Drivetrain of a muscle-powered vehicle

Abstract

A drive train (4) for a human-powered vehicle (2) is described. The drive train (4) has a pedal crankshaft (6). The drive train (4) has a first means (8) for determining (S1) a first torque applied by a driver of the vehicle (2) to the pedal crankshaft (6). The drive train (4) has a second means (10) for determining (S2) a second torque applied by the driver of the vehicle (2) to the pedal crankshaft (6). The drive train (4) has a control device (10) for controlling (S3) the drive train (4) as a function of the determined first torque and as a function of the determined second torque. Furthermore, a human-powered vehicle (2) having such a drive train (4) is described. Furthermore, a method for controlling such a drive train (4) of such a human-powered vehicle (2) is described.

Description

Technical area

[0001] The present invention relates to a drive train for a human-powered vehicle. Furthermore, the following invention relates to a human-powered vehicle having such a drive train. Furthermore, the following invention relates to a method for controlling a drive train of a human-powered vehicle. State of the art

[0002] Human-powered vehicles can also have a drive motor to assist in propulsion. For example, a pedelec, as a human-powered vehicle, can have an electric motor to assist in propulsion. The assistance provided by the drive motor must be controlled. For safety reasons, for example, assistance may only be provided when a rider of the vehicle is pedaling. To determine whether the rider is pedaling, a rider torque can be measured. The rider torque is the torque that the rider of the vehicle applies to a pedal crankshaft of the vehicle to drive the vehicle using muscle power. The rider torque to be measured can have a value that is from a torque range that covers various orders of magnitude of torque.To measure driver torque, a respective sensor must be designed to measure driver torques of different magnitudes. Strain gauges are often used to measure driver torques. Strain gauges exhibit hysteresis effects. When measuring torques with a strain gauge of different magnitudes, an offset error or other errors, such as linearity and gain errors, may occur. EP2609002A1, for example, describes how such an offset error can be corrected to determine the driver torque more precisely and control the drive motor accordingly. Description of the invention

[0003] The object of the invention is to improve a drive train for a human-powered vehicle such that driver torque can be determined more precisely and easily. This object is achieved by the subject matter of the independent claims.

[0004] In one aspect, the present invention relates to a drive train for a human-powered vehicle. The human-powered vehicle can be a bicycle, e-bike, pedelec, or cargo bike. The drive train has a pedal crankshaft. For example, two crank arms can be connected to the pedal crankshaft in a rotationally fixed manner, with a pedal being rotatably mounted at one end of each crank arm. The pedal crankshaft can thus also be referred to as a pedal crankshaft. The pedal crankshaft can be rotatably mounted on a frame of the vehicle by means of a bearing of the vehicle.

[0005] The drivetrain further comprises a first means for determining a first torque applied by the driver of the vehicle to the pedal crankshaft. The driver can apply drive force to pedals, and thus a torque can be applied by the driver to the pedal crankshaft. The first torque can be a driver torque. The first means can be configured to determine the torque applied by the driver of the vehicle to the pedal crankshaft at specific times, for example, at least at a specific first time.

[0006] The drivetrain further comprises a second means for determining a second torque applied by the driver of the vehicle to the pedal crankshaft. The second means can be configured to determine a torque simultaneously with the first means. The second torque can be a driver torque. For example, the driver torque applied to the pedal crankshaft can be determined as a first torque and as a second torque simultaneously with the first means and the second means. The determined first torque can be the same as or different from the determined second torque.

[0007] In addition to the first and second means, the drivetrain may have further means for determining a third and further torques applied by the driver of the vehicle to the pedal crankshaft. These further torques may also be driver torques.

[0008] The drivetrain further comprises a control device for controlling the drivetrain as a function of the determined first torque and as a function of the determined second torque. The control can be an open-loop control and alternatively or additionally a closed-loop control. The control device can, for example, be configured to control the drivetrain as a function of further determined torques, such as a determined third torque. The control device can be configured to control the drivetrain as a function of several, for example all, determined driver torques. The drivetrain can comprise a drive motor for providing drive power for driving the vehicle. The control device can be configured to control the drive motor as a function of the determined first torque and as a function of the determined second torque.

[0009] With such a drivetrain, the driver torque can be determined redundantly. Depending on the redundantly determined driver torque, for example by adjusting or comparing the first torque with the second torque, the control of the drivetrain can be provided with a reduced probability of failure with regard to one of the two means for determining the driver torque and thus with improved safety. Furthermore, the redundant determination of the driver torque and comparison of the two determined torques can improve accuracy, which can improve the control of the drivetrain and thus the driving behavior of the vehicle. The control of the drivetrain can be carried out with greater accuracy with regard to determining the driver torque, since, for example, the driver's pedaling can be detected more accurately.This can lead to improved comfort and convenience through precise control of the drivetrain, for example, by switching a drive motor on or off. It can also improve the control of the drive motor. This can lead to improved drivetrain safety and thus the safety of the vehicle for the driver. Performance measurement, which may be dependent on the specific driver torque, can also be improved in this way.

[0010] For example, it is known from the prior art to determine the rider torque using strain gauges on the crankshaft. This determined value is often non-zero, even though in reality, at the time the rider torque is determined, no torque is being applied by the rider to the crankshaft. This can result, for example, from hysteresis effects of the strain gauge. In such situations, it is not possible to correctly control the drivetrain in dependence on the rider torque using a drivetrain known from the prior art. Alternatively, it is known from the prior art to correct such effects using correction methods. However, this is time-consuming and computationally intensive.

[0011] With the drive train presented here and the control as a function of both the first and the second determined torque and, for example, by comparing the determined first torque with the determined second torque, such a problem of the prior art can be solved. Just as it is known from the prior art that the determined rider torque is used to control or regulate a drive motor or for further processing or storage, a particularly precise determination of the rider torque can be advantageous. The torque sensors with strain gauges known from the prior art can be shaped in such a way that the strain gauges can be arranged on the pedal crankshaft. With a rider torque determined in this way, the drive motor or the pedals can be switched on or off.Driver support through control and, alternatively or additionally, regulation of the drive motor may be performed suboptimally. For example, a jerk in the pedal may occur due to inaccurate activation or deactivation of assistance or inaccurate control or regulation of the drive motor in the current state of the art.

[0012] Furthermore, the current state of the art may compromise vehicle safety if the driver is not actually pedaling, but a non-zero driver torque is detected, for example, due to strain gauge hysteresis effects. Determining driver performance for training purposes may also be inaccurate if performed using a drivetrain and a means for determining driver torque.

[0013] According to a further embodiment, the drive train can be characterized in that the first means for determining the first torque is configured in a first measuring range. The first measuring range can be narrow compared to other measuring ranges; for example, the second measuring range can be 5 Nm, 10 Nm, 20 Nm, or 50 Nm wide. For example, the first measuring range can range from 0 Nm to 5 Nm, 10 Nm, 20 Nm, or 50 Nm. The second means can be configured to determine the second torque in a second measuring range. The second measuring range can be 100 Nm, 200 Nm, or 500 Nm wide, for example. The second measuring range can range from 0 Nm to 100 Nm, 200 Nm, or 500 Nm. Alternatively, the second measuring range can range from 5 Nm, 10 Nm, 20 Nm, or 50 Nm to 100 Nm, 200 Nm, or 500 Nm. The first and second measuring ranges can be different, for example, with different widths.For example, the first measuring range can be narrower than the second measuring range. Alternatively, the first and second measuring ranges can be identical, for example, have the same width. If the first and second measuring ranges are different, the two measuring ranges can overlap; for example, a sub-range of the first measuring range can also be a sub-range of the second measuring range. Alternatively, the first and second measuring ranges can be disjoint, i.e., they can have no identical sub-ranges. For example, a union of the first measuring range and the second measuring range is connected. For example, the first measuring range can range from 5 Nm to 50 Nm, and the second measuring range can range from 50 Nm to 200 Nm. The union can therefore range from 5 Nm to 200 Nm.If the drive train, as previously mentioned according to one embodiment, has more than two means for determining the torque, the different means for determining the torque can have different measuring ranges. These measuring ranges can also, for example, form a contiguous union as a range.

[0014] The driver torque can thus be determined using the drive train with the first means and a first measuring range, and with the second means and a second measuring range. The first means can, for example, be set up to be able to determine the driver torque particularly precisely in the first measuring range. The second means can be set up to be able to determine the driver torque particularly precisely in the second measuring range. By combining the control of the drive train as a function of the determined first and the determined second torque, the accuracy with which the driver torque is determined and the control of the drive train is carried out can be improved. This can, for example, be useful in the case of small driver torques, if the first means is set up to determine the driver torque in a small first measuring range compared to the second measuring range.It is known from the prior art to determine driver torque using strain gauges. Hysteresis effects are known in this case. The coarser the strain gauges used to determine driver torque, the greater the hysteresis effect. To measure a large driver torque, coarse strain gauges must be used. Therefore, it is difficult to measure small driver torques accurately and without significant disadvantages due to hysteresis effects using the prior art. Therefore, determining driver pedaling due to driver torque is difficult with drivetrains known from the prior art.

[0015] Accordingly, it may be advantageous, as with the drivetrain presented here, to use and combine different strain gauges as the first and second means with different measuring ranges, for example, a smaller first measuring range and a larger second measuring range, to determine the driver torque. A hysteresis effect when determining, for example, small driver torques, for example, to accurately detect whether a driver is pedaling or not, may be smaller for the first means with a smaller first measuring range than for the second, larger measuring range.

[0016] Thus, in absolute values, the hysteresis effect occurring when determining the first torque with the first mean can be comparatively small.

[0017] In comparison, the prior art has the disadvantage that a means for determining driver torque must be able to measure the driver torque across the entire measuring range and must cover this entire measuring range, for example, with a sensor system. For example, compared to the prior art, the drivetrain described in this way can improve resolution and accuracy, for example, with small driver torque values, such as when the driver torque is zero.

[0018] The drivetrain, for example, can be used to determine the driver torque partially redundantly. The driver torque can be determined partially redundantly in that, for example, the first means covers a first measuring range and the second means covers a second measuring range, wherein the first measuring range is a sub-range of the second measuring range. The driver torque can be determined redundantly in this sub-range. The second measuring range can, for example, cover the entire relevant driver torque range. The control device for controlling the drivetrain can, for example, be switched over depending on the situation, wherein either the determined first or the determined second torque is used to control the drivetrain.

[0019] According to a further embodiment, the drive train can be characterized in that the first means is configured to determine the first torque with a first accuracy. The second means can be configured to determine the second torque with a second accuracy. The first and second accuracies can be different or the same. For example, the first means for determining the first torque can be configured with a first, smaller measuring range with a first, higher accuracy. The second means for determining the second, larger measuring range can be configured with a second, lower accuracy. For example, the first means can be configured to have a high accuracy for small driver torques.For example, the first means can have a first accuracy in a first measuring range which is higher than the second accuracy of the second means in the second measuring range, which also includes the first measuring range. In sub-ranges of the second measuring range which do not include the first measuring range, the second accuracy can, for example, be higher than the first accuracy. For example, a torque, i.e. a driver torque, can be determined for a specific value using both the first and the second means. The control device can, for example, be configured to use the specific torque value which was determined with a higher accuracy to control the drive train. In this way, the driver torque can be determined particularly precisely using the present drive train and the drive train can be controlled depending on this.Thus, the first means can be configured to determine driver torques of small magnitude and the second means can be configured to determine driver torques of large magnitude.

[0020] According to a further embodiment, the drive train can be characterized in that the first means is a sensor for measuring the first torque. The second means can be a sensor for measuring the second torque. For example, the sensor as the first means can comprise strain gauges. The sensor as the first means can, for example, have a small measuring range. The sensor can operate based on the magnetostrictive principle. The first means can, for example, be configured to measure only small absolute values ​​of the driver torque compared to otherwise measurable values ​​of the driver torque. This allows it to be determined particularly precisely whether the driver is pedaling or not.

[0021] According to a further embodiment, the drive train can be characterized in that the second means is the control device for calculating the second torque as a function of a further measured variable. The first means can also be the control device for calculating the first torque as a function of a further measured variable. In one embodiment, the first means can be a sensor for measuring the first torque and the second means can be the control device for calculating the second torque as a function of a further measured variable. The calculation of the second torque can be carried out as a function of mathematical models. For example, this can be carried out as a function of machine models. Further measured variables can be input variables for these mathematical models for determining the second torque, the driver torque.These additional measured variables can be other measured variables of the vehicle, such as the power of the drive motor, the torque of the drive motor, the rotational speed of the drive motor, the vehicle speed, the rotational speed of a wheel of the vehicle, such as the driven wheel, the vehicle acceleration, the rotational acceleration of a wheel, such as the driven wheel, the vehicle inclination, the slope inclination, the crank angle of the vehicle's cranks, the cadence of the crank, the pedal force, the bearing force of a crank bearing, or variables derived therefrom. This additional measured variable can, for example, be measured directly or indirectly using a sensor.

[0022] For example, the second means can have a larger second measuring range than the first measuring range and thus be configured to determine the driver torque across all possible values ​​of the driver torque. At the same time, the second accuracy of the second means can be lower than the first accuracy of the first means. Thus, a calculation, for example an approximate determination depending on a further measured variable, can be sufficient to determine the second torque in the second measuring range. Especially when the second means is the control device and not a further, dedicated sensor for measuring the second torque, an additional sensor in the vehicle can be dispensed with. This makes the vehicle more cost-effective, easier to maintain, and thus also makes the drivetrain less complex.Additional measured values ​​already provided by the vehicle for other functions can be used to calculate the second torque depending on this.

[0023] According to a further embodiment, the drive train can be characterized in that the drive train can have the drive motor for providing drive force to assist the driver of the vehicle in driving the vehicle. The driver can additionally provide drive force applied to pedals of the vehicle to drive the vehicle. The drive motor can be an electric motor. The control device can be configured to perform at least one of switching the assistance by the drive motor on and off depending on at least one of the determined first torque and the determined second torque. The control device can be configured to control and, alternatively or additionally, regulate the drive motor depending on at least one of the determined first torque and the determined second torque.Thus, the drive train can be used to switch the drive motor support on or off depending on whether the rider is pedaling or not, and in general the drive motor can be regulated and controlled alternatively or additionally depending on whether the rider is pedaling or not.

[0024] A second aspect of the present invention relates to a human-powered vehicle with a drive train according to an embodiment of the first aspect of the present invention. The vehicle can be a bicycle, e-bike, pedelec, or cargo bike. Respective features, embodiments, and advantages can be found in the descriptions of the first aspect. Conversely, features, embodiments, and advantages of the second aspect also represent features, embodiments, and advantages of the first aspect.

[0025] A third aspect of the present invention relates to a method for controlling a drive train of a human-powered vehicle. The vehicle can be a bicycle, e-bike, pedelec, or cargo bike. The drive train can have a pedal crankshaft, and crank arms can be connected in a rotationally fixed manner to the pedal crankshaft. For example, two crank arms can be connected in a rotationally fixed manner to the pedal crankshaft, with a pedal rotatably mounted at one end of each crank arm. The pedal crankshaft can therefore also be referred to as a pedal crankshaft.

[0026] The method may include a step of determining a first torque applied by a driver of the vehicle to the pedal crankshaft using a first means. The determination may be performed, for example, using a sensor for measuring the first torque. Furthermore, the method may include a step of determining a second torque applied by the driver of the vehicle to the pedal crankshaft using a second means. The second means may be a control device of the vehicle for calculating the second torque as a function of a further measured variable.

[0027] Furthermore, the method can comprise controlling the drive train as a function of the determined first torque and as a function of the determined second torque. Controlling the drive train can comprise controlling and alternatively or additionally regulating a drive motor of the drive train. For example, the power and alternatively or additionally the torque of the drive motor can be increased if at least one of the determined first torque and the determined second torque has increased, for example over a certain time range. For example, the power and alternatively or additionally the torque of the drive motor can be reduced if at least one of the determined first torque and the determined second torque has decreased, for example over a certain time range.For example, the increase and, alternatively or additionally, the decrease of at least one of the power and the torque of the drive motor can be proportional to the increase or decrease of the determined first torque and, alternatively or additionally, the determined second torque. For controlling the drive train, a comparison of the determined first torque with the determined second torque can be performed.

[0028] Such a method makes it possible to determine the driver torque particularly precisely. This can be done, for example, by at least partially comparing the determined first torque with the determined second torque. This makes it possible, for example, to precisely determine whether a driver is pedaling or not. This allows the drivetrain to be controlled depending on the determined driver torque. This can increase both the comfort and safety of the driver when using the vehicle.

[0029] According to a further embodiment, the method can be characterized in that the drive train can have the drive motor for providing drive force to assist the driver of the vehicle in driving the vehicle. The assistance can be switched on by the drive motor if at least one of the determined first torque and the determined second torque exceeds a first threshold. For example, the first torque can be determined for a first measuring range around the value zero. If, for example, the first determined torque exceeds the first threshold, the assistance can be switched on by the drive motor. Thus, for example, it can be determined with a first accuracy whether the driver is pedaling or not.

[0030] According to a further embodiment, the method can be characterized in that the drive train can have the drive motor for providing drive force to assist the driver of the vehicle in driving the vehicle. The assistance by the drive motor can be switched off if at least one of the determined first torque and the determined second torque falls below a second threshold. The second threshold can be equal to or different from the first threshold. For example, the second threshold can be smaller than the first threshold. For example, the assistance can be switched off if the determined first torque falls below the second threshold. Thus, the first torque can be determined with a high degree of accuracy using the first means. The switching off can be carried out depending thereon.This allows for particularly precise determination of whether the rider is pedaling or not, and the assistance can be switched off based on this. This can increase the safety of the process, as assistance is not provided when the rider is not pedaling.

[0031] According to a further embodiment, the method can be characterized in that controlling the drive train can comprise determining a target gear ratio of the drive train. The target gear ratio can, for example, be a target gear ratio of a transmission of the drive train. The transmission can, for example, be arranged between the pedal crank and a driven wheel of the vehicle. The transmission can be arranged between the drive motor and the driven wheel. The gear ratio of the drive train can be the gear ratio of the transmission between the pedal crank and the driven wheel or between the drive motor and the driven wheel. The target gear ratio can be determined as a function of one of the determined first torque and the determined second torque.

[0032] According to a further embodiment, the method can be characterized in that the determined target gear ratio can be displayed via a display device of the vehicle. For example, specific target gear ratios can thus be output to the driver of the vehicle. Alternatively or additionally, at least one of the determined first torque and the determined second torque can be displayed as driver torque. Thus, the determined driver torque can be output to the driver to signal a recommendation regarding the target gear ratio of the drivetrain. For example, the display device can be a display on a handlebar of the vehicle or an app on a wearable, a smartwatch, or an app on the driver's mobile phone. The driver can thus be informed whether or not the gear ratio of the drivetrain should be changed.

[0033] According to a further embodiment, the method can be characterized in that an adjustment of a gear ratio of the drive train can be carried out depending on the determined target gear ratio. The adjustment of the gear ratio can be carried out manually by the driver. The adjustment of the gear ratio can be carried out automatically by the drive train, for example by the control device of the drive train. In this case, the adjustment of the gear ratio can be carried out depending on at least one of the determined first torque and the determined second torque, i.e., for example, depending on the determined driver torque. The gear ratio of the drive train can thus be adapted to a changed driver torque, for example automatically and without the driver having to do anything.

[0034] According to a further embodiment, the method can be characterized in that, when adjusting the gear ratio, a downshift of the gear ratio to a lower gear can be performed if at least one of the determined first torque and the determined second torque exceeds a third threshold. The third threshold can be different from or the same as the first and alternatively or in addition to the second threshold. Thus, a downshift can occur when the determined driver torque is particularly high and exceeds the third threshold. This makes it possible to maintain a cadence range that is comfortable for the driver, and the driver torque to be applied by the driver does not have to be too high. Alternatively, an upshift of the gear ratio to a higher gear can be performed if at least one of the determined first torque and the determined second torque exceeds the third threshold.For example, this can be helpful during an acceleration process.

[0035] According to a further embodiment, the method can be characterized in that, when adjusting the gear ratio, an upshift of the gear ratio to a higher gear can be performed if at least one of the determined first torque and the determined second torque falls below a fourth threshold. The fourth threshold can be the same as or different from the third threshold and alternatively or in addition to the second and first thresholds. Thus, for example, it can be achieved that when the driver torque decreases and falls below the fourth threshold, a lower gear is used in order to make pedaling easier for the driver. Thus, for example, the driver can ride faster and a cadence range that is comfortable for the driver can be maintained.Alternatively, a downshift of the gear ratio to a lower gear may be performed if at least one of the determined first torque and the determined second torque falls below the third threshold value. Short description of the characters Fig. Figure 1 shows a schematic diagram of a drive train of a muscle-powered vehicle. Fig. 2 shows schematically steps of a method for controlling a Fig. 1 schematically shows the drive train of a muscle-powered vehicle. Detailed description of embodiments

[0036] Fig. Figure 1 schematically shows a human-powered vehicle 2 with a drive train 4. The human-powered vehicle 2 is a pedelec. The drive train 4 has a pedal crankshaft 6, on which crank arms (not shown) are arranged. At each end of each crank arm, a pedal (not shown) is rotatably mounted for applying muscle power to propel the vehicle 2.

[0037] The drive train 4 has a first means 8 for determining S1 a first torque applied by the driver of the vehicle 2 to the pedal crankshaft 6. The determination S1 is a step of a schematically shown in Fig. 2 for controlling the drivetrain 4 of the vehicle 2. In the embodiment shown, the first means 8 is a sensor for measuring S1.1 the first torque. The sensor is a torque sensor based on torque strips.

[0038] The drive train 4 has a second means 10 for determining S2 a second torque applied by the driver of the vehicle 2 to the pedal crankshaft 6. The second means 10 is a control device 10 for calculating S2.1 the second torque as a function of a further measured variable. This further measured variable is measured with a sensor 9. In the embodiment, the further measured variable is a pedal force on pedals connected to the pedal crankshaft 6 via crank arms. The calculation S2.1 of the second torque is carried out as a function of the further measured variable. The control device 10 is communicatively connected to the first means 8, the sensor, as well as to the further sensor 9 for measuring the pedal force.

[0039] In an alternative embodiment, sensor 9 is configured to measure the second torque. In such an embodiment, both the first torque and the second torque are measured with a respective torque sensor. Thus, such an embodiment comprises finer strain gauges for measuring S1.1 the first torque and coarser strain gauges for measuring the second torque.

[0040] Furthermore, the control device 10 is configured to control S3 the drive train 4 as a function of the determined first torque and as a function of the determined second torque.

[0041] The drive train 4 has a drive motor 12 for providing drive power to assist the driver of the vehicle 2 in driving the vehicle 2. The drive motor 12 is communicatively connected to the control device 10. The control device 10 is configured to carry out at least one of a switching on S3.1 and a switching off S3.2 of the assistance by the drive motor 12 depending on at least one of the determined first torque and the determined second torque. In this case, the switching on S3.1 for assistance is carried out when at least one of the determined first torque and the determined second torque exceeds a first threshold value. If, for example, one of the determined first torque and the determined second torque, i.e. the driver torque, exceeds the first threshold value, pedaling is detected and the assistance is switched on.

[0042] The deactivation S3.2 of the assistance by the drive motor 12 is carried out when at least one of the determined first torque or the determined second torque falls below a second threshold. The first and second thresholds are different, and the second threshold is smaller than the first threshold. If, for example, the determined first torque, here the determined driver torque, falls below the second threshold, it is determined that the driver is no longer pedaling. The deactivation S3.2 is then carried out. Assistance by the drive motor 12 is no longer provided when the driver is no longer pedaling. This increases safety and comfort when using the vehicle 2 with the drive train 4 and when carrying out the method S3 for controlling the drive train 4.

[0043] The first means 8 for determining S1 of the first torque is configured to determine the first torque in a first measuring range. The first measuring range is oriented around zero for small torques and is comparatively small compared to a second measuring range. The second means 10 is configured to determine S2 of the second torque in the second measuring range. The first and second measuring ranges are different. The second measuring range is larger than the first measuring range and covers medium and larger driver torques. Thus, the first measuring range ranges from approximately 0 Nm to 50 Nm and the second measuring range from approximately 50 Nm to 250 Nm. In an alternative embodiment, the first measuring range ranges from approximately 0 Nm to 50 Nm and the second measuring range from approximately 0 Nm to 250 Nm, with subranges of the first and second measuring ranges overlapping.

[0044] The first means 8 is configured to determine S1 of the first torque with a first accuracy. The second means 10 is configured to determine S2 of the second torque with a second accuracy. The first and second accuracies are different, with the first accuracy being higher than the second accuracy. Thus, the first means 8 is configured to determine the first torque with a higher accuracy than the second means 10 is configured to determine the second torque with a lower accuracy.

[0045] In the embodiment, the first means 8 and the second means 10 for determining the driver torque are used as follows. If the driver torque is relatively small, for example, less than 50 Nm, the first means 8 is used to determine the driver torque. Here, the torque sensor is used as the first means 8 for measuring S1.1 the first torque. The control S3 of the drive train 4 is then carried out as a function of the determined first torque for driver torque values ​​in the first measuring range. In this driver torque range, the control S3 is carried out independently of the determined second torque. If the driver torque is greater, the second torque values ​​determined with the second means 10 are used to control S3 of the drive train 4. In this driver torque range, the control S3 is carried out independently of the determined first torque.In this measuring range, the first means 8 cannot determine any torque. For example, if the driver is already pedaling with a comparatively high driver torque, the second means 10 is used to determine S2 of the driver torque, which is then used to perform control S3.

[0046] Thus, for controlling S3, the determined first torque is used for driver torques that lie within the first measuring range, and the determined second torque is used for those that do not lie within the first measuring range. This ensures that the determined driver torque from the determined first and the determined second torque is always used to control S3 of the drive train 4, which has been determined with greater accuracy or which can be determined at all using one of the two means 8, 10. For example, high driver torques of around 200 Nm can only be determined using the second means 10, but not the first means 8. Thus, the driver torque can be determined with a high degree of accuracy both for small driver torques and for large driver torques.

[0047] Controlling S3 of the drive train 4 further includes determining S3.3 a target gear ratio of the drive train 4. The drive train 4 has a transmission with a gear ratio. The transmission is arranged between the pedal crankshaft 6 and a driven wheel of the vehicle 2. Determining S3.3 of the target gear ratio is performed as a function of at least one of the determined first torque and the determined second torque.

[0048] Furthermore, a display S3.4 of the determined target gear ratio is performed via a display device 14 of the vehicle 2. The display device 14 is a display on the handlebar of the vehicle 2. In an alternative embodiment, the determined driver torque is displayed via the display device 14 of the vehicle 2.

[0049] Furthermore, an adjustment S3.5 of a gear ratio of the drive train 4, here the transmission, between the pedal crankshaft 6 and the driven wheel is performed depending on the determined target gear ratio. The adjustment S3.5 is performed manually by the driver of the vehicle 2 via a gear lever. In an alternative embodiment, the adjustment S3.5 of the gear ratio is performed automatically and without active user intervention.

[0050] When adjusting the gear ratio S3.5, a downshift S3.5.1 of the gear ratio to a lower gear is performed if at least one of the determined first torque and the determined second torque exceeds a third threshold value. This ensures that the driver does not have to apply too much driver torque and can continue pedaling within a cadence range that is comfortable for the driver. Furthermore, when adjusting the gear ratio S3.5, an upshift S3.5.2 of the gear ratio to a higher gear is performed if at least one of the determined first torque and the determined second torque falls below a fourth threshold value. This allows the driver to drive faster and pedal within a comfortable cadence range. This ensures that the driver torque is within a window of torque values ​​that is comfortable for the driver and the driver can comfortably drive vehicle 2.

[0051] For downshifting S3.5.1 and upshifting S3.5.2, the determined first or second torque which was determined with a higher accuracy or which can be determined at all in the respective torque range with the respective means 8, 10 is used for comparison with the third or fourth threshold value. Reference symbol 2 muscle-powered vehicle 4 Drivetrain 6 Crankshaft 8 first means for determining a first torque 9 Sensor 10 Control device, second means for determining the second torque 12 Drive motor 14 Display device S1 Determine the first torque S1.1 Measuring the first torque S2 Determine the second torque S2.1 Calculating the second torque S3 Control of the drive train S3.1 Activation of support by the drive motor S3.2 Switching off the support by the drive motor S3.3 Determining a target gear ratio of the drive train S3.4 Display of the determined target ratio via the display device S3.5 Adjusting the drivetrain ratio S3.5.1 Downshifting the gear ratio S3.5.2 Upshifting the gear ratio QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 2609002A1

[0002]

Claims

[1] Drive train (4) for a muscle-powered vehicle (2), wherein the drive train (4) has a pedal crankshaft (6); wherein the drive train (4) has a first means (8) for determining (S1) a first torque applied by a driver of the vehicle (2) to the pedal crankshaft (6); wherein the drive train (4) has a second means (10) for determining (S2) a second torque applied by the driver of the vehicle (2) to the pedal crankshaft (6); and wherein the drive train (4) has a control device (10) for controlling (S3) the drive train (4) as a function of the determined first torque and as a function of the determined second torque. [2] Drive train (4) according to claim 1, characterized byin that the first means (8) is arranged to determine (S1) the first torque in a first measuring range and the second means (10) is arranged to determine (S2) the second torque in a second measuring range, wherein the first and the second measuring range are different. [3] Drive train (4) according to one of the preceding claims, characterized by in that the first means (8) is arranged to determine (S1) the first torque with a first accuracy, and the second means (10) is arranged to determine (S2) the second torque with a second accuracy, wherein the first and the second accuracy are different. [4] Drive train (4) according to one of the preceding claims, characterized by that the first means (8) is a sensor for measuring (S1.1) the first torque. [5] Drive train (4) according to one of the preceding claims, characterized bythat the second means (10) is the control device (10) for calculating (S2.1) the second torque as a function of a further measured variable. [6] Drive train (4) according to one of the preceding claims, characterized by in that the drive train (4) has a drive motor (12) for providing drive force to assist the driver of the vehicle (2) in driving the vehicle (2), and in that the control device (10) is designed to carry out at least one of switching on (S3.1) and switching off (S3.2) the assistance by the drive motor (12) as a function of at least one of the determined first torque and the determined second torque. [7] Muscle-powered vehicle (2) with a drive train (4) according to one of claims 1 to 6. [8] A method for controlling a drive train (4) of a muscle-powered vehicle (2), wherein the drive train (4) has a pedal crankshaft (6), comprising the steps of: determining (S1) a first torque applied by a driver of the vehicle (2) to the pedal crankshaft (6) using a first means (8); determining (S2) a second torque applied by the driver of the vehicle (2) to the pedal crankshaft (6) using a second means (10); and controlling (S3) the drive train (4) as a function of the determined first torque and as a function of the determined second torque. [9] Method according to claim 8, characterized byin that the drive train (4) has a drive motor (12) for providing drive force to assist the driver of the vehicle (2) in driving the vehicle (2), and a connection (S3.1) of the assistance by the drive motor (12) is carried out when at least one of the determined first torque and the determined second torque exceeds a first threshold value. [10] Method according to one of claims 8 or 9, characterized by in that the drive train (4) has a drive motor (12) for providing drive force to assist the driver of the vehicle (2) in driving the vehicle (2), and a switching off (S3.2) of the assistance by the drive motor (12) is carried out when at least one of the determined first torque and the determined second torque falls below a second threshold value. [11] Method according to one of claims 8 to 10, characterized byin that the control (S3) of the drive train (4) comprises determining (S3.3) a target gear ratio of the drive train (4), wherein the determination (S3.3) of the target gear ratio is carried out as a function of at least one of the determined first torque and the determined second torque. [12] Method according to claim 11, characterized by that a display (S3.4) of the determined target gear ratio is carried out via a display device (14) of the vehicle (2). [13] Method according to one of claims 11 or 12, characterized by that an adjustment (S3.5) of a transmission ratio of the drive train (4) is carried out depending on the determined target transmission ratio. [14] Method according to claim 13, characterized bythat when adjusting (S3.5) the gear ratio, a downshift (S3.5.1) of the gear ratio to a lower gear is carried out if at least one of the determined first torque and the determined second torque exceeds a third threshold value. [15] Method according to one of claims 13 or 14, characterized by that when adjusting (S3.5) the gear ratio, an upshift (S3.5.2) of the gear ratio to a higher gear is carried out if at least one of the determined first torque and the determined second torque falls below a fourth threshold value.

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