Arrangement for recording bearing parameters of a bottom bracket of a bicycle

Abstract

The invention relates to an arrangement (1) for detecting bearing parameters of a bottom bracket (10) of a bicycle (100), comprising a bottom bracket (10) which has an inner ring (11) and an outer ring (12), a voltage source (2) which is designed to generate an electrical voltage between the inner ring (11) and the outer ring (12) of the bottom bracket (10), and a detection unit (3) which is designed to detect an electrical impedance between the inner ring (11) and the outer ring (12) of the bottom bracket (10) at at least two detection positions (5) distributed around the circumference of the bottom bracket (10), wherein the detection unit (3) is designed to determine at least one predetermined bearing parameter based on at least two electrical impedances at different detection positions (5).

Description

Prior ArtThe present invention relates to an arrangement for detecting bearing parameters of a bottom bracket of a bicycle, to a bicycle, and to a method for detecting bearing parameters of a bottom bracket of a bicycle.Drive arrangements of bicycles, such as in particular electric bicycles, are known, which have a drive unit that can generate a motor torque for assisting a pedaling force of a driver. In this case, the generation of the engine torque usually takes place as a function of a pedaling torque generated by the muscle force of the driver. For this purpose, it is necessary to record the value of the momentarily generated pedaling torque, for example by means of a corresponding sensor system. It is also known, for example, that information on a force exerted by a driver on the short-circuit operation can be obtained on the basis of a bearing force on a pedal bearing of the electric bicycle, and that the drive unit is actuated on the basis thereof. Such a system is shown, for example, in DE 10 2010 001 775 A1.Disclosure of the InventionThe arrangement according to the invention having the features of claim 1 is distinguished in contrast in that bearing parameters on a bottom bracket of a bicycle can be determined precisely in a particularly simple and cost-effective manner. In addition, for example, a simple determination of the bearing force can be made possible. This is achieved according to the invention by an arrangement for detecting bearing parameters of a bottom bracket of a bicycle, comprising a bottom bracket which comprises an inner ring and an outer ring, a voltage source, and a detection unit. The bottom bracket bearing can preferably be designed as a rolling bearing, wherein rolling bodies can roll between the inner ring and the outer ring. The voltage source is configured to generate an electrical voltage, preferably an electrical alternating voltage, between the inner ring and the outer ring of the bottom bracket. The detection unit is configured to detect an electrical impedance between the inner ring and the outer ring of the bottom bracket at at least two detection positions which are distributed around the circumference of the bottom bracket. The detection unit is also configured to determine at least one predetermined bearing parameter of the bottom bracket based on at least two electrical impedances at different detection positions.Preferably, the electrical voltage, in particular alternating voltage, can be generated by means of the voltage source directly between the inner ring and the outer ring. Alternatively preferably, the electrical voltage can be generated indirectly between the inner ring and the outer ring. It is particularly advantageous if the voltage source is configured to generate an electrical potential on a pedal shaft in contact with the inner ring of the pedal bearing.In other words, an arrangement is provided in which an electrical impedance is detected between the inner ring and the outer ring on the bottom bracket based on a generated voltage, in particular alternating voltage, between the inner ring and the outer ring. In particular, an electrical impedance is thereby detected simultaneously at two different and preferably opposite circumferential positions of the bottom bracket. On the basis of these two detected electrical impedances, the predetermined bearing parameter is subsequently determined. The determination of the bearing parameter is based in particular on the assumption that different radial forces act on the bottom bracket due to the pedal actuation by means of the pedaling force of a rider of the bicycle. These forces cause a mechanical pressure in the bottom bracket bearing, for example between the rolling bodies and inner ring and outer ring, as a result of which different electrical resistances are then present in the radial direction by the bottom bracket bearing. That is to say that the electrical impedance changes between the outer ring and the inner ring during operation of the bicycle due to the alternating mechanical pressure in the radial direction in the bottom bracket bearing. By detecting the electrical impedance at the two or also at a plurality of preferably opposite positions, information about the instantaneous load on the bottom bracket bearing and based thereon on the predetermined bearing parameter can be obtained.The arrangement thus offers the advantage that the bearing parameters on the bottom bracket can be detected by means of a particularly simple and cost-effective and space-saving structure. By detecting based on electrical impedances, a particularly simple structure can be made possible, which takes up little additional space and can be accommodated in a particularly flexible manner on a wide variety of pedal bearings.The dependent claims include preferred developments of the invention.The at least one predetermined bearing parameter preferably comprises a, preferably radial, bearing force on the bottom bracket bearing. That is, the detection unit is configured to determine a bearing force in amplitude and direction at the bottom bracket as bearing parameter. In particular, the bearing force can be used further to determine a momentary pedaling torque of a rider of the bicycle based thereon. This means that, with a particularly simple and cost-effective construction, a determination of the pedaling torque manually applied by the rider can be determined by means of the arrangement when the pedals of the bicycle are operated. For example, if the bicycle is an electric bicycle, further advantageous functions can thereby be provided, such as, for example, driver's intention recognition. This means that, depending on the determined bearing forces or the determined pedaling torque, provision of an engine torque to a drive unit for motor-assisted pedaling force of the driver can preferably be adapted. Alternatively preferably, the determined bearing force on the bottom bracket can also be used to determine instantaneous pedal forces of a rider of the bicycle, and preferably then to control the provision of a motor torque solely on the basis of the determined pedal forces.Particularly preferably, the bearing force comprises a bearing force direction and a bearing force amount. As a result, the instantaneous mechanical load situation on the bottom bracket can be estimated particularly precisely. On the basis of this, a particularly accurate determination of the pedaling torque of the driver can thus be carried out.The detection unit is preferably configured to determine the at least one predetermined bearing parameter based on at least one impedance quotient. The impedance quotient comprises exactly two impedances of opposite detection positions, in particular with respect to a tread axis. An impedance quotient of exactly two impedances which are detected at detection positions opposite one another with respect to the pedal axis is considered in particular as the impedance quotient. As a result, the influence of the mechanical load on the bottom bracket and thus the at least one predetermined bearing parameter can be determined particularly easily and precisely.Particularly preferably, the detection unit is configured to detect the electrical impedance at exactly four detection positions arranged uniformly distributed around the circumference of the bottom bracket. It is thus preferable for exactly two impedance quotients of the impedances from the respectively opposite detection positions to be determined. In particular, the bearing force can thus be determined particularly easily and at the same time precisely with the bearing force direction and the bearing force amount.The predetermined bearing parameter preferably comprises a rotational speed and / or a temperature. This means that, on the basis of the change over time of the impedances, for example, it is thus possible to draw conclusions about the rotational speed, in particular of the inner ring, and thus preferably of a pedal shaft, that is to say also a carcass. Preferably, for this purpose, the impedances are monitored over time by means of the detection unit. The temperature can likewise be estimated, for example, by monitoring the impedances over time. Thus, a monitoring of the bearing parameters of the bottom bracket and, for example, a correction of the impedance-temperature dependence can be carried out in a particularly flexible manner and by means of a simple construction.Further preferably, the detection unit is configured to determine the predetermined storage parameter by means of a machine learning algorithm. This means that, for example, a self-learning determination of the bearing parameters can be provided by way of a temporal acquisition and evaluation of data during operation of the bicycle. As a result, with a particularly simple structural design of the arrangement, a particularly flexible and precise detection of the bearing parameters can take place.The outer ring of the bottom bracket is preferably surrounded by an electrically insulating sleeve. At each detection position, the electrically insulating sleeve is penetrated in the radial direction by an electrical contact element. In particular, the sleeve can be of annular design and be arranged, for example, directly on an outer circumference of the outer ring of the bottom bracket bearing. This allows a simple and defined mechanical mounting of the pedal bearing, for example in a housing or frame of the bicycle. The electrical contact elements, which can be formed, for example, as substantially cylindrical pins made of an electrically conductive material, permit electrical contacting of the outer ring through the sleeve. Thus, a simple and inexpensive construction can be provided.Alternatively preferably, a contact foil can be arranged between the outer ring and the housing, which in particular has a plurality of electrical contact points with the outer ring. This makes it possible to determine the impedances particularly sensitive and thus precisely.The electrically insulating sleeve and the electrical contact elements are preferably designed in such a way as to allow a movement of the bottom bracket relative to a housing on which the bottom bracket is held. In particular, the sleeve and the contact elements permit a defined limited movement in the radial direction. In particular, the contact elements can be designed as spring contacts which exert a spring force on the outer ring of the pedal bearing. The mechanical principle of the detection of the bearing parameters can thus be reliably implemented with a particularly simple and cost-effective construction.Furthermore, the invention leads to a bicycle, preferably an electric bicycle, which comprises the described arrangement. The bicycle preferably comprises a crank drive which has cranks, a pedal shaft and two pedal bearings for supporting the pedal shaft. In addition, the bicycle comprises a chainring, which is connected to the pedal shaft, and a drive unit, which is configured to provide an engine torque for assisting a rider torque generated by a rider, in particular by means of muscle power. The pedal shaft is mounted within the drive unit by means of the two pedal bearings. In this case, the arrangement described above is configured to record a bearing force on at least one of the two pedal bearings. The bearing force determination by means of the arrangement results in the advantage that the pedal can thus be designed in a particularly simple and cost-effective manner, wherein a reliable determination of the forces used for the actuation of the drive unit is nevertheless possible.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 an electric bicycle with an arrangement according to a preferred embodiment of the invention, FIG. 2 shows a simplified schematic detailed view of the arrangement of FIG. 1, FIG. 3 shows a simplified schematic view of an illustration of the measuring principle of the arrangement of FIG. 1, and FIG. 4 shows a further simplified schematic detailed view of the arrangement of FIG. 1.Preferred Embodiments of the InventionFIG. 1 shows a simplified schematic view of an electric bicycle 100 with an arrangement 1 for detecting storage parameters according to a preferred exemplary embodiment of the invention. The arrangement 1 is illustrated in a simplified schematic detailed view in FIG. 2.The electric bicycle 100 has a crank drive with two cranks 104 opposite each other with respect to a pedal axle 30. Pedals are arranged on the cranks 104, by means of which a driver can generate a driver torque by means of muscle power.In addition, the crank drive comprises a pedal shaft 108 which is connected to the cranks 104 in a rotationally fixed manner, and two pedal bearings 10 for rotatably mounting the pedal shaft 108.The electric bicycle 100 further comprises a sprocket 107 that is connected to the pedal shaft 108 in a rotationally fixed manner and a bicycle chain that is in engagement with the sprocket 107.In order to assist the driver torque with an additional motor torque, the electric bicycle 100 comprises a drive unit 106, which is configured to generate the motor torque, preferably by means of an electric motor, which is supplied with electrical energy in particular by an electrical energy store 109.The pedal shaft 108 is preferably mounted in the drive unit 106 by means of the two pedal bearings 10.The bottom bracket bearing 10 is designed as a rolling bearing and comprises an inner ring 11 and an outer ring 12 and a plurality of rolling bodies 19 arranged between the inner ring 11 and the outer ring 12.During motor-assisted operation of the electric bicycle 100, the motor torque is adapted as a function of the driver torque applied by the driver. The driver torque is determined by determining a bearing force 50 on at least one, preferably on the chainring-side, bottom bracket 10 by means of the arrangement 1, as described below with reference to FIG. 2.The arrangement 1 comprises a voltage source 2 which is configured to generate an electrical voltage between an inner ring 11 of the bottom bracket 10 and an outer ring 12 of the bottom bracket 10. In particular, this is achieved by applying an electrical potential to the pedal shaft 108, wherein the pedal shaft 108 is in direct mechanical contact with the inner ring 11.An alternating voltage is preferably generated by means of the voltage source 2.The arrangement 1 further comprises a detection unit 3. The detection unit 3 comprises a plurality of sensor elements 32 and an evaluation unit 31, which is connected to all sensor elements 32.Each of the sensor elements 32 is configured to detect an electrical impedance between the inner ring 11 and the outer ring 12 of the bottom bracket 10 at a predetermined detection position 5.In the exemplary embodiment shown, exactly four sensor elements 33, and thus also exactly four detection positions 5, are provided. The detection positions 5 are arranged uniformly distributed around the circumference of the outer ring 12.The evaluation unit 31 is configured to acquire and evaluate measured values of the sensor elements 32 in order to determine the bearing parameters of the pedal bearing 10. In detail, a radial bearing force 50, which comprises a bearing force amount and a bearing force direction, is determined as bearing parameter.To detect the bearing force 50, the detection unit 3 determines an impedance quotient from the impedances at the two respectively opposite detection positions 5. That is, a first impedance quotient is obtained from the impedances of the vertically upper and lower detection positions 5, and a second impedance quotient is obtained from the impedances of the horizontally left and right detection positions 5.The bearing force 50 can then be estimated on the basis of the two impedance quotients thus determined, preferably on the basis of a previously known calibration of the arrangement 1 and / or by means of a machine learning algorithm.This detection is based on the principle that the electrical impedance is dependent on a magnitude and direction of the pressure between inner ring 11 and outer ring 12, which is caused by the pedaling force of the driver and / or the motor force of drive unit 106. This is illustrated, for example, with reference to FIG. 3.FIG. 3 shows a simplified schematic view of a force distribution on the rolling bodies 19 of the bottom bracket bearing 10 in the case of two different resulting bearing forces 50. As a result, the highest pressing is present on the rolling bodies 19 arranged at the top furthest to the left in FIG. 3. On these rolling bodies 19 there is thus the highest conductivity between inner ring 11 and outer ring 12 and thus the lowest impedance. Accordingly, the greatest impedance is the smallest due to the smallest pressing on the rolling elements 19 arranged on the right in the horizontal direction. In the horizontal direction, the configuration illustrated above in FIG. 3 thus has a significantly smaller impedance quotient in comparison to the vertical direction. Thereby, for example, the direction of the resulting bearing force 50 can be estimated.In an analogous manner, in the configuration shown at the bottom in FIG. 3, with the bearing force 50 oriented vertically, a significantly smaller impedance quotient is present in comparison to the horizontal direction.Based on the knowledge of the instantaneous values of the impedance quotient and based on the previously known mechanical properties of the bottom bracket 10, the amount of the instantaneous bearing force 50 can also be estimated.In addition to estimating the bearing force 50, an estimation of further bearing parameters, such as preferably a temperature and a rotational speed, can be carried out, preferably by means of a machine learning algorithm.FIG. 4 shows further structural details of the arrangement 1 of the preferred exemplary embodiment. In detail, the arrangement 1 further comprises an electrically insulating sleeve 14 surrounding the outer ring 12 of the bottom bracket 10. By means of the sleeve 14, for example, a simple fastening of the bottom bracket 10 in a housing (not shown) of the drive unit 106 can take place, for example, by the bottom bracket 10 being held in a recess of the housing via the sleeve 14.Furthermore, the arrangement 1 comprises a plurality of contact elements 15, which are designed as metallic spring contacts and which penetrate the sleeve 14 in the radial direction. In detail, each contact element 15 is arranged at a respective detection position 5 and aligned in the radial direction. Each contact element 15 is in mechanical contact with the outer ring 12 of the bottom bracket 10 and protrudes completely through the sleeve 14 in the radial direction. As a result, the detection of the impedance at the contact elements 15 can take place radially outside the sleeve 14 in a simple manner.The sleeve 14 and the electrical contact elements 15 are designed to be resilient in such a way as to allow a certain movement of the bottom bracket 10 relative to the housing on which the bottom bracket 10 is held. This allows an optimized mechanical construction and an improved detection accuracy to be provided.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2010 001 775 A1

[0002]

Claims

Arrangement for detecting bearing parameters of a bottom bracket bearing (10) of a bicycle (100), comprising: - a bottom bracket bearing (10) comprising an inner ring (11) and an outer ring (12), - a voltage source (2) which is configured to generate an electrical voltage between the inner ring (11) and the outer ring (12) of the bottom bracket bearing (10), and - a detection unit (3) which is configured to detect an electrical impedance between the inner ring (11) and the outer ring (12) of the bottom bracket bearing (10) at at least two detection positions (5) arranged distributed around the circumference of the bottom bracket bearing (10), - wherein the detection unit (3) is configured to determine at least one predetermined bearing parameter on the basis of at least two electrical impedances at different detection positions (5).Arrangement according to claim 1, wherein the at least one predetermined bearing parameter comprises a, in particular radial, bearing force (50).The assembly of claim 2, wherein the bearing force (50) comprises a bearing force direction and a bearing force amount.Arrangement according to one of the preceding claims, wherein the detection unit (3) is configured to determine the at least one predetermined bearing parameter based on at least one impedance quotient which comprises exactly two impedances of opposite detection positions (5).Arrangement according to one of the preceding claims, wherein the detection unit (3) is configured to detect the electrical impedance at exactly four detection positions (5) arranged uniformly distributed around the circumference of the bottom bracket (10).Arrangement according to one of the preceding claims, wherein the predetermined bearing parameter comprises a rotational speed and / or a temperature.Arrangement according to one of the preceding claims, wherein the detection unit (3) is configured to determine the predetermined storage parameter by means of a machine learning algorithm.Arrangement according to one of the preceding claims, wherein the outer ring (12) is surrounded by an electrically insulating sleeve (14), which is penetrated in the radial direction by a respective electrical contact element (15) at each detection position (5).Arrangement according to claim 8, wherein the electrically insulating sleeve (14) and the electrical contact elements (15) are configured to allow a movement of the bottom bracket (10) relative to a housing on which the bottom bracket (10) is held.Bicycle, in particular an electric bicycle, comprising an assembly (1) according to any one of the preceding claims.Method for detecting bearing parameters of a bottom bracket bearing (10) of a bicycle (100), comprising the steps of: - generating an electrical voltage between an inner ring (11) and an outer ring (12) of the bottom bracket bearing (10), - detecting an electrical impedance between the inner ring (12) and the outer ring (12) of the bottom bracket bearing (10) at at least two detection positions (5) arranged distributed around the circumference of the bottom bracket bearing (10), and - determining at least one predetermined bearing parameter based on at least two electrical impedances at different detection positions (5).

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