Method for operating a bicycle gear system

Abstract

The invention relates to a method (50) for operating a gearshift (105) of a bicycle (100), comprising the steps of: detecting a rotational movement of a rear wheel (111) of the bicycle (100), detecting a rotational movement of a crank-side output element (102) of the bicycle (100), determining a gear ratio (61) from the rotational movement of the rear wheel (111) and the rotational movement of the output element (102), determining at least two gear ratios (61) at different times within a predetermined time interval (63), and recognizing a gearshift design (105) as a continuous gearshift if the at least two determined gear ratios (61) differ from each other by at least one predetermined first gear difference (66).

Description

Prior ArtThe present invention relates to a method of operating a gear shift of a bicycle, a shifting system of a bicycle, and a bicycle.Shifting systems for bicycles are known which can have discrete gear stages, such as for example in a derailleur with several different large sprockets. In addition, shifting systems with continuously variable transmission ratios are known. Particularly when used in electric bicycles, functions, for example software functions, are often present, which are operated depending on the type of circuit. Knowledge of the type of the shift and determination of the instantaneous transmission ratios are usually required.Disclosure of the InventionThe method according to the invention having the features of claim 1 is distinguished in that precise information about the gear shift can be determined in a simple and reliable manner. In particular, a type of gear shift can be determined automatically using simple means and on each bicycle. This is achieved according to the invention by a method for operating a gear shift of a bicycle, preferably an electric bicycle, comprising the steps of:detecting a rotational movement of a rear wheel of the bicycle,detecting a rotational movement of a crank-side output element of the bicycle,determining a gear ratio from the rotational movement of the rear wheel and the rotational movement of the output element,determining at least two gear ratios at different points in time and within a predetermined time period; anddetecting a design of the gear shift as a continuous gear shift when the at least two gear ratios determined deviate from one another by at least one predetermined first gear difference.As a rotational movement, a rotational speed and / or a rotational speed and / or an angular speed is preferably detected.The crank-side output element is preferably in engagement with a transmission element which enables torque transmission from the output element to the rear wheel of the bicycle. The transmission element can be, for example, a chain or a belt. The crank-side output element can preferably be a chain plate.A gear shift which can provide continuously variable transmission ratios is considered in particular as a continuous gear shift. That is, any gear ratio may be set within a gear ratio range.A difference between the two gear ratios determined is considered in particular as the first gear difference.In other words, a method is provided in which the rotational movements of the rear wheel and crank-side output element are put into relation to one another in order to determine the gear ratios. In this case, at least two gear ratios determined are compared with one another within the predetermined time period. If the accordingly determined deviation between these two gear ratios is greater than or equal to a predetermined first gear difference, it is recognized in response to the gear shift being a continuous gear shift. In particular, the recognition is based on the fact that only continuous shifts can realize an incrementally small change in the gear ratio and, for example, only discrete shifts can realize large changes in a very short time range. In particular, discrete shifts cannot realize an incrementally small change in gear ratio in a short period of time. Because the rotational movements of the rear wheel and the crank-side output element are detected, the influence of the changing transmission ratio is thus detected unambiguously and in a simple manner.The method thus offers the advantage that a particularly simple possibility for automatically determining a type of gear shift can be provided. The method can be used on any desired bicycles. In particular when used on an electric bicycle, which functions are based on the type of gear shift, for example, in particular software functions, such as a speed estimate, which is carried out on the basis of, among other things, a current estimated transmission ratio, a particularly simple and reliable operation of such functions can thus advantageously be provided. For example, it is not necessary that the type of circuit must be programmed or set manually in advance.The dependent claims include preferred developments of the invention.Preferably, a plurality of gear ratios, in particular more than two, are determined at different times, wherein the type of gear shift is detected on the basis of the plurality of gear ratios. Particularly preferably, the mode of operation is recognized as a continuous mode of operation if an incremental change in the gear ratios over time is determined by means of the plurality of gear ratios. Preferably, the gear ratios are continuously monitored over time, for example continuously in time or at discrete times. As a result, it can be detected particularly reliably and precisely that a gear shift of continuous design is present.Preferably, the recognition of the type of gear shift is carried out only while a torque transmission is present at a drive train of the bicycle. This means that in particular all steps of the method which lead to the detection of the type of construction are carried out only while, for example based on sensors, it is determined simultaneously that the torque transmission is present at the drive train. Alternatively or additionally preferably, the detection of the design is stopped or interrupted if an interruption of the torque transmission at the drive train is determined. That is, the recognition of the design takes place only while the rider and / or a drive unit of the bicycle is providing propulsion, that is to say, for example, only while the drive train of the bicycle is tensioned. Alternatively preferably, this operating state can also be characterized in that a transmission element, such as a chainring, and a rear wheel of the bicycle execute a synchronous rotational movement. This allows a particularly reliable and accurate execution of the method.Particularly preferably, the method further comprises the step of: recognizing a type of gear shift as a discrete gear shift if the at least two gear ratios determined deviate from one another by at least one predetermined second gear difference within the predetermined time period. The gear shift is preferably detected as a discrete gear shift if a sudden change in the gear ratio by at least the second gear difference is detected. The second path difference is a multiple of the first path difference. Preferably, the second gear difference corresponds to a change in the gear ratios by at least 5%, preferably at least 7.5%. A gear shift with several discrete transmission ratios is considered in particular as a discrete gear shift. That is, predetermined gear changes are always carried out by means of the discrete gear shift when the transmission ratio in the drive train of the bicycle is changed. That is, in response to determining that the gear ratios differ from each other by at least the second gear difference, a large jump in the gear ratio can be detected in a short time. Such a jump is possible only in discrete gear shifts, for example, so that such a jump can be detected reliably and in a simple manner.Preferably, the first gear difference corresponds to a change in the gear ratios by at least 0.5%, and preferably at most 3%.More preferably, the predetermined time period is at least 0.5 seconds, and preferably a maximum of 1 second.Preferably, the method further comprises the steps of:determining an absolute average relative difference between two gear ratios determined successively, in particular by relating an amount of a difference between the two successive gear ratios to exactly one of these two gear ratios, preferably the gear ratio later in time, anddetermining a relative average gear ratio based on the absolute average relative differences, in particular by performing a weighted determination of an average value for all determined absolute average relative differences. This allows for a particularly precise detection, for example, since all measurement inaccuracies and tolerances in the detection of the rotational movements are also mapped, for example. For example, this can be used as a reference value for the detection of various switching processes. Furthermore, it can be determined, for example, that no shift has taken place if new measured values of the gear ratios are substantially within a range defined by the average gear ratio, of preferably plus / minus at most 5%, preferably at most 7%.Preferably, the method further comprises the steps of:determining a reference gear ratio as an average value of a plurality of determined gear ratios,determining a first difference between the reference gear ratio and a currently determined gear ratio, in particular as the magnitude of a difference between the reference gear ratio and the currently determined gear ratio, andincrementing a counter when said determined first difference is a multiple of said determined relative average gear ratio. A value k1 can be used as a multiple, for example, which is preferably parameterizable. Preferably, the value k1 can be exactly 3.The determination of the reference gear ratio and the subsequent steps preferably take place only in one operating mode if no discrete gear change has been detected. Alternatively or additionally preferably, these steps are carried out only while there is torque transmission at the drive train of the bicycle. Thus, for example, if the first difference is too great, i.e., exceeds a predetermined value, for example, it can likewise be recognized that the gear shift is a continuous gear shift.More preferably, the method further comprises the steps of:determining an absolute average gear ratio based on a plurality of determined gear ratios, in particular by relating an amount of a difference between an average value of a plurality of determined gear ratios and a current gear ratio to the current gear ratio,determining a second difference between the determined absolute average gear ratio and the currently determined gear ratio; andincrementing a counter when said determined second difference is a multiple of said determined relative average gear ratio. A value k2 can be used as a multiple, for example, which is preferably parameterizable. Preferably, the value k2 can be exactly 3. Thus, for example, in response to a detection that the second difference exceeds a predetermined value, it can be detected that the gear shift is a continuous gear shift.The method preferably further comprises the step of: detecting the type of gear shift as a continuous gear shift when the counter reaches or exceeds a predefined value, preferably of at least 3, preferably at least 5.Further preferably, the method further comprises the step: detecting a transmission ratio change, in particular by a shifting process, based on the determined gear ratios, and preferably depending on the detected type of gear shift. That is, the method can additionally have a shift detection which detects shifting operations of the gear shift.Particularly preferably, the detection of the rotational movement of the rear wheel takes place by means of a speed sensor and / or by means of a rotational speed sensor. The speed sensor can have, for example, a reed sensor which preferably generates exactly one measurement pulse per rotation of the rear wheel, wherein the rotational movement of the rear wheel can be determined on the basis of the generated measurement pulses.The rotational movement of the crank-side output element is preferably detected by means of a wheel speed sensor and / or, in particular if the bicycle is an electric bicycle, which preferably has a motor in the region of the crank drive, by means of a motor speed sensor.Preferably, the recognition of the type of gear shift is only performed when each freewheel in a drive system of the bicycle is closed and / or when there is torque transmission via the gear shift. For example, a freewheel can be arranged between cranks and output element. A present torque transmission via the gear shift can be detected, for example, by means of a torque sensor. This makes it possible to ensure a precise execution of the method in a particularly reliable manner.The method preferably further comprises the step of: outputting information representing the type of gear shift, preferably by means of a display device and / or via a user interface. That is, for example, the type of gear shift can be displayed directly to a driver via the display device. Alternatively or additionally, for example, the information about the type of gear shift can be output via any user interface, such as, for example, a communication via a user device.Further preferably, the method can further comprise the step of: outputting information representing a gear change, preferably by means of a display device and / or via a user interface. That is, the driver can be informed about an automatically detected gear change, for example.Furthermore, the invention leads to a shifting system of a bicycle, preferably an electric bicycle, comprising a gear shift and a control unit. The control unit is configured to carry out the described method.The invention further relates to a bicycle, preferably an electric bicycle, which comprises the described shifting system.Brief Description of the DrawingsThe invention is described below with reference to an exemplary embodiment in conjunction with the figures. Functionally identical components are identified in the figures by the same reference numerals. The following shows: FIG. 1 is a simplified schematic view of a bicycle in which a method for operating a gear shift of the bicycle is performed according to a preferred embodiment of the invention, FIG. 2 is a greatly simplified schematic view of steps of the method of the preferred embodiment, FIG. 3 shows a simplified schematic view of gear ratios of a discrete gear shift, which can be determined when carrying out the method, and FIG. 4 is a simplified schematic view of gear ratios of a continuous gear shift, which can be determined when the method is carried out.Preferred Embodiments of the InventionFIG. 1 shows a simplified schematic view of a bicycle 100 with a shifting system 107 comprising a gear shift 105 and a control unit 106. In the exemplary embodiment shown, the gear shift 105 is arranged at least on a rear wheel hub of the bicycle 100. A torque transmission takes place via the gear shift 105 from a crank-side output element 102 and via a transmission element 112 to the rear wheel 111, wherein the gear shift 105 is configured to set various transmission ratios.The crank-side output element 102 is formed as a chain plate, and the transmission element 112 is formed as a chain. Alternatively preferably, the transmission element 112 can be designed, for example, as a belt, wherein the output element can be, for example, a belt pulley. The output element 102 is connected in a rotationally fixed manner to cranks 104 to which pedals are fastened, via which a rider of the bicycle 100 can apply a pedaling force.The gear shift 105 may include an electronic actuation device that causes a gear change, i.e., a change in a transmission ratio in the drive train of the bicycle 100, in response to receiving electronic actuation signals. The electronic actuation signals may be generated manually by the driver and / or automatically by the control unit 106. Alternatively preferably, the gear shift 105 can have manual actuation, for example by means of cable pull.The bicycle 100 is preferably an electric bicycle which comprises a drive unit 101, in particular with an electric motor. Preferably, the control unit 106 is integrated into the drive unit 101. The drive unit 101 can be supplied with electrical energy by means of an electrical energy store 109 of the bicycle 100. The drive unit 101 may assist the pedaling force generated by muscle power of the rider of the bicycle 100 by an electric motor generated motor torque.The control unit 6 is configured to perform a method 50 for operating the gear shift 105 of the bicycle 100. The method steps of the method 50 are illustrated schematically in a greatly simplified manner in FIG. 2.By means of the method 50, a type of gear shift 105 can be automatically recognized. FIGS. 3 and 4 show exemplary signal curves which can occur in two different variants of the type of gear shift 105, for further explanation of the method.In method 50, in first step 51, a detection of a rotational movement of rear wheel 111 and a detection of a rotational movement of crank-side output element 102 are carried out simultaneously. Preferably, a sensor-based detection of a rotational speed is carried out in each case, for example by means of a rotational speed sensor, speed sensor or the like.The detection of the rotational movements can preferably take place continuously in time or alternatively at points discrete in time.In step 52, a gear ratio is ascertained by relating the detected rotational movement of the rear wheel 111 and the detected rotational movement of the crank-side output element 102.Subsequently, in step 53, a comparison of two gear ratios determined is made. In this case, two gear ratios are compared, which were determined at different points in time, but within a predetermined time period. For example, two gear ratios are compared with one another, which were determined at a time interval of 0.5 seconds.Furthermore, in the following step 54, a recognition of the type of gear shift 105 is carried out. In this case, the gear shift 105 is recognized either as a continuous gear shift, which can provide continuously variable transmission ratios, or as a discrete gear shift, which can provide a plurality of different discrete transmission ratios.It is particularly advantageous to detect the type of gear shift 105 in such a way when a discrete gear shift is initially assumed. If the criteria for a continuous gear shift are preferably detected a plurality of times during the execution of the method, the type of gear shift 105 can be detected as a continuous gear shift in response thereto.The type of gear shift 105 is identified in step 54 by analysis of the comparison in step 53.In detail, the gear shift 105 can be recognized as a continuous gear shift if the two gear ratios compared in step 53 differ from one another within the predetermined time period by at least one predetermined first gear difference, which preferably corresponds to a change in the gear ratios by at least 0.5%, and preferably at most 3%.For example, the type of gear shift 105 can additionally be recognized as a discrete gear shift even if the two gear ratios compared in step 53 deviate from one another by more than a second gear difference, which is a multiple of the first gear difference, for example corresponds to a change in the gear ratios by at least 7.5%.Furthermore, an additional explanation of the method 50 is provided below with reference to FIGS. 3 and 4, which show exemplary specific profiles of gear ratios during operation of the bicycle 100.FIG. 3 shows a diagram 60 in which an exemplary gear ratio curve 65 for a discrete gear shift is shown. In the diagram 60, measured values for the gear ratio 61 over time 62 are shown.As can be seen in FIG. 3, the gear ratio profile 65 has a plurality of substantially constant sections, in which, for example, only one fluctuation is present which is dependent on measurement tolerances. In these sections, the gear shift 105 has a constant transmission ratio in each case, so that the rotational movements of the rear wheel 111 and the crank-side output element 102 do not change relative to one another.Furthermore, a plurality of gear jumps 67 are shown in the diagram 60, at which a sudden change of the gear ratio 61 takes place. At these gear jumps 67, a gear change of the gear shift 105 takes place.When carrying out method 50, time span 63 is considered, for example. In this case, in comparison with step 53, the respective gear ratio 61 at the beginning and end of this time period 63 is considered. In this case, the comparison of step 53 provides that the respective gear ratios 61 are substantially equal.Furthermore, an analysis can also be carried out, for example, of the further time period 63' within which one of the gear jumps 67 lies. In this case, significantly different gear ratios 61 are present at the beginning and end of the further time period 63'. In detail, there is a determined gear difference 64 which is greater than a second gear difference 68, which is marked by way of example. Assuming that such a large gear difference 64 and a sudden change of the gear ratios 61 only occur due to a sudden change of a transmission ratio, as is possible by a discrete gear shift, the gear shift 105 can therefore also be detected as a discrete gear shift in response to the determination of such a large gear difference 64, which is larger than the second gear difference 68.Furthermore, FIG. 4 shows a diagram 60 in which an exemplary gear ratio curve for a continuous gear shift is shown. In the diagram 60 of FIG. 4, measured values for the gear ratio 61 over time 62 are likewise shown.As can be seen in FIG. 4, the gear ratio profile 65 has regions 69, in which the gear ratio 61 increases continuously with time 62. In these ranges 69, a continuous change, in particular an increase, of the transmission ratio takes place by the continuous gear shift 105. As a result, during this change of the transmission ratio, rotational movements which change relative to one another are likewise present at the rear wheel 111 and crank-side output element 102, resulting in the continuously increasing gear ratio profile 65.If it is determined during the execution of method 50 by analysis of gear ratios 61 in predetermined time period 63, as exemplarily indicated in FIG. 4, that corresponding determined gear difference 64 is greater than an exemplarily indicated first gear difference 66, then it can be recognized based on this that gear shift 105 is a continuous gear shift.Thus, by means of the method 50, a recognition of the type of gear shift 105 of the bicycle 100 can be carried out automatically with simple means. On the basis thereof, for example, further functions, such as, for example, a determination of shifting processes and / or speeds, which can be carried out, for example, on the basis of knowledge of a current transmission ratio of the gear shift 105, can be carried out precisely.

Claims

Method for operating a gearshift (105) of a bicycle (100), comprising the steps of: - detecting a rotational movement of a rear wheel (111) of the bicycle (100), - detecting a rotational movement of a crank-side output element (102) of the bicycle (100), - determining a gear ratio (61) from the rotational movement of the rear wheel (111) and the rotational movement of the output element (102), - determining at least two gear ratios (61) at different times within a predetermined time period (63), and - detecting a type of the gearshift (105) as a continuous gearshift if the at least two determined gear ratios (61) deviate from one another by at least one predetermined first gear difference (66).The method of claim 1, wherein the identification of the type of gear shift (105) is only performed while there is a torque transfer to a drive train of the bicycle (100).Method according to one of the preceding claims, further comprising the step of: - identifying a type of the gear shift (105) as a discrete gear shift if the at least two gear ratios (61) determined deviate from one another by at least one predetermined second gear difference (68), wherein the second gear difference (68) is a multiple of the first gear difference (66).Method according to any one of the preceding claims, wherein the first gear difference (66) corresponds to a change in gear ratios by at least 0.5%, and preferably at most 3%.Method according to one of the preceding claims, wherein the predetermined time period (63) is at least 0.5 seconds, preferably at most 1 second.Method according to any of the preceding claims, further comprising the steps of: - determining an absolute average relative difference between two successively determined gear ratios (61), and - determining a relative average gear ratio based on the absolute average relative differences.Method according to claim 6, further comprising the steps of: - determining a reference gear ratio as an average value of a plurality of determined gear ratios (61), - determining a first difference between the reference gear ratio and a current determined gear ratio (61), and - incrementing a counter if the determined first difference is a multiple of the determined relative average gear ratio.Method according to claim 6 or 7, further comprising the steps of: - determining an absolute average gear ratio based on a plurality of determined gear ratios (61), - determining a second difference between the absolute average gear ratio and a current determined gear ratio (61), and - incrementing a counter if the determined second difference is a multiple of the determined relative average gear ratio.Method according to one of claims 7 or 8, comprising the step of: - detecting the type of gear shift (105) as a continuous gear shift when the counter reaches or exceeds a predefined value.Method according to one of the preceding claims, further comprising the step of: - detecting a transmission ratio change, in particular by a shifting process, based on the gear ratios (61) determined.Method according to one of the preceding claims, wherein the rotary movement of the rear wheel (111) is detected by means of a speed sensor and / or by means of a rotational speed sensor.Method according to one of the preceding claims, wherein the rotary movement of the crank-side output element (102) is detected by means of a carcass sensor and / or by means of an engine speed sensor.Method according to any of the preceding claims, wherein the recognition of the type of gear shift (105) is performed only when each freewheel in a drive system of the bicycle (100) is closed and / or when there is a torque transmission via the gear shift (105).A shifting system of a bicycle (100) comprising a gear shift (105) and a control unit (106), wherein the control unit (106) is configured to perform the method (50) according to any one of the preceding claims.Bicycle, in particular electric bicycle, comprising a shifting system (107) according to claim 14.

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