阅读说明：本技术 扭矩晶体管和带有扭矩晶体管的电动自行车 (Torque transistor and electric bicycle with torque transistor ) 是由 E·冯雷曼 于 2020-04-02 设计创作，主要内容包括：本发明涉及一种用于具有辅助马达的肌肉力量操作的交通工具的传动系的扭矩传递装置。扭矩传递装置包括输出轴、用于将由肌肉力量产生的扭矩传递至输出轴的第一输入轴、用于将辅助马达产生的扭矩传递到输出轴的第二输入轴,以及自由轮功能,当辅助马达停用时,该自由轮功能防止肌肉力量操作的交通工具的使用者不得不使辅助马达跟随旋转。根据本发明规定,扭矩传递装置具有机械离合器,该机械离合器设计成：如果在第一输入轴处在驱动旋转方向上作用在输出轴上的扭矩占优势,则将扭矩从第二输入轴传递到输出轴,并且如果在第一输入轴处逆着驱动旋转方向作用在输出轴上的扭矩占优势,则不会将扭矩从第二输入轴传递到输出轴。(The invention relates to a torque transmission device for a muscle-power-operated vehicle drive train having an auxiliary motor. The torque transfer device comprises an output shaft, a first input shaft for transferring torque generated by muscle power to the output shaft, a second input shaft for transferring torque generated by the auxiliary motor to the output shaft, and a freewheel function that prevents a user of a muscle-powered vehicle from having to follow the auxiliary motor in rotation when the auxiliary motor is deactivated. According to the invention, the torque transmission device has a mechanical clutch which is designed to: if a torque acting on the output shaft in the driving direction of rotation prevails at the first input shaft, a torque is transmitted from the second input shaft to the output shaft, and if a torque acting on the output shaft against the driving direction of rotation prevails at the first input shaft, no torque is transmitted from the second input shaft to the output shaft.)

1. A torque transmission device for a power train of a muscle-power operated vehicle having an auxiliary motor,

comprising: an output shaft (3),

a first input shaft (1) for transmitting torque generated by muscular power to the output shaft (3),

a second input shaft (2) for transmitting torque generated by the auxiliary motor to the output shaft (3),

and having a freewheel function which prevents a user of the muscle-power-operated vehicle from having to rotate the auxiliary motor with following when the auxiliary motor is deactivated,

characterized in that the torque transmission device has a mechanical clutch which is designed to: -transmitting torque from the second input shaft (2) to an output shaft (3) if a torque acting on the output shaft (3) in a driving rotational direction (15) prevails at the first input shaft (1), and-not transmitting torque from the second input shaft (2) to the output shaft (3) if a torque acting on the output shaft (3) against the driving rotational direction (15) prevails at the first input shaft (1).

2. The torque transmitting device of claim 1, wherein the mechanical clutch is a clutch lock-in clutch operable in the absence of any power source.

3. Torque transmitting device according to claim 1 or 2, characterized in that said output shaft (3), first input shaft (1) and second input shaft (2) are arranged coaxially to each other and are substantially rotatably mounted with respect to each other, wherein between said first input shaft (1) and said output shaft (3) there is a captive engagement with a gap (14) allowing a relative rotation between said first input shaft (1) and said output shaft (3) within a circumferential gap,

wherein at least one clamping element (4) is arranged between the second input shaft (2) and the output shaft (3) by means of a clamping lock such that if the output shaft (3) is rotated by the first input shaft (1) in a driving rotational direction (15), the clamping element (4) is in any case in a release position or brought into the release position and the second input shaft (2) does not rotate in the driving rotational direction either or rotates more slowly than the output shaft (3) and the first input shaft (1),

wherein, if the second input shaft (2) is rotated temporarily faster than the output shaft (3) in the driving rotation direction (15), the clamping element (4) is transferred from the release position into a locking position by a relative rotation between the output shaft (3) and the second input shaft (2) such that a catch engagement is produced between the second input shaft (2) and the output shaft (3), wherein the clamping element (4) is in any case held in the locking position as long as a torque acting in the driving rotation direction (15) is transmitted via the first input shaft (1) and via the second input shaft (2) to the output shaft (3),

and wherein the first input shaft (1) comprises an unlocking element (5) which in any case actively moves the clamping element (4) from the locking position into the release position if the first input shaft (1) is rotated relative to the output shaft (3) counter to the driving rotation direction (15) within a circumferential gap (14) which exists between the first input shaft (1) and the output shaft (3).

4. The torque transmitting device according to claim 3, characterized in that the clamping element (4) is a rolling element arranged between a first clamping surface (11) of the output shaft (3) and a second clamping surface (12) of the second input shaft (2), wherein the distance between the first clamping surface (11) and the second clamping surface (12) seen in the driving rotation direction (15) decreases such that in the locked position of the clamping element (4) there is a self-locking between the clamping element (4) and the first clamping surface (11) and the second clamping surface (12).

5. Torque transmitting device according to claim 4, characterized in that said clamping elements (4) are clamping rollers.

6. Torque transmitting device according to claim 4 or 5, characterized in that said clamping element (4) has a cylindrical or conical design.

7. Torque transmitting device according to claim 6, characterized in that said clamping element (4) has a circular cross section or a circular cross section with at least one protrusion (17) in a cross section perpendicular to the longitudinal axis of said clamping element (4).

8. Torque transmitting device according to one of claims 4 to 7, characterized in that the rotational axis of said clamping element is parallel to a common axis (8) of said output shaft (3), said first input shaft (1) and said second input shaft (2).

9. The torque transmitting device according to one of claims 4 to 8, characterized in that the first clamping surface (11) and the second clamping surface (12) are formed by conical surfaces, wherein the center radius of the second clamping surface (12) is constant across the entire circumference of the second input shaft (2), and wherein the center radius of the first clamping surface (11) varies as seen in the circumferential direction.

10. The torque transmitting device according to one of claims 4 to 9, characterized in that the clamping element (4) is received in a first recess (9) of the output shaft (3), wherein the first clamping surface (11) is formed by a partial surface of the first recess (9).

11. The torque transmission device according to claim 10, characterized in that a second recess (10) is formed in the output shaft (3) following the first recess (9) seen in the driving rotation direction (15), wherein the unlocking element (5) of the first input shaft (1) is a pin engaged in the second recess (10), wherein a catching engagement is produced between the first input shaft (1) and the output shaft (3) by the engagement between the pin and the second recess (10) in the driving rotation direction (15), and wherein a circumferential gap (14) between the first input shaft (1) and the output shaft (3) is given by a combined expansion of the first recess (9) and the second recess (10) seen in the circumferential direction, which is larger than a combined expansion of the clamping element (4) and the pin seen in the circumferential direction And (5) opening the paper.

12. Torque transmission device according to one of claims 1 to 11, characterized in that the second input shaft (2) coaxially encloses the output shaft (3).

13. Torque transmission device according to claim 12, characterized in that the second input shaft (2) is designed as a crown wheel.

14. Torque transmission device according to one of claims 1 to 13, characterized in that the first input shaft (1) extends through the output shaft (3).

15. The torque transmitting device according to one of claims 1 to 14, characterized in that it comprises a plurality of clamping elements (4) arranged distributed in the circumferential direction.

16. Torque transmitting device according to one of claims 1 to 15, characterized in that said clamp lock comprises an annular tensioning element (16), said annular tensioning element (16) being designed to support said clamp element (4) during the transition to said locking position.

17. Bicycle with an auxiliary motor and a torque transmission device according to one of claims 1 to 16, wherein the auxiliary motor is designed as an intermediate motor and is coupled to the second input shaft (2).

Technical Field

The present invention relates to a torque transmission device for a power train of a muscle-power operated vehicle with an auxiliary motor according to the preamble of independent claim 1. Within the scope of the present application, the term "muscle-power-operated vehicle" in principle encompasses all types of muscle-power-operated vehicles, in particular water vehicles such as a pedal boat. However, the invention is particularly applicable to electric bicycles or mopeds having an intermediate motor or a bottom bracket motor.

Background

The universal torque transfer device according to the preamble of independent claim 1 comprises an output shaft, a first input shaft for transferring torque generated by muscle power to the output shaft, a second input shaft for transferring torque generated by an auxiliary motor to the output shaft, and a freewheel function preventing a user of a muscle-power operated vehicle from having to rotate the auxiliary motor in a follow-up manner when the auxiliary motor is deactivated or not switched on.

Universal torque transmitting devices are known from the prior art and are used, for example, in electric bicycles with intermediate motors. EP 700826 a1 discloses a bicycle with an auxiliary motor and a controller based on a detected muscle-operated torque. In the solutions known from the prior art, the electrical sensor detects whether the rider exerts pressure on the pedal to move the bicycle forward. If this pressure is applied to the pedal, the assist motor is activated to assist the rider. If the rider no longer exerts any pressure on the pedals or rotates the pedals in the opposite direction, this will also be detected by the electrical sensor and the assistance of the auxiliary motor will be reduced or deactivated. Electrical systems are prone to faults and malfunctions, and therefore must be designed redundantly, in particular in safety-relevant areas, so that, for example, a bicycle can be braked safely even in the event of a sensor failure. Furthermore, the output shaft carrying the chain ring (chain ring) is usually firmly connected to or formed by the first input shaft. The second input shaft is also typically securely connected to the output shaft. The flywheel function is usually performed by a flywheel, which is mounted in the auxiliary motor itself or in a transmission arranged between the auxiliary motor and the output shaft. In order to prevent the auxiliary motor from having to rotate in a follow-up manner or backwards during backward pedaling, in the solutions known from the prior art, an additional freewheel needs to be mounted in addition to the first freewheel. Another bicycle with an auxiliary motor is known from EP 3254945 a1, wherein the drive unit is controlled by a torque detection unit.

Disclosure of Invention

The object of the present invention is to further develop a universal torque transmission device such that particularly compact and inexpensive construction results can be ensured, and at the same time the two freewheel functions described above are ensured. Furthermore, a reliable deactivation of the auxiliary motor support power should be ensured.

This object is achieved by the features of the independent claim 1. In a torque transmission device according to the preamble of independent claim 1, the solution according to the invention is therefore that the torque transmission device comprises a mechanical clutch which is designed to: if a torque acting on the output shaft in the driving direction of rotation prevails at the first input shaft, a torque is transmitted from the second input shaft to the output shaft, and if a torque acting on the output shaft against the driving direction of rotation prevails at the first input shaft, no torque is transmitted from the second input shaft to the output shaft.

Advantageous embodiments of the invention are the subject matter of the dependent claims.

In a preferred embodiment of the invention, the clutch is a mechanical clutch operable without a power source. Preferably, the mechanical clutch is designed as a clamp lock. Mechanical clutches have a higher reliability than electrical systems. In electrical systems, there is a risk that, for example, the battery or the energy storage will run out, leading to a malfunction of the system. Furthermore, a cable break in the sensor or power cord can lead to system failure. This is a significant challenge especially in vehicles used mainly outdoors, since these must preferably operate for many years even at different temperatures and for example when it is snowing and raining. Therefore, electrical systems in the safety and vehicle fields must be designed for double or even triple redundancy.

According to a further particularly preferred embodiment of the invention, the output shaft, the first input shaft and the second input shaft are arranged coaxially with one another and are mounted substantially rotatably relative to one another, wherein between the first input shaft and the output shaft there is a catch engagement with a clearance which allows a relative rotation between the first input shaft and the output shaft within a certain circumferential clearance, wherein at least one clamping element is arranged like a clamping lock between the second input shaft and the output shaft such that, if the output shaft is rotated by the first input shaft in the driving rotation direction, the clamping element is in any case in the release position or brought into the release position and the second input shaft rotates neither rotationally nor more slowly in the driving rotation direction than the output shaft and the first input shaft, wherein, if the second input shaft rotates temporarily faster in the driving rotation direction than the output shaft, the clamping element is transferred from the release position into the locking position by a relative rotation between the output shaft and the second input shaft, such that a catch engagement is produced between the second input shaft and the output shaft, wherein the clamping element is in any case held in the locking position as long as a torque acting in the drive rotational direction is transmitted via the first input shaft and via the second input shaft to the output shaft, and wherein the first input shaft comprises an unlocking element which in any case actively moves the clamping element from the locking position into the release position if the first input shaft is rotated against the drive rotational direction relative to the output shaft within a circumferential gap existing between the first input shaft and the output shaft. Thus, the clutch provided according to the invention is closed if the clamping element is in the locked position. The clutch provided according to the invention opens once the locking element is in the release position.

This embodiment has the advantage that the two freewheel functions shown above are integrated in a single functional unit. Another advantage is that the torque transmitted via the clamping element is limited to the maximum torque of the auxiliary motor. However, if two independent freewheel wheels are used, one of the two freewheel wheels must be designed for the maximum torque exerted on the output shaft by the user of the muscle-powered vehicle. The particularly preferred embodiment thus allows an overall very compact and lightweight construction.

According to the above particularly preferred embodiment, the output shaft, the first input shaft and the second input shaft are arranged coaxially with respect to each other. Unless otherwise stated, references below such as "in the circumferential direction" or the like refer to the common geometric axis of the output shaft, the first input shaft, and the second input shaft.

According to another particularly preferred embodiment of the invention, the clamping element is a rolling element which is arranged between the first clamping surface of the output shaft and the second clamping surface of the second input shaft, wherein the distance between the first clamping surface and the second clamping surface, seen in the circumferential direction, is reduced such that in the locked position of the clamping element there is a self-locking between the clamping element and the first clamping surface and the second clamping surface. The clamping element, which is designed as a rolling element, can rotate freely in the release position, but there is a relative rotation between the output shaft and the second input shaft, wherein the second input shaft rotates faster in the driving rotation direction than the output shaft, it is caught and carried by the second clamping surface of the second input shaft, thereby rolling along the first clamping surface in the circumferential direction into the locking position in which the above-mentioned self-locking takes place. In a relative rotation in the opposite direction, the self-locking is cancelled in a simple manner.

The clamping elements are particularly preferably clamping rollers. The cylindrical clamping roller can be easily manufactured and at the same time allows the transmission of high torques in a compact configuration. For example, the clamping element may alternatively also have a conical design. The clamping element may have a circular cross-section in a cross-section perpendicular to the longitudinal axis of the clamping element. However, according to a preferred embodiment, the clamping element has a circular cross-section with at least one protrusion. Particularly preferably, the clamping element has a circular cross section with two projections. The lobes represent cam surfaces which optimise power transmission between the second input shaft and the output shaft. In particular, if two projections are provided, there is a surface in the area between the projections which optimizes the power transmission between the second input shaft and the output shaft. Furthermore, the positioning of the clamping element is improved by the projection.

Further preferably, the axis of rotation of the clamping element lies on a common axis parallel to the output shaft, the first input shaft and the second input shaft.

According to another preferred embodiment of the invention, the first clamping surface and the second clamping surface are formed by conical surfaces, wherein the center radius of the second clamping surface is constant across the entire circumference of the second input shaft, and wherein the center radius of the first clamping surface varies as seen in the circumferential direction. This embodiment also contributes to a compact design and safety function of the clamping mechanism.

According to a further preferred embodiment of the invention, the clamping element is received in a first recess of the output shaft, wherein the first clamping surface is formed by a partial surface of the first recess. Such an embodiment contributes to a simple construction of the torque transmission device according to the invention and allows a simple positioning of the clamping element.

It is particularly advantageous here if the second recess is formed in the output shaft following the first recess, seen in the circumferential direction, wherein the unlocking element of the first input shaft is a pin engaged in the second recess, wherein a catching engagement is produced between the first input shaft and the output shaft by the engagement between the pin and the second recess in the driving rotation direction, and wherein the circumferential gap between the first input shaft and the output shaft is given by a combined expansion or dilation of the first recess and the second recess, seen in the circumferential direction, which is greater than the combined expansion or dilation of the clamping element and the pin, seen in the circumferential direction. This embodiment contributes to a particularly compact and simple construction. Furthermore, in this embodiment, the number of components required is particularly small. By means of the circumferential gap, a certain relative movement between the first input shaft and the output shaft can be generated. Due to the relative movement, the clamping element can be moved into a locking position, in which torque is transmitted from the second drive shaft to the output shaft, and into a release position, in which no torque is transmitted from the second input shaft to the output shaft.

According to another particularly preferred embodiment of the invention, the second input shaft coaxially encloses the output shaft. This embodiment also contributes to a compact construction. It is particularly advantageous if the second input shaft is designed as a crown wheel. The crown wheel can be driven in a simple manner by means of a pinion of the motor shaft engaging in a corresponding gear of the crown wheel.

According to another preferred embodiment of the invention, the first input shaft extends through the output shaft. This embodiment also contributes to a compact construction.

In a further particularly preferred embodiment of the invention, the torque transmission device comprises a plurality of clamping elements which are distributed in the circumferential direction. By means of the plurality of clamping elements, particularly high torques can be transmitted via the clamping elements. As many unlocking elements or pinions as clamping elements are advantageously provided. Particularly preferably, the clamping elements and the unlocking elements are arranged uniformly distributed in the circumferential direction. This results in a particularly advantageous power transmission. Thereby also resulting in a longer service life.

In a further preferred embodiment of the invention, the clamp lock comprises an annular tensioning element which is designed to support the clamping element during the transition to the locking position. The clamping element may, for example, be made of an elastic material, such as natural rubber or synthetic rubber. However, the tensioning element can also be a worm spring, which consists of a thin spiral wire, wherein the wire is elastic due to the spiraling. The tensioning element supports the clamping element during the transition to the locking position, wherein torque is transmitted from the second input shaft to the output shaft. By means of the tensioning element acting as an elastic element or spring, a force or torque is exerted on the clamping element. The torque supports the clamping bodies as they move into the locked position. Since the clamping element in this embodiment is pretensioned into the locking position by the tensioning element, the slightest relative movement between the second input shaft and the output shaft is sufficient to produce a frictional contact between the second input shaft and the output shaft. The tensioning element can ensure that all clamping elements are transferred into the locking position. This is particularly advantageous because despite the relative movement between the second input shaft and the output shaft, the grease required for lubrication can cause the clamping element to stick to the release position and not to shift into the locking position or to roll or slide into the locking position. The clamping element preferably abuts with its inner periphery under tension against the clamping element. However, the tensioning element can also abut with its outer circumference against the clamping element under tension. In both cases, the clamping elements also preferably have bearing surfaces which are not cylindrical relative to the axis of the respective clamping element, but rather form cam surfaces at which the tensioning elements abut so that, by cooperation of the tensioning elements and the cam surfaces, a torque is exerted on the clamping elements. More preferably, the bearing surface is embodied as a projection axially projecting from the base body of the clamping element. More preferably, the bearing surface extends through the axis of the clamping element.

The invention also provides a bicycle with an auxiliary motor according to the invention and a torque transmission device, wherein the auxiliary motor is embodied as an intermediate motor and is coupled with the second input shaft.

Embodiments of the present invention are described in more detail below with reference to the accompanying drawings.

Drawings

In the drawings:

FIG. 1: there is shown a partial cross-sectional view of a bottom bracket area of an electric bicycle having a torque-transmitting device according to the present invention in accordance with a first embodiment,

FIG. 2: a cross-sectional view through the torque transmitting device according to the invention of figure 1 in the axial position of the clamping element and the unlocking element is shown,

FIG. 3: the cross-sectional view of fig. 2 is shown, with the auxiliary motor deactivated, with the user of the electric bicycle operating the pedals in a forward direction,

FIG. 4: the cross-sectional view of figure 2 is shown when the auxiliary motor is initially supported,

FIG. 5: the cross-sectional view of figure 2 is shown as the auxiliary motor provides continuous support to the user of the electric bicycle,

FIG. 6: the cross-sectional view of figure 2 is shown at the moment when pedal movement ceases,

FIG. 7: the cross-sectional view of figure 2 is shown with the electric bicycle user operating the pedal rearwardly and the auxiliary drive member off,

FIG. 8: the cross-sectional view of figure 2 is shown when the pedal is operated backwards by a user of the electric bicycle and the second input shaft is rotated in a forward direction due to activation of the auxiliary drive,

FIG. 9: the cross-sectional view of figure 2 is shown when the electric bicycle is pushed backwards,

FIG. 10: a cross-sectional view of another embodiment of a torque transmitting device according to the present invention having a tensioning element is shown,

FIG. 11: there is shown the clamping element of the torque transmitting device according to the invention of fig. 10, showing in detail the front end of the clamping element, an

FIG. 12: a perspective view of the clamping element of figure 11 is shown.

Detailed Description

In the following description, like parts are denoted by like reference numerals. Reference is made to the previous or subsequent figure descriptions if the figures contain reference numbers that are not discussed in detail in the associated description of the figures.

Fig. 1 shows a perspective view, partially in section, of a bottom bracket area of an electric bicycle with a torque transmitting device according to a first embodiment. The bottom bracket shaft 1 of the electric bicycle, to which the pedals, not shown, are attached, forms a first input shaft of the torque transmitting device according to the invention. The first input shaft 1 extends through a hollow cylindrical output shaft 3 of the torque transmitting device. The hollow cylindrical output shaft 3 in turn supports a chain ring support 7, at which chain ring 6 is attached. The driving torque applied at the output shaft 3 is transmitted to the rear wheel of the electric bicycle via a chain, not shown. The torque transmitting device according to the invention further comprises a second input shaft 2, which is also hollow and radially surrounds the output shaft 3. The second input shaft 2 is designed as a crown wheel. Therefore, it has a tapered tooth surface into which the pinion gear 13 of the output shaft of the electric assist motor of the electric bicycle is engaged. The second input shaft 2 is therefore driven only by an auxiliary drive, which is not shown in further detail. All three shafts, i.e. the output shaft 3, the first input shaft 1 and the second input shaft 2, are arranged coaxially with each other and are substantially rotatably mounted with respect to each other. They share a common geometric axis 8 as shown in fig. 1.

The torque device according to the present invention is configured such that torque can be transmitted to the output shaft 3 via both the input shafts 1 and 2. The torque transmission device according to the invention has two freewheel functions integrated in a single functional unit. The first freewheel function prevents the user of the electric bicycle from having to rotate the auxiliary motor in a follow-up manner while pedaling forward if the auxiliary motor is deactivated or not activated. The second freewheel function ensures that the auxiliary motor does not have to follow up against the normal direction of rotation if the user of the electric bicycle steps backwards without transmitting torque to the rear wheel. The rear hub is therefore also equipped with a corresponding freewheel.

The function of the torque transmitting device according to the invention is explained below. Between the output shaft 3 and the second input shaft 2 a number of cylindrical clamping rollers 4 are arranged, which ensure, like a clamping lock, a torque transmission from the second input shaft 2 to the output shaft 3 in normal operation. The clamping rollers 4 are arranged evenly distributed across the periphery of the output shaft 3 and are received in corresponding recesses 9 at the outer periphery of the output shaft 3. As is clearly shown in fig. 1, the axis of the clamping roller 4 is oriented non-parallel to the axis 8 of the torque transmission device according to the invention. Instead, they are at an oblique angle to a common axis 8 of the output shaft 3, the first input shaft 1 and the second input shaft 2. Thus, the clamping rollers 4 act between the clamping surfaces of the output shaft 3 and the second input shaft 2, which are substantially conical.

Fig. 2 shows a cross-sectional view of the torque transmission device according to the invention, orthogonal to the axis 8, in the axial position of the clamping roller 4. The clamping surface 12 on the side of the second input shaft 2d is formed by a rotationally symmetrical conical surface. The clamping surface 11 on the side of the output shaft is constituted by the base of the recess 9 of the outer periphery of the output shaft 3. Fig. 2 clearly shows that the clamping surface 11 is raised clockwise as seen in the circumferential direction or in the drive direction 15, so that the distance between the clamping surface 11 and the clamping surface 12 decreases in the clockwise direction. A second recess 10 is formed in the outer contour of the output shaft 3, beside each recess 9, also seen in the circumferential direction. As shown in fig. 2, the pin-like extension 5 of the first input shaft 1 is engaged in the second recess 10. The pin-like extensions 5 are not shown in fig. 1 for clarity.

By engaging the pin-like extensions 5 in the recesses 10 of the outer contour of the output shaft 3, there is substantially a captive engagement between the first input shaft 1 and the output shaft 3. This means that if the first input shaft 1 is rotated in or against the driving rotation direction 15, the output shaft 3 substantially follows the rotation. However, the capture engagement has a gap. As shown in fig. 2, the combined expansion of the first recess 9 and the second recess 10, viewed in the circumferential direction, is greater than the combined expansion of the clamping roller 4 and the pin 5 arranged beside it, also viewed in the circumferential direction. There is thus a gap 14 which is shown in fig. 2 and which acts in the circumferential direction.

If the user of the electric bicycle steps forward and accordingly in the rotational drive direction 15, the first input shaft 1 rotates clockwise in the illustration in fig. 3. The pin-like extensions 5 of the first input shaft will abut against the side of the second recess 10 on the right side of each figure after they have overcome the gap 14, so that the output shaft 3 rotates with the first input shaft 1. The clamping rollers 4 remain in the left corner of the respective first recess 9 and are free to rotate, as indicated by the arrows in the clamping rollers 4 in fig. 3.

If the auxiliary motor is now activated, the second input shaft 2 also rotates clockwise as shown in fig. 4. In order to be able to transfer torque from the auxiliary motor to the output shaft, the second input shaft 2 must briefly rotate faster than the output shaft 3. The clamping roller 4 is entrained by this relative movement and rolls to the right along the raised clamping surface 11 until it is jammed between the clamping surface 11 of the output shaft 3 and the clamping surface 12 of the second input shaft 2, whereby self-locking occurs. This situation is shown in fig. 5. The torque is now transmitted to the output shaft 3 via both the first input shaft 1 and the second input shaft 2.

If the user of the electric bicycle keeps the pedals against the torque of the second input shaft 2, the pin-like extensions 5 exert a counterclockwise force on the grip rollers 4. This situation is shown in fig. 6. If the static friction of the clamping rollers is overcome, they will start to rotate or slide again. The frictional connection between the second input shaft and the output shaft is then interrupted. The second input shaft is free to rotate. This may be the case, for example, if the assist motor is accelerating faster than the rider wishes. The electric bicycle may of course have a corresponding torque sensor, in which case it will measure a negative torque that will cause the auxiliary motor to be deactivated.

Fig. 7 shows the behavior of the torque transmission device according to the present invention when the driver of the electric bicycle steps backward. The pin-like extension 5 pushes the clamping roller 4 counter clockwise until the clamping roller is caught between the pin-like extension 5 and the left side of the first recess 9. Torque is now transferred from the first input shaft or pin-like extension 5 via the clamping rollers 4 counter-clockwise to the output shaft 3. The output shaft 3 rotates counterclockwise together with the first input shaft. However, the frictional connection between the output shaft and the second input shaft is cancelled, so that the auxiliary motor does not have to follow the rotation during this backward movement of the pedal. As shown in fig. 8, the auxiliary motor is activated in the driving rotation direction, which causes the second input shaft 2 to rotate clockwise, having no effect on the gripping rollers 4 and the backward movement of the first input shaft 1 and the output shaft 3.

Finally, fig. 9 shows the behavior of the electric bicycle when pushed backward. In this case the output shaft 3 rotates anticlockwise and in its movement drives the pin-like extension 5 of the first input shaft. Due to the relative rotation between the output shaft 3 and the second input shaft 2, the clamping roller 4 rolls to the right along the first clamping surface 11 into a locking position, wherein a self-locking between the clamping roller 4 and the output shaft 3 and the second input shaft 2 takes place. When the electric bicycle is pushed backwards, the auxiliary motor therefore also follows the rotation.

FIG. 10 illustrates a cross-sectional view through another exemplary embodiment of a torque transmitting device according to the present invention. The torque-transmitting devices are substantially of the same design as the torque-transmitting devices according to the embodiment of fig. 1 to 9. In the embodiment shown in fig. 10, the torque transmission device additionally comprises a tensioning element 16, the tensioning element 16 being designed to support the clamping element 4 during the transition to the locking position. The clamping element 16 has an annular design and abuts against a corresponding bearing surface 18 of the clamping element 4. As shown in fig. 11 and 12, the bearing surface 18 is embodied as a projection 20 which projects axially from a base body 19 of the clamping element 4. The tensioning element has an elastic design such that a tensioning force is generated by the tensioning element. By resting the tensioning element 16 at the point of the support surface 18, a force or torque, respectively, can thus be generated on the clamping element 4. By means of this torque, the clamping element 4 is supported in the moved or switched-to locked position. The tensioning element 16 can be made, for example, of an elastic material, such as natural rubber or synthetic rubber, by means of which a tensioning force is generated. The tensioning element 16 may alternatively be made of spring wire, for example. By spiraling the wire, a worm spring is created, which may also create a tensioning force. The clamping elements 4 of the clamp lock must be well lubricated. Thus, in the embodiment according to fig. 1 to 9, the clamping element 4 may remain stuck in the release position and not roll or slide or be transferred into the locking position due to the relative movement between the second input shaft 2 and the output shaft 3 and the centrifugal and/or gravitational force. By means of the tensioning element 16 of the torque transmission device according to the second embodiment of fig. 10, the clamping elements 4 are supported during the transition from the release position to the unlocking position, so that all clamping elements are reliably and quickly brought into the locking position.

The projection 20 with the bearing surface 18 projects from the base body 19 of the clamping element 4 by approximately 1mm to 10mm, preferably 2mm to 5mm, so that the tensioning element 16 can rest thereon well and does not require too much installation space for the projection 20 in a clamping lock. The support surface 18 extends approximately straight radially from one side of the peripheral edge of the clamping element 4 to the other side of the peripheral edge. Preferably, the bearing surface 18 extends here approximately through a center point, the cross section of which extends perpendicularly to the longitudinal axis of the clamping element 4. Thereby, a large torque can preferably be generated at the clamping element 4 by means of the bearing surface 18. The bearing surface 18 has a curvature 21 near the outer periphery of the clamping element 4. By this curvature 21, the tensioning element 16 is mechanically loaded less when it rests on the support surface 18 than in the case in which the clamping element 16 rests on a sharp edge.

The clamping element 16 shown in fig. 10 generates a tensioning force which is directed towards the common axis 8. In this arrangement, the tensioning element 16 should rest on the region of the clamping element 4 close to the axis. The region close to the axis is the region of the clamping element 4 which, as viewed in fig. 1, is closer to the common axis 8 of the three shafts 1, 2 and 3. The projection 20 thus forms an area close to the axis.

A tensioning force away from the common axis 8 can also be generated to the outside by the tensioning element. In this arrangement, which is not shown, the tensioning element should rest against a region of the clamping element remote from the axis.

As shown in fig. 12, the clamping element 4 comprises a base body with a circular cross section and two projections 17. The protrusion 17 enlarges the circumference of the clamping element 4 like two cams, thereby improving the power transmission between the second input shaft 2 and the output shaft 3 and the positioning or orientation of the clamping element 4.

List of reference numerals

1 first input shaft

2 second input shaft

3 output shaft

4 clamping element

5 unlocking element

6 chain ring

7 chain ring support

8 axes of rotation

9 first recess

10 second recess

11 first clamping surface

12 second clamping surface

13 pinion

14 circumferential clearance

15 direction of rotation

16 tensioning element

17 projection

18 bearing surface

19 base body

20 projection

21 curvature