Electric bicycle drive unit with torque measurement device

Abstract

The invention relates to an electric bicycle drive unit (D U ) for being arranged coaxially with a bottom bracket in a bottom bracket area of a bicycle frame. The drive unit (D U ) comprises a torque sensor device (S T ) for measuring a total rider torque (T R ), a bottom bracket axle (S B ), an electric motor device (M E ) arranged coaxially with the bottom bracket axle (S B ), an output hollow axle (S O ) for transmitting the motor torque (T M ) and the rider torque (T R ) onto a bicycle drive train, and a rider torque coupling device (D CR ) for coupling the rider torque (T R ) from the bottom bracket axle (S B ) onto the output hollow axle (S O ) and a motor torque coupling device (D CM ) for coupling the motor torque (T M ) onto the output hollow axle (S O ). The torque sensor device (S T ) is arranged in an axial area (P A ) of the drive unit defined by an output hollow axle section (S OS ), wherein the axial area (P A ) is provided for transmitting the rider torque (T R ) and the motor torque (T M ).

Description

Technical Field

[0001] This invention relates to a drive unit for an electric bicycle. Background Technology

[0002] The position or direction indicators used throughout the following description, such as “left,” “right,” “front,” “back,” “up,” and “down,” correspond to the rider’s perspective on the bicycle.

[0003] Electric-assisted mountain bikes are becoming increasingly popular. These bikes, also known as electric mountain bikes or E-MTBs for short, are categorized into "off-road," "trail," "endurance," and "downhill" types and are used for sports.

[0004] In such applications, high demands are placed on the stability, frame rigidity, and handling of electric mountain bikes. Regarding handling, the bike's center of gravity is particularly important. A high center of gravity affects cornering performance and increases the risk of tipping over during hard braking or steep downhill sections.

[0005] Of particular importance is the distance between the bicycle's center of gravity and the rear axle. The further forward the bicycle's center of gravity is in the direction of travel, the greater the risk of tipping over, and the more difficult it is for the rider to lift the front wheel, especially without drive torque assistance.

[0006] Lifting the front wheels is one of the most important driving techniques, applicable to various driving situations. This allows you to traverse larger obstacles and steps, or to climb speed bumps at high speeds.

[0007] Furthermore, in electric mountain bikes, the distance between the rear axle and the bottom bracket axle tends to increase compared to mountain bikes without an additional drive unit, because the motor also occupies structural space in the bottom bracket axle area, and thus provides less radial free space for the rear tire there.

[0008] In fully suspended bicycles, the structural space required for the bridging components between the chainstays of the rear chainstays in the bottom bracket area, typically for stability reasons, is also affected by the electric auxiliary drive unit. Depending on the movement of the rear chainstays used for the rear wheel suspension, structural space conflicts may also arise with the rotational joints of the rear wheel suspension located in the bottom bracket area.

[0009] In addition, electric mountain bikes, and more broadly, other bicycle models with electric auxiliary drive systems to assist the rider, also known as pedal bikes on the market, require the detection of the rider's input power for motor control. The motor is designed solely to support the rider's power through a suitable multiplier. For both legal and safety reasons, the motor should not function as a drive unit when no torque is applied by the rider through the pedals.

[0010] For electric mountain bikes, it is especially important to quickly and accurately measure the torque applied by the rider, as many off-road riding situations require fast reaction time and good drive adjustability.

[0011] In the market, this torque measurement method, using strain gauges and non-contact magnetostrictive torque measurement, has been largely established. To avoid the necessity of sliding contact when using strain gauges for measurement, the power supply to the strain gauge sensors is mostly achieved through induction, and the signal transmission from the sensor to the evaluation electronics is also wireless.

[0012] In mid-drive motors (currently dominant in the e-mountain bike market) that are not concentric with the bottom bracket shaft, the motor torque is transmitted from the motor shaft, parallel to the bottom bracket shaft, to the output hollow shaft of the drive unit and thus to the sprockets of the bike's drivetrain. Torque transmission from the motor to the output hollow shaft is typically achieved via a gear train or a toothed belt. In this configuration, the torque measurement device can be easily placed within the drive unit, allowing measurement of only the torque applied by the rider, independent of the current motor torque.

[0013] Therefore, the motor torque is introduced into the output hollow shaft between the rider torque measurement area and the chain link connection area, that is, relative to the torque flow downstream of the rider torque measurement, so that the rider torque measurement is not disturbed by the motor torque.

[0014] A disadvantage of this non-concentric mid-mounted motor drive unit is that the drive unit has a large extension perpendicular to the motor axis or the bottom bracket axis in at least one direction. This extension along the motor axis or bottom bracket axis is also large because the reduction gear or transmission mechanism leading to the bottom bracket axis requires structural space beyond the motor width. This results in a drive unit that is typically not compact and often has a serrated shape. Consequently, optimal integration of the drive unit into the bicycle frame is difficult to achieve.

[0015] A mid-drive motor unit arranged concentrically with the bottom bracket axle allows for a more compact design and thus better integration into the bicycle frame. Examples of this type of drive unit are known in the professional field under the name TQ HPR 120S and by document DE202014010823U1 (hereinafter referred to as DE'823). Despite its compact design, the size of this mid-drive motor still presents challenges for integration into modern electric mountain bikes. In particular, the approximately 140mm outer diameter of the drive unit's housing poses a problem, as this housing diameter can lead to structural space conflicts in bicycle frames with short chainstay lengths (especially 470mm and smaller) and in common wheel sizes (27.5 inches or 29 inches).

[0016] To ensure sufficient radial free space for the rear wheel, ideally, the outer diameter of the mid-drive motor, which is concentric with the bottom bracket axle, should not exceed 100 mm. An excessively large outer diameter of the mid-drive motor can also make it difficult to position the pivot point near the bottom bracket on a suspension-type bicycle frame, which is important for the characteristics of the rear chainstay suspension.

[0017] In the aforementioned known concentric drive units, the device used to measure rider torque largely results in a relatively large housing diameter. This known concentric drive unit uses a sensor unit supplied by NCTE AG for magnetostrictive measurement of rider torque. In this sensor unit, rider torque is measured on a specially designed torsional measuring hollow shaft surrounding the bottom support shaft.

[0018] For this purpose, the torsion measuring hollow shaft is connected to the bottom support shaft in a torque-resistant manner at one of its axial ends. At its other axial end, the torsion measuring hollow shaft is rotatably connected relative to the bottom support shaft, but is connected to the output hollow shaft of the drive unit via a free wheel in relation to the direction of rotation.

[0019] This known arrangement allows for the isolated measurement of the torque applied by the rider to the two pedals or crank arms, as well as the motor torque and possible bending moment. As mentioned earlier, the motor torque in this drive unit is introduced downstream of the torque measurement into the output hollow shaft of the drive unit only with respect to the torque flow. In this case, the device for torque measurement is located radially inside the motor and transmission.

[0020] However, this known arrangement for measuring rider torque results in a relatively large overall diameter of the drive unit, particularly due to the additional torsional measuring hollow shaft required for the measurement. This similarly increased diameter of multiple components of the drive unit, including the increased shaft diameter and correspondingly large bearing diameter, leads to a correspondingly significant increase in the weight of the drive unit. Finally, the cable routing from the torque measuring device to the electric motor controller within this drive unit is also often complex and thus contributes to the problem. Summary of the Invention

[0021] Based on the prior art, the object of the present invention is to provide an electric bicycle drive unit that overcomes the aforementioned disadvantages. In particular, in the case of a mid-mounted motor in a bicycle constructed concentrically with the bottom bracket, it should be possible to measure the rider's torque, thereby enabling a smaller radial structural dimension of the drive unit.

[0022] This objective is achieved by an electric bicycle drive unit that is arranged coaxially with the bottom bracket in the bottom bracket area of ​​the bicycle frame.

[0023] The drive unit includes a torque sensor device for measuring the total rider torque, which consists of the rider torque on the left and the rider torque on the right; a bottom support shaft; an electric motor device arranged coaxially with the bottom support shaft; an output hollow shaft for transmitting the motor torque and rider torque to the bicycle drivetrain; a rider torque coupling device for coupling the rider torque from the bottom support shaft to the output hollow shaft; and a motor torque coupling device for coupling the motor torque to the output hollow shaft.

[0024] The coupling devices for rider torque and motor torque are typically separate freewheels, such as clamping freewheels. However, for specific applications, rigid coupling devices that rotate in both directions or switching clutches can also be considered.

[0025] Depending on the implementation of the motor, this type of drive unit often includes a reduction gear mechanism for transmitting auxiliary motor torque to the bottom support shaft; however, drive units without a gear mechanism for directly driving the bottom support shaft are also known.

[0026] According to the invention, the drive unit is characterized in that a torque sensor device is arranged in the axial region of the drive unit, which is defined by and passed through a section of the output hollow shaft, wherein the axial region is passed through by not only the total rider torque but also the total motor torque during the operation of the drive unit.

[0027] In other words, this means that rider torque can be measured on the output hollow shaft using the present invention. This positioning for measuring rider torque known in the prior art for non-concentric mid-drive motors has not yet been applicable to this type of drive unit, which is concentrically constructed with the bottom bracket, because the motor or transmission output hollow shaft there, for geometric reasons, in principle surrounds the drive unit's output hollow shaft, at least in the area where only rider torque is applied and motor torque is not yet acting on the output hollow shaft. Therefore, until now, it has been impossible to directly operate on the shaft that guides the rider torque to be measured.

[0028] According to a preferred embodiment of the invention, the rider torque coupling device is arranged in the axial region and radially inside the output hollow shaft. Here, a torque sensor device is configured to detect changes in the diameter or circumferential stress of the output hollow shaft in the output hollow shaft section and / or changes in the diameter or circumferential stress of the rider torque coupling device in the region of the output hollow shaft section.

[0029] For this purpose, strain gauges rotating together on the outer diameter of the output hollow shaft can be arranged in the region of the output hollow shaft section, or the circumferential stress of the output hollow shaft can be determined by magnetostriction or magnetoelasticity, i.e., the material stress along the circumferential direction of the output hollow shaft. In cases where the diameter change or circumferential stress of the rider torque coupling device is determined by the output hollow shaft instead of the diameter change or circumferential stress of the output hollow shaft, the output hollow shaft can be made of a material permeable to magnetic lines of force or magnetic fields, at least in the output hollow shaft section, such as aluminum, and particularly constructed with thin walls.

[0030] This implementation utilizes the fact that the rider torque coupling device, especially when it is constructed as a freewheel, such as a clamping roller freewheel or more generally a clamping freewheel, expands radially elastically when subjected to rider torque loading. This expansion is also transmitted to the output hollow shaft section within which the rider torque coupling device is located. This radial elastic expansion and the associated increase in diameter result in circumferential material stresses in the rider torque coupling device and in the output hollow shaft section.

[0031] These circumferentially extending material stresses are superimposed on the shear stresses caused by the motor torque in the output hollow shaft section. However, due to the principle of superposition in physics, the tensile and shear stresses extending in the circumferential direction do not affect each other, at least not in the first order or in the first approximation, but are independent of each other. In this way, the rider's total torque in the output hollow shaft section can be measured independently of the motor torque.

[0032] According to another preferred embodiment of the invention, the drive unit includes a motor output hollow shaft disposed between the motor assembly and the motor torque coupling device. This drive assembly or motor output hollow shaft is coaxially and radially disposed outside the output hollow shaft section in the axial region and is configured to be permeable to magnetic fields. A torque sensor device is configured for non-contact detection of the rider's total torque in the output hollow shaft section. To measure the rider's total torque as accurately as possible, the motor output hollow shaft is preferably constructed to be as thin-walled as possible in the axial region.

[0033] Therefore, in this embodiment, the motor torque and the rider torque pass through the axial region separately, more precisely by means of the motor output hollow shaft, and the rider torque is determined by non-contactly measuring the material stress passing through the motor output hollow shaft in the output hollow shaft section.

[0034] Here, the material stress in the output hollow shaft section can be measured either by a non-contact strain gauge device or by a non-contact magnetostrictive measurement.

[0035] According to another embodiment, the rider's total torque is measured by the difference between the total torque measured by a torque sensor device in the output hollow shaft section and the motor torque. The motor torque can be measured separately in the motor. However, preferably, the motor torque is calculated based on the current intensity or power absorbed by the motor and then subtracted from the measured total torque.

[0036] In principle, this invention is independent of the structural design of the motor device, that is, independent of the type of motor, and independent of the speed reduction transmission mechanism and its structural design contained in the motor device.

[0037] According to another embodiment of the invention, the motor device preferably includes a cycloidal drive or a strain wave drive, the latter also known as a harmonic drive. Such a drive has particular advantages: achieving a very high transmission ratio in only one stage, while possessing an extremely compact size and high torque load capacity. Attached Figure Description

[0038] Embodiments of the present invention will now be described exemplarily with reference to the accompanying drawings.

[0039] in:

[0040] Figure 1 A side view of an electric mountain bike according to the prior art is shown from the drive side.

[0041] Figure 2 : corresponding to Figure 1 The views and schematic diagrams show an electric mountain bike having one embodiment of a drive unit according to the present disclosure;

[0042] Figure 3 This diagram shows a longitudinal cross-sectional view illustrating the working principle of a coaxial drive unit for a bottom support, as known from the prior art.

[0043] Figure 4 : corresponding to Figure 3 The schematic diagram illustrates the working principle of a drive unit similar to the first and fifth embodiments below according to this disclosure;

[0044] Figure 5 : An exploded cross-sectional perspective view of the first embodiment is shown;

[0045] Figure 6 : Shows according to Figure 5 A longitudinal sectional view of the implementation method;

[0046] Figure 7 A longitudinal sectional view of the second embodiment is shown.

[0047] Figure 8 A longitudinal sectional view of the third embodiment is shown.

[0048] Figures 9A-9C A longitudinal sectional view of the fourth embodiment is shown. Detailed Implementation

[0049] Figure 1 A mountain bike with an electric auxiliary drive system according to the prior art is shown. The mountain bike has a frame 1, which has a spring-loaded rear chainstay 2. The drivetrain 3 of the mountain bike includes a bottom bracket axle S. B Bottom support assembly A B sprocket R C 4. Rear derailleur, located on rear wheel axle A R The multi-stage pinion flywheel 5 and the transmission chain 6 are mounted on it.

[0050] In addition, mountain bikes are equipped with an electric drive unit (D) to assist the rider. U The electric drive unit is configured as a so-called mid-mounted motor, that is, it is arranged in the bottom support assembly A. B The area includes an electric motor device M according to the prior art. EA Drive unit D U Equipped with energy storage device S E .

[0051] Used to drive drive unit D U Motor device M E Energy storage device S E Arranged on the down tube T of the bicycle frame 1 L In the middle. Due to the motor device M EA and energy storage device SE Arranged on the bottom support shaft S B In front or above, thus forming Figure 1 The driving unit D shown U and energy storage device S E The common center of gravity C G Obviously, the bicycle's center of gravity shifts relatively high and forward due to this component, which has a considerable mass, resulting in the disadvantages described in the introduction of the instruction manual, especially in terms of handling and riding safety.

[0052] Figure 2 A schematic diagram illustrates a drive unit D according to the present disclosure. U The main components and parts of the electric mountain bike according to the implementation method.

[0053] For the sake of simplicity and clarity, in addition to the schematic diagrams of most components, Figure 2 According to (not shown in the text) Figure 1 The drivetrain 3 and the wheel suspension components located in front of the longitudinal midplane of the bicycle.

[0054] The motor housing H M And thus also fixed to the motor housing H M On the energy storage device S E Battery casing H B Here, at the two frame interfaces or fixed axle F M1 and F M2 It is connected to or can be connected to the vehicle frame 1. Energy storage device S E or battery casing H B With the help of two fixed points or a fixed axis F B1 and F B2 With motor housing H M connect.

[0055] This eliminates the need to base on... Figure 1 The energy storage device S required in the prior art E An additional fixing interface between the bicycle frame 1 and the frame reduces complexity, weight, and cost. Figure 2 An alternative to the scheme shown is the energy storage device S. E It can also be used with drive unit D U The other components are arranged together in a single common housing.

[0056] and Figure 1 In contrast to drive units that are non-coaxially constructed and arranged, the coaxial drive unit D in a bicycle... U Center of mass C GIt is significantly lower and significantly further back, thereby mitigating the shortcomings described in the introduction of the manual, especially those related to handling and driving safety.

[0057] In addition, using the bottom support shaft S B Drive unit D constructed coaxially U (wherein, therefore the motor shaft S) M The longitudinal axis and the bottom support axis S B (The longitudinal axis coincides) to realize the drive unit D U Its particularly compact design, thus relative to, for example, according to Figure 1 The non-coaxially constructed drive unit allows the structural space freed up in the bottom support region D1 to be used for other components, particularly in the current embodiment for energy storage devices S having battery cells C contained therein. E And in addition, for pivot bearing P S Or rear lower control arm A S The connection.

[0058] In addition, the chain support length or rear wheel axle A R and bottom bracket shaft S B The spacing between them is due to the very compact coaxial drive unit D, especially in terms of diameter. U It is advantageous to keep it shorter and to have sufficient radial free space in the bottom support area D1 for the rear tire.

[0059] Figure 3 This illustrates a motor device M, known from the prior art, which typically includes a transmission mechanism. EB The bottom bracket coaxial drive unit D U A schematic diagram of the longitudinal section of an example. Figure 3 The figure shown in the figure is particularly useful for measuring rider torque T. R Its operating principle is, for example, consistent with the drive unit known from DE'823. The motor and transmission are in... Figure 3 It is not shown in detail, but rather through point-like area MEBs, see Figures 15, 22, 26, 31 and 39 of E'823.

[0060] It can be seen that the known driving unit D U To measure the rider's total torque T R And the hollow shaft S, which especially needs to be torsion measured, H The rider's total torque is the torque T applied by the rider to the left pedal crank. RL and the torque T applied by the rider to the right pedal crank RR Composition. Therefore, the rider's total torque T R Guided by reference to the attached diagram, on the right side and bottom support axis S BFixed connection to torsion measurement hollow shaft S H Among them, the rider's total torque T R For example, by means of radial arrangement on the torsion measuring hollow shaft S H External torque sensor S T Non-contact measurement. Subsequently, the rider's total torque T... R By constructing it as a freewheel D CR The rider torque input coupling device is guided to the drive unit D U The output hollow shaft S0.

[0061] On the output hollow shaft S0, the rider's total torque T R Then, via the same structure as flywheel D, CM The motor torque input coupling device is combined into a total driving torque T. T Total driving torque T T via the output hollow shaft S O axial region P A Output hollow shaft section S OS Conducted to (not shown) sprocket R C This is then transmitted to the bicycle's drivetrain 3.

[0062] exist Figure 3 It can be easily seen from this that the known driving unit D U It has a large radial diameter and requires a relatively large overall structural space, especially for the torsion measurement hollow shaft S, which is particularly needed for torque measurement. H And due to the torsion measurement of hollow shaft S H The other component sensor device S is arranged coaxially. T Flywheel D CR and D CM And motor unit M with motor and reduction gear transmission device EB As described in the introduction to this disclosure.

[0063] Unlike this, Figure 4 To correspond to Figure 3 The schematic diagram illustrates the working principle of the drive unit according to this disclosure, which is similar to the first and fifth embodiments described below.

[0064] First, we can see that according to Figure 3 According to the existing technology, the driving unit D U Motor device M EB The outline is drawn again with dashed lines. It can be seen from this that the driving unit D according to this disclosure is used. U It achieves a very large saving in structural space.

[0065] Such as combination Figure 4 According to Figure 3 As shown in the prior art, the solution according to this disclosure allows for the complete elimination of the need for... Figure 3 Torsion measurement of hollow shaft S H In the prior art, a torsional measuring hollow shaft S is required (and is typically relatively long). H Because the torque is measured there by the torsion of the hollow shaft S H This is achieved through rotational torsional deformation, where the corresponding torsional stress, i.e., in the torsion measurement of the hollow shaft S, is... H The shear stress extending in the circumferential direction is measured by coaxially surrounding the hollow shaft S for torsion measurement. H Sensor device S T To measure, and then determine the rider's total torque T. S Therefore, the rider's torque T S and motor torque T M Only then can it be on another axis, in the drive unit D U The output hollow shaft S0 is merged.

[0066] It can be seen that this method, commonly used in existing technologies for measuring rider torque T, R The method resulted in: at the bottom support shaft S B The middle region requires three coaxially nested hollow shafts (bottom support shaft S). B (Not included): First, the torsion measurement of the hollow shaft S H Secondly, the hollow shaft S for torsion measurement H Coaxially arranged to house the sensor device S T The axis, and as the axis S arranged on the bottom support B The third axis in the same axial region, and finally the motor shaft S. M .

[0067] if Figure 3 Even though it is merely a schematic and not a scaled-down diagram, this still clearly indicates that the drive unit D... U The relatively large diameter. Specifically, it consists of three coaxial hollow shafts S. H S T and S M The significant structural space occupied in the radial direction is no longer available for the motor unit M. EB The rotor / stator and transmission mechanism. Therefore, the motor unit M E It must be offset radially outward and / or axially, which correspondingly results in an overall decrease in the drive unit D. U The length and / or outer diameter are significantly increased.

[0068] This can also be seen from Figures 15, 22, 26, 31, and 39 of DE'823. In Figure 15 of DE'823, reference numeral 140 indicates the torsion hollow shaft S. H (This is referred to as the measuring axis), and reference numeral 184 indicates the sensor device S. T (This is referred to as the coil frame), and reference numeral 174 indicates the motor shaft S. M (This is referred to here as the support shaft or rotor shaft). In the other figures of DE'823, these components are not labeled, but they are equally clearly visible.

[0069] According to Figure 4 The driving unit D U In this implementation method, the hollow shaft S for torsion measurement can be omitted. H and sensor device S T Two mutually nested axes, because according to this disclosure, a hollow output axis S can be used. O The same section S OS axial region P A Measuring rider torque T S The motor torque is also guided through this axial region.

[0070] According to Figures 4 to 6 and Figures 9A to 9C In this implementation, this is achieved as follows: the rider torque T R Guided through the axial region P A Radial freewheel D in CR The axial region is related to the output hollow shaft S O Segment S OS Consistent, in which the radial freewheel D CR When loading rider torque T R When the output hollow shaft S is generated outwards. O The radial force on the output hollow shaft S O It widens radially outward.

[0071] By outputting the hollow shaft S O In its section S OS This radial widening in the output hollow shaft S O Material stress is generated in the process and extends along the circumferential direction. This material stress is generated by the surrounding hollow output shaft S. O Segment S OS Sensor device S T Non-contact measurement is preferred. This is achieved by detecting the output hollow shaft S. O The radial flywheel D CR Induced circumferential stress to measure rider torque T R In fact, it will not be affected by the same flow through the output hollow shaft S.O The same section S OS Motor torque T M The effect may be significant distortion because of the motor torque T M Only on the output hollow shaft S O Segment S OS Shear stress is generated along the circumferential direction.

[0072] From the motor torque T M Output hollow shaft S O Segment S OS The shear stress caused by the rider's torque T R Also in section S OS The circumferential stresses induced by the torque extend in mutually perpendicular spatial directions, and are therefore independent of each other at least in the first order or approximation based on the principle of physical superposition, which in turn affects the rider's torque T. R The required accuracy for the measurement is usually sufficient. However, higher accuracy can be achieved by either measuring the motor torque T in the motor itself. M Either calculate the motor torque T from the motor current. M Then, the corresponding correction factor is applied to the rider torque T. R On the measured values.

[0073] In other words, based on Figures 4 to 6 and Figures 9A to 9C In the implementation method, the output hollow shaft S O It can also be used to measure hollow shafts, thus completely eliminating the need for the torsion hollow measuring shaft S required in the prior art. H Because the drive unit D, which is usually located in the drive unit, has been eliminated. U Measurement of hollow shaft S in the axial middle region H It also eliminated the sensor device S, which is usually in the form of a hollow shaft. T Arranged in drive unit D U The necessity of this axial intermediate region. Instead, the sensor device S T It can be axially away from the motor unit M E Ground arrangement on output hollow shaft S O Segment S OS In the middle, this comes from Figure 4 It is very clearly visible in the middle.

[0074] With the cancellation of the basis Figure 3 Torsional hollow shaft S H With the sensor device S T From drive unit D U The axial middle region is moved out, and the rider torque T is measured directly in the output hollow shaft S0. RIt is also possible that, with the help of axial flywheel D CMA Motor torque T M Introduced into the output hollow shaft, as this is based on Figure 4 and Figures 9A to 9C As implemented in the above-mentioned methods.

[0075] Especially in Figure 4 As is clearly visible in the diagram, the torsion measurement hollow shaft S implemented by this disclosure H The omission of the sensor device S and the similar implementation T The significant change in positioning leads to a substantial reduction in the structural space required for the sensor device. Therefore, according to Figure 4 Motor device M E It can be compared to the drive unit D known from the prior art. U Motor device M in EA (See according to) Figure 3 Motor device M EA In Figure 4 The outline shown in the dashed line is constructed much more compactly.

[0076] Therefore, based on this disclosure, the electric bicycle drive unit D U In particular, it can be a coaxial structure, the electric bicycle drive unit D U It can be constructed to be significantly more compact and lighter than drive units known from the prior art.

[0077] Figure 5 The drive unit D according to this disclosure is shown. U An exploded cross-sectional perspective view of the first embodiment. Here, only the drive housing H is shown relative to the other components. D Shown separately in exploded view, so all other components are in their designated positions. All bearing assemblies or support parts are indicated by reference numeral B.

[0078] It can be seen that the motor device M E It includes motors shown only schematically. M And in this configuration, it is a cycloidal transmission mechanism G C The speed reduction transmission mechanism. Cycloidal transmission device G C Includes two cycloidal wheels W C The cycloidal wheel is supported by a bearing assembly B, such as ball bearings, on two eccentrically and rotationally phase-shifted locations on the motor shaft S. M On the bearing housing F E Above. The cycloidal wheel W C It has cycloidal teeth or cams along its outer periphery, which are constructed in accordance with their shape. Figure 5 The wavy teeth (not shown) are in the driver housing H Dinternal tooth region S i In the middle meshing, the internal tooth region S i The number of teeth is typically greater than that of a cycloidal gear W. C The number of teeth is greater than 1. Therefore, for this cycloidal transmission mechanism G... C Typical very high transmission ratio.

[0079] Because the aforementioned gear ratio is relative to the cycloidal wheel W, which rotates very slowly around its own axis relative to the motor speed. C via transmission pin P T The rotary motion is transmitted to the driven flange F O Driven flange F O The rotation is then transmitted via the motor freewheel D CM Guided to drive unit D U The output hollow shaft S0.

[0080] via the bottom support shaft S B The imported rider torque is transmitted through the rider freewheel D. CR This torque is also transmitted to the output hollow shaft S0. The combined torque of the rider and the motor is then used as the total torque T. T Guided to sprocket R C It is then directed from there into the bicycle's drivetrain 3.

[0081] Figure 6 It shows according to Figure 5 A longitudinal sectional view of the drive unit. Besides... Figure 5 The components or parts shown in the diagram, Figure 6 The torque T of the rider on the left is also shown. RL Right-side rider torque T RR and motor torque T M The flow path is also shown in the drive unit D. U During operation, it is not only determined by the rider's total torque T R Moreover, the total motor torque T M The axial region P through which it flows A .

[0082] However, due to the torque sensor device S T In the axial region P A The arrangement in the middle can be independently, and at least in the first approximation, unaffected by the motor torque T. M The influence of measuring the rider's total torque T R In this embodiment, the rider torque coupling device, i.e., the one currently used for the rider torque T R Freewheel D CR It is also located in this axial region.

[0083] For this measurement, the sensor device S...T For the output hollow shaft S O In the output hollow shaft section S OS Radial deformation in the region or the resulting radial deformation along the output hollow shaft section S OS The sensor device measures the material stress extending in the circumferential direction, and measures the torque T of the guiding rider. RL or T RR By, for example, a clamping roller or, more generally, a clamping freewheel D. CR The clamping roller freewheel D appears when the rider torque coupling device is used. CR The diameter was widened for measurement.

[0084] In other words, in this embodiment, in the clamping free wheel D CR The measurement output of the hollow shaft section S in the region OS The circumferential stress at the outer diameter. The material stress extending in the circumferential direction is related to the rider's torque T. R Proportional, making the sensor device S T It can be based on the actual rider torque T R Calibration is performed by the manufacturer.

[0085] In the output hollow shaft section S OS The same phenomenon also occurs in [the context of] the freewheel D via the motor. CM Import to output hollow shaft S O And through the output hollow shaft S O Guided motor torque T M The resulting torsional or shear stress, based on the principle of physical superposition, does not cause the rider's torque T to decrease. R The measured values ​​are distorted, at least not in the first order or in the first approximation. Furthermore, the distortion can be based on the torsional or shear stress caused by the motor torque, using the output hollow shaft S. O The corresponding dimensions are used to maintain the elastic deformation in relation to the free wheel D via the clamping element. CR The output hollow shaft section S is realized OS The significant radial expansion is compared to a negligible low level.

[0086] Through sensor device S T Targeted measurement of circumferential stress alone can further improve rider torque T. R The measurement accuracy or its relationship with the motor torque T M Isolation. For measurements using strain gauges, the strain gauges are arranged and oriented circumferentially in the output hollow shaft section S. OS This makes the shear stress caused by torsion almost negligible in the measurement. Equivalently, through the sensor device S... TThe introduction of a corresponding magnetic field can optimize measurement accuracy in variant schemes employing magnetostrictive measurement.

[0087] In summary, in this embodiment, the output hollow shaft section S OS The material deformation direction is therefore in the axial region P A The accelerator torque T is used and distinguished from the sensor device so that it can be measured during the measurement. R With motor torque T M isolation.

[0088] In order to further improve the rider torque T measured in this way R The accuracy can be determined approximately based on the electrical power absorbed by motor M or based on the operating point of motor M (motor torque depends on factors such as current, voltage, speed, and temperature), in order to correct for errors due to motor torque T. M The rider torque T caused by shear stress R Possible distortions in the measured values, but only at higher orders.

[0089] In sensor device S T and drive housing H D The radially identifiable free space between them can be used for other components, such as for a speed reduction gear G. C Components used in electronic components such as motor controllers and battery controllers, or in energy storage devices.

[0090] Figure 7 The drive unit D is shown in longitudinal section. U The second embodiment. In this embodiment, the rider torque T R The measurement also occurs in the axial region P of the output hollow shaft SO. A This is carried out in the output hollow shaft section S. OS In accordance with... Figure 5 and Figure 6 The implementation methods differ, depending on... Figure 7 In the implementation method, the motor torque T M Physically related to the rider's torque T R Separately guided through axial region P A .

[0091] Therefore, according to Figure 7 The driving unit D U Including the arrangement in the motor unit M E Motor torque coupling device D CM The motor driven hollow shaft S between OM Motor driven hollow shaft S OM In the axial region P A Middle and output hollow shaft section S OSCoaxial arrangement and in the output hollow shaft section S OS The radially outer arrangement is configured to be permeable to magnetic fields. Motor driven hollow shaft S OM For the axial region P A The magnetic field in the middle can be achieved, for example, by the following method: the motor driven hollow shaft S OM At least in the axial region P A It is made of a paramagnetic material, such as aluminum, and preferably has a relatively small wall thickness.

[0092] The paramagnetic and preferably thin-walled section S of the motor driven hollow shaft OM The dimensions are determined in this way, so that in the axial region P A There exists a magnetostrictive sensor S T Sufficient axial structural space. In this way, it is possible to use the sensor device S T Driven by a motor, the hollow shaft S OM Non-contact measurement in the output hollow shaft section S OS The torque T of the rider alone is the only factor in the torque. R The torque generated.

[0093] Therefore, downstream of the torque measurement (towards the sprocket R) C (in the direction) only through the motor freewheel D CM Motor torque T M It is introduced onto the output hollow shaft S0. Therefore, in this way, it can be connected to the motor torque T. M Measuring rider torque T in complete isolation R Torque measurement on the output hollow shaft S0 can be performed in this arrangement on the rider freewheel D. CR In the axial region or in the axial region S0 of the output hollow shaft S0, which is fully or mainly subjected to torsional loading only. OS Measurement in the middle.

[0094] Figure 8 The drive unit D is shown in longitudinal section. U The third embodiment. In this embodiment, the rider torque T R and motor torque T M And through the free wheel D CR Or Freewheel D CM Introduced into the output hollow shaft S O In this embodiment, by means of sensor device S T In the output hollow shaft section S OS Torque measurement is performed in the region where, in this embodiment, the output hollow shaft section is measured by the total torque T. T , that is, the torque T of the rider R and motor torque TM The sum of all flows through.

[0095] In order to derive information about the rider torque T used for motor control from this measurement R A suitable signal is used to measure the motor torque T, preferably in real time or over a very short time interval. M And from the total torque T measured separately T Subtract from the middle.

[0096] To save structural space and cost, it is preferable not to directly measure the motor torque T. M Instead, it is calculated based on the electrical power absorbed by the motor. Rider torque T R The accuracy of the determination is due to the calculation and subtraction of the motor torque T. M While slightly reduced, this can be easily achieved in the output hollow shaft section S. OS Torque measurements in the region are at least partially compensated again.

[0097] This arrangement also enables particularly low-cost manufacturing, thereby achieving high rider torque T R A smaller compromise in terms of measurement accuracy.

[0098] Figures 9A to 9C According to Figure 9B sectional view and according to Figure 9B The enlarged partial view shows the drive unit D according to the present disclosure. U The fourth embodiment, wherein, in Figure 9A The cross-sectional orientation and viewing direction are given in the text.

[0099] According to Figures 5 to 7 The implementation methods differ, and the driving unit D U exist Figures 9A to 9C As shown in the diagram, it is installed into bicycle frame 1, similar to... Figure 2 As illustrated in the diagram. Furthermore, in Figures 9A to 9C According to China Figure 1 Or, the viewing direction on the cross-section of the bicycle (or 2) extends from back to front, therefore the sprocket RC is... Figure 9B and 9C The attached diagram is located on the right side of the illustration.

[0100] Conversely, the sprocket RC is Figures 3 to 7 The diagram is located on the left, and correspondingly, it is based on... Figure 1 Or 2 bicycles, facing according to Figures 3 to 7 The observation direction of the corresponding section extends from front to back. In other words, this means that, according to Figure 9B and 9C The diagram is relative to Figures 3 to 7The diagram is viewed in a mirror image.

[0101] according to Figures 9A to 9C The fourth embodiment differs from the one based on the working principle of torque measurement and therefore on the force flow. Figures 4 to 6 This is closely related to the first implementation method.

[0102] Figure 9B and 9C The drive unit D is shown in longitudinal section. U The torque T of the rider on the left RL The right-hand rider torque T RR and motor torque T M The variation curves are again shown using correspondingly different dashed lines. Furthermore, the axial region P is shown again. A In drive unit D U During operation, the total torque of the entire rider T R and the total motor torque T M All flow through this axial region.

[0103] As in Figure 5 Or like in 5, in Figure 9B Or, in 9C, you can see the motor device M. E Here is the motor stator M S Motor rotor M R and motor shaft S M .

[0104] Motor shaft S M Acting on the cycloidal transmission device G C The cycloidal transmission device is connected to the motor shaft S M Together, it includes the rotating eccentric bearing housing F E 、and the internal tooth region S i Meshing, externally geared cycloidal wheel W C In addition, there is the transmission pin P. T and driven flange F O .

[0105] Due to the high transmission ratio range determined by the system, the single-stage cycloidal transmission device G... C Sufficient to move the motor rotor M R The relatively high rotational speed must be reduced to the sprocket R on the bicycle drivetrain 3. C At relatively low speeds.

[0106] Figure 9C by Figure 9B The enlarged partial view particularly shows the axial region P. A In this embodiment, in the drive unit D U During operation, not only the total torque of the rider T RMoreover, the total motor torque T M It flows through this axial region.

[0107] exist Figure 9C From left to right, follow the motor torque T M and the rider's total torque T R The force flow can first be seen in the motor freewheel D. CMA It is shown only as a schematic block diagram here, and in particular, components such as the freewheel are not shown, and its specific implementation is not meaningful to the subject matter of this disclosure. However, preferably, the motor freewheel D CMA It is an axial freewheel, which helps to design the drive unit D in a particularly space-saving manner. U See also based on Figure 4 It also has an axial freewheel D CMA Implementation methods and basis Figure 3 Existing technology.

[0108] According to Figures 9A to 9C In the implementation of the method, such as in accordance with Figures 4 to 6 As in the implementation method, the motor freewheel D CM Cycloidal transmission device G C The output torque is obtained from the driven flange F of the cycloidal transmission device. O Guided to the output hollow shaft section S OS Above, the hollow output shaft section defines the axial region P. A A torque sensor device S is arranged in this axial region. T .

[0109] Here, firstly, as in accordance with Figure 3 As in existing technologies, the rider's total torque T R and motor torque T M Together they guide through the axial region P A and the output hollow shaft section S arranged there OS .

[0110] However, according to this disclosure, and according to... Figure 3 Unlike existing technologies, the rider's total torque T R The size is directly in the axial region P A Neutralization in the output hollow shaft section S arranged there OS The total torque T of the rider was measured in the middle. R and motor torque T M All flow through the hollow output shaft section.

[0111] This is especially true in Figure 9C It is clearly visible in the middle. There, the rider's total torque T R and motor torque T M Output hollow shaft SO Output hollow shaft section S OS The bundles are concentrated and flow together through the output hollow shaft S. O The output hollow shaft section S OS In this embodiment, it is achieved through bearing sleeve B. B For example, by means of a sliding bearing sleeve, mounted on sprocket R C The area on the right, at the bottom support axis S B superior.

[0112] According to Figures 9A to 9C In the currently considered implementation, the rider's total torque T R This is also related to the motor torque T. M The motor torque was measured independently in the output hollow shaft section S. OS The total torque T flowing through the middle and the rider R The same output hollow shaft S O The cross-section of the material.

[0113] This is in accordance with Figures 4 to 6 In a similar implementation, the rider torque input coupling device D is used in the following manner. CR (i.e., rider torque freewheel, even when the rider is not operating the pedals and the bottom bracket axle S) B Therefore, when stationary, the rider's torque freewheel also allows the motor to drive the output hollow shaft, thereby driving the bicycle transmission system 3) arranged in the axial region P. A In the middle and radial directions on the output hollow shaft S O Within, and for example constructed as a clamping element freewheel D CR .

[0114] Once the rider passes the pedal crank C P The rider's torque T RR or T RL Apply to the bottom support shaft S B Up, then pedal crank C P and bottom bracket shaft S B Start rotating, thus activating the clamping freewheel D CR And it begins to close.

[0115] Clamping free wheel D CR The closure always occurs at the bottom support shaft S. B Compared to the driven flange F of the motor or transmission mechanism O It rotates faster, and therefore more efficiently than the output hollow shaft S. O This is done when rotating faster. However, the bottom support shaft S BThis difference in rotational speed between the output hollow shaft S0 and the output hollow shaft S0 is always a prerequisite for the rider's torque to be introduced into the powertrain 3, and it always exists when the rider actively or with a certain force pedals.

[0116] Based on closed clamping free wheel D CR Then the rider's total torque T R Guided by clamping freewheel D CR The clamping of the freewheel body between the inner and outer rings of the freewheel generates a significant radial force within the clamping freewheel. These forces are transmitted to the output hollow shaft section S. OS This causes the hollow output shaft section to widen radially elastically. This, in turn, induces material stress in the hollow output shaft section S. OS It extends in the circumferential direction.

[0117] In the output hollow shaft section S OS Material stress extending in the circumferential direction Figure 9C The symbol T, which points to an arrow in the plane of the diagram, is used in the diagram. C To represent the stress T of these materials. C The measurement is performed by the sensor device S T It is preferably performed without contact. In this way, and based on the material stress T extending in the circumferential direction... C With the motor torque T M In the output hollow shaft section S OS The above-mentioned physical superposition principle between the shear stresses generated in the process can be verified by the sensor device S. T Determine rider torque T with high precision R .

[0118] As in Figure 9B Neutralization Figure 9C As can be seen in the enlarged partial view, the sensor device S T Including coil frame B C In the illustrated embodiment, the coil holder carries three measuring coils C. W1 C W2 and C W3 .

[0119] exist Figure 9B and 9C The sensor device S shown in the figure T The structure, operating principle, and evaluation electronics are not the subject of this disclosure, but rather the subject of unpublished patent application US 63 / 286,370 (US'370). The disclosure of US'370 is hereby incorporated by reference into the disclosure of this patent application, thereby disclosing a sensor device S according to the disclosure of US'370.T The sensor device S described in this disclosure T In the electric bicycle drive unit D U The combination of features, implementation methods and advantages of the arrangement.

[0120] In the three measuring coils C W1 C W2 and C W3 In the middle, the measuring coil C on the left, which is related to the attached figure. W1 Used to detect the output hollow shaft section S OS The change in the magnetic field is used to infer the output hollow shaft section S. OS Material stress in the figure. The average measurement coil C is associated with the attached figure. W2 Used to excite the output hollow shaft section S OS Eddy currents and / or magnetic fields within the material. Based on the principle of magnetoelasticity, in the case of ferromagnetic materials, such as the output hollow shaft S preferably made of steel... O In this case, there is a correlation between mechanical and magnetic properties. This correlation exists between material load and associated geometric deformation (here, the output hollow shaft segment S). OS In the case of radial widening, the output hollow shaft section S OS Its magnetic properties change.

[0121] The left-hand measuring coil C, which is related to the attached figure, W1 The detection is performed by the intermediate measuring coil C associated with the attached figure. W2 Induced current or magnetic field in the output hollow shaft section S OS The changes in the output hollow shaft section are caused by voltage or deformation. The measuring coil C on the right side of the attached diagram... W3 Temperature compensation is used for measurement. This is necessary because in the sensor device S T Temperature fluctuations on the order of 100K may occur in the region, especially due to motors M and M S M R Fever.

[0122] Particularly advantageous is that the measuring coils CW1, CW2, and CW3, if in Figure 9B and 9C As can be seen, it is constructed in the form of windings extending circumferentially. In this way, the coil frame B can be manufactured very simply and inexpensively. C And sensor device S T It can also withstand high loads and associated vibration or temperature loads. Measuring coil C W1 C W2 C W3The details of the manufacture and design of the components, as well as their circuitry and evaluation electronics, are the subject of the aforementioned U.S. application US'370, the disclosure of which is incorporated herein by reference.

[0123] Output hollow shaft section S OS The illustrated embodiment has two surrounding grooves G. R1 and G R2 One or two grooves G R1 and G R2 The presence and / or selection of size and geometry affect the sensor device S T The characteristic curves can be measured, especially through one or two grooves G. R1 and G R2 Appropriate selection and construction to optimize the sensor device S T Measuring rider torque T R Sensitivity and accuracy.

[0124] exist Figure 9B and 9C In the embodiment shown, coil frame B C Arranged on the right side of the housing cover C HR B, the protrusion on the left inner side S Above, the protrusion outputs a hollow shaft S. O Bearing B R The bearing housing is formed. This arrangement is achieved through the bearing housing protrusion B thus provided. S The dual application is meaningful and has additional advantages in the drive unit D. U During operation, the bottom support shaft and / or housing cover C may experience issues due to high chain traction or pedal force. HR The deformation is also conveyed to coil frame B. C This ensures coil holder B C Even in drive unit D U Even under high load, it remains in contact with the measuring body, i.e., with the output hollow shaft section S. OS They are largely coaxial.

Claims

1. An electric bicycle drive unit (D U ), which is arranged coaxially with the bottom bracket in the bottom bracket area (D1) of the bicycle frame (1), the drive unit (D U This includes a torque sensor device (S) T The torque sensor device is used to measure the torque (T) of the rider on the left. RL ) and the rider torque on the right (T RR The total torque of the rider (T) constitutes the total torque of the rider. R Bottom support shaft (S) B ); and the bottom support shaft (S) B Coaxially arranged electric motor unit ME ); used to measure motor torque (T) M ) and total torque of the rider (T) R The output hollow shaft (S) is transmitted to the bicycle drivetrain (3). O ) and used to measure the rider's total torque (T) R From the bottom support shaft (S) B Coupled to the output hollow shaft (S) O The rider torque coupling device (D) on the ) CR ) and used to measure motor torque (T) M Coupled to the output hollow shaft (S) O Motor torque coupling device (D) on the motor CM ), Its features are, The torque sensor device (S) T The output hollow shaft section (S) is arranged in the drive unit. OS ) defined axial region (P A In the axial region (P) A It is also set to guide the rider's total torque (T) R ) and motor torque (T) M ),as well as The rider torque coupling device (D) CR Arranged in the axial region (P) A In and radially arranged in the output hollow shaft (S) O Within, wherein the torque sensor device (S) T ) Set up to detect the output hollow shaft (S) O ) and / or the rider torque coupling device (D CR In the output hollow shaft section (S) OS The diameter variation or circumferential stress in the region.

2. The driving unit according to claim 1, Its features Arranged in the motor unit (M) E ) and the motor torque coupling device (D CM The motor driven hollow shaft (S) between ) OM The motor driven hollow shaft is located in the axial region (P). A The output hollow shaft section (S) OS Coaxially arranged in the output hollow shaft section (S) OS The torque sensor device (S) is arranged radially outward and configured to be permeable to magnetic fields. T ) set for the output hollow shaft section (S) OS Non-contact detection of the rider's total torque (T) R ).

3. The driving unit according to claim 1, Its features are, The rider's total torque (T) R ) by the torque sensor device (S T In the output hollow shaft section (S) OS The total torque (T) measured in the ) T ) and the motor torque (T) M The difference in formation is used to determine this.

4. The drive unit according to any one of claims 1 to 3, Its features are, The motor device (M) E This includes cycloidal transmission devices (G) C (or strain wave transmission device) 5. The drive unit according to any one of claims 1 to 3, Its features are, The sensor device (S) T ) includes coil devices (C W1 C W2 C W3 ( ), used to detect the magnetoelastic properties of the output hollow shaft section that are related to material stress or deformation.

6. The driving unit according to claim 5, Its features are, The coil device (C) W1 C W2 C W3 At least one coil of the coil is formed by a wire turn that extends substantially circumferentially.

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