WO2024074454A1

WO2024074454A1 - Arrangement 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

Info

Publication number: WO2024074454A1
Application number: PCT/EP2023/077240
Authority: WO
Inventors: Sigmund Braun
Original assignee: Robert Bosch Gmbh
Priority date: 2022-10-07
Filing date: 2023-10-02
Publication date: 2024-04-11

Abstract

The invention relates to an arrangement (10) for measuring a bearing force of a bottom bracket (24) of a vehicle (100) which can be operated by means of muscle power and/or motor power, the arrangement comprising a bottom bracket (24), a bearing receptacle (5), which at least partly annularly engages around the bottom bracket (24), a bearing force sensor (51), and a measuring unit (6), wherein a flexible bar (53) which is bendable in a radial direction is formed on the bearing receptacle (5), wherein the bearing force sensor (51) is designed to detect a deformation of the flexible bar (53), and wherein the measuring unit (6) is designed to measure a bearing force on the bearing bracket (24) on the basis of the deformation of the flexible bar (53), which has been detected by means of the bearing force sensor (51).

Description

Title

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

State of the art

The present invention relates to a drive arrangement of an electric bicycle, an electric bicycle comprising the drive arrangement, and a method for operating a drive arrangement.

Drive arrangements of vehicles that can be operated with muscle power and/or motor power, such as electric bicycles, are known, which have a drive unit that can generate a motor torque to support the pedaling force of a driver of the vehicle. The motor torque is usually generated as a function of a driver torque generated by the driver's muscle power. This requires recording the value of the driver torque currently generated, for example by means of an appropriate sensor system. It is also known, for example, that based on a bearing force on a bottom bracket of the electric bicycle, information can be obtained about a force exerted by a driver on the pedals, and that the drive unit is actuated based on this. Such a system is shown, for example, in DE 102010 001 775 A1.

Disclosure of the invention

The arrangement according to the invention with the features of claim 1 is distinguished by the fact 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. In addition, for example, a simple determination of the bearing force independent of the orientation of a drive unit, for example on a bicycle frame of an electric bicycle. 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 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 holder which at least partially surrounds the bottom bracket in a ring shape, a bearing force sensor, and a detection unit. In particular, the bearing holder surrounds the bottom bracket essentially completely, preferably except for a predetermined gap area. The bearing holder is in particular designed to hold the bottom bracket. For example, the bearing holder can be designed as a bearing shell. A bending beam that can be bent in the radial direction, in particular on one side, is formed on the bearing holder. The bearing force sensor is designed to detect a deformation, that is to say in particular a bending, of the bending beam. The detection unit is also designed to detect a bearing force on the bottom bracket based on the deformation of the bending beam detected by the bearing force sensor. In particular, the bearing force is considered to be a total resulting force in the area of the bottom bracket, which occurs, for example, due to a motor torque and/or a driver torque. The detection unit is particularly preferably set up to determine a bearing force direction and a bearing force amount of the bearing force on the bottom bracket based on the detected deformation of the bending beam.

In other words, an arrangement is provided which has a bearing receptacle on the bottom bracket, on which an at least partially flexible area in the form of the bending beam is provided. As a result, the mechanical loads acting on the bottom bracket are transferred from the bottom bracket to the bending beam, which can deform it. In particular, the bending beam is designed to be freely movable on one side in the radial direction. This deformation can be detected by means of 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 mount and bottom bracket. Alternatively or additionally, the bearing force can be determined based on a calibration of the system.

A variety of types of sensors can be used as bearing force sensors, which are 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.

The arrangement therefore offers the advantage that the bearing force on the bottom bracket can be recorded using a particularly simple, cost-effective and space-saving structure. By using the bending beam, a particularly sensitive structure can be provided. In particular, since one end of the bending beam is designed to be freely movable, even small bearing forces can lead to deformations of the bending beam, which can be easily and precisely recorded. This means that small bearing forces in particular can be determined very precisely. When used on an electric bicycle, this offers the advantage that, for example, small torque values can be recorded precisely and sensitively, which can, for example, enable particularly precise control of a drive unit depending on the driver's torque.

The subclaims contain preferred developments of the invention.

Preferably, a portion of the bearing support is designed as a bending beam that can be bent in the radial direction. This means that the bending beam is an integral part of the bearing support itself. This makes it possible to provide a particularly simple design of the arrangement.

The bearing receptacle preferably has a slot, in particular a radial one. The bending beam is adjacent to the slot. In other words, the bending beam is formed by a portion of the bearing receptacle such that the bearing receptacle is slotted, with a freely movable end that is adjacent to the slot corresponding to a freely movable end of the bending beam. This allows for particularly simple and A construction can be provided in a cost-effective manner that enables the advantageous properties of the sensitive bending beam.

The bearing holder particularly preferably has two bending beams and one bearing force sensor per bending beam. The two bending beams are preferably designed symmetrically with respect to the slot 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 of identical 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 in such a way as to detect a force in the tangential direction with respect to a shaft, for example a pedal shaft, crankshaft, output shaft or the like. This makes it possible to provide a particularly simple and space-saving arrangement, which also enables a reliable determination of a bearing force direction and a bearing force amount of the total resulting bearing force.

Preferably, the arrangement further comprises a stop that limits a movement of the bending beam in the radial direction. In particular, the stop limits a maximum deflection in the radial direction of a free end of the bending beam. This makes it possible to provide a particularly high level of mechanical robustness of the arrangement using a simple and cost-effective construction. In particular, the stop can limit the deformability of the bending beam to a maximum level. This can prevent damage to the bearing mount, for example. In addition, robust and reliably precise positioning of the bottom bracket is ensured by means of the bearing mount. The stop also offers the advantage that the bending beam can be optimally designed for clear and easily detectable deformability in a certain bearing force range. For example, for particularly sensitive detection, the bending beam can be easily deformable at low bearing forces, with the stop preventing excessive deformation. The stop is also preferably arranged in such a way that, when the bottom bracket is not under load, a predetermined air gap is formed between a free end of the bending beam and the stop. The air gap is preferably a maximum of 0.1 mm when the bottom bracket is not under load. The air gap thus allows the bending beam to be freely deformed until the stop is reached, so that the bearing force can be detected particularly precisely based on this. The air gap can be set in a particularly simple manner, for example when assembling the arrangement by aligning the stop accordingly.

Preferably, the arrangement further comprises a housing. The bearing holder has a fastening area 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 holder to the housing, a precise and in particular immovable mounting of the bottom bracket relative to the housing is provided. The fastening area can, for example, be a section of the bearing holder that corresponds to at least one third, preferably at least half, preferably a maximum of three quarters, of the entire ring of the bearing holder along the circumferential direction.

Preferably, the fastening area is fixed to the housing by means of a screw connection. In particular, the screw connection comprises several screws distributed around the circumference of the bearing holder. Alternatively or additionally, the fastening area is preferably fixed to the housing by means of a welded connection and/or by means of an adhesive connection and/or by means of 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.

The arrangement preferably further comprises a fastening element by means of which the fastening area is fixed to the housing. This means that the bearing holder is fixed directly or indirectly to the housing by means of the fastening element. This makes it possible to provide a particularly simple and cost-effective manufacture and assembly of the arrangement, for example because a precise alignment of the bearing holder and fastening element is made possible separately from the housing. The fastening element is particularly preferably designed as a disk, which is preferably circular. The fastening element is arranged in a recess in the housing, in particular together with the bearing holder. The recess preferably has an inner geometry that corresponds to an outer geometry of the fastening element. This enables a particularly simple and cost-effective construction and assembly of the arrangement. For example, the recess and fastening element can have geometries that are easy and precise to manufacture.

Preferably, the fastening region is formed as at least part of an outer circumference of the bearing holder. This means that in particular the bearing holder is fixed to the housing in that the outer circumference of the bearing holder is at least partially fixed directly to the housing, preferably 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 construction of the arrangement. In addition, a particularly high positional accuracy of the bearing holder and thus of the bottom bracket can be provided, since, for example, the recess in the housing can be manufactured in a simple and cost-effective manner with high accuracy. This is particularly advantageous if the housing is a deep-drawn component, preferably a sheet metal housing in which the recess is manufactured by deep-drawing.

The bearing receptacle is preferably arranged in a recess in the housing. A radially outer external dimension of the free end of the bending beam is smaller by a predetermined gap than an internal dimension of the recess in the housing. In other words, the radially outer external dimension of the free end of the bending beam is set back by the predetermined gap from the preferably circular outer contour of the fastening element. The gap is preferably a maximum of 0.5 mm, preferably a maximum of 0.2 mm, in particular at least 0.01 mm. The housing thus forms a stop for the bending beam, in particular without a separate component being required for the stop. This makes it possible to provide a particularly simple and cost-effective construction with few components. Preferably, a A stop area is provided for the bending beam, with the gap being provided between the stop area and the housing. Preferably, there is a gap between a remaining area of the bending beam and the recess that is larger than the gap, so that in particular free movement of the bending beam is possible and the bending beam only rests against the stop area.

The bearing holder preferably has a holding area. At least a partial area of the holding area and an edge of the recess in the housing are designed such that the partial area of the holding area and the edge of the recess undercut each other in the radial direction. The holding area is also arranged on a side of the bearing holder facing away from the free end of the bending beam. In other words, the bearing holder is designed such that the free end of the bending beam and the holding area are arranged on opposite sides of the bearing holder. The holding area rests on the housing in such a way that the position of the bearing holder, in particular along a direction that extends, for example, from the free end to the holding area, is held precisely defined relative to the bearing. This ensures particularly reliably that the predetermined gap between the inner dimension of the recess and the free end of the bending beam is precisely maintained. In addition, the gap with low tolerances can be ensured particularly reliably during production in a simple and cost-effective manner. The holding region can, for example, have a region that protrudes at least radially outward from an annular base region of the bearing holder and a region that protrudes therefrom in a tangential direction.

The holding area is particularly preferably designed in a ring shape and is essentially completely in contact with the edge of the recess. In particular, the entire bearing receptacle thus has two ring-shaped partial areas which are arranged next to one another in the radial direction, whereby these 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 precisely to enable a defined relative arrangement. This makes it possible to provide optimum positional tolerance with particularly simple and cost-effective design and manufacture.

Preferably, the holding area is designed as a bearing seat for another bearing. In other words, the holding area is designed to accommodate another bearing, such as a bearing on a shaft of a transmission, preferably an intermediate shaft, for example of a multi-stage transmission. This means that several functions can be fulfilled simultaneously in a simple and cost-effective manner using just a few components.

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

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

Alternatively or additionally, the bearing force sensor preferably has a magnetic sensor. For example, the magnetic sensor can be a Hall sensor, in particular by means of which a relative position change of a partial area of the bending beam to another component, such as the housing, can be directly detected in a simple and particularly precise manner.

The invention further relates to a drive arrangement of a vehicle that can be operated with muscle power and/or motor power, in particular an electric bicycle, comprising a crank drive, which has cranks, a shaft, for example a pedal shaft, and two bottom brackets for supporting the shaft. In addition, the drive arrangement comprises an output element, which is connected to the shaft, and a drive unit, which is designed to generate a motor torque to support a pedal operated by a driver, in particular by means of Muscle power, generated by the driver. Preferably, a chainring can be provided as the output element. Alternatively, another output element can be provided that is set up for connection to a transmission element in order to enable torque to be transmitted from the shaft to a drive wheel of the vehicle. The shaft is mounted within the drive unit by means of the two bottom brackets. Furthermore, the drive arrangement comprises the arrangement described above for detecting a bearing force on one of the two bottom brackets. The bearing force sensor is arranged in the axial direction of the shaft at the level of the bottom bracket arranged on the output side. In other words, a drive arrangement is provided which has the bearing force sensor in the area of that of the two bottom brackets which is arranged closer to the output element. Preferably, the output element is connected to the shaft in a rotationally fixed manner. In particular, the shaft is designed in one piece. The bearing force determination by means of the bearing force sensor results in the advantage that the shaft can thus be designed in a particularly simple and cost-effective manner, while still allowing a reliable determination of the forces used to actuate the drive unit.

The bearing receptacle preferably has the holding area, which is ring-shaped. In addition, the drive arrangement further comprises a gear with an intermediate shaft and an intermediate shaft bearing. For example, the gear can be designed as a multi-stage gear, in particular as a spur gear. The holding area of the bearing receptacle forms a bearing seat of the intermediate shaft bearing. This means that the intermediate shaft bearing is held in a defined manner 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 with few components, in which particularly small tolerances can be maintained in the arrangement of the bearings and shafts.

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. The invention further relates to a method for operating one of the drive arrangements described above. The method comprises the steps:

- Determining a deformation of the bending beam, and

- Determining a bearing force direction and a bearing force amount of a resulting bearing force on the output-side bottom bracket based on the determined deformation. The method is characterized by being particularly simple and cost-effective to implement, whereby precise results for the bearing force direction and the bearing force amount on the output-side bottom bracket can be determined.

The method preferably further comprises the step of determining an output force on the output element based on the bearing force direction and the bearing force amount of the bearing force. 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 the chainring.

The method further preferably comprises the step of: determining the driver torque applied by the driver based on the determined output force and the motor torque, in particular when an electric bicycle, which comprises the drive arrangement, is operated simultaneously with muscle power and motor power. In particular, the motor torque is previously known based on a motor control. The driver torque is preferably determined by determining a driver force, wherein the driver force corresponds to a portion of the output force which is generated by the driver's muscle power. In particular, a relationship between driver torque and driver force is defined by the previously known geometric properties of the drive arrangement, in particular of the chainring. The driver force is preferably determined by subtracting a motor force from the total output force, wherein the motor force corresponds to a force applied to the bicycle chain which results from the motor torque. Thus The driver torque can be determined particularly easily and precisely.

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 amount. Particularly preferably, the drive unit is controlled as a function of the determined driver torque. This means that a motor torque is provided to support the pedal force of the driver as a function of the bearing force or the driver torque, which is determined based on the determined bearing force.

Preferably, the bearing force direction and the bearing force amount are determined based on a calibration of the drive arrangement. The calibration is carried out by determining a ratio of the respective forces detected by the bearing force sensors during an actuation of the crank drive in a predetermined calibration configuration. In the calibration configuration, the crank drive is actuated with an actuation force in a predetermined actuation direction. Particularly preferably, the calibration is carried out by detecting several ratios in several different predetermined actuation directions. The calibration is preferably carried out once in the mounted state of the drive arrangement on an electric bicycle.

Short description of the drawings

The invention is described below using an exemplary embodiment in conjunction with the figures. In the figures, functionally identical components are each identified by the same reference numerals. In the following:

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

Figure 2 is a detailed sectional view of the drive arrangement of Figure 1, Figure 3 is a perspective detailed view of the drive arrangement of Figure 1,

Figure 4 is a further detailed view of the drive arrangement of Figure 1,

Figure 5 is a perspective view of a detail of the drive arrangement of Figure 1,

Figure 6 is a further detailed view of the drive arrangement of Figure 1,

Figure 7 shows a further detailed view of the drive arrangement of Figure 1 with an alternative orientation of the drive unit,

Figure 8 is a detailed sectional view of a drive arrangement according to a second embodiment of the invention,

Figure 9 is a perspective view of a detail of the drive arrangement of Figure 8,

Figure 10 is an alternative perspective view of the detail of Figure 9,

Figure 11 is a simplified schematic view of a detail of a

Drive arrangement according to a third embodiment of the invention,

Figure 12 is a perspective view of a detail of the drive arrangement of Figure 11, and

Figure 13 is a further perspective view of a detail of the drive arrangement of Figure 11.

Preferred embodiments of the invention

Figure 1 shows a simplified schematic view of an electric bicycle 100 with a drive arrangement 1 according to a first embodiment of the Invention. The drive arrangement 1 is shown in a detailed sectional view in Figure 2.

The drive arrangement 1 has a crank drive 2 with two cranks 21 opposite one another with respect to a pedal axis 22a. Pedals 25 are arranged on the cranks 21, via which a driver can generate a driver torque on the drive arrangement 1 using muscle power.

In addition, the crank drive 2 comprises a shaft, for example 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.

The drive arrangement 1 further comprises an output element 3, which is a chainring and which is connected in a rotationally fixed manner to the pedal shaft 22, and a bicycle chain 7 as a transmission element, which is in engagement with the chainring 3.

In order to support the driver torque with an additional engine torque, the drive arrangement 1 comprises a drive unit 4 which is designed to generate the engine 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.

The treadle 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, within which the bearing 23 is arranged (see Figure 2). In particular, the bearing collar 43 is an integral part of a housing 40 of the drive unit 4.

When the electric bicycle 100 is operated with motor support, the motor torque is adjusted depending on the driver torque applied by the driver. The driver torque is determined by a determination of a bearing force 59 on the output-side bottom bracket 24 is determined as described below.

To determine the driver 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 for 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.

With knowledge of the geometry and mechanics of the crank drive 2 and the engine torque of the drive unit 4, a portion of the output force 60 that is applied by the drive unit 4, i.e. an engine force, can be determined. By subtracting the engine force from the total output force 60, the driver force, which corresponds to the portion of the output force 60 that is applied by the driver's muscle power, can thus be determined in a simple manner. The corresponding driver torque can then also be determined in a simple manner using the geometric properties of the drive arrangement 1.

The bearing force 59 is determined in the present drive arrangement 1 by means of a simple, compact and cost-effective construction, 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 area of the output-side bottom bracket 24.

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.

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 expansion and/or compression, along exactly one predetermined direction, namely in the radial direction with respect to the pedal axis 22a. 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.

The bearing force sensors 51, 52 are arranged on a radially outer side of a bearing holder 5. The bearing holder 5 is a component that is designed separately from the housing 40 of the drive unit 4 and is designed in particular as a bearing shell. In the first exemplary embodiment, the bearing holder 5 has an essentially square outer geometry.

Figure 5 shows a perspective view of the bearing holder 5.

The bottom bracket 24 is arranged in a recess of the bearing holder 5, wherein in the unloaded state preferably substantially the entire inner circumference of the bearing holder 5 is in contact with an outer circumference of the bottom bracket 24.

The bearing holder 5 is also slotted, with a slot 57 which extends completely through the entire bearing holder 5 in the radial direction.

The bearing holder 5 also has a fastening area 50 which is fastened to the housing 40. The fastening area 50 is an axial end face of the bearing holder 5, which is in full contact with the housing 40. In the first embodiment, the fastening area 50 is fixed to the housing 40 by means of a total of three screw connections 58a.

In addition, the bearing holder 5 has two bending beams 53, each of which is arranged between the slot 57 and the fastening area 50. The bending beams 53 are designed in such a way that they can deform in the radial direction. In Figure 4, the bending beams 53 are marked by hatching. On the radially outer side of each bending beam 53 there is a flat flattening 41 on which the respective bearing force sensor 51, 52 is arranged.

If the crank mechanism 2 is loaded by the pedal force of the rider, 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 movable bending beams 53, the bearing force 59 leads to a deflection of the bending beams 53 in the radial direction. This deformation can be detected by means of the bearing force sensors 51, 52 designed as strain gauges.

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

The free movement of the bending beams 53 in the radial direction enables particularly sensitive detection with appropriate mechanical design. This means, for example, that by appropriately designing the thickness of the bending beams 53 in the axial and/or radial direction, it is possible for a clearly measurable deformation to occur even with small bearing forces. In particular, this enables detection of low torques applied by the driver with high accuracy.

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 are spaced apart in the axial direction from the housing wall against which the fastening area 50 of the bearing holder 5 rests. This means that in the axial direction there is a gap 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 area 50 rests. As a result, the deformation of the bending beams 53 is not influenced by friction, for example. 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 distortion of the measurement results due to stresses caused by static friction can be avoided or reduced.

The arrangement 10 further comprises a stop 7 which limits the movement of each bending beam 53 in the radial direction. The stop 7 is fixed immovably to the housing 40 of the drive unit 4. The stop 7 is located in the extension of the slot 57 and has a stop surface 75 for each bending beam 53, against which the free ends 53a of the bending beams 53 can rest essentially in the radial direction when the bending beams 53 deform in the radial direction. In particular, the stop surfaces 75 are arranged parallel to the flats 41 of the bending beams 53 in the unloaded state.

The stop 7 is designed and fixed to the housing 4 in such a way that in the unloaded state, i.e. when the bottom bracket 24 is not loaded, there is a predetermined air gap 70 between each free end 53a or between each flattened area 41 of each bending beam 53 and the respective stop surface 75. This allows the bending beams 53 to deform completely freely until they rest against the stop 7. The stop 7 can provide a particularly high level of mechanical robustness for the arrangement 10.

In order to be able to determine the output force 60 acting on the bicycle chain 7, and thus also the driver torque as described above, based on the determined bearing force 59, it is necessary to know the relative orientation of the chain device 70 of the bicycle chain 7 and the drive unit to one another, i.e. the installation position of the drive unit 4 on the bicycle frame 101. This is illustrated by Figures 6 and 7, which show different installation positions of the drive unit 4.

As can be seen in Figures 6 and 7, there are different

Alignment of chain direction 70 and drive unit 4 to each other. In order to correctly determine the output force 60 based on the bearing force 59, knowledge of the geometric relationship between the drive unit 4 and the chain device 70 is necessary.

For this purpose, a one-time calibration of the drive arrangement 1 is carried out. During the calibration, no engine torque is generated by the drive unit 4.

During calibration, in a first step, the crank drive 2 can be arranged so 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 driver 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 resulting force from the actuating force and the output force 60. Calibration is preferably carried out 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.

In a second step of the calibration, the crank mechanism 2 is arranged so that the cranks 21 are aligned vertically, i.e. orthogonal to the chain device 70. In this second calibration configuration, the lower crank 21 is actuated with an actuating force which is also aligned vertically, i.e. orthogonal to the chain device 70 and parallel to the crank 21. As above, the actuating force is applied by the driver 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. The actuating force nevertheless causes a bearing force 59.

Based on the forces 55, 56 of the bearing force sensors 51, 52 recorded in both steps of the calibration, a ratio of the two forces 55, 56 can be used to determine an alignment of the bearing force sensors 51, 52 relatively to the previously known positions of the cranks 21 and/or the bicycle chain 7. In this way, the orientation of the drive unit 4 relative to the bicycle chain 7 can also be determined. The orientation determined in this way can then be used as a basis for determining the driver torque based on the bearing force direction and the bearing force amount of the bearing force 59.

Figure 8 shows a detailed sectional view of a drive arrangement 1 according to a second embodiment of the invention. The second embodiment essentially corresponds to the first embodiment with an alternative design of the fastening and arrangement of the bearing holder 5 in the housing 40 of the drive unit 4. Figures 9 and 10 show further detailed views of the drive arrangement 1 of the second embodiment.

In the second embodiment, the bearing holder 5 is arranged in a recess 65 of the housing 4. The recess 65 is circular and arranged coaxially to the pedal axis 22a. The recess 65 can, for example, be stepped, as can be seen in Figure 8, and extend completely through a wall of the housing 4. The pedal shaft 22 (not shown in Figure 8) protrudes completely through the recess 65 of the housing 4.

In addition, the arrangement 10 in the second embodiment comprises a separate fastening element 60, by means of which the bearing holder 5 is fixed in the housing 4. The fastening element 60 is a circular ring disk, which can be made of metal, for example.

The bearing holder 5 is fixed to the fastening area 50 by means of a welded connection 58b on the fastening element 60. The welded connection 58b extends over the entire fastening area for a firm and reliable connection. Analogous to the first embodiment, there is a small axial gap between the bending beams 53 of the bearing holder 5 and the fastening element 60 for unhindered mobility of the bending beams 53. The fastening element 60 has an outer diameter corresponding to the inner diameter of the recess 65.

The fastening element 60 is immovably fixed to the housing 40, for example by means of a press connection and/or by means of a welded connection and/or by means of an adhesive connection. The fastening element 60 thus indirectly fastens the bearing holder to the housing 40 of the drive unit 4.

The bearing holder 5 is designed and fixed to the fastening element 60 in such a way that a radially outer dimension 53b of the free end 53a of the bending beam 53 is smaller by a predetermined gap dimension 53c (see Figure 9) than an outer dimension of the fastening element 60 and thus also than an inner dimension 65a of the recess 65. This causes the inner circumference of the recess 65 to act as a stop. This means that if one of the bending beams 53 is deformed radially outward by the bearing force 59, this deformation is limited by the free end 53a of the bending beam 53 resting on the inner circumference of the recess 65. This makes it possible to provide a particularly simple and lightweight construction of the drive arrangement 1. In addition, this is particularly simple and cost-effective to manufacture.

Figure 11 shows a simplified schematic view of a detail of a drive arrangement 1 according to a third embodiment of the invention. Figures 12 and 13 show further views of the drive arrangement 1 of the third embodiment. The third embodiment essentially corresponds to the second embodiment of Figures 8 to 10, with the difference of an alternative design of the bearing holder 5 and the housing 40.

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 holder 5 is arranged is formed by the deep-drawing process. This can be seen, for example, in Figure 12. In the third embodiment, the bearing holder 5 additionally has a holding area 54 which is ring-shaped. The holding area 54 and the base area of the bearing holder 5, which is also ring-shaped and forms the bearing seat for the bottom bracket 24, together form a one-piece component which is essentially in the shape of an "8".

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.

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 region 54, in particular by means of a press connection.

Due to the "8-shaped" geometry of the bearing holder 5 and the recess 65 of the housing 40, there is an undercut 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 11 by the reference symbol 54a.

In the third embodiment, a precise, unambiguous fixation of the bearing holder 5 in the housing 40 is achieved by the outer circumference of the bearing holder 5 and by the inner edge 65b of the recess 65. In particular, the outer circumference of the bearing holder 5 in the third embodiment forms the fastening area 50 for fixing the bearing holder 5 to the housing 40.

The special geometry with the undercut 54a along the direction 22d thus enables a precisely defined relative position of the bearing holder 5 and the housing 40 to be achieved in a particularly simple and cost-effective manner using only a few components. In particular, this enables the special geometry with the gap dimension 53c, namely such that the free ends 53a of the bending beams 53 of the bearing holder 5 are in the predetermined gap dimension 53c with respect to the inner dimension 65a of the recess 65 of the housing 40.

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

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

As can be seen in Figure 12, the recess 65 of the housing 40 is formed with several different sub-areas. A holding area recess 65d is provided for receiving the holding area 54 of the bearing holder 5. This holding area recess 65d is formed as a depression which does not completely penetrate the housing 40.

In the area of the base area of the bearing holder 5, which is provided as a bearing seat for the bottom bracket 24, the recess 65 has a first shoulder 65c, which is designed, for example, similar to the fastening area 50 of the second embodiment of Figures 8 to 10 (see in particular Figure 10), and against which the bearing holder 5 rests flat. In addition, the recess 65 has a second shoulder 65b, which is deeper than the first shoulder 65c in order to prevent mechanical contact between the bearing holder 5 and the housing 40 in this area. Furthermore, the recess 65 has a through-opening for the passage of the pedal shaft 22.

Figure 13 shows an example of a fully assembled arrangement of bearing support 5 and housing 40. The bearing support 5 is pressed into the recess 65 of the housing 40 and then fixed in the housing in the axial direction, in particular in a form-fitting manner, by means of several fixing areas 5c. The fixing areas 5c are preferably This creates a plastic deformation of parts of the housing 40, for example by means of caulking. This allows the assembly of the drive arrangement 1 to be carried out particularly easily, in a time-efficient and cost-effective manner.

Claims

Expectations

1 . Arrangement for detecting a bearing force of a bottom bracket (24) of a vehicle (100) operable with muscle power and/or motor power, comprising:

- a bottom bracket (24),

- a bearing holder (5) which at least partially surrounds the bottom bracket (24) in a ring shape,

- a bearing force sensor (51), and

- a detection unit (6),

- wherein a bending beam (53) which can be bent in the radial direction is formed on the bearing holder (5),

- wherein the bearing force sensor (51) is arranged 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 a portion of the bearing holder (5) is designed as the bending beam (53) bendable in the radial direction.

3. Arrangement according to one of the preceding claims, wherein the bearing holder (5) has a, in particular radial, slot (57), and wherein the bending beam (53) adjoins the slot (57).

4. Arrangement according to one of the preceding claims, wherein the bearing holder (5) has two bending beams (53) and one bearing force sensor (51, 52) per bending beam (53).

5. Arrangement according to one of the preceding claims, further comprising a stop (7) which limits a movement of the bending beam (53) in the radial direction. Arrangement according to claim 5, wherein the stop (7) is arranged such that in the unloaded state of the bottom bracket (24) a predetermined air gap (70) is arranged between a free end (53a) of the bending beam (53) and the stop (7). 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). Arrangement according to claim 7, wherein the fastening region (50) is fixed to the housing (40) by means of a screw connection (58a) and/or by means of a weld connection (58b) and/or by means of an adhesive connection and/or by means of a press connection. Arrangement according to one of claims 7 or 8, further comprising a fastening element (60) by means of which the fastening region (50) is fixed to the housing (40), in particular wherein the fastening element (60) is designed as a disk, in particular a circular disk. Arrangement according to claim 7 or 8, wherein the fastening region (50) is at least a part of an outer circumference of the bearing receptacle (5). Arrangement according to one of claims 7 to 10, wherein the bearing receptacle (5) is arranged in a recess (65) of the housing (4), and wherein a radially outer dimension (53b) of the free end (53a) of the bending beam (53) is smaller than an inner dimension (65a) of the recess (65) of the housing (4) by at least a predetermined gap dimension (53c). Arrangement according to claim 11, wherein the bearing receptacle (5) has a holding region (54), wherein at least a partial region of the holding region (54) and an edge (65b) of the recess (65) of the housing (40) undercut one another in the radial direction, and wherein the holding region (54) is arranged on a side of the bearing receptacle (5) facing away from the free end (53a) of the bending beam (53).

13. Arrangement according to claim 11, wherein the holding region (54) is annular and is substantially completely in contact with the edge (65a) of the recess (65).

14. Arrangement according to claim 13, wherein the holding region (54) is designed as a bearing seat for a further bearing.

15. 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.

16. Drive arrangement of a vehicle (100) operable with muscle power and/or motor power, comprising:

- a crank drive (2) with cranks (21), a shaft (22), and two bottom brackets (23, 24) for supporting the shaft (22),

- an output element (3) which is connected to the shaft (22),

- a drive unit (4) which is arranged to provide an engine torque to support a driver torque applied by a driver,

- wherein the shaft (22) is mounted in the drive unit (4) by means of the two bottom brackets (23, 24), and

- an arrangement according to one of the preceding claims

- wherein the bearing force sensor (51) is arranged in the axial direction of the shaft (22) at the level of the bottom bracket (24) arranged on the output side.

17. Drive arrangement according to claim 16, wherein the bearing receptacle (5) has the holding region (54) which is annular, 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.

18. Vehicle operable with muscle power and/or motor power, comprising a drive arrangement (1) according to claim 16 or 17.

19. Method for operating a drive arrangement (1) according to claim 16 or

17, 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. Method according to claim 19, further comprising the steps:

- determining an output force (60) on the output element (3) 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). Method according to one of claims 19 or 20, further comprising the step:

- Controlling a motor torque generated by the drive unit (4) depending on the bearing force direction and the bearing force amount.