In particular, such reference characters are not intended to limit the claims to the particular example embodiments described in the detailed description and the drawings.

TABLE-US-00001 Reference characters 1 drive device 2 transmission 3 driven shaft 4 shifting device 5 pedal crankshaft 6 pedal crank 7 electric machine 8 rotor shaft 9 freewheel unit 10 control device 11 first sensor 12 second sensor 13 third sensor 100 bicycle 101 flexible traction drive mechanism 102 driving wheel 103 front wheel 104 frame 105 bicycle handlebars 106 input means 107 display device 108 saddle 109 pedals 110 first chainring 111 chain 112 second chainring B energization G gear selection G1 next-smaller gear G2 currently engaged gear K crank angle R rotational speed of rotor shaft T time T1 point in time T2 point in time T3 point in time T4 point in time T5 point in time T6 point in time T7 point in time T8 point in time