Drive assembly of vehicle that can be operated with muscle and / or motor forces

Abstract

The invention relates to a drive assembly (1) of a vehicle (100) which can be operated with muscle and / or motor forces, in particular of an electric bicycle, comprising: an output shaft (22) which is designed to be connected to a crank (21) of a crank drive (2); a motor (4), which is designed to generate a motor torque on the output shaft (22) in order to support a driver torque exerted by a driver, a motor shaft (42) of the motor (4) being arranged coaxially to the output shaft (22); at least one bearing (24) by means of which the driven shaft (22) is supported; at least one bearing force sensor (51, 52), in particular two bearing force sensors (51, 52), which are designed to detect the force (55, 56); and a detection unit (6) which is designed to detect a bearing force (59) on the bearing (24) on the basis of the force (55, 56) detected by the bearing force sensor (51, 52).

Description

Technical Field

[0001] The present invention relates to a drive assembly for a vehicle capable of operating using muscle force and / or motor force, a vehicle including said drive assembly capable of operating using muscle force and / or motor force, and a method for operating the drive assembly. Background Technology

[0002] A drive assembly for a vehicle (e.g., an electric bicycle) that operates using muscle force and / or motor force is known, having a drive unit that generates motor torque to support the pedal force of the vehicle's rider. Typically, the motor torque is generated based on the rider torque produced by the rider's muscle force. For this purpose, it is necessary to detect the value of the currently generated rider torque, for example, using a suitable sensor system. It is also known, for example, that the force applied by the rider to the crank drive mechanism can be obtained based on the bearing force on the electric bicycle's bearings, and the drive unit can be operated based on this. Such a system is shown, for example, in DE 10 2010 001 775 A1. Summary of the Invention

[0003] In contrast, the drive assembly according to the invention, having the features of claim 1, is characterized by its ability to accurately determine the bearing forces on the bearings of a vehicle capable of operating using muscle force and / or motor force in a particularly simple and cost-effective manner. Furthermore, simple bearing force determination can be achieved, for example, regardless of the orientation of the motor (e.g., on the frame of an electric bicycle). Based on such determined bearing forces, other functions of the drive assembly can advantageously be provided efficiently and at low cost. This is achieved by a drive assembly for a vehicle capable of operating using muscle force and / or motor force, comprising a driven shaft, a motor, at least one bearing (by which the driven shaft is supported), at least one bearing force sensor (especially two bearing force sensors), and a detection unit. The driven shaft is configured for connection to a crank of a crank drive mechanism. For example, the crankshaft can therefore also be referred to as the driven shaft. The motor is configured to generate motor torque on the driven shaft, the motor torque being configured to support a driver torque applied by the driver. Here, the motor shaft of the motor is arranged coaxially with the driven shaft. The bearing is configured to support the driven shaft. Furthermore, each bearing force sensor is configured to detect a force separately. In particular, the two bearing force sensors are arranged at different circumferential positions relative to the driven shaft. The detection unit is configured to detect the bearing force on the bearing based on the force detected by the bearing force sensors, especially the force detected by the bearing force sensors.

[0004] Here, bearing force is specifically considered as the resultant force in the bearing region, which arises, for example, due to motor torque and / or driver torque. Particularly preferably, the detection unit is configured to determine the bearing force direction and magnitude based on the detected force.

[0005] Preferably, each bearing force sensor is configured to detect (especially only) force along a predetermined direction. Preferably, the two bearing force sensors are arranged at the height of the bearing in the axial direction of the driven shaft.

[0006] In other words, a drive assembly with two force sensors on a bearing is provided. Since the two bearing force sensors are arranged around the periphery, measurements of the force in two different directions are obtained. This preferably allows for the simple determination of the bearing force direction and magnitude at the current bearing force. Preferably, this determination of the bearing force direction and magnitude is based on the known relative mounting positions of the two bearing force sensors and, in particular, on the known measurement direction of the bearing force sensors (along which the corresponding force is measured).

[0007] Various types of sensors can be used as bearing force sensors, which are suitable for detecting mechanical forces acting in a predetermined direction. For example, a bearing force sensor can be configured to detect tensile and / or compressive forces.

[0008] For a particularly simple configuration, the two force sensors are preferably structurally identical.

[0009] Therefore, this drive assembly has the following advantages: namely, bearing forces on the bearing can be detected by means of a particularly simple, low-cost, and space-saving structure. Furthermore, a particularly space-saving arrangement can be provided by using a force sensor (which can be achieved, for example, through a particularly simple, lightweight structure that occupies little installation space). Moreover, particularly reliable and accurate bearing force detection can be achieved by using a force sensor (which is typically insensitive to magnetic field interference or has very low interference sensitivity).

[0010] Another advantage of the drive assembly is that the direction and magnitude of the bearing force can be precisely determined, regardless of the drive unit's mounting position on the e-bike. That is, the drive unit can be arranged on the e-bike frame in any orientation (especially regarding rotation around the pedal bearing axis). By arranging two force sensors staggered in the circumferential direction, the combined bearing force can be accurately detected in any orientation of the drive unit without adapting the force sensor arrangement to the mounting position. Here, the optimal determination of the combined bearing force can be based on a one-time calibration of a readily implementable system.

[0011] By arranging the driven shaft and motor shaft coaxially, the drive assembly also offers the advantage that the motor and driven shaft can be arranged coaxially as well. This allows for a particularly compact structural form of the drive assembly. In particular, it enables the motor (which typically occupies a considerable portion of the total installation space of the drive assembly) to be optimally placed coaxially with the driven shaft. This arrangement has a particularly advantageous effect on the compact overall structure of the drive assembly, especially when the largest gear of the transmission is arranged, for example, on the driven shaft. Thus, the remaining transmission volume can, for example, extend only slightly from the axial projection plane of the motor, where this volume can be relatively narrow and, especially, relatively centrally arranged along the axial direction, which further advantageously influences the structure of the drive assembly. Furthermore, the drive assembly is characterized by low cost due to fewer and relatively simple components. In addition, this allows for a lightweight drive assembly.

[0012] The dependent claims include preferred extensions of the invention.

[0013] Preferably, the drive assembly includes two bearings for supporting the driven shaft. That is, the driven shaft is rotatably supported by these two bearings. Here, the driven shaft has a driven interface configured for connection with a driven element. Preferably, this driven element can be a sprocket. Alternatively, preferably, another driven element can be provided, configured for connection with a transmission element to achieve torque transmission from the driven shaft to the vehicle drive wheel. Here, a bearing force sensor is arranged in the axial direction of the driven shaft at the height of the bearing arranged on the driven side. In other words, a drive assembly is provided that has a bearing force sensor in the region of the two bearings closer to the bearing where the driven element is arranged. Preferably, the driven interface is torsionally connected to the driven shaft. In particular, the driven shaft is here constructed as a single piece. By measuring the bearing force using a bearing force sensor, the following advantages are achieved: the driven shaft can therefore be constructed particularly simply and cost-effectively, while still reliably determining, for example, the force used to operate the motor.

[0014] Particularly preferably, the drive assembly further includes a bearing receiver that at least partially surrounds the bearing annularly. In particular, the bearing receiver substantially completely surrounds the bearing, preferably extending to a predetermined clearance region. The bearing receiver is specifically configured to hold the bearing. For example, the bearing receiver can be constructed as a bearing housing.

[0015] Preferably, a curved beam capable of bending in the radial direction is constructed on the bearing receiving portion, wherein at least one of the two bearing force sensors is arranged on the curved beam. In particular, the force on the curved beam is detected by means of the bearing force sensor, which can be based on the deformation of the curved beam caused by the bearing force. By using the curved beam, a particularly sensitive structure can be provided. Especially because one end of the curved beam is constructed to be freely movable, even a small bearing force can cause deformation of the curved beam, thus allowing for simple and accurate force detection. This allows for very precise determination of even small bearing forces. This provides advantages, for example, in applications such as electric bicycles, such as the ability to accurately and sensitively detect small torque values, thereby enabling, for example, particularly precise control of the motor that depends on the rider's torque.

[0016] Preferably, a portion of the bearing receiving section is constructed as a curved beam capable of bending in the radial direction. That is, the curved beam is an integrated component of the bearing receiving section itself. This provides a particularly simple structure for the assembly.

[0017] Preferably, the bearing receiving portion has a groove, particularly radial. Here, the bending beam abuts the groove. In other words, the bending beam is constructed through a portion of the bearing receiving portion such that the bearing receiving portion is constructed with a groove, wherein the freely movable end abutting the groove corresponds to the freely movable end of the bending beam. This allows for a structure that achieves the advantageous characteristics of a sensitive bending beam in a particularly simple and cost-effective manner.

[0018] Particularly preferably, the bearing receiving portion has two curved beams, and each curved beam has a bearing force sensor. Preferably, the two curved beams are constructed symmetrically with respect to the groove and preferably have the same geometric characteristics. This allows for particularly accurate detection of the bearing force. For a particularly simple and cost-effective configuration, the two bearing force sensors are preferably structurally identical. Preferably, the two bearing force sensors are arranged to point in different directions so as to detect bearing forces in different directions. Preferably, each of the two bearing force sensors is constructed and arranged to detect the force in the tangential direction relative to the driven shaft. This provides a particularly simple and space-saving assembly that can also reliably determine the bearing force direction and magnitude of the entire combined bearing force.

[0019] Preferably, the component further includes a stop that limits the radial movement of the bending beam. Specifically, the stop limits the maximum radial offset of the free end of the bending beam. This provides particularly high mechanical robustness of the component with a simple and inexpensive structure. In particular, the stop limits the deformability of the bending beam to a maximum extent. This, for example, prevents damage to the bearing receiving portion. Furthermore, it ensures robust and reliable precise positioning of the bearing by means of the bearing receiving portion. Moreover, the stop provides the advantage that the bending beam can be optimally designed to have well-defined and easily detectable deformability within a specific bearing force range. Therefore, for example, for particularly sensitive detection, slight deformability of the bending beam under low bearing forces can be provided, wherein excessive deformation is prevented by the stop.

[0020] More preferably, the stop is arranged such that, in the unloaded state of the bearing, a predetermined air gap is formed between the free end of the bending beam and the stop. Preferably, the maximum air gap in the unloaded state is 0.1 mm. Due to the air gap, the bending beam remains freely deformable until it reaches the stop, thereby enabling particularly accurate bearing force detection. The air gap can be adjusted, for example, during assembly of the assembly by corresponding alignment of the stop in a particularly simple manner.

[0021] Preferably, the drive assembly further includes a transmission arranged between the motor and the driven shaft. The transmission is configured to transmit torque between the motor shaft and the driven shaft. The motor shaft is, in particular, a component of the motor. Specifically, the transmission thus achieves the gear ratio between the motor and the driven shaft. Preferably, the driven shaft is the vehicle's crankshaft, to which the crank of a crank-driven mechanism can be connected. In particular, in this case, the pedal force applied by the vehicle driver using muscle force on the driven shaft can be obtained particularly reliably and directly. The transmission is preferably a spur gear transmission. Particularly preferably, the transmission is a two-stage transmission. Preferably, the transmission includes an intermediate shaft parallel to the motor shaft and the driven shaft, wherein the torque transmission between the motor shaft and the driven shaft is indirectly carried out via a corresponding gear pair between the intermediate shaft and the respective shaft.

[0022] Preferably, the transmission is constructed as a (preferably two-stage) spur gear transmission. That is, it has (preferably two) spur gear stages to provide a predetermined transmission ratio between the driven shaft and the crankshaft. This allows for optimal torque transmission of the drive unit in an electric bicycle while maintaining a compact and simple structure. This spur gear transmission is characterized by its exceptionally high efficiency, thereby ensuring high efficiency during the operation of the drive components.

[0023] Preferably, the transmission has an intermediate shaft arranged parallel to the driven shaft. That is, specifically, the axis of the intermediate shaft is arranged parallel to the axis of the driven shaft. The transmission is configured to transmit torque between the driven shaft and the motor shaft via the intermediate shaft. In other words, torque is transmitted from the motor shaft to the driven shaft via the intermediate shaft. This allows for a transmission with a predetermined gear ratio between the driven shaft and the motor shaft in a particularly simple manner and with few components. Furthermore, the gear ratio can be easily adjusted, for example, by proportionally scaling the intermediate shaft (especially with corresponding gears).

[0024] Particularly preferably, the transmission has a first gear and a second gear. The first gear and the second gear are respectively connected to the intermediate shaft in a torsion-resistant manner. For example, the first gear, the second gear, and the intermediate shaft can be constructed as a single integral component. This provides a simple, low-cost, and robust structure.

[0025] Preferably, the transmission has motor teeth configured on the motor shaft. In particular, a portion of the motor shaft is thus configured as a gear with motor teeth. Here, a first gear meshes with the motor teeth. This can thus further advantageously promote a compact, simple, and low-cost structure.

[0026] More preferably, the transmission has a third gear that can be torsionally connected to the driven shaft. In particular, the third gear can be additionally arranged in a manner rotatable relative to the driven shaft in a one-way clutch mode. Here, the third gear meshes with a second gear on the intermediate shaft. Specifically, torque transmission from the intermediate shaft to the driven shaft can therefore be performed via the third gear.

[0027] Particularly preferably, the drive assembly further includes a one-way clutch between the motor shaft and the driven shaft. Particularly preferably, the one-way clutch is arranged between the third gear and the crankshaft. In particular, the one-way clutch is configured to switch between a torsional connection and a relatively free-rotating connection between the third gear and the driven shaft. Preferably, the one-way clutch locks in the driving direction of the motor and disengages when the motor is stationary and the crank is operated. Alternatively or additionally, the one-way clutch can be configured for controllable operation, for example, by means of a control unit. In particular, the motor can thus be decoupled from the driven shaft by means of the one-way clutch, for example, to cut off motor support, especially when exceeding a predetermined vehicle speed.

[0028] Particularly preferably, the motor is arranged on the side of the transmission facing the driven interface. That is, the motor is arranged closer to the driven element in the axial direction of the driven shaft than the transmission. Alternatively, preferably, the motor is arranged on the side of the transmission away from the driven interface. That is, in this case, the transmission is arranged closer to the driven interface than the motor. In other words, the motor can be arranged on the right or left side relative to the vehicle's direction of travel, and the drive assembly can be mounted on the vehicle.

[0029] Preferably, the drive assembly further includes a housing. Here, the bearing receiver has a fastening region that is fixed to the housing (particularly immovably). The housing may be, for example, the housing of a motor. By fixing the bearing receiver to the housing, precise (particularly immovable) retention of the bearing relative to the housing is provided. The fastening region may, for example, be a section of the bearing receiver that corresponds in the circumferential direction to at least one-third, preferably at least half, and preferably at most three-quarters of the entire ring of the bearing receiver.

[0030] Preferably, the fastening area is secured to the housing by means of a threaded connection. In particular, the threaded connection includes a plurality of bolts distributed around the periphery of the bearing receiving portion. Alternatively or additionally preferably, the fastening area is secured to the housing by means of a welded connection and / or an adhesive connection and / or a press-fit connection. Preferably, the welded connection and / or adhesive connection are fully constructed on the fastening area to provide a particularly robust fixation.

[0031] More preferably, the assembly further includes a fastening element by means of which the fastening area is secured to the housing. That is, the bearing receiver is directly or indirectly secured to the housing by means of the fastening element. This provides a particularly simple and cost-effective way to manufacture and assemble the assembly, for example, by achieving precise alignment of the bearing receiver and the fastening element with the housing.

[0032] Particularly preferably, the fastening element is constructed as a disc, which is preferably circular. Here, the fastening element (especially together with the bearing receiving portion) is arranged in a recess in the housing. Preferably, the recess has an internal geometry corresponding to the external geometry of the fastening element. This allows for a particularly simple and cost-effective structure and assembly of the component. For example, the recess and the fastening element can have simple and precisely manufacturable geometries.

[0033] Preferably, the fastening area is formed as at least a portion of the outer periphery of the bearing receiver. That is, the bearing receiver is secured to the housing by at least a portion of the outer periphery of the bearing receiver being directly fixed to the housing (preferably by means of a press fit connection between the outer periphery and the housing). This provides a particularly simple, lightweight, and low-cost structure for the assembly. Furthermore, it provides particularly high positional accuracy for the bearing receiver and therefore the bearing, because, for example, the notch in the housing can be manufactured simply and cost-effectively with high precision. Particularly advantageously, the housing can be a drawn member, preferably a sheet metal housing in which the notch is formed by drawing.

[0034] Preferably, the bearing receiving portion is arranged in a recess in the housing. Here, the radial outer dimension of the free end of the bending beam is smaller than the inner dimension of the recess in the housing by a predetermined gap size. In other words, the radial outer dimension of the free end of the bending beam is recessed by a predetermined gap size relative to the (preferably circular) outer contour of the fastening element. Preferably, the gap size is at most 0.5 mm, more preferably at most 0.2 mm, particularly preferably at most 0.1 mm, and especially at least 0.01 mm. Thus, the housing forms a stop for the bending beam, especially eliminating the need for a separate component for the stop. Therefore, a particularly simple and inexpensive structure with fewer components can be provided. Preferably, a stop area is provided on the free end of the bending beam, wherein a gap size is provided between the stop area and the housing. Preferably, a gap larger than the gap size exists between the remaining area of ​​the bending beam and the recess, thereby enabling free movement of the bending beam, in particular, and ensuring that the bending beam abuts only in the stop area.

[0035] Preferably, the bearing force sensor has a strain gauge. For example, by mounting a strain gauge on a bending beam, its deformation can be detected particularly easily. With the strain gauge, for example, extension and / or compression can be determined, and based on this, deformation can be determined, and, for example, the mechanical force on the bending beam can also be determined.

[0036] Alternatively or additionally preferably, the bearing force sensor has a piezoelectric element. This allows for the determination of deformation and / or currently acting force on a bending beam in a particularly simple, space-saving, and cost-effective manner, similar to a strain gauge.

[0037] Alternatively or additionally preferably, the bearing force sensor has a magnetic sensor. For example, the magnetic sensor may be a Hall sensor, especially by means of which the relative positional change of a portion of a bent beam with respect to another component (e.g., a housing) can be detected directly, simply, and with particular accuracy.

[0038] Preferably, the drive assembly further includes a crank transmission mechanism with a crank. Here, the crank (especially torsional) is connected to or fixed to the driven shaft. With the aid of the crank, the driver can apply a pedal force to the driven shaft using muscle force to generate pedal torque.

[0039] Furthermore, the present invention relates to a vehicle, particularly an electric bicycle, capable of operating using muscle force and / or motor force, which includes the aforementioned drive assembly.

[0040] Furthermore, the present invention relates to a method for operating the aforementioned driver component. The method includes the following steps: - Force is determined using two bearing force sensors, and - The bearing force on the bearing is determined based on the force detected by the bearing force sensor. This method is characterized by its particularly simple and low-cost feasibility, and it can obtain accurate results of the bearing force on the bearing.

[0041] Preferably, the method further includes the step of determining the driven force on the driven element based on the bearing force (especially the bearing force direction and bearing force magnitude). Here, the driven force is considered as the force applied to the driven element by the transmission element (e.g., a bicycle chain), especially during the operation of an electric bicycle. Preferably, the driven force exists on the outer periphery of the sprocket and is in a predetermined direction along which the bicycle chain (e.g., towards the rear wheel) extends. Preferably, the determination of the driven force is additionally based on the known geometric characteristics of the drive assembly, especially the sprocket.

[0042] Further preferably, the method includes the following steps: determining the driver torque applied by the driver based on the obtained drive force and motor torque, especially when the operation of the electric bicycle including the drive assembly utilizes both muscle force and motor force. In particular, the motor torque is known based on the motor controller. Preferably, the driver torque is determined by determining the driver force, which corresponds to the portion of the drive force generated by the driver's muscle force. In particular, the relationship between the driver torque and the driver force is defined by the known geometric characteristics of the drive assembly, especially the sprocket. The driver force is preferably determined by subtracting the motor force from the total drive force, where the motor force corresponds to the force applied to the bicycle chain generated by the motor torque. Therefore, the driver torque can be determined in a particularly simple and accurate manner.

[0043] Preferably, the method further includes the step of controlling the motor torque generated by the motor according to the bearing force direction and bearing force magnitude. Particularly preferably, the motor is controlled according to the determined driver torque. That is, the motor torque for supporting the driver's pedal force is provided based on the bearing force or driver torque determined based on the determined bearing force.

[0044] Preferably, the bearing force direction and magnitude are determined based on the calibration of the drive assembly. Here, calibration is performed by measuring the ratios between corresponding forces detected by a bearing force sensor during operation of the crank drive mechanism in a predetermined calibration configuration. In the calibration configuration, the crank drive mechanism is operated using an operating force in a predetermined operating direction. Particularly preferably, calibration is performed by detecting multiple ratios in multiple different predetermined operating directions. Preferably, calibration is performed in a single operation while the vehicle is mounted on the electric bicycle. Attached Figure Description

[0045] The present invention will now be described with reference to the accompanying drawings and embodiments. In the drawings, components with the same function are identified by the same reference numerals. The following are shown: Figure 1 A simplified schematic diagram of an electric bicycle with a drive assembly according to a first embodiment of the present invention. Figure 2 : Figure 1 A cross-sectional view of the driving component. Figure 3 : Figure 1 A simplified sectional view of the driving components, used to illustrate how they function. Figure 4 : Figure 1 A 3D detailed view of the driving components. Figure 5 : Figure 1 Another detailed view of the driving component, Figure 6 : Figure 1 Another detailed view of the driving component, and Figure 7 : A cross-sectional view of the driving component according to the second embodiment of the present invention. Detailed Implementation

[0046] Figure 1 A simplified schematic diagram of an electric bicycle 100 with a drive assembly 1 according to a first embodiment of the present invention is shown. The drive assembly 1 is shown in cross-sectional view. Figure 2 The details of the driving component 1 in the first embodiment are shown in the figure. Figures 3 to 5 middle.

[0047] The drive assembly 1 has a crank transmission mechanism 2 with two cranks 21 opposite to the pedal shaft 22a. Pedals 25 are arranged on the cranks 21, through which the driver can generate driver torque on the drive assembly 1 by means of muscle force.

[0048] In addition, the crank drive mechanism 2 includes a driven shaft 22 that is torsionally connected to the crank 21, and two bearings 23 and 24 for rotatably supporting the driven shaft 22.

[0049] The drive assembly 1 also includes a driven element 3 (which is a sprocket and is torsionally connected to the driven interface 35 of the driven shaft 22) and a bicycle chain 107 (which meshes with the sprocket 3) as a transmission element.

[0050] In order to support the driver's torque with additional motor torque, the drive assembly 1 includes a motor 4, preferably an electric motor, which is supplied with electrical energy by an energy storage device (not shown) and is configured to generate motor torque.

[0051] The drive assembly 1 is preferably fastened to the bicycle frame 101 of the electric bicycle 100 by means of the housing 40.

[0052] Driven shaft 22 is supported in housing 40 by means of two bearings 23, 24. Here, housing 40 has a bearing collar 43 at the bearing 23 opposite to the driven side, and the bearing 23 is arranged in the bearing collar (see Figure 2 In particular, the bearing collar 43 is an integral part of the housing 40.

[0053] Furthermore, the drive assembly 1 includes a transmission 8. The transmission 8 is configured to transmit torque between the motor shaft 42 and the driven shaft 22 of the motor 4.

[0054] Here, the transmission 8 is arranged between the motor 4 and the driven interface 35 along the direction of the pedal shaft 22a. Relative to the travel direction A (see...) Figure 1 and 2 The driven interface 35 is therefore located on the right side of the driven shaft 22, while the motor 4 is located on the left side. In other words, excluding the left crank 21, the motor 4 forms the leftmost element of the drive assembly 1.

[0055] Transmission 8 is a two-stage spur gear transmission. That is, transmission 8 includes multiple gears configured as spur gears that mesh with each other for torque transmission. Its arrangement will be described in more detail below.

[0056] In drive assembly 1, the motor shaft 42 and driven shaft 22 of motor 4 are arranged coaxially with each other. That is, the motor shaft 42 and driven shaft 22 are each arranged to rotate about a common pedal shaft 22a. For this purpose, the motor shaft 42 of motor 4 (which is particularly torsionally connected to the rotor of motor 4) is constructed as a hollow shaft. Driven shaft 22 extends through motor shaft 42.

[0057] Driven shaft 22 and motor shaft 42 are rotatably supported relative to each other by means of bearing 48.

[0058] The motor shaft 42 of the motor 4 extends axially beyond the rotor of the motor 4. Motor teeth 84 are constructed on this extended area of ​​the motor shaft 42.

[0059] The motor teeth 84 mesh with the first gear 81 of the transmission 8. The first gear 81 is torsionally connected to the intermediate shaft 85 of the transmission 8. The intermediate shaft 85 extends along the intermediate shaft axis 80 and is arranged to be freely rotatable about the intermediate shaft axis 80.

[0060] Furthermore, the transmission 8 includes a second gear 82, which is also torsionally connected to the intermediate shaft 85. Preferably, the first gear 81, the second gear 82, and the intermediate shaft 85 can be constructed as a single integral component, or alternatively as independent interconnected components.

[0061] Furthermore, the transmission 8 includes a third gear 83, which is arranged to rotate about the pedal shaft 22a. A one-way clutch 89 is located here between the third gear 83 and the driven shaft 22, which enables the third gear 83 and the driven shaft 22 to be torsionalally connected or arranged to rotate freely relative to each other.

[0062] Therefore, the torque transmission of the motor torque generated by the motor 4 can be transmitted from the motor shaft 42 to the intermediate shaft 85 via the motor teeth 84 and the first gear 81, and then to the driven shaft 22 via the second gear 82, the third gear 83 and the corresponding switching one-way clutch 89.

[0063] Here, the coaxial arrangement of the drive assembly 1 with the motor 4 and the driven shaft 22 provides the following advantages: a particularly compact structural form of the drive assembly 1 can be achieved. The motor 4 (which geometrically forms the largest element of the drive assembly 1) can be positioned particularly advantageously relative to the driven shaft 22 through its coaxial arrangement. Furthermore, due to the special configuration of the transmission 8, the largest gear (i.e., the third gear 83) is also arranged on the driven shaft 22, thus allowing for a particularly small extension of the other components of the drive assembly 1 in the radial direction relative to the pedal shaft 22a, since the remaining transmission volume only slightly extends from the axial projection plane of the motor 4.

[0064] A circuit board 9, which is part of the drive assembly 1, is located between the rotor 4 and the transmission 8. The circuit board 9 may, for example, have 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 transmission in a direction relative to the pedal shaft 22a.

[0065] Here, the drive assembly 1 also has a connecting element 90, which may be configured, for example, as a plug for electrical connection. Here, the connecting element 90 is connected to the circuit board 9 and is arranged in the axial direction to protrude from the circuit board 9 away from the driven side.

[0066] During motor-supported operation of the electric bicycle 100, the motor torque is adjusted according to the driver torque applied by the driver. Here, the driver torque is obtained by determining the bearing force 59 on the driven-side bearing 24, as described below.

[0067] To determine the driver torque based on bearing force 59, several known mechanical and geometric relationships, as well as the motor torque known from the operation of motor 4, were used. Specifically, the following relationship was used here: on sprocket 3 (see...) Figure 3 The driving force 60 related to the propulsion of the electric bicycle 100 causes a reaction force of equal magnitude and parallel to but opposite direction on the driven side bearing 24.

[0068] Given the geometry and mechanical mechanism of the crank drive mechanism 2 and the motor torque of the motor 4, the portion of the power 60 applied by the motor 4, i.e., the motor force, can be determined. By subtracting the motor force from the total power 60, the driver force, corresponding to the portion of the power 60 applied by the driver's muscle force, can thus be easily determined. The corresponding driver torque can then be easily determined using the geometry of the drive assembly 1 as well.

[0069] Here, in the current drive assembly 1, the bearing force 59 is obtained using a simple, compact, and inexpensive structure that also allows for particularly sensitive and accurate detection. For this purpose, the drive assembly 1 has two bearing force sensors 51 and 52, which are arranged in the region of the driven-side bearing 24.

[0070] The arrangement of the two bearing force sensors 51 and 52 is shown in Figure 3 and Figure 4 In this case, the two bearing force sensors 51 and 52 are located at the height of the driven side bearing 24 in the axial direction of the driven shaft 22.

[0071] Here, each of the two bearing force sensors 51, 52 is constructed as a strain gauge and is set to detect forces 55, 56 (e.g., generated by mechanical elongation and / or compression) along exactly one predetermined direction (i.e., the radial direction relative to the pedal shaft 22a).

[0072] The two bearing force sensors 51 and 52 are connected to the detection unit 6, which determines the individual forces 55 and 56, and in addition determines all other forces and torques.

[0073] Here, bearing force sensors 51 and 52 are arranged radially outward of the bearing receiving portion 5. The bearing receiving portion 5 is a component constructed separately from the housing 40 of the motor 4, and is particularly constructed as a bearing housing. In the first embodiment, the bearing receiving portion 5 has a substantially annular external geometry.

[0074] Figure 4 The image shows a perspective view of the bearing receiving part 5.

[0075] Here, the bearing 24 is arranged in the recess of the bearing receiving portion 5, wherein, in the unloaded state, it is preferable that substantially the entire inner periphery of the bearing receiving portion 5 is in contact with the outer periphery of the bearing 24.

[0076] In addition, the bearing receiving part 5 is slotted with a groove 57 that extends completely through the entire bearing receiving part 5 in the radial direction.

[0077] The bearing receiving part 5 also has a fastening area 50, which is fastened to the housing 40. The fastening area 50 is the axial end face of the bearing receiving part 5, which is in full contact with the fastening element 50a fixed to the housing 40.

[0078] Here, the bearing receiving part 5 is arranged in the recess 65 of the housing 4 (see Figure 6 The notch 65 is circular and arranged coaxially with the pedal shaft 22a. For example, as shown... Figure 6 As can be seen, the notch 65 can be constructed in a stepped shape and extend completely through the wall of the housing 4. Here, the driven shaft 22 (in Figure 6 (Not shown in the image) The notch 65 passes completely through the housing 4.

[0079] Furthermore, assembly 10 includes a separate fastening element 50a, by means of which the bearing receiving portion 5 is secured within the housing 4. The fastening element 50a is a circular annular disc, which may be formed, for example, from metal.

[0080] The bearing receiving portion 5 is fixed to the fastening element 50a at the fastening region 50 by means of a welded connection 58b. Here, the welded connection 58b extends across the entire surface of the fastening region 50 to achieve a strong and reliable connection. Similar to the first embodiment, a small axial gap exists between the bending beam 53 of the bearing receiving portion 5 and the fastening element 50a to allow for unimpeded movement of the bending beam 53.

[0081] The fastening element 50a has an outer diameter corresponding to the inner diameter of the notch 65.

[0082] Here, the fastening element 50a is fixed immovably to the housing 40, for example by means of a press fit connection and / or by means of a welded connection and / or by means of an adhesive connection. Therefore, the bearing receiving part is indirectly fastened to the motor 4 housing 40 by means of the fastening element 50a.

[0083] Furthermore, the bearing receiving portion 5 has two curved beams 53, which are respectively arranged between the groove 57 and the fastening region 50. The curved beams 53 are configured such that they can deform in the radial direction. Figure 4 In the middle, the curved beam 53 is marked with a shaded area.

[0084] Each curved beam 53 has a flat, shaving portion 41 on its radially outer side, and corresponding bearing force sensors 51 and 52 are arranged on the shaving portion.

[0085] Here, the bearing receiving part 5 is constructed and fixed to the fastening element 50a such that the radial outer dimension 53b of the free end 53a of the bending beam 53 is smaller than the outer dimension of the fastening element 50a and therefore also smaller than the inner dimension 65a of the notch 65 by a predetermined clearance dimension 53c (see [reference]). Figure 4 This allows the inner periphery of the notch 65 to function as a stop. That is, if one of the bending beams 53 deforms radially outward due to the bearing force 59, the deformation is limited by the free end 53a of the bending beam 53 abutting against the inner periphery of the notch 65. This provides a particularly simple and lightweight structure for the drive assembly 1. Furthermore, it can therefore be manufactured particularly simply and at a low cost.

[0086] If the crank drive mechanism 2 is subjected to the force of the driver's pedal, this will induce a bearing force 59 on the bearing 24. Since the bearing 24 is held in the housing 40 of the motor 4 by means of the bearing receiver 5, the bearing force 59 acts accordingly on the bearing receiver 5. Due to the special configuration of the bearing receiver 5 having a movable bending beam 53, the bearing force 59 causes the bending beam 53 to deflect in the radial direction. This deformation can be detected by means of bearing force sensors 51, 52 configured as strain gauges.

[0087] Based on the known geometric and mechanical properties of component 10 described above, the total composite bearing force 59, i.e., the bearing force direction and bearing force magnitude, can be obtained based on the detected deformation.

[0088] The free movement of the bending beam 53 in the radial direction allows for particularly sensitive detection in the corresponding mechanical design. That is, for example, by appropriately designing the thickness of the bending beam 53 in the axial and / or radial directions, it is possible to achieve clearly measurable deformation even under small bearing forces. In particular, this allows for the high-precision detection of low torque applied by the driver.

[0089] To ensure exceptionally high precision by minimizing the deformation of the bending beam 53, the bending beam 53 is spaced apart from the fastening element 50a in the axial direction (the fastening area 50 of the bearing receiving portion 5 abuts against this fastening element). That is, in the axial direction, there is a gap between the axial end face 50b of each bending beam 53 facing the fastening element 50a and the fastening element 50a (where the end face 50a of the fastening area 50 abuts accordingly). Thus, the deformation of the bending beam 53 is not affected by friction, for example.

[0090] Furthermore, the bending beam 53 and / or bearing 24 can be configured such that a region with the lowest possible friction is formed between the radially inner side of the bending beam 53 and the radially outer side of the bearing 24, thereby, for example, avoiding or reducing measurement distortion caused by stress due to static friction.

[0091] Furthermore, the drive assembly 1 includes stops 7, which respectively limit the radial movement of each curved beam 53. Here, the stops 7 are formed by the housing 40. The stops 7 are located on the extension line of the groove 57.

[0092] In order to determine the driven force 60 acting on the bicycle chain 107 from the determined bearing force 59, and thus the driver torque as described above, it is necessary to know the chain direction 70 of the bicycle chain 107 and the relative orientation of the motor 4 with respect to each other, i.e., the mounting position of the motor 4 on the bicycle frame 101.

[0093] In order to accurately determine the power source 60 based on the bearing force 59, it is necessary to know the geometric relationship between the motor 4 and the chain direction 70.

[0094] Therefore, a one-time calibration of drive component 1 is performed. During the calibration, motor 4 does not generate motor torque.

[0095] During calibration, in the first step, the crank drive mechanism 2 can be arranged so that the crank 21 is horizontally aligned. In this first calibration configuration, exactly one crank 21 (i.e., the crank 21 pointing forward in the direction of travel) is operated with a pre-known operating force. Here, the operating force is vertical, i.e., orthogonal to the crank 21 and aligned with the chain direction 70. Thus, the entire operating force is transmitted to the bicycle chain 107. Here, the corresponding bearing force 59 corresponds to the resultant force composed of the operating force and the driven force 60.

[0096] In the second step of calibration, the crank drive mechanism 2 is arranged so that the crank 21 is vertically aligned. In this second calibration configuration, the lower crank 21 is operated using an operating force that is also vertically aligned (i.e., orthogonal to the chain direction 70 and parallel to the crank 21). In this second operating configuration, due to the corresponding alignment of the crank drive mechanism 2, the drive force 60 is zero. The operating force still induces a bearing force 59.

[0097] Based on the forces 55 and 56 detected by bearing force sensors 51 and 52 respectively in the two calibration steps, the orientation of the bearing force sensors 51 and 52 relative to the crank 21 and / or the bicycle chain 107 can be inferred from the ratio of the two forces 55 and 56. Therefore, the orientation of the drive unit relative to the bicycle chain 107 can also be determined. This determined orientation can then be used as the basis for calculating the rider torque based on the bearing force direction and magnitude of bearing force 59.

[0098] Figure 7 A cross-sectional view of the drive assembly 1 according to a second embodiment of the present invention is shown. The second embodiment substantially corresponds to the first embodiment, differing only in the alternative arrangement of the components of the drive assembly 1. In the second embodiment, the motor 4 is arranged on the driven side, i.e., between the transmission 8 and the driven interface 35. Specifically, the motor 4 is arranged between the driven-side bearing 24 and the first gear 81 of the transmission 8. That is, the motor 4 is located on the right side relative to the travel direction A. This provides an alternative geometric arrangement of the components of the drive assembly 1. In the second embodiment, the connecting element 90 on the circuit board 9 is further arranged to protrude in the direction of the driven side.

Claims

1. A drive assembly for a vehicle (100), particularly an electric bicycle, capable of operating using muscle force and / or motor force, comprising: - Driven shaft (22), the driven shaft being configured to connect to the crank (21) of the crank drive mechanism (2), - Motor (4), the motor being configured to generate motor torque on the driven shaft (22) to support driver torque applied by the driver, - Wherein, the motor shaft (42) of the motor (4) is coaxially arranged with the driven shaft (22), - At least one bearing (24), by means of which the driven shaft (22) is supported. - At least one bearing force sensor (51, 52), especially two bearing force sensors (51, 52). - Wherein, the bearing force sensors (51, 52) are configured to detect forces (55, 56), and - Detection unit (6), the detection unit is configured to detect the bearing force (59) on the bearing (24) based on the force (55, 56) detected by the bearing force sensors (51, 52).

2. The driving component according to claim 1, wherein, The two bearing force sensors (51, 52) are arranged at different circumferential positions relative to the driven shaft (22).

3. The driving component according to any one of the preceding claims, - It includes two bearings (23, 24) for supporting the driven shaft (22). - in, The driven shaft (22) has a driven interface (35) configured for connection with the driven element (3), and - Wherein, the bearing force sensor (51) is arranged in the axial direction of the driven shaft (22) at the height of the bearing (24) arranged on the driven side.

4. The drive assembly according to any one of the preceding claims further includes a bearing receiving portion (5) that at least partially surrounds the bearing (24) annularly.

5. The driving component according to claim 4, wherein, A bending beam (53) capable of bending in the radial direction is constructed on the bearing receiving part (5), wherein at least one of the bearing force sensors (51, 52) is arranged on the bending beam (53).

6. The drive assembly according to claim 4 or 5, wherein, A portion of the bearing receiving part (5) is constructed as a curved beam (53) that can be bent in the radial direction, wherein the bearing receiving part (5) has a groove (57) in particular in the radial direction, wherein the curved beam (53) is adjacent to the groove (57).

7. The drive component according to any one of claims 4 to 6, wherein, The bearing receiving part (5) has two curved beams (53), wherein one of the two bearing force sensors (51, 52) is arranged in each curved beam (53).

8. The drive assembly according to any one of claims 5 to 7, further comprising a stop (7) that limits the movement of the bending beam (53) in the radial direction.

9. The driving component according to claim 8, wherein, The stop (7) is arranged such that, in the unloaded state of the bearing (24), a predetermined air gap (70) is provided between the free end (53a) of the bending beam (53) and the stop (7).

10. The drive assembly according to any one of the preceding claims further includes a transmission (8) arranged between the motor (4) and the driven shaft (22) and configured to transmit torque between the motor shaft (42) and the driven shaft (22).

11. The driving component according to claim 10, wherein, The transmission (8) is constructed, in particular, as a two-stage spur gear transmission.

12. The drive assembly according to claim 10 or 11, wherein, The transmission (8) has an intermediate shaft (85) arranged parallel to the driven shaft (22), wherein the transmission (8) is configured to transmit torque between the motor shaft (42) and the driven shaft (22) via the intermediate shaft (85).

13. The drive assembly according to any one of claims 10 to 12, - in, The transmission (8) has a first gear (81) and a second gear (82), wherein the first gear (81) and the second gear (82) are torsionally connected to the intermediate shaft (85). - In particular, the transmission (8) has motor teeth (84) constructed on the motor shaft (42), wherein the first gear (81) meshes with the motor teeth (84). - In particular, the transmission (8) has a third gear (83) that can be torsionally connected to the driven shaft (82), wherein the third gear (83) meshes with the second gear (82).

14. The drive assembly according to any one of claims 10 to 13, further comprising a one-way clutch (89) between the motor shaft (42) and the driven shaft (22).

15. The drive assembly according to any one of claims 10 to 14, wherein, The motor (4) is arranged on the side of the transmission (8) away from the driven interface (35), or the motor (4) is arranged on the side of the transmission (8) facing the driven interface (35).

16. The driving component according to any one of the preceding claims, wherein, The bearing force sensor (51) has strain gauges and / or piezoelectric elements and / or magnetic sensors.

17. The drive assembly according to any one of the preceding claims further includes a crank transmission mechanism (2) with a crank (21), wherein, The crank (21) is connected to the driven shaft (22).

18. A vehicle capable of operating by muscle force and / or motor force, comprising a drive assembly (1) according to any of the preceding claims.

19. A method for operating a drive component (1) according to any one of the preceding claims, comprising the steps of: - The forces (55, 56) are determined by means of at least one bearing force sensor (51, 52), and especially the two bearing force sensors (51, 52), and - The bearing force (59) on the bearing (24) is determined based on the forces (55, 56) detected by the bearing force sensors (51, 52).

20. The method of claim 19, further comprising the step of: - The driven force (60) on the driven element (3) is determined based on the obtained bearing force (59), and - The driver torque applied by the driver is determined based on the motor torque of the power source (60) and the motor (4).

21. The method according to any one of claims 19 or 20, further comprising the step of: - The motor torque generated by the motor (4) is controlled according to the obtained bearing force (59).

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