TW202502608A - Drive arrangement for a vehicle operable by muscle power and/or motor power - Google Patents

Abstract

The invention concerns a drive arrangement (1) for a vehicle (100) operable by muscle power and/or motor power, in particular an electric bicycle, comprising an output shaft (22) which is configured for connection to cranks (21) of a crank drive (2), a motor (4) which is configured to generate a motor moment to support a rider torque applied by a rider to the output shaft (22), wherein a motor shaft (42) of the motor (4) is arranged coaxially to the output shaft (22), at least one bearing (24) by means of which the output shaft (22) is mounted, at least one bearing force sensor (51, 52), in particular two bearing force sensors (51, 52), wherein the bearing force sensor (51, 52) is configured to detect a force (55, 56), and a detection unit (6) which is configured to detect a bearing force (59) at the bearing (24) based on the force (55, 56) detected by the bearing force sensor (51, 52).

Description

Drive configuration for vehicles operated by muscle or motor

The present invention relates to a driving arrangement for a vehicle operated by muscle power and/or a motor, a vehicle operated by muscle power and/or a motor comprising the driving arrangement, and a method for operating the driving arrangement.

Drive arrangements are known for vehicles that are operated by muscle force and/or motors, such as electric bicycles, which comprise a drive unit that can generate a motor torque to support the pedaling force of the rider of the vehicle. Usually, the motor torque is generated as a function of the rider torque generated by the rider's muscle force. To this end, the value of the instantaneous rider torque must be detected, for example, by means of corresponding sensors. It is also known that, for example, based on the bearing forces at the bearings of the electric bicycle, conclusions can be drawn about the forces applied by the rider to the crank drive and the drive unit is actuated based thereon. Such a system is disclosed, for example, in DE 10 2010 001 775 A.

In contrast, the drive arrangement according to the present invention having the features as claimed in claim 1 is distinguished in that the bearing forces at the bearings of a vehicle operated by muscle force and/or motor force can be accurately determined in a particularly simple and economical manner.

Also for example, the bearing forces can be easily determined, for example on a bicycle frame of an electric bicycle, regardless of the orientation of the motor. Based on the bearing forces thus determined, further functions of the drive arrangement can advantageously be provided efficiently and economically. This is achieved by a drive arrangement for a vehicle operated by muscle force and/or a motor, which comprises an output shaft, a motor, at least one bearing by means of which the output shaft is mounted, at least one bearing force sensor (in particular two bearing force sensors) and a detection unit. The output shaft is configured for connection to a crank of a crank drive. For example, the crank shaft can also be referred to as an output shaft. The motor is configured to generate a motor torque at the output shaft intended to support the rider torque applied by the rider. The motor shaft of the motor is here coaxially arranged to the output shaft. The bearing is provided for mounting the output shaft. Furthermore, each bearing force sensor is configured to detect a force. In particular, the two bearing force sensors are arranged at different circumferential positions relative to the output shaft. The detection unit is configured to detect a bearing force at the bearing based on the force detected by the bearing force sensor, in particular the force detected by the bearing force sensor.

The bearing force is understood to mean in particular the total resulting force in the region of the bearing, for example due to motor torque and/or rider torque. Particularly preferably, the detection unit is configured to determine the bearing force direction and the bearing amount of the bearing force at the bearing based on the detected forces.

Preferably, each bearing force sensor is configured to detect force, in particular exclusively in a predetermined direction. Preferably, two bearing force sensors are arranged at the height of the bearing in the axial direction of the output shaft.

In other words, a drive arrangement is provided which has two force sensors at the bearing. Since the two bearing force sensors are distributed around the circumference, force measurements are determined in two different directions. Preferably, the bearing force direction and the bearing force of the instantaneous bearing force at the bearing can thus be easily determined. Preferably, the bearing force direction and the bearing force are determined based on previously known mounting positions of the two bearing force sensors relative to one another and in particular based on previously known measuring directions of the bearing force sensors along which the respective forces are measured.

Suitable bearing force sensors may be any type of sensor suitable for detecting mechanical forces acting in a predetermined direction. For example, a bearing force sensor may be configured to detect tension and/or compression.

In a particularly simple embodiment, the two force sensors may preferably be identical.

The drive arrangement thus offers the advantage that the bearing force at the bearing can be detected by means of a particularly simple, economical and compact structure. A particularly compact arrangement can also be provided by using force sensors which can be distinguished, for example, by means of a particularly simple and lightweight structure and which take up very little installation space. Furthermore, the use of force sensors which are generally insensitive or only slightly sensitive to interference from magnetic fields allows a particularly reliable and precise detection of the bearing force.

A further advantage of the drive configuration is that the bearing force direction and the bearing force can be determined exactly independently of the mounting position of the drive unit on the e-bike. This means that the drive unit can be arranged in any orientation on the bicycle frame of the e-bike, in particular with respect to the rotation about the pedal bearing axis. Since the two force sensors are arranged offset in the circumferential direction, the resulting bearing forces can be detected exactly in any orientation of the drive unit without having to adapt the configuration of the force sensors to the mounting position. The resulting bearing forces can preferably be determined on the basis of a one-time calibration of the system which can be easily performed.

Due to the coaxial arrangement of the output shaft and the motor shaft, the drive arrangement furthermore offers the advantage that the motor and the output shaft can also be arranged coaxially. Thus, a particularly compact design of the drive arrangement is possible. In particular, the motor, which for example often occupies a considerable part of the entire installation space of the drive arrangement, can be optimally positioned coaxially with the output shaft. In particular, this arrangement is particularly advantageous for a compact overall design of the drive arrangement if, for example, the largest gear of a gear mechanism is arranged on the output shaft. Thus, the remaining gear volume can, for example, extend only slightly beyond the axial projection surface of the motor, so that this volume can be relatively rigid and, in particular, relatively centrally arranged in the axial direction, which has a further advantageous effect on the construction of the drive arrangement. The drive arrangement is also distinguished by its low cost, since the components are few and relatively simple. In addition, a low weight of the drive arrangement can be achieved as a result.

The dependent claims relate to preferred improvements of the present invention.

Preferably, the drive arrangement comprises two bearings for mounting the output shaft. This means that the output shaft is mounted in a rotatable manner by means of two bearings. The output shaft has an output interface configured for connection to an output element. Preferably, such an output element may be a chain ring. Alternatively, preferably, another output element may be provided, which is configured for connection to a transmission element in order to allow torque transmission from the output shaft to the drive wheel of the vehicle. The bearing force sensor is arranged at the height of the output side bearing in the axial direction of the output shaft. In other words, a drive arrangement is provided in which a bearing force sensor is placed in the region of one of the two bearings which are arranged closer to the output element. Preferably, the output interface is fixedly connected to the output shaft in a rotatable manner. In particular, the output shaft is formed in one piece. Bearing force measurement by means of a bearing force sensor offers the advantage that the output shaft can be designed particularly simply and economically, wherein the force used, for example, to actuate the motor can still be reliably determined.

Particularly preferably, the drive arrangement further comprises a bearing receiver, which at least partially surrounds the bearing in a ring-like manner. In particular, the bearing receiver substantially completely surrounds the bearing, preferably except for a predefined gap region. The bearing receiver is particularly configured to hold the bearing. For example, the bearing receiver can be configured as a bearing housing.

Preferably, a bending rod that can be bent in the radial direction is formed at the bearing receiver, wherein at least one of the bearing force sensors is arranged on the bending rod. In particular, with the aid of the bearing force sensor, a force on the bending rod is detected, which force can be caused by a deformation of the bending rod caused by the bearing force. Due to the use of a bending rod, a particularly sensitive structure can be provided. In particular, because one end of the bending rod is formed to be freely movable, for example even relatively small bearing forces can cause a deformation of the bending rod, whereby these forces can be easily and accurately detected. Therefore, particularly small bearing forces can be determined very accurately. This offers the advantage, for example when used on an electric bicycle, that low torque values can be detected precisely and sensitively, whereby the motor can be controlled particularly precisely, for example depending on the rider torque.

Preferably, a portion of the bearing receiver can be configured as a bending rod that can be bent in the radial direction. This means that the bending rod is an integral part of the bearing receiver. Thus, a particularly simple construction of the arrangement can be achieved.

Preferably, the bearing receiver has an in particular radial groove. The bending rod adjoins this groove. In other words, the bending rod is formed by a section of the bearing receiver, so that the bearing receiver is slotted, wherein the freely movable end adjoining the slot corresponds to the freely movable end of the bending rod. Thus, in a particularly simple and economical manner, a construction is provided which provides the advantageous properties of a sensitive bending rod.

Particularly preferably, the bearing receiver has two bending rods and a bearing force sensor arranged on each bending rod. Preferably, the two bending rods are formed symmetrically with respect to the slot and preferably have the same geometric properties. Therefore, the bearing force can be detected particularly accurately. For a particularly simple and economical design, the two bearing force sensors can preferably be identical. Preferably, the two bearing force sensors are oriented in different directions so that bearing forces in different directions can be detected. Preferably, each of the two bearing force sensors is configured and arranged to detect forces in a tangential direction relative to the output shaft. This provides a particularly simple and compact arrangement which also allows the bearing force direction and the bearing force to be reliably determined for the total resulting bearing force.

Preferably, the arrangement further comprises a stop which limits the movement of the bending rod in the radial direction. In particular, the stop limits the maximum deflection of the free end of the bending rod in the radial direction. Thus, by means of a simple and economical construction, a particularly high mechanical stability of the arrangement can be provided. In particular, the stop can limit the deformability of the bending rod to a maximum amount. Thus, for example, damage to the bearing receiver can be avoided. In addition, a stable and reliably precise positioning of the bearing is ensured by means of the bearing receiver. In addition, the stop provides the advantage that the bending rod can be optimally designed to have an undefined, easily detectable deformability within a specific bearing force range. Thus, for example, for particularly sensitive detection, easy deformation of the bending rod at low bearing forces can be provided, wherein the stop prevents excessive deformation.

Preferably, the stop is configured such that in the unloaded state of the bearing, a predetermined air gap exists between the free end of the bending rod and the stop. Preferably, the air gap in the unloaded state is a maximum of 0.1 mm. The air gap thus allows free deformation of the bending rod until the stop is reached, so that the bearing force can be detected particularly accurately on this basis.

The air gap can be set particularly easily during installation of the arrangement, for example by means of a corresponding orientation of the stop element.

Preferably, the drive arrangement further comprises a gear mechanism arranged between the motor and the output shaft. The gear mechanism is configured to transmit torque between the motor shaft and the output shaft. The motor shaft is in particular an integral part of the motor. In particular, the gear mechanism allows a translation ratio between the motor and the output shaft. Preferably, the output shaft is a crankshaft of the vehicle, to which the crank of the crank drive can be connected. In particular, in this case, the pedaling force applied to the output shaft by the muscle force of the rider of the vehicle can be determined particularly reliably and directly. The gear mechanism is preferably a spur gear mechanism. Particularly preferably, the gear mechanism is a double-stage spur gear mechanism. Preferably, the gear mechanism comprises an intermediate shaft parallel to the motor shaft and the output shaft, and wherein torque transfer between the motor shaft and the output shaft occurs indirectly via the intermediate shaft and respective gear pairs between the respective shafts.

Preferably, the gear mechanism is configured as a preferably two-stage spur gear mechanism. This means that preferably there are two spur gear stages for providing a predetermined gear ratio between the output shaft and the crankshaft. Thus, with a compact construction and a simple design, an optimal torque transmission for the drive unit of the electric bicycle can be provided. Such spur gear mechanisms are distinguished by a particularly high efficiency, which ensures a high efficiency of the operation of the drive arrangement.

Preferably, the gear mechanism has an intermediate shaft arranged parallel to the output shaft. This means, in particular, that the intermediate shaft axis of the intermediate shaft is arranged parallel to the output shaft axis of the output shaft. The gear mechanism is configured here to transmit torque between the output shaft and the motor shaft via the intermediate shaft. This means that the torque transmission occurs via the intermediate shaft from the motor shaft of the motor to the output shaft. Thus, a gear mechanism with a predetermined gear ratio between the output shaft and the motor shaft can be provided particularly easily and with very few components. Furthermore, the gear ratio can be adjusted in a simple manner, for example, by scaling the intermediate shaft, in particular with corresponding gears.

Particularly preferably, the gear mechanism has a first gear and a second gear. The first gear and the second gear are each rotatably fixedly connected to the intermediate shaft. For example, the first gear, the second gear and the intermediate shaft can be configured together as an integral component. Thus, a simple, economical and stable construction can be ensured.

Preferably, the gear mechanism has a motor gearing formed on the motor shaft. In particular, a portion of the motor shaft is thus configured as a gear with a motor gearing. The first gear here engages with the motor gearing. This can further advantageously support a compact, simple and economical construction.

Preferably, the gear mechanism has a third gear which is rotationally fixedly connected to the output shaft. In particular, the third gear can also be arranged rotatably relative to the output shaft in freewheel mode. The third gear here engages with the second gear of the intermediate shaft. In particular, torque can be transmitted from the intermediate shaft to the output shaft via the third gear.

Particularly preferably, the drive arrangement further comprises a freewheel device between the motor shaft and the output shaft. Particularly preferably, the freewheel device is arranged between the third gear and the crank shaft. In particular, the freewheel is configured to be able to switch between a rotationally fixed connection and a relatively freely rotatable connection between the third gear and the output shaft. Preferably, the freewheel device is locked in the drive direction of the motor and is opened when the motor has stopped and during actuation of the crank. Alternatively or in addition, the freewheel device can, for example, be configured so that it can be operated controllably, for example by means of a control unit. In particular, by means of the freewheel device, the motor can be decoupled from the output shaft, for example in order to disconnect the motor support, in particular when the vehicle exceeds a predetermined speed.

Particularly preferably, the motor is arranged on a side of the gear mechanism facing the output interface. This means that the motor is arranged closer to the output element than the gear mechanism in the axial direction of the output shaft. Or preferably, the motor is arranged on a side of the gear mechanism facing away from the output interface. In other words, in this case, the gear mechanism is arranged closer to the output interface than the motor. In other words, the motor can be arranged on the right or left side relative to the direction of travel of the vehicle on which the drive arrangement can be arranged.

Preferably, the drive arrangement further comprises a housing. The bearing receiver here has a fastening region which is particularly immovably fixed to the housing. The housing can be, for example, the housing of a motor. By fastening the bearing receiver to the housing, a precise and particularly immovable retention of the bearing relative to the housing is provided. The fastening region can be, for example, a portion of the bearing receiver which corresponds in the circumferential direction to at least one third, preferably at least one half, preferably at most three quarters of the entire ring of the bearing receiver.

Preferably, the fastening region is fixed to the housing by means of a threaded connection. In particular, the threaded connection comprises a plurality of screws distributed around the circumference of the bearing receiver. Alternatively or in addition, preferably, the fastening region is fixed to the housing by means of a welding connection and/or a joint connection and/or a press connection. Preferably, the welding connection and/or the joint connection are formed over the entire area of the fastening region in order to provide a particularly stable fixation.

Preferably, the arrangement also comprises a fastening element, by means of which the fastening region is fastened to the housing. This means that the bearing receiver is fastened to the housing directly or indirectly by means of the fastening element. Thus, for example, a particularly simple and economical production and installation of the arrangement can be provided, since the exact orientation of the bearing receiver and the fastening element can be separated from the housing.

Particularly preferably, the fastening element is configured as a preferably circular disk. The fastening element is here arranged in particular together with the bearing receptacle in a recess of the housing. Preferably, the recess has an inner geometry that corresponds to the outer geometry of the fastening element. This allows a particularly simple and economical construction and mounting of the arrangement. For example, the recess and the fastening element can have simple geometries that can be produced precisely.

Preferably, the fastening area is formed as at least part of the outer periphery of the bearing receiver. This means in particular that the bearing receiver is fixed to the housing in that the outer periphery of the bearing receiver is preferably at least partially fixed directly to the housing by means of a press connection between the outer periphery and the housing. As a result, a particularly simple, lightweight and economical construction of the arrangement can be provided. Furthermore, a particularly high positional accuracy of the bearing receiver and therefore of the bearing can be provided, since, for example, the recess in the housing can be produced simply and economically with high precision. This is particularly advantageously possible if the housing is a drawn component, preferably a sheet metal housing in which the recess is produced by deep drawing.

Preferably, the bearing receiver is arranged in a groove of the housing. The radial outer dimension of the free end of the bending rod is smaller than the inner dimension of the housing groove by a predetermined gap size. In other words, the radial outer dimension of the free end of the bending rod is offset by a predetermined gap size relative to the preferably circular outer contour of the fastening element. Preferably, the gap size is a maximum of 0.5 mm, preferably a maximum of 0.2 mm, and particularly preferably a maximum of 0.1 mm. Therefore, the housing forms a stop for the bending rod, and in particular no separate component is required for the stop. Therefore, a particularly simple and economical construction can be provided with very few components. Preferably, the stop zone is arranged at the free end of the bending rod, wherein the gap size is arranged between the stop zone and the housing. Preferably, between the remaining area of the bending rod and the groove, there is a gap greater than the gap size, so that in particular free mobility of the bending rod is possible and the bending rod rests exclusively against the stop zone.

Preferably, the bearing force sensor comprises a strain gauge. By mounting the strain gauge on the bending rod, for example, its deformation can be particularly easily detected. The strain gauge can, for example, determine the extension and/or compression of the bending rod and, based thereon, the deformation of the bending rod and, for example, the mechanical force on the bending rod.

Alternatively or additionally, the bearing force sensor preferably comprises a piezoelectric element. Thus, similar to a strain gauge, the deformation of the bending rod and/or the instantaneous force acting on the bending rod can be determined in a particularly simple, compact and economical manner.

Alternatively or additionally, preferably, the bearing force sensor comprises a magnetic sensor. For example, the magnetic sensor can be a Hall sensor, in particular with the aid of which a relative position change of a part of the bending lever relative to another component (such as the housing) can be easily and particularly accurately detected.

Preferably, the drive arrangement comprises a crank drive with a crank. The crank is connected to the output shaft or is fixed, in particular rotatably fixed, to the output shaft. With the help of the crank, the rider can exert a pedaling force by muscle force, thereby generating a pedal torque on the output shaft.

Furthermore, the invention relates to a vehicle operated by muscle power and/or motor, in particular an electric bicycle, comprising the described drive arrangement.

Furthermore, the invention relates to a method for operating a drive arrangement as described above. The method comprises the following steps: -   Determining the force by means of two bearing force sensors, and -   Determining the bearing force at the bearing based on the force detected by the bearing force sensors. The method is distinguished in that it can be carried out particularly easily and economically, wherein an exact result for the bearing force at the bearing can be determined.

Preferably, the method further comprises the step of determining the output force at the output element based on the bearing forces, in particular the bearing force direction and the bearing force amount. The output force here is the force exerted on the output element by the transmission element, such as a bicycle chain, in particular during operation of the electric bicycle. Preferably, the output force is present on the outer periphery of the chain ring and in a predefined direction in which the bicycle chain extends, for example to the rear wheel. Preferably, the output force is also determined based on the drive configuration, in particular previously known geometric properties of the chain ring.

More preferably, the method comprises the step of determining a rider torque applied by the rider based on the determined output force and the motor torque, in particular in the case of an electric bicycle comprising a drive arrangement operated simultaneously by muscle force and motor force. In particular, the motor torque is previously known from a motor controller. Preferably, the rider torque is determined by determining a rider force, wherein the rider force corresponds to a portion of the output force generated by the rider's muscle force. In particular, the correlation between the rider torque and the rider force is defined by previously known geometrical properties of the drive arrangement, in particular the chain rings. The rider force is preferably determined by subtracting the motor force from the total output force, wherein the motor force corresponds to the force applied to the bicycle chain due to the motor torque. Therefore, the rider torque can be determined particularly easily and accurately.

Preferably, the method further comprises the step of controlling the motor torque generated by the motor depending on the bearing force direction and the bearing force. Particularly preferably, the motor is controlled depending on the determined rider torque. This means that the motor torque for supporting the rider's pedaling force is provided depending on the bearing force or the rider torque determined based on the determined bearing force.

Preferably, the bearing force direction and the bearing force are determined based on a calibration of the drive arrangement. The calibration is based on the ratio of the respective forces detected by the bearing force sensors during actuation of the crank drive in a predefined calibration configuration. In the calibration configuration, the crank drive is actuated in a predefined actuation direction by the actuation force. Particularly preferably, the calibration is performed by detecting a plurality of ratios in a plurality of different predefined actuation directions. Preferably, the calibration is performed when the drive arrangement is mounted on an electric bicycle.

Fig. 1 shows a simplified schematic diagram of an electric bicycle 100 having a drive arrangement 1 according to a first exemplary embodiment of the present invention. The drive arrangement 1 is shown in a cross-sectional view in Fig. 2. Details of the drive arrangement 1 of the first exemplary embodiment are shown in Figs. 3 to 5.

The drive arrangement 1 has a crank drive 2, which has two cranks 21 positioned opposite each other relative to the pedal axis 22a. Pedals 25 are arranged on the cranks 21, via which the rider can generate a rider torque at the drive arrangement 1 by muscle force.

The crank drive 2 also includes an output shaft 22 rotatably fixedly connected to the crank 21 , and two bearings 23 , 24 for rotatably mounting the output shaft 22 .

The drive arrangement 1 further comprises: an output element 3, which is a chain ring and is rotatably fixedly connected to the output interface 35 of the output shaft 22; and a bicycle chain 107, which serves as a transmission element engaged with the chain ring 3.

In order to support the rider torque with additional motor torque, the drive arrangement 1 comprises a motor 4, preferably an electric motor, which is in particular supplied with electrical energy from an electrical energy storage area (not shown in the figure) and is configured to generate a motor torque.

The drive arrangement 1 is preferably attached to the bicycle frame 101 of the electric bicycle 100 by means of the housing 40 .

The output shaft 22 is mounted in the housing 40 via two bearings 23, 24. On the bearing 23 facing away from the output, the housing 40 has a bearing collar 43 in which the bearing 23 is arranged (see FIG. 2). The bearing collar 43 is in particular an integral part of the housing 40.

The drive arrangement 1 also includes a gear mechanism 8. The gear mechanism 8 is configured to transmit torque between the motor shaft 42 of the motor 4 and the output shaft 22.

The gear mechanism 4 is arranged here between the motor 2 and the output interface 35 along the direction of the pedal axis 22a. Relative to the travel direction A (see FIGS. 1 and 2 ), the output interface 35 is therefore on the right side of the output shaft 22 and the motor 4 is on the left side. In other words, apart from the left crank 22, the motor 4 is the element of the drive arrangement 1 that is farthest to the left.

The gear mechanism 8 is a two-stage spur gear mechanism. This means that the gear mechanism 8 includes a plurality of gears configured as spur gears that mesh to transmit torque. Its configuration is described in more detail below.

In the drive arrangement 1, the motor shaft 42 of the motor 4 and the output shaft 22 are arranged coaxially with each other. This means that the motor shaft 42 and the output shaft 22 are each arranged rotatably around a common pedal axis 22a. For this purpose, the motor shaft 42 of the motor 4, which is particularly rotatably fixedly connected to the rotor of the motor 4, is formed as a hollow shaft. The output shaft 22 extends through the motor shaft 42.

The output shaft 22 and the motor shaft 42 are rotatably mounted relative to each other by means of bearings 48 .

The motor shaft 42 of the motor 4 axially protrudes beyond the rotor of the motor 4. The motor gearing 84 is formed on this protruding area of the motor shaft 42.

The motor gear 84 is engaged with the first gear 81 of the gear mechanism 8. The first gear 81 is rotatably fixedly connected to the intermediate shaft 85 of the gear mechanism 8. The intermediate shaft 85 extends along the intermediate shaft axis 80 and is configured so as to be freely rotatable around the intermediate shaft axis 80.

In addition, the gear mechanism 8 includes a second gear 82 that is also rotatably fixedly connected to the intermediate shaft 85. Preferably, the first gear 81, the second gear 82 and the intermediate shaft 85 are formed together as an integral component, or alternatively as separate components connected together.

In addition, the gear mechanism 8 comprises a third gear 83 rotatably arranged around the pedal axis 22a. Between the third gear 83 and the output shaft 22 is a freewheel device 89, which allows a rotatably fixed connection or arrangement of the third gear 83 and the output shaft 22, wherein the third gear and the output shaft can rotate freely relative to each other.

Therefore, the torque from the motor torque generated by the motor 4 can be transmitted from the motor shaft 42 to the intermediate shaft 85 via the motor gear 84 and the first gear 81, and transmitted to the output shaft 22 via the second gear 82 and the third gear 83 and correspondingly via the switching freewheel device 89.

By means of the coaxial arrangement of the motor 4 and the output shaft 22, the drive arrangement 1 here offers the advantage of a particularly compact design of the drive arrangement 1. The motor 4, which geometrically forms the largest element of the drive arrangement 1, can here be positioned particularly advantageously by means of a coaxial arrangement with the output shaft 22. Also due to the special design of the gear mechanism 8, the largest gear, namely the third gear 83, is also arranged on the output shaft 22, so that a particularly small extent of the other components of the drive arrangement 1 in the radial direction relative to the pedal axis 22a is possible, since the remaining gear volume extends only slightly from the axial projection surface of the motor 4.

A circuit board 9 as part of the drive arrangement 1 is also present between the motor 4 and the gear mechanism 8. This circuit board 9 may, for example, comprise a control unit or be configured as part of a control unit. In particular, the circuit board 9 is arranged between the motor 4 and the first gear 81 of the gear mechanism relative to the direction of the pedal axis 22a.

The drive arrangement 1 also has a connection element 90 which can be configured, for example, as a plug for an electrical plug-in connector. The connection element 19 is connected here to the circuit board 9 and is arranged to protrude from the circuit board 9 in the axial direction facing away from the output.

For the motor-supported 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 here by determining the bearing force 59 at the output side bearing 24, as described below.

To determine the rider torque based on the bearing force 59, several known mechanical and geometric relationships are used, as well as the motor torque known from the operation of the motor 4. Specifically, it is known that the output force 60 at the chain ring 3 associated with the propulsion of the electric bicycle 100 (see FIG. 3 ) causes a reaction force at the output side bearing 24 that is equal in magnitude and parallel thereto in the opposite direction.

With knowledge of the geometry and mechanism of the crank drive 2 and the motor torque of the motor 4, a certain proportion of the output force 60 applied by the motor 4, i.e., the motor force, is determined. Therefore, the rider force corresponding to the proportion of the output force 60 applied by the rider's muscle force can be easily determined by subtracting the motor force from the total output force 60. The corresponding rider torque can then also be easily determined based on the geometric properties of the drive arrangement 1.

The bearing force 59 of the drive arrangement 1 according to the invention is determined here by means of a simple, compact and economical construction which also allows particularly sensitive and precise detection. For this purpose, the drive arrangement 1 has two bearing force sensors 51, 52 arranged in the region of the output-side bearing 24.

3 and 4 show the arrangement of two bearing force sensors 51 and 52. The two bearing force sensors 51 and 52 are located at the height of the output side bearing 24 in the axial direction of the output shaft 22.

Each of the two bearing force sensors 51, 52 is configured as a strain gauge and is designed to detect forces 55, 56 resulting from mechanical extension and/or compression in precisely one predetermined direction, namely in the radial direction relative to the pedal axis 22a.

The two bearing force sensors 51 , 52 are connected to a detection unit 6 which determines the individual forces 55 , 56 and also all further forces and moments.

The bearing force sensors 51, 52 are arranged here on the radially outer side of the bearing receiver 5. The bearing receiver 5 is a component which is formed separately from the outer housing 40 of the motor 4 and is configured in particular as a bearing housing. In a first exemplary embodiment, the bearing receiver 5 has a substantially circular annular outer geometry.

FIG. 4 shows a perspective view of the bearing receiver 5.

The bearing 24 is arranged in the groove of the bearing receiver 5, wherein in the unloaded state, preferably, substantially the entire inner periphery of the bearing receiver 5 is in contact with the outer periphery of the bearing 24.

The bearing receiver 5 is also formed with a groove 57 which extends completely through the entire bearing receiver 5 in the radial direction.

The bearing receiver 5 also has a fastening region 50 attached to the housing 40. The fastening region 50 is an axial end face of the bearing receiver 5 which is in contact with a fastening element 50a fixed to the housing 40 over its entire area.

The bearing receiver 5 is disposed in a groove 65 of the housing 4 (see FIG. 6 ). The groove 65 is circular and is disposed coaxially with the pedal axis 22 a. For example, as shown in FIG. 6 , the groove 65 can be formed stepwise and extend completely through the wall of the housing 4. The output shaft 22 (not shown in FIG. 6 ) protrudes completely through the groove 65 of the housing 4.

Furthermore, the arrangement 10 has a separate fastening element 50a, by means of which the bearing receiver 5 is fastened in the housing 4. The fastening element 50a is a circular ring which can be made, for example, of metal.

The bearing receiver 5 is fixed to the fastening element 50a at the fastening area 50 by means of a welded connection 58b. The welded connection 58b extends completely over the entire fastening area 50 for a strong and reliable connection. Similar to the first exemplary embodiment, there is a small axial gap between the bending rod 53 of the bearing receiver 5 and the fastening element 50a so that the movability of the bending rod 53 is not hindered.

The fastening element 50a has an outer diameter corresponding to the inner diameter of the groove 65.

The fastening element 50a is fixedly secured to the housing 40, for example by means of a press connection and/or a welding connection and/or a joining connection. Thus, the fastening element 50a ensures that the bearing receiver is indirectly fastened to the housing 40 of the motor 4.

Furthermore, the bearing receiver 5 has two bending rods 53 disposed between the groove 57 and the fastening area 50. The bending rods 53 are configured so that they can be deformed in the radial direction. The bending rods 53 are indicated by hatching in FIG. 4 .

On the radially outer side of each bending rod 53 is a flattened portion 41, and respective bearing force sensors 51, 52 are disposed on the flattened portion.

The bearing receiver 5 is configured and fixed to the fastening element 50a so that the radial outer dimension 53b of the free end 53a of the bending rod 53 is smaller than the outer dimension of the fastening element 50a and therefore also than the inner dimension 65a of the groove 65 by a predetermined gap size 53c (see FIG. 4 ). This means that the inner circumference of the groove 65 acts as a stop. In other words, if one of the bending rods 53 is deformed radially outward by the bearing force 59, this deformation is limited by the contact of the free end 53a of the bending rod 53 on the inner circumference of the groove 65. Therefore, a particularly simple and lightweight construction of the drive arrangement 1 can be provided. This can also be produced particularly easily and economically.

When the crank drive 2 is loaded by the pedaling force of the rider, a bearing force 59 is generated at the bearing 24. Since the bearing 24 is held in the outer housing 40 of the motor 4 by means of the bearing receiver 5, this bearing force 59 acts accordingly on the bearing receiver 5. Due to the special design of the bearing receiver 5 and the movable bending rod 53, the bearing force 59 causes a deflection of the bending rod 53 in the radial direction. This deformation can be detected by means of bearing force sensors 51, 52 configured as strain gauges.

Based on the above-mentioned previously known geometric and mechanical properties of the arrangement 10, the entire resulting bearing force 59, i.e. the bearing force direction and the bearing force, can be determined based on the detected deformation.

Due to the free mobility of the bending rod 53 in the radial direction, a particularly sensitive detection is possible by a corresponding mechanical design. This means, for example, that by a corresponding design of the thickness of the bending rod 53 in the axial and/or radial direction, it can be ensured that a clearly measurable deformation occurs even at relatively small bearing forces. In particular, low torque levels applied by the rider can thus be detected with great accuracy.

In order to ensure that the bending rod 53 achieves particularly high precision due to minimal deformation, the bending rod 53 is spaced apart from the fastening element 50a in the axial direction, and the fastening area 50 of the bearing receiver 5 abuts against the fastening element. This means that in the axial direction, there is a gap between the axial end surface 50b of each bending rod 53 facing the fastening element 50a and the fastening element 50a, and the end surface 50a of the fastening area 50 abuts against the fastening element. Therefore, the deformation of the bending rod 53 is not affected by, for example, friction.

Furthermore, the bending rod 53 and/or the bearing 24 may be configured such that a region of minimal friction is formed between the radially inner side of the bending rod 53 and the radially outer side of the bearing 24, so that, for example, tampering of measurement results by stress induced by adhesion friction may be avoided or reduced.

Furthermore, the drive arrangement 1 comprises a stop 7 which limits the movement of the bending rods 53 in the radial direction. The stop 7 is formed here by the housing 40. The stop 7 is located in the extension of the groove 57.

In order to be able to determine the output force 60 acting on the bicycle chain 107 based on the determined bearing force 59 and thus determine the rider torque described above, it is necessary to know the chain direction 70 of the bicycle chain 107 and the relative position of the motor 4 with respect to each other, that is, the mounting position of the motor 4 on the bicycle frame 101.

Therefore, in order to be able to correctly determine the output force 60 based on the bearing force 59, it is necessary to know the geometric relationship between the motor 4 and the chain direction 70.

To this end, a one-time calibration of drive configuration 1 is performed. During the calibration, motor 4 generates no motor torque.

During calibration, in a first step, the crank drive 2 can be configured so that the cranks 21 are oriented horizontally. In this first calibration configuration, exactly one crank 21 (i.e. the crank 21 pointing forward in the direction of travel) is actuated by the previously known actuation force. The actuation force is vertical here, i.e. orthogonal to the crank 21 and to the chain direction 70. Thus, the entire actuation force is transmitted to the bicycle chain 107. The corresponding bearing force 59 here corresponds to the force generated by the actuation force and the output force 60.

In a second calibration step, the crank drive 2 is configured so that the crank 21 is oriented vertically. In this second calibration configuration, the lower crank 21 is actuated by an actuating force which is also oriented vertically, i.e. orthogonal to the chain direction 70 and parallel to the crank 21. In this second actuation configuration, due to the corresponding orientation of the crank drive 2, the output force 60 is equal to zero. However, the bearing force 59 is caused by the actuating force.

Based on the forces 55, 56 detected from the bearing force sensors 51, 52 in the two calibration steps, the position of the bearing force sensors 51, 52 relative to the previously known position of the crank 21 and/or the bicycle chain 107 can be derived from the ratio of the two forces 55, 56. Thus, the position of the drive unit relative to the bicycle chain 107 can also be determined. The position determined in this way can then serve as the basis for determining the rider torque based on the bearing force direction and the bearing force of the bearing force 59.

FIG. 7 shows a cross-sectional view of a drive configuration 1 according to a second exemplary embodiment of the present invention. The second exemplary embodiment substantially corresponds to the first exemplary embodiment, wherein the alternative configuration of the components of the drive configuration 1 is different. In the second exemplary embodiment, the motor 4 is configured on the output side, that is, between the gear mechanism 8 and the output interface 35. In detail, the motor 4 is configured between the output side bearing 24 and the first gear 81 of the gear mechanism 8. This means that the motor 4 is located on the right side of the travel direction A. Therefore, an alternative geometric configuration of the components of the drive configuration 1 can be provided. In the second exemplary embodiment, the connecting element 90 on the circuit board 9 is also configured to protrude in the direction of the output side.

1: Drive configuration 10: Configuration 100: Vehicle/E-bike 101: Bicycle frame 107: Bicycle chain 2: Crank drive 21: Crank 22: Output shaft 22a: Pedal axis 23: Bearing 24: Output side bearing 25: Pedal 3: Output element/chain ring 35: Output interface 4: Motor 40: Housing 41: Flattening part 42: Motor shaft 43: Bearing collar 48: Bearing 5: Bearing receiver 50: Fastening area 50a: Fastening element/end face 50b: Axial end face 51: Bearing force sensor 52: Bearing force sensor 53: Bending rod 53a: Free end 53b: Radial outer dimension 53c: Predefined gap size 55: Force 56: Force 57: Groove 58b: Welded connection 59: Bearing force 6: Detection unit 60: Output force 65: Groove 65a: Internal dimension 7: Stopper 70: Chain direction 8: Gear mechanism 80: Intermediate shaft axis 81: First gear 82: Second gear 83: Third gear 84: Motor gearing 85: Intermediate shaft 89: Freewheel device 9: Circuit board 90: Connecting components A: Direction of travel

The present invention is described below with reference to illustrative embodiments in conjunction with the drawings. In the drawings, components that are functionally equivalent carry the same reference symbols. In the drawings: [FIG. 1]    shows a simplified schematic diagram of an electric bicycle having a drive configuration according to a first exemplary embodiment of the present invention, [FIG. 2]    shows a cross-sectional view of the drive configuration from FIG. 1, [FIG. 3]    shows a simplified detailed cross-sectional view of the drive configuration from FIG. 1 to illustrate the function, [FIG. 4]    shows a perspective detailed view of the drive configuration from FIG. 1, [FIG. 5]    shows another detailed view of the drive configuration from FIG. 1, [FIG. 6]    shows another detailed view of the drive configuration from FIG. 1, and [FIG. 7]    shows a cross-sectional view of the drive configuration according to a second exemplary embodiment of the present invention.

1:Drive configuration

100: Vehicles/Electric Bicycles

101:Bicycle frame

107:Bicycle chain

2: Crank drive

21: Crank

22: Output shaft

22a: Pedal axis

25: Pedal

3: Output element/chain ring

4: Motor

59: Bearing capacity

60: Output

70: Chain direction

A: Direction of travel

Claims (21)

A drive arrangement for a vehicle (100) operated by muscle power and/or a motor, in particular an electric bicycle, comprising: an output shaft (22) configured to be connected to a crank (21) of a crank drive (2), a motor (4) configured to generate a motor torque to support a rider torque applied to the output shaft (22) by a rider, wherein a motor shaft (42) of the motor (4) is arranged coaxially with the output shaft (22), at least one bearing (24) by means of which the output shaft (22) is mounted, at least one bearing force sensor (51, 52), in particular two bearing force sensors (51, 52), The bearing force sensor (51, 52) is configured to detect force (55, 56), and the detection unit (6) is configured to detect the bearing force (59) at the bearing (24) based on the force (55, 56) detected by the bearing force sensor (51, 52). A drive configuration as claimed in claim 1, wherein the two bearing force sensors (51, 52) are arranged at different circumferential positions relative to the output shaft (22). A drive arrangement as in any of the preceding claims, comprising two bearings (23, 24) for mounting the output shaft (22), wherein the output shaft (22) has an output interface (35) configured for connection to an output element (3), and wherein the bearing force sensor (51) is arranged at the height of the outlet side bearing (24) in the axial direction of the output shaft (22). A drive arrangement as claimed in any of the preceding claims, further comprising a bearing receiver (5) which at least partially surrounds the bearing (24) in the form of a ring. A driving configuration as claimed in claim 4, wherein a bending rod (53) capable of bending in a radial direction is formed at the bearing receiver (5), wherein at least one of the bearing force sensors (51, 52) is arranged on the bending rod (53). A drive arrangement as claimed in claim 4 or 5, wherein a portion of the bearing receiver (5) is configured as a bending rod (53), the bending rod can be bent in the radial direction, and wherein the bearing receiver (5) has a particularly radial groove (57), and wherein the bending rod (53) is adjacent to the groove (57). A drive arrangement as claimed in any one of claims 4 to 6, wherein the bearing receiver (5) has two bending rods (53), and wherein one of the two bearing force sensors (51, 52) is arranged on each bending rod (53). A drive arrangement as in any one of claims 5 to 7, further comprising a stopper (7) which limits the movement of the bending rod (53) in the radial direction. A drive configuration as claimed in claim 8, wherein the stopper (7) is configured so that when the bearing (24) is in an unloaded state, a predetermined air gap (70) exists between the free end (53a) of the bending rod (53) and the stopper (7). A drive arrangement as claimed in any of the preceding claims, further comprising a gear mechanism (8) disposed between the motor (4) and the output shaft (22) and configured to transmit torque between the motor shaft (42) and the output shaft (22). A drive configuration as claimed in claim 10, wherein the gear mechanism (8) is configured as a double-stage spur gear mechanism. A drive arrangement as claimed in claim 10 or 11, wherein the gear mechanism (8) has an intermediate shaft (85) arranged parallel to the output shaft (22), and wherein the gear mechanism (8) is configured to transmit torque between the motor shaft (42) and the output shaft (22) via the intermediate shaft (85). A drive configuration as claimed in any one of claims 10 to 12, wherein the gear mechanism (8) has a first gear (81) and a second gear (82), wherein the first gear (81) and the second gear (82) are rotatably fixedly connected to the intermediate shaft (85), particularly wherein the gear mechanism (8) has a motor gear (84) formed on the motor shaft (42), and wherein the first gear (81) is engaged with the motor gear (84), particularly wherein the gear mechanism (8) has a third gear (83) rotatably fixedly connected to the output shaft (82), and wherein the third gear (83) is engaged with the second gear (82). A drive arrangement as claimed in any one of claims 10 to 13, further comprising a freewheel device (89) between the motor shaft (42) and the output shaft (22). A drive configuration as in any one of claims 10 to 14, wherein the motor (4) is arranged on the side of the gear mechanism (8) facing away from the output interface (35), or wherein the motor (4) is arranged on the side of the gear mechanism (8) facing the output interface (35). A drive arrangement as claimed in any of the preceding claims, wherein the bearing force sensor (51) comprises a strain gauge and/or a piezoelectric element and/or a magnetic sensor. A drive arrangement as claimed in any of the preceding claims, further comprising a crank drive (2) having cranks (21), wherein the cranks (21) are connected to the output shaft (22). A vehicle operated by muscle power and/or motor, comprising a drive arrangement (1) as claimed in any of the preceding claims. A method for operating a drive arrangement (1) as claimed in any of the preceding claims, comprising the steps of: determining a force (55, 56) by means of at least one bearing force sensor (51, 52), in particular both bearing force sensors (51, 52), and determining a bearing force (59) at the bearing (24) based on the force (55, 56) detected by the bearing force sensor (51, 52). The method of claim 19, further comprising the steps of: determining an output force (60) at the output element (3) based on the determined bearing force (59), and determining the rider torque applied by the rider based on the output force (60) and the motor torque of the motor (4). A method as claimed in any one of claims 19 or 20, further comprising the step of: Controlling the motor torque generated by the motor (4) depending on the determined bearing force (59).