Assembly for measuring a bearing force of a bottom bracket of a vehicle which can be operated by means of muscle power and / or motor power

Abstract

The invention relates to an assembly for measuring a bearing force of a bottom bracket of a vehicle which can be operated by means of muscle power and / or motor power, the assembly comprising a bottom bracket, a bearing receptacle which completely annularly encloses the bottom bracket, a bearing-force sensor, and a measuring unit, a portion of the bearing receptacle being designed as a flexible bar which can be deformed in a radial direction, the bearing-force sensor being designed to detect a deformation of the flexible bar, and the measuring unit being designed to measure a bearing force at the bottom bracket on the basis of the deformation, detected by means of the bearing-force sensor, of the flexible bar.

Description

[0001] Description

[0002] title

[0003] Arrangement for detecting a bearing force of a bottom bracket of a vehicle that can be operated with muscle power and / or motor power

[0004] State of the art

[0005] The present invention relates to an arrangement for detecting a bearing force of a bottom bracket of a vehicle operable with muscle power and / or motor power, a drive arrangement of a vehicle operable with muscle power and / or motor power, a vehicle operable with muscle power and / or motor power, and a method for operating a drive arrangement.

[0006] Drive arrangements for vehicles that can be operated using muscle power and / or motor power, such as electric bicycles, are known. These vehicles have a drive unit that can generate a motor torque to assist the pedaling force of a rider of the vehicle. Typically, the motor torque is generated as a function of the rider torque generated by the rider's muscle power. This requires recording the value of the currently generated rider torque, for example, using appropriate sensors. It is also known, for example, that based on a bearing force at a bottom bracket of the electric bicycle, information can be obtained about a force exerted by a rider on the pedal operation, and that the drive unit can be actuated based on this force. Such a system is shown, for example, in DE 10 2010 001 775 A1.

[0007] Disclosure of the invention The arrangement according to the invention with the features of claim 1 is distinguished in that a bearing force on a bottom bracket of a vehicle that can be operated with muscle power and / or motor power can be precisely determined in a particularly simple and cost-effective manner. Based on the bearing force determined in this way, further functions of a drive arrangement can advantageously be provided efficiently and cost-effectively. This is achieved according to the invention by an arrangement for detecting a bearing force of a bottom bracket of a vehicle that can be operated with muscle power and / or motor power, comprising a bottom bracket, a bearing receptacle which completely surrounds the bottom bracket in a ring shape, a bearing force sensor, and a detection unit. The bearing receptacle is designed in particular to hold the bottom bracket. For example, the bearing receptacle can be designed as a bearing shell.A portion of the bearing mount is designed as a radially deformable bending beam. In particular, the bending beam is slightly elastically deformable when a force is applied to the bottom bracket. The bearing force sensor is configured to detect deformation of the bending beam. The detection unit is also configured to detect a bearing force at the bottom bracket based on the deformation of the bending beam detected by the bearing force sensor. The bearing force is viewed as the total resulting force in the region of the bottom bracket, which occurs, for example, due to motor torque and / or rider torque. Particularly preferably, the detection unit is configured to determine a bearing force direction and a bearing force magnitude of the bearing force at the bottom bracket based on the detected deformation of the bending beam.

[0008] In other words, an arrangement is provided which has a bearing receptacle on the bottom bracket, on which an at least partially flexible region in the form of a bending beam is formed. The bending beam preferably extends only around part of a circumference of the bottom bracket. For example, the remaining partial regions of the bearing receptacle can be designed and / or attached to be essentially non-deformable. As a result, the mechanical loads acting on the bottom bracket are transferred from the bottom bracket to the bending beam, which can cause the latter to deform. This deformation can be detected by the bearing force sensor. By evaluating the measured values ​​of the bearing force sensor using the detection unit, the bearing force acting on the bottom bracket can then be determined. For example, the relationship between deformation and bearing force can be determined based on previously known geometric and mechanical properties of the bearing receptacle and bottom bracket.Alternatively or additionally, the bearing force can be determined based on a calibration of the system.

[0009] A variety of sensors can be used as bearing force sensors, suitable for detecting deformations of the bending beam. For example, the deformations can be detected directly and / or indirectly based on the forces acting on the bending beam.

[0010] The arrangement therefore offers the advantage that the bearing force at the bottom bracket can be measured using a particularly simple, cost-effective and space-saving design. The use of the bending beam enables a particularly sensitive design. In particular, even small bearing forces can be determined very precisely. When used on an electric bicycle, this offers the advantage that, for example, small torque values ​​can be measured precisely and sensitively, enabling, for example, particularly precise control of a drive unit based on the rider's torque. The fact that the bearing mount completely encompasses the bottom bracket also provides a particularly robust and precise mount for the bottom bracket.

[0011] The subclaims contain preferred developments of the invention.

[0012] The bearing receptacle on the bottom bracket is preferably designed as a circumferentially closed ring. In particular, the ring is designed as a one-piece component. This means that the bearing receptacle preferably always has a predetermined minimum thickness in the radial direction all the way around the bottom bracket. This makes it possible to provide a particularly robust arrangement with precise bearings. In particular, this makes it easy to achieve a high positional tolerance of the bottom bracket. The bearing receptacle is preferably designed as a ring that is at least partially concentric with the bottom bracket and has a tangential flattened area on its outer circumference. The bearing force sensor is arranged on the tangential flattened area. The tangential flattened area is particularly preferably arranged on the bending beam. In particular, the flattened area is designed as a flat surface that is preferably arranged orthogonal to a radial direction.The bearing force sensor can preferably be mounted on the tangential flattening, particularly in such a way that the bearing force sensor can detect the deformation of the bending beam in this area. This allows for a particularly simple and cost-effective design and assembly of the arrangement.

[0013] Particularly preferably, the bearing mount has two bending beams and one bearing force sensor per bending beam. Two partial areas of the bearing mount are each designed as bending beams. The bending beams are preferably designed and arranged symmetrically and preferably have identical geometric properties. This enables particularly precise detection of the bearing force. For a particularly simple and cost-effective design, the two bearing force sensors can preferably be identical in construction. The two bearing force sensors are preferably arranged aligned in different directions in order to be able to detect bearing forces in different directions. Each of the two bearing force sensors is preferably designed and arranged to detect a force in a tangential direction with respect to the pedal shaft.This allows for a particularly simple and space-saving arrangement to be provided, which also enables a reliable determination of a bearing force direction and a bearing force magnitude of the total resulting bearing force.

[0014] The arrangement preferably further comprises a housing. The bearing receptacle has a fastening region that is fixed to the housing, in particular immovably. The housing can be, for example, a housing of a drive unit. By fixing the bearing receptacle to the housing, a precise, and in particular immovable, mounting of the bottom bracket relative to the housing is provided. The fastening region can, for example, be a section of the bearing receptacle that, along the circumferential direction, corresponds to at least one-third, preferably at least half, and preferably at most three-quarters, of the entire ring of the bearing receptacle.

[0015] Preferably, the fastening area is fixed to the housing by means of a screw connection. In particular, the screw connection comprises a plurality of screws. Alternatively or additionally, the fastening area is preferably fixed to the housing by means of a welded connection and / or an adhesive connection and / or a press connection. Preferably, the welded connection and / or adhesive connection is formed over the entire surface of the fastening area in order to provide a particularly robust fixation.

[0016] More preferably, the assembly further comprises a fastening element by means of which the fastening region is fixed to the housing. This means that the bearing receptacle is fixed directly or indirectly to the housing by means of the fastening element. This allows for particularly simple and cost-effective manufacture and assembly of the assembly, for example, because precise alignment of the bearing receptacle and fastening element is enabled separately from the housing.

[0017] Preferably, the fastening region is formed as at least part of an outer circumference of the bearing receptacle. This means that, in particular, the bearing receptacle is fixed to the housing in that the outer circumference of the bearing receptacle at least partially rests directly on the housing and / or is fixed, for example by means of a press connection between the outer circumference and the housing. This makes it possible to provide a particularly simple, lightweight, and cost-effective design of the arrangement. In addition, a particularly high positional accuracy of the bearing receptacle and thus of the bottom bracket can be provided because, for example, the recess in the housing can be manufactured in a simple and cost-effective manner with high precision. This is particularly advantageous if the housing is a formed component, preferably a sheet metal housing in which the recess is produced by forming.Particularly preferably, a predetermined distance is formed between the partial region of the bearing support, which is designed as a radially deformable bending beam, and the housing, in particular to which the bearing support is attached. In other words, the predetermined distance is an air gap, in particular an axial one, between the bending beam and the housing. This allows the bending beam to move unhindered, enabling particularly precise and sensitive detection of the bearing forces.

[0018] Preferably, the bearing mount is arranged in a recess in the housing. At least one predetermined gap is formed between an outer periphery of a partial area of ​​the bending beam and an inner periphery of the recess. This ensures free mobility and deformability of the bending beam, enabling reliable and precise detection of the occurring bearing forces.

[0019] Further preferably, the bearing receptacle has a holding area configured as a bearing seat for another additional bearing. In other words, the holding area is configured to accommodate another bearing, such as a bearing of a shaft of a transmission, preferably an intermediate shaft, for example, of a multi-stage transmission. This allows multiple functions to be fulfilled simultaneously in a simple and cost-effective manner using a small number of components.

[0020] Preferably, at least a portion of the holding region and an edge of the recess in the housing are designed such that the portion of the holding region and the edge of the recess undercut each other in the radial direction. The holding region is arranged in particular on a side of the bearing mount facing away from the bending beam. In other words, the bearing mount is designed such that the bending beam and the holding region are arranged on opposite sides of the bearing mount. The holding region rests against the housing in such a way that the position of the bearing mount is held in a precisely defined manner relative to the bearing. This ensures precise positioning of the components of the arrangement in a particularly reliable and simple manner.The holding area can, for example, have a region that protrudes at least radially outwards from an annular base area of ​​the bearing holder and a region that protrudes from this in the tangential direction.

[0021] Particularly preferably, the holding region is annular and is essentially in complete contact with the edge of the recess. In particular, the entire bearing receptacle thus has two annular partial regions which are arranged next to one another in the radial direction and are connected to one another at a connection point to form a one-piece component. For example, the bearing receptacle can thus be designed in the shape of an "8". In particular, the connection point forms a narrowing of the outer circumference of the bearing receptacle, whereby the undercut with the housing can be provided in order to enable the precisely defined relative arrangement. In this way, an optimal positional tolerance can be provided with particularly simple and cost-effective design and manufacture.

[0022] The bearing force sensor preferably has a strain gauge. For example, by attaching a strain gauge to the bending beam, its deformation can be measured particularly easily and precisely. The strain gauge can be used, for example, to determine strain and / or compression, and based on this, the deformation, and also, for example, a mechanical force on the bending beam.

[0023] Alternatively or additionally, the bearing force sensor preferably comprises a piezo element. This allows, similar to a strain gauge, a deformation and / or a momentarily acting force on the bending beam to be determined in a particularly simple, space-saving, and cost-effective manner.

[0024] Alternatively or additionally, the bearing force sensor preferably comprises a magnetic sensor. For example, the magnetic sensor can be a Hall sensor, in particular by means of which a relative positional change of a partial region of the bending beam to another component, such as the housing, can be directly detected in a simple and particularly precise manner. Furthermore, the invention relates to a drive arrangement of a vehicle operable with muscle power and / or motor power, in particular an electric bicycle, comprising a crank drive having cranks, a pedal shaft, and two bottom brackets for supporting the pedal shaft. In addition, the drive arrangement comprises an output interface connected to the pedal shaft and a drive unit configured to provide a motor torque to assist a rider torque generated by a rider, in particular by means of muscle power.The output interface can in particular be connected directly or indirectly to the pedal shaft. In particular, the output interface is designed for connection to an output element. A chainring can preferably be provided as the output element. Alternatively, another output element can preferably be provided which is designed for connection to a transmission element in order to enable torque transmission from the pedal shaft to a drive wheel of the vehicle. The pedal shaft is mounted within the drive unit by means of the two bottom brackets. Furthermore, the drive arrangement comprises the above-described arrangement for detecting a bearing force at one of the two bottom brackets. The bearing force sensor is arranged in the axial direction of the pedal shaft at the level of the bottom bracket arranged on the output side.In other words, a drive assembly is provided which has the bearing force sensor in the region of the bottom bracket that is closer to the output interface, and thus to an output element. Preferably, the output element is connected to the pedal shaft in a rotationally fixed manner via the output interface. In particular, the pedal shaft is formed as a single piece. Determining the bearing force using the bearing force sensor offers the advantage that the pedal shaft can be designed particularly simply and cost-effectively, while still allowing a reliable determination of the forces to be used to actuate the drive unit.

[0025] The bearing receptacle preferably has the holding area, which can be annular, for example. In addition, the drive arrangement further comprises a gear unit with an intermediate shaft and an intermediate shaft bearing. For example, the gear unit can be designed as a multi-stage gear unit, in particular as a spur gear unit. The holding area of ​​the bearing receptacle forms a bearing seat for the intermediate shaft bearing. This means that the intermediate shaft bearing is held on the housing by the holding area. This makes it possible to provide a lightweight drive arrangement with a particularly simple and cost-effective design and manufacture using few components, in which particularly tight tolerances can be maintained in the arrangement of the bearings and shafts.

[0026] Furthermore, the invention leads to a vehicle that can be operated with muscle power and / or motor power, in particular an electric bicycle, which comprises the drive arrangement described.

[0027] Furthermore, the invention relates to a method for operating the drive arrangement described above. The method comprises the following steps:

[0028] - Determining a deformation of the bending beam, and

[0029] - Determining the bearing force direction and magnitude of a resulting bearing force at the output-side bottom bracket based on the determined deformation. This method is characterized by its particularly simple and cost-effective implementation, allowing precise results for the bearing force direction and magnitude at the output-side bottom bracket to be determined.

[0030] The method preferably further comprises the step of determining an output force on an output element connected to the output interface based on the bearing force direction and the bearing force magnitude. The output force is considered to be a force exerted on the output element by a transmission element, such as a bicycle chain, in particular during operation of the electric bicycle. The output force is preferably present on an outer circumference of the chainring and in a predetermined direction along which the bicycle chain extends, for example, to a rear wheel. The output force is preferably additionally determined based on previously known geometric properties of the drive arrangement, in particular of the chainring.The method further preferably comprises the step of determining the rider torque applied by the rider based on the determined output force and the motor torque, in particular when an electric bicycle comprising the drive arrangement is operated simultaneously using muscle power and motor power. In particular, the motor torque is known in advance based on a motor control system. The rider torque is preferably determined by determining a rider force, wherein the rider force corresponds to a portion of the output force generated by the rider's muscle power. In particular, a relationship between rider torque and rider force is defined by the known geometric properties of the drive arrangement, in particular of the chainring.Rider force is preferably determined by subtracting the motor force from the total output force, where the motor force corresponds to the force acting on the bicycle chain resulting from the motor torque. This allows the rider torque to be determined particularly simply and precisely.

[0031] Preferably, the method further comprises the step of controlling a motor torque generated by the drive unit as a function of the bearing force direction and the bearing force magnitude. Particularly preferably, the drive unit is controlled as a function of the determined rider torque. This means that a motor torque is provided to assist the rider's pedaling power as a function of the bearing force, or rather, the rider torque, which is determined based on the determined bearing force.

[0032] Preferably, the bearing force direction and magnitude are determined based on a calibration of the drive assembly. Calibration is performed by determining a ratio of the respective forces detected by the bearing force sensors during actuation of the crank mechanism in a predetermined calibration configuration. In the calibration configuration, the crank mechanism is actuated with an actuation force in a predetermined actuation direction. Calibration is particularly preferably performed by detecting multiple ratios in several different predetermined actuation directions. Calibration is preferably performed once in the mounted state of the drive assembly on an electric bicycle. Brief Description of the Drawings

[0033] The invention is described below using exemplary embodiments in conjunction with the figures. In the figures, functionally identical components are identified by the same reference numerals. Here:

[0034] Figure 1 is a simplified schematic view of an electric bicycle with a drive arrangement according to a first embodiment of the invention,

[0035] Figure 2 is a detailed sectional view of the drive arrangement of Figure 1,

[0036] Figure 3 is a perspective detailed view of the drive arrangement of Figure 1,

[0037] Figure 4 is a perspective view of a detail of the drive arrangement of the first embodiment of the invention,

[0038] Figure 5 shows a further detailed view of the drive arrangement of Figure 1,

[0039] Figure 6 shows a further detailed view of the drive arrangement of Figure 1 with an alternative orientation of the drive unit,

[0040] Figure 7 shows a further detailed view of the drive arrangement of Figure 1

[0041] Figure 8 is a perspective view of a detail of a drive arrangement according to a second embodiment of the invention,

[0042] Figure 9 is a perspective view of a detail of a drive arrangement according to a third embodiment of the invention,

[0043] Figure 10 is a simplified schematic view of a detail of the drive arrangement of Figure 9, and Figure 11 is a perspective view of a detail of a drive arrangement according to a fourth embodiment of the invention.

[0044] Preferred embodiments of the invention

[0045] Figure 1 shows a simplified schematic view of an electric bicycle 100 with a drive assembly 1 according to a first embodiment of the invention. The drive assembly 1 is shown in a detailed sectional view in Figure 2.

[0046] The drive assembly 1 comprises a crank mechanism 2 with two cranks 21 located opposite one another with respect to a pedal axis 22a. Pedals 25 are arranged on the cranks 21, via which a rider can generate a rider torque on the drive assembly 1 using muscle power.

[0047] In addition, the crank drive 2 comprises a pedal shaft 22, which is connected in a rotationally fixed manner to the cranks 21, and two bottom brackets 23, 24 for the rotatable mounting of the pedal shaft 22.

[0048] The drive assembly 1 further comprises an output interface 30, to which an output element 3, which is a chainring, is connected in a rotationally fixed manner, and a bicycle chain 7 as a transmission element, which engages with the chainring. In the illustrated embodiment, the output interface 30 is an integral component of the pedal shaft 22, and thus the output element 3 is directly connected in a rotationally fixed manner to the pedal shaft 22. Preferably, the output interface 30 or the output element 3, in an alternative (not shown) embodiment, can also be indirectly connected to the pedal shaft 22, for example via an additional output shaft, which can particularly preferably be designed as a hollow shaft coaxial with the pedal shaft 22.

[0049] To support the rider torque with additional motor torque, the drive assembly 1 comprises a drive unit 4, 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 storage device (not shown). The drive unit 4 is preferably attached to a bicycle frame 101 of the electric bicycle 100.

[0050] The pedal shaft 22 is mounted in the drive unit 4 by means of the two bearings 23, 24. The drive unit 4 has a bearing collar 43 on the bearing 23 facing away from the output shaft, within which the bearing 23 is arranged (see Figure 2). In particular, the bearing collar 43 is an integral component of a housing 40 of the drive unit 4 or, alternatively, can be attached to the housing 40.

[0051] During motor-assisted operation of the electric bicycle 100, the motor torque is adjusted depending on the rider torque applied by the rider. The rider torque is determined by determining a bearing force 59 on the output-side bottom bracket 24, as described below.

[0052] To determine the rider torque based on the bearing force 59, several known mechanical and geometric relationships as well as the motor torque known from the operation of the drive unit 4 are used. In detail, the relationship used is that an output force 60 relevant to the propulsion of the electric bicycle 100 causes a reaction force of the same magnitude and parallel to it in the opposite direction at the output-side bottom bracket 24.

[0053] With knowledge of the geometry and mechanics of the crank drive 2 and the motor torque of the drive unit 4, a portion of the output force 60 generated by the drive unit 4, i.e., a motor force, can be determined. By subtracting the motor force from the total output force 60, the rider force, which corresponds to the portion of the output force 60 generated by the rider's muscle power, can thus be easily determined. The corresponding rider torque can then also be easily determined using the geometric properties of the drive arrangement 1. In the present drive arrangement 1, the bearing force 59 is determined using a simple, compact, and cost-effective design, which also allows particularly sensitive and precise detection. For this purpose, the drive arrangement 1 has two bearing force sensors 51, 52, which are arranged in the region of the output-side bottom bracket 24.

[0054] The arrangement of the two bearing force sensors 51, 52 is shown in Figures 3 and 4. Both bearing force sensors 51, 52 are located in the axial direction of the pedal shaft 22 at the level of the output-side bottom bracket 24.

[0055] Each of the two bearing force sensors 51, 52 is designed as a strain gauge and is configured to detect a force 55, 56 resulting, for example, from a mechanical extension and / or compression along exactly one predetermined direction, namely in the radial direction with respect to the pedal axis 22a.

[0056] The two bearing force sensors 51, 52 are connected to a detection unit 6, which determines the respective forces 55, 56 and also determines all other forces and moments.

[0057] The bearing force sensors 51, 52 are arranged on a radially outer side of a bearing support 5. The bearing support 5 is a component formed separately from the housing 40 of the drive unit 4, which is designed in particular as a bearing shell.

[0058] In the first embodiment, the bearing support 5 has a substantially circular outer geometry. Figure 4 shows a perspective view of the bearing support 5.

[0059] In detail, the bearing mount 5 is designed as a circumferentially closed, one-piece ring that completely surrounds the bottom bracket 24. Preferably, the bottom bracket 24 can be pressed into the bearing mount 5 by means of a press connection. The bearing mount 5 has a tangential flattening 41 on the outer circumference 42 for each bearing force sensor 51, 52, to which the corresponding bearing force sensor 51, 52 is fixed, in particular by means of a material connection, such as an adhesive connection or a welded connection.

[0060] Each flattening 41 is designed as a flat surface which is arranged tangentially. In particular, the flattenings 41 are arranged orthogonally to a radial direction. Alternatively, the flattenings 41 can also be arranged inclined at a different angle to the radial direction.

[0061] The bottom bracket 24 is arranged in a recess of the bearing holder 5, in particular pressed in by means of a press connection.

[0062] The bearing support 5 also has a fastening area 50 that is fastened to the housing 40. The fastening area 50 is an axial end face of the bearing support 5, which is in flat contact with the housing 40. The fastening area 50 can be fixed to the housing 40, for example, by means of a material-to-material and / or force-to-fit connection.

[0063] In addition, the bearing support 5 has two bending beams 53, each arranged radially within each flattened portion 41. The bending beams 53 are designed such that they can deform in the radial direction. In Figure 4, the bending beams 53 are indicated by hatching.

[0064] The bending beams 53 preferably have a smaller cross-section than the rest of the bearing support 5, in particular with respect to the radial direction.

[0065] If the crank mechanism 2 is loaded by the rider's pedaling force, this causes the bearing force 59 on the bottom bracket 24. Since the bottom bracket 24 is held in the housing 40 of the drive unit 4 by means of the bearing holder 5, this bearing force 59 has a corresponding effect on the bearing holder 5. Due to the special design of the bearing holder 5 with the bending beams 53, the bearing force 59 leads to a deflection of the bending beams 53 in the radial direction. In particular, due to the smaller cross-section of the bending beams 53 in the radial direction, the deformation of the bearing holder 5 occurs specifically close to the bearing force sensors 51, 52. This deformation can be detected by means of the bearing force sensors 51, 52 designed as strain gauges.

[0066] Based on the above-described known geometric and mechanical properties of the arrangement 10, the total resulting bearing force 59, namely the bearing force direction and the bearing force magnitude, can be determined based on the detected deformations.

[0067] In order to ensure particularly high precision by ensuring that the deformation of the bending beams 53 is as unaffected as possible, the bending beams 53 can be spaced apart in the axial direction from the housing wall against which the fastening region 50 of the bearing support 5 rests. This means that in the axial direction, a predetermined distance 53d, i.e., an air gap, exists between an axial end face 50b of each bending beam 53 facing the housing wall and the housing wall against which the end face 50a of the fastening region 50 rests (see Figure 7). This is achieved by the end face 50b in the region of the bending beams 53 being slightly offset compared to the end face 50a on the fastening region 50. In Figure 7, the distance 53d is indicated by a line 40a, which represents the housing wall. As a result, the deformation of the bending beams 53 is not influenced by friction, for example.

[0068] Furthermore, the bending beams 53 and / or the bottom bracket 24 can be designed such that a region with the lowest possible friction is formed between the radially inner side of the bending beams 53 and the radially outer side of the bottom bracket 24, so that, for example, a falsification of the measurement results due to stresses caused by static friction can be avoided or reduced.

[0069] In order to determine the output force 60 acting on the bicycle chain 7, and thus also the rider torque as described above, based on the determined bearing force 59, the relative orientation of the chain direction 70 of the bicycle chain 7 and the drive unit 4 to each other, i.e., the installation position of the drive unit 4 on the bicycle frame 101, can be used. This is illustrated by Figures 5 and 6, which show different installation positions of the drive unit 4.

[0070] As can be seen in Figures 5 and 6, there are different alignments of the chain direction 70 and the drive unit 4 relative to each other. In order to accurately determine the output force 60 based on the bearing force 59, the geometric relationship between the drive unit 4 and the chain direction 70 can be used.

[0071] For this purpose, a one-time calibration of the drive assembly 1 is performed. During the calibration, no motor torque is generated by the drive unit 4.

[0072] During calibration, in a first step, the crank drive 2 can be arranged such that the cranks 21 are aligned horizontally, i.e., parallel to the chain direction 70. In this first calibration configuration, exactly one crank 21, namely the crank 21 pointing forward in the direction of travel, is actuated with an actuating force. The actuating force is aligned vertically, i.e., orthogonal to the crank 21 and the chain direction 70, and is applied by the rider actuating the pedal. As a result, the entire actuating force is transferred to the bicycle chain 7. A corresponding bearing force 59 corresponds to a resultant force from the actuating force and the output force 60. Calibration preferably takes place after the drive unit 4 has been mounted in a bicycle frame 101 of the electric bicycle 100.Particularly preferably, the crank 21 is actuated with a predetermined, precisely known actuating force, so that the amount of the output torque can be determined precisely.

[0073] In a second calibration step, the crank mechanism 2 is arranged such that the cranks 21 are aligned vertically, i.e., orthogonal to the chain direction 70. In this second calibration configuration, the lower crank 21 is actuated with an actuating force that is also aligned vertically, i.e., orthogonal to the chain direction 70 and parallel to the crank 21. As above, the actuating force is applied by the rider actuating the pedal 25. In this second actuating configuration, the output force 60 is zero due to the corresponding alignment of the crank mechanism 2. However, a bearing force 59 is still caused by the actuating force.

[0074] Based on the forces 55, 56 of the bearing force sensors 51, 52 recorded in both calibration steps, a relationship between the two forces 55, 56 can be used to determine the orientation of the bearing force sensors 51, 52 relative to the previously known positions of the cranks 21 and / or the bicycle chain 7. This also allows the orientation of the drive unit 4 relative to the bicycle chain 7 to be determined. The orientation thus determined can then be used as the basis for determining the rider torque based on the bearing force direction and the bearing force magnitude of the bearing force 59.

[0075] Figure 8 shows a perspective view of a detail of a drive arrangement 1 according to a second exemplary embodiment of the invention. The second exemplary embodiment essentially corresponds to the first exemplary embodiment of Figures 1 to 7, with the difference that only a single bearing force sensor 51 is provided and a corresponding alternative design of the bearing support 5. In detail, the bearing support 5 has only a single tangential flattening 41, to which the bearing force sensor 51 is fastened. Accordingly, radially inward, the bearing support 5 has only a single bending beam 53. This makes it possible to provide a particularly simple and cost-effective drive arrangement 1.

[0076] Preferably, the drive assembly 1 of the second embodiment is calibrated with knowledge of the installation position of the bearing force sensor 51 relative to the other components of the electric bicycle 100, in particular relative to the chain direction 70. This allows a reliable and precise determination of the bearing force in a simple manner using the single bearing force sensor 51. Figure 9 shows a perspective view of a detail of a drive assembly 1 according to a third embodiment of the invention. The third embodiment essentially corresponds to the first embodiment of Figures 1 to 7 with the difference of an alternative design of the bearing receptacle 5 in an area facing away from the bearing force sensors 51, 52. Figure 10 shows a further view of the drive assembly 1 of the third embodiment.

[0077] In the third embodiment, the housing 40 is preferably designed as a solid sheet metal housing. In other words, the housing 40 is formed from one or more deep-drawn components. The recess 65, in which the bearing support 5 is arranged, is formed by the deep-drawing process. This can be seen, for example, in Figure 10.

[0078] In the third exemplary embodiment, the bearing mount 5 additionally has a retaining region 54, which is annular. The retaining region 54 and the likewise annular base region of the bearing mount 5, which forms the bearing seat for the bottom bracket 24, together form a one-piece component, which is essentially shaped like an "8."

[0079] The holding area 54 has a further recess 54b, which is designed in particular as a circular through-opening. The recess 54 is coaxial with an intermediate shaft axis 22b, which is parallel to the pedal axis 22a.

[0080] Housing 40 and bearing receptacle 5 are designed such that an inner edge 65b of the recess 65 of the housing 40 is essentially completely in contact with the outer circumference of the holding area 54, in particular by means of a press connection.

[0081] Due to the "8-shaped" geometry of the bearing receptacle 5 and the recess 65 of the housing 40, an undercut is thus present in a plane perpendicular to the pedal axis 22a and along a direction 22d that corresponds to a straight line connecting the two axes 22a, 22b. The undercut is identified in Figure 10 by the reference numeral 54a. In the third exemplary embodiment, a precise, unambiguous fixation of the bearing receptacle 5 in the housing 40 is thus achieved by the outer circumference of the bearing receptacle 5 and by the inner edge 65b of the recess 65. In particular, the outer circumference of the bearing receptacle 5 in the third exemplary embodiment thus forms the fastening area 50 for fixing the bearing receptacle 5 to the housing 40.

[0082] Due to the special geometry with the undercut 54a along the direction 22d, a precisely defined relative position of the bearing support 5 and the housing 40 is achieved in a particularly simple and cost-effective manner with few components.

[0083] The recess 54b of the holding area 54 of the bearing support 5 forms a further bearing seat for another bearing (not shown). This is preferably a bearing seat for an intermediate shaft bearing, by means of which an intermediate shaft of a transmission (not shown) of the drive assembly 1 can be mounted. This enables the integration of several functions with particularly small positional tolerances in a particularly simple and cost-effective manner.

[0084] In particular, the recess 54b can be provided as a bearing seat for any bearing of any shaft.

[0085] Figure 11 shows a perspective view of a detail of a drive assembly 1 according to a fourth exemplary embodiment of the invention. The fourth exemplary embodiment essentially corresponds to the third exemplary embodiment of Figures 9 and 10, with the difference of a further alternative design of the bearing receptacle 5, which is formed without an undercut. This means that in a radial direction relative to the axes 22a, 22b, no undercut is provided in the holding area 54b with the housing (not shown in Figure 11). This enables particularly simple and cost-effective production and simple assembly of the drive assembly 1.

Claims

Claims 1. An arrangement for detecting a bearing force of a bottom bracket (24) of a vehicle (100) that can be operated using muscle power and / or motor power, comprising: a bottom bracket (24), a bearing receptacle (5) that completely surrounds the bottom bracket (24) in a ring shape, a bearing force sensor (51), and a detection unit (6), wherein a partial region of the bearing receptacle (5) is designed as a bending beam (53) that is deformable in the radial direction, wherein the bearing force sensor (51) is configured to detect a deformation of the bending beam (53), and wherein the detection unit (6) is configured to detect a bearing force at the bottom bracket (24) based on the deformation of the bending beam (53) detected by means of the bearing force sensor (51).

2. Arrangement according to claim 1, wherein the bearing receptacle (5) on the bottom bracket (24) is designed as a circumferentially closed, in particular one-piece, ring.

3. Arrangement according to claim 1 or 2, wherein the bearing receptacle (5) is designed as a ring which is at least partially concentric with the bottom bracket (24) and which has a tangential flattening (41) on the outer circumference (42) on which the bearing force sensor (51) is arranged.

4. Arrangement according to one of the preceding claims, wherein two partial regions of the bearing holder (5) are each designed as a bending beam (53) and wherein the arrangement (10) has one bearing force sensor (51, 52) per bending beam (53).

5. Arrangement according to one of the preceding claims, further comprising a housing (40), wherein the bearing receptacle (5) has a fastening region (50) which is fixed to the housing (40), in particular wherein the fastening region (50) is fixed to the housing (40) by means of a screw connection and / or by means of a welded connection and / or by means of an adhesive connection and / or by means of a press connection.

6. Arrangement according to one of the preceding claims, further comprising a housing (40), wherein the partial region of the bearing holder (5), which is designed as a bending beam (53) deformable in the radial direction, is arranged at a predetermined distance (53d) from the housing (40).

7. Arrangement according to one of claims 5 or 6, wherein the bearing receptacle (5) is arranged in a recess (65) of the housing (4), and wherein at least one predetermined gap (53c) is present between at least one outer circumference (53b) of a partial region of the bending beam (53) and an inner circumference (65a) of the recess (65).

8. Arrangement according to one of the preceding claims, wherein the bearing receptacle (5) has a holding area (54), and wherein the holding area (54) is designed as a bearing seat for a further bearing.

9. Arrangement according to claim 8, wherein at least a partial region of the holding region (54) and an edge (65b) of the recess (65) of the housing (40) undercut each other in the radial direction.

10. Arrangement according to one of the preceding claims, wherein the bearing force sensor (51) comprises a strain gauge and / or a piezo element and / or a magnetic sensor.

11. Drive arrangement of a vehicle (100) operable with muscle power and / or motor power, in particular an electric bicycle, comprising: a crank mechanism (2) with cranks (21), a pedal shaft (22), and two bottom brackets (23, 24) for supporting the pedal shaft (22), an output interface (30) which is connected to the pedal shaft (22), a drive unit (4) which is designed to provide a motor torque to support a rider torque applied by a rider, wherein the pedal shaft (22) is mounted in the drive unit (4) by means of the two bottom brackets (23, 24), and an arrangement (10) according to one of the preceding claims, wherein the bearing force sensor (51) is arranged in the axial direction of the pedal shaft (22) at the level of the bottom bracket (24) arranged on the output side.

12. Drive arrangement according to claim 11, wherein the bearing receptacle (5) has the holding region (54), further comprising a gear with an intermediate shaft and an intermediate shaft bearing, wherein the holding region (54) forms a bearing seat of the intermediate shaft bearing.

13. A vehicle operable by muscle power and / or motor power, in particular an electric bicycle, comprising a drive arrangement (1) according to claim 11 or 12.

14. A method for operating a drive arrangement (1) according to claim 11 or 12, comprising the steps: Determining a deformation of the bending beam (53), and Determining a bearing force direction and a bearing force amount of a bearing force (59) on the output-side bottom bracket (24) based on the determined deformation.

15. The method of claim 14, further comprising the steps: Determining an output force (60) on an output element (3) connected to the output interface (30) based on the bearing force direction and the bearing force amount of the bearing force (59), and Determining the driver torque applied by the driver based on the output force (60) and an engine torque of the drive unit (4).

16. The method according to any one of claims 14 or 15, further comprising the step: Controlling a motor torque generated by the drive unit (4) as a function of the bearing force direction and the bearing force amount.

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