Freewheel device for an electric drive of a vehicle

Abstract

Freewheel device for an electric drive of a vehicle, comprising a first disc (4), which has a plurality of positive-locking receptacles (6), and a second disc (13), which has a plurality of positive-locking members (14), wherein one of the discs (4) is arranged in a rotationally fixed manner and the other disc (13) is arranged rotatably in or on a housing (2), wherein, by turning the discs (4, 13) relative to each other, the positive-locking members (14) and the positive-locking receptacles (6) can be moved into engagement with and out of engagement from each other, wherein the positive-locking members (14) with the positive-locking receptacles (6) in a blocking direction are in a blocked state and in a freewheeling direction are in a freewheeling state, wherein a spring device (21), which braces the two discs (4, 13) axially against each other, is provided, wherein the rotatable disc (13) is coupled to a drive element (8) which turns the disc and introduces a torque, and wherein a resistance device (25), which is coupled to the drive element (8) and generates a resistance torque counteracting the rotation of the drive element (8) when a torque is introduced, is provided in the housing (2).

Description

[0001] Freewheel device for an electric drive of a vehicle

[0002] The invention relates to a freewheel device for an electric drive of a vehicle.

[0003] Such a freewheel device is used, for example, in transmissions and serves as an overrunning clutch when two driven rotating elements, such as shafts, are coupled together. The freewheel device implements an overrunning function when a first rotating element rotates faster than the second rotating element, or a decoupling function when, for example, the second rotating element is stationary and only the first rotating element is rotating.

[0004] An example of a known freewheel device is described in DE 30 35 751. A face clutch ring is mounted on a driven shaft and is connected to the shaft in a rotationally fixed manner. The face clutch ring has a plurality of face claws on its face. A second face clutch ring is assigned to the face clutch ring and also has face claws on its face. These second face clutch ring interacts with the face claws of the first face clutch ring to transmit torque, so that torque can be transmitted from the driven shaft via the first face clutch ring to the second face clutch ring. This second face clutch ring, in turn, is connected in a rotationally fixed manner to a second shaft to which the torque can be transmitted. The freewheel device described in DE 30 35 751 is intended for connection to an electric engine starter, via which an internal combustion engine can be started via the freewheel device.The engine starter is connected to the first shaft, while the internal combustion engine is connected to the second shaft. When the engine starts, the second shaft accelerates, so that it overtakes the driven first shaft as its speed increases. Due to the geometry of the face jaws, this causes the second face clutch ring, which is axially displaceable against a spring, to be axially displaced and disengaged from the first face clutch ring. The two are thus separated, allowing the two shafts to rotate independently of each other. The freewheel device according to the invention is intended for use in an electric drive of a vehicle.This vehicle could, for example, be an electric-powered bicycle, which on the one hand offers the option of generating propulsion via the pedals and a crankshaft acting on a chain wheel, and on the other hand offers the option of generating propulsion via the electric motor. In the case of motor-driven propulsion, the crankshaft must be unlocked via the freewheel device. If such a freewheel device is used in such a bicycle, the rider can actively generate torque via the freewheel device by pedaling and thereby rotating the crankshaft, which is connected via the freewheel device to the output on a chain wheel. To do this, it is only necessary to set the freewheel device to a locking function in which torque transfer is possible.This requires that corresponding form-locking elements engage in corresponding form-locking receptacles of the torque transmission elements involved, which, however, are not yet engaged with each other at the moment the pedal crankshaft is actuated by the rider. Therefore, a corresponding rotation of the pedal crankshaft is required before this mechanical torque-transmitting engagement occurs. For this purpose, depending on the pitch of the form-locking elements and the form-locking receptacles, the pedal crankshaft must be turned by one degree, naturally associated with a correspondingly longer pedal angle travel. Until this engagement occurs, the rider is essentially pedaling "without force", meaning that they are not subjected to any haptically perceptible resistance from the bicycle's mechanical drive system until the form-locking engagement occurs. This is sometimes perceived as annoying, however.

[0005] The invention is therefore based on the object of providing an improved freewheel device.

[0006] To solve this problem, the invention provides a freewheel device for an electric drive of a vehicle, comprising a first disc having a plurality of positive locking receptacles and a second disc having a plurality of positive locking elements, wherein one of the discs is arranged in a rotationally fixed manner and the other disc is arranged rotatably in or on a housing, wherein the positive locking elements and the positive locking receptacles can be brought into and out of engagement with one another by rotating the discs relative to one another, wherein the positive locking elements are in a locked state with the positive locking receptacles in a locking direction and in a freewheeling state in a freewheeling direction, wherein a spring device is provided which axially braces the two discs against one another, wherein the rotatable disc is coupled to a drive element which rotates it and introduces a torque, and wherein a resistance device is provided in the housing,which is coupled to the drive element and, when a torque is introduced, generates a resistance moment that counteracts the rotation of the drive element.

[0007] The freewheel device according to the invention, which is suitable or designed for an electric drive of a vehicle, in particular for a human-powered vehicle such as a bicycle or the like, has, on the one hand, a disc mechanism forming the freewheel. This comprises a first and a second disc, wherein a plurality of positive-locking receptacles, for example a plurality of recesses or openings arranged equidistantly in the circumferential direction, are provided on the first disc, and a plurality of positive-locking elements, for example corresponding projections, are provided on the second disc, likewise arranged equidistantly in the circumferential direction. One disc is arranged in a rotationally fixed manner in or on a housing; it can also be part of a housing, while the other disc is rotatably received in the housing.By rotating the rotatable disc relative to the fixed disc, the form-locking elements can be rotated relative to the form-locking receptacles, or vice versa, until the latter are engaged. When these are engaged in one direction of rotation, a locking state is created, meaning that torque can be transferred from one disc via the form-locking elements to the other disc and its form-locking receptacles. If the disc is rotated in the other direction, the form-locking is released and the discs rotate freely relative to one another, which is also achieved when the housing is actively rotated while the first disc is stationary. Consequently, there is a corresponding locking direction and a freewheeling direction and consequently a locking state and a freewheeling state within the freewheel.

[0008] To engage the form-locking elements with the form-locking receptacles, a spring device is provided that essentially axially clamps the two discs against each other. If one of the discs rotates relative to the other, the axial clamping forces the form-locking elements against the other disc and, at the appropriate rotational position, is then pressed into the form-locking receptacles. When the form-locking is released, i.e., when the discs are again rotated relative to each other, the form-locking elements are pushed out of the form-locking receptacles, e.g., by means of a ramp, against the restoring force of the spring element.

[0009] The rotatable disc of the freewheel device according to the invention is coupled to a drive element that rotates it and introduces a torque, in the case of application in an electric bicycle the pedal crankshaft, via which the rider can actively introduce a torque into the drive.

[0010] To prevent the rider from having the tactile sensation of pedaling "emptily" until the positive locking is achieved, the freewheel device according to the invention features a resistance device in the housing, which is also coupled to the drive element and, when a torque is introduced via the drive element, generates a resistance moment that counteracts the rotation of the drive element. Consequently, this resistance device generates a resistance moment immediately upon the start of the rotation of the drive element, i.e., the pedal crankshaft, initiated, for example, via the bicycle pedals. This resistance moment is felt by the rider haptically via the pedals. This resistance moment persists until the positive locking elements and the positive locking receptacles are engaged in such a way that from then on, the torque is transmitted to the output via the pedal crankshaft and the freewheel device.This means that the resistance device bridges the time until the torque-transmitting positive engagement is achieved by creating a tactile resistance moment on the pedals. This means that the rider experiences this resistance moment when pedaling and therefore does not have the feeling of "empty" pedaling. Once this positive engagement is achieved, the resistance device can also reduce the opposing resistance moment again, as it is no longer required for further operation.

[0011] By assigning the resistance device to the actual freewheel, implemented via the two discs, a high torque capacity can be provided through the positive engagement, while at the same time, a virtually play-free shifting action can be achieved through the opposing temporary resistance torque, which the user can experience. This is because upon initial engagement, i.e., pedaling, the resistance torque is immediately built up via the resistance device, generating the resistance or counter-torque. This allows for correspondingly resistive pedaling until the freewheel, i.e., the disc arrangement, can slip and the positive engagement engages.Because both the rotating disc and the resistance device are coupled to the drive element that introduces the torque, both are moved synchronously and simultaneously during rotation. This immediately builds up the resistance torque, but also initiates the disc rotation and initiates the locking process until it is completed with sufficient disc rotation via the drive element. From this moment on, the torque is transferred via the positive connection, as described.

[0012] The resistance device can, for example, be a friction or clamping device that generates a friction or clamping moment as a resistance moment. The rotation initiated by the drive element within the resistance device consequently creates friction or clamping, which generates the corresponding friction or clamping moment, which counteracts the rotational movement of the drive element as a resistance moment.

[0013] In further detail, the resistance device can have a first resistance disc coupled to the drive element and a second resistance disc mounted in the housing for rotational stability. Resistance bodies are arranged between the two resistance discs and abut against them, via which the resistance moment can be generated when the first resistance disc rotates relative to the second resistance disc. The resistance device is therefore also designed as a disc arrangement. It has two resistance discs that can be rotated relative to one another. The first resistance disc is actively rotated by the drive element. The second resistance disc is mounted in the housing for rotational stability and cannot rotate relative to the housing. Appropriate resistance bodies are arranged between the two.As soon as the first resistance disc is rotated relative to the second resistance disc, the resistance moment can be generated through the interaction of the resistance bodies with both resistance discs.

[0014] Ramp-like contours can be provided on one or both resistance discs, onto which the resistance bodies run when the resistance discs are rotated. This ramp-like contour can therefore introduce axial tension into the resistance disc arrangement, which in turn makes it difficult to rotate the first resistance disc, which, as described, is rotated relative to the second resistance disc via the drive element. The axial tension caused by the resistance bodies running onto the ramp-like contours therefore opposes the rotation of the disc, meaning that the driven resistance disc can be rotated more slowly relative to the other resistance disc, which can be perceived haptically on the pedals.

[0015] In this context, it is expedient if a certain degree of elasticity is integrated into the resistance device, which allows the two resistance discs to be axially clamped accordingly, but also allows them to be sufficiently rotated relative to each other until they form-fit, without excessive jamming or excessive friction occurring beforehand. According to a further development of the invention, this elasticity can be achieved by the resistance device having a further spring device, by means of which the resistance discs are axially clamped against each other. This spring device therefore clamps both resistance discs axially against each other, and consequently also clamps the clamping bodies between the resistance discs.At the same time, the elasticity integrated into the spring device also allows for a certain degree of flexibility when the clamping bodies run onto the ramp-like contours, so that on the one hand the tension is increased, but on the other hand twisting is still possible due to the integrated elasticity.

[0016] In this context, it is advantageous if the first resistance disc is axially movable against a restoring force of the additional spring device. Accordingly, when the resistance bodies run onto the ramp-like contours, the axial tension increases. This tension is further increased by the fact that the spring element is additionally compressed by the deflection of the first resistance disc, thus increasing the tension, up to a maximum resistance moment, which can be adjusted by the hardness of the additional spring device. The first resistance disc thus works against this spring element and compresses it as the resistance bodies run onto the contours, thereby increasing or even maximally limiting the tension within the disc arrangement until the positive locking occurs.Maximum deformation should be reached as quickly as possible so that the maximum resistance moment builds up almost instantly, and the user immediately feels the resistance consistently. The additional spring device is preferably a disc spring or a disc spring assembly, which allows for homogeneous axial spring loading of the first resistance disc. The disc spring or disc spring assembly is supported axially on the housing on one side and axially on the first resistance disc on the other.

[0017] The resistance bodies themselves are expediently balls or rollers guided in a cage, which run on corresponding raceways of the first and second resistance disc, one of these raceways additionally being provided with the ramp-shaped contours. In other words, the resistance body can be a second freewheel, which in this case is designed as an axial ball freewheel and which, in terms of its effect, is "connected" in series with the freewheel. The reduction of the resistance moment begins immediately upon engagement of the positive connection, since the housing in which the resistance device is arranged then rotates at the same speed as the drive element, meaning that no torque acts on the first resistance disc.The resistance disc arrangement can essentially relax again, which means that the resistance discs can again rotate slightly relative to each other and the resistance bodies run off the ramp-like contours again and there is again an axial reset of the previously axially deflected first resistance disc, supported by the relaxing further spring device.

[0018] The spring mechanism associated with the actual freewheel and axially clamping the two discs can also be designed in the form of a disc spring or a disc spring assembly. The disc spring or disc spring assembly is supported axially on the rotating disc on one side and axially on the housing or the second resistance disc on the other. Here, too, the disc spring or disc spring assembly allows for homogeneous axial clamping of the two discs relative to each other.

[0019] An advantageous development of the invention provides that the spring device and the further spring device have different spring hardnesses, wherein the spring device preferably has a lower spring hardness than the further spring device. The first spring device braces the two freewheel discs axially against one another, as described. During operation, when the freewheel is open and consequently the second disc, which is fixedly arranged in the housing, rotates faster than the first disc, which is the case when, for example, travel is only via the electric motor, there is inevitably no positive connection, i.e. the second disc with the positive connection receptacles rotates over the first disc with the positive connection elements.Since the positive locking elements snap into the positive locking receptacles in every specific rotational position due to preload and are then pushed out again, this inevitably generates noise, i.e., a rattling noise resulting from the snap-in process. This noise can be reduced if the clamping force is selected to be sufficiently low. This is possible with the freewheel device according to the invention, since this spring device only has to provide a relatively low axial clamping force, which is just sufficient to slightly axially displace the rotatable first disc in order to press the positive locking elements into the positive locking receptacles.Due to the low axial tension and thus the low spring hardness of the first spring device, in the freewheeling case the snap-in process of the form-locking elements into the form-locking receptacles is relatively soft, which leads to low noise generation due to the axial abutment of the components against each other, compared to the situation when the form-locking elements are driven into the form-locking receptacles with high axial clamping force.

[0020] The situation is reversed with the additional spring mechanism, which has a correspondingly higher spring rate. As described above, this additional spring mechanism sets the maximum resistance torque, which the driver also experiences via the pedals. Ideally, this should be within a range that corresponds to the torque the driver applies in the positive engagement state, but also experiences haptically. The goal is that, immediately upon generating the resistance torque, the driver experiences a driving situation that does not change significantly even when the positive engagement occurs, thus transmitting torque via the freewheel.

[0021] As described, the function of the freewheel device according to the invention is based, among other things, on the fact that both the rotatable disc of the freewheel and the rotatable resistance disc of the resistance device are coupled to the common drive element, so that consequently both the freewheel and the resistance device are actuated synchronously. This coupling is expediently realized via a respective toothed connection. The drive element, i.e. the driving shaft, which passes through the freewheel and the resistance device, is provided with straight teeth, for example a serration, on its outer circumference. Both the rotatable disc and the second resistance disc also have corresponding teeth or serrations on the inner circumference of their central openings, via which the toothing engagement is realized.

[0022] The invention is explained below using exemplary embodiments with reference to the drawings. The drawings are schematic representations and show:

[0023] Figure 1 is a perspective, sectioned exploded view of a freewheel device according to the invention,

[0024] Figure 2 shows the exploded view from Figure 2 in a different direction,

[0025] Figure 3 is a sectional view of the assembled freewheel device from Figure 1, with the freewheel or the first and second disc in a position where a torque can be transmitted from the drive element to the housing,

[0026] Figure 4 shows the freewheel device from Figure 3 with the freewheel in an intermediate position immediately before the drive element is turned,

[0027] Figure 5 shows the freewheel device from Figure 4 after slight rotation of the drive element with simultaneous rotation of the rotatable disc and the first resistance disc, the drive element not being shown, and

[0028] Figure 6 shows the freewheel device from Figure 5 after further rotation of the drive element and the rotatable disc as well as the first resistance disc, whereby the positive connection has been established but the resistance device has not yet reset.

[0029] Figures 1 and 2 show different exploded views of a freewheel device 1 according to the invention. This comprises a cup-shaped housing 2 with a cylindrical housing section 3 and a first disc 4 which forms the housing base and is integrally formed thereon. The first disc 4 has a central opening 5 and a plurality of trapezoidal positive-locking receptacles 6 arranged equidistantly around the circumference. A measuring sleeve 7 is seated on the first disc 4. When the freewheel device 1 is installed in the drive of a bicycle driven by an electric motor, measurement information can be accessed via this measuring sleeve, which can be used, for example, to control the electric motor. The measuring sleeve 7, in turn, is penetrated by a drive element 8, which in the example of the bicycle is a crankshaft that can be actively rotated via the bicycle's pedals.The hollow cylindrical drive element 8 here has a toothed section 9 with a longitudinal serration, which toothed section 9 serves to form a toothed connection to two disc components to be described below.

[0030] Two retaining grooves 10, 11 are formed on the cylindrical housing section 3, axially offset from one another, into each of which two support rings, to be described below, are snapped. Likewise, several longitudinal grooves 12 are formed on the housing section 3, which serve to accommodate retaining sections of components to be described below, in order to accommodate them in a rotationally fixed manner in the housing 2.

[0031] Also shown is a second disk 13, which has a plurality of form-locking elements 14 on its upper side facing the first disk 4. These are designed as semicircular, flared projections that are suitable for engaging in the corresponding form-locking receptacles 6 in defined rotational positions relative to the first disk 4. Each form-locking element 14 has a leading edge 15, with which the form-locking element 14 strikes against a wall 16 of the respective form-locking receptacle 6 in the case of form-lock, i.e. when it engages in a form-locking receptacle, so that a torque-transmitting form-lock connection is created. Furthermore, each form-locking element 14 has a ramp-like upper side geometry 17, which in turn allows the form-locking elements 14 to slide out of the form-locking receptacles 6 again when the disks 4, 13 are rotated relative to one another opposite to the stop direction.The rotatable second disc 13 has a circumferential support flange 18 on its edge, on which a spring element is supported, as described below. Furthermore, an internal toothing 20 is formed on the inner circumference of a central opening 19 of the second disc 13, which positively engages the toothed section 9 in the assembled position to create a torque-resistant connection.

[0032] Also shown is a first spring device 21 in the form of a leaf spring 22. This is supported by its outer edge 23 in the assembly position on the support flange 18. The disc spring 22 has a plurality of radially inwardly projecting spring tabs 24, which, in the assembly position, are axially supported on a resistance device 25, which is described below.

[0033] Furthermore, a first support 26 is provided, which is snapped into the groove 10 in the assembled position. This serves as an axial support on which the resistance device 25 is supported in the axial direction on the housing side.

[0034] The resistance device 25, in turn, has a first resistance disk 26 with a central opening 27, which in turn is provided with a toothed section 28, which also meshes positively with the toothed section 9, thus forming a torque-resistant connection. A raceway 29 for resistance elements 30, here in the form of balls, is formed on one side surface of the first resistance disk 26. The cage 31, designed here as a flat cage, has a plurality of projections 32 formed radially outwardly. These projections engage in the grooves 12 in the assembled position to secure the cage 31 in the circumferential direction on the housing side. The annular cage also has a central opening 33, which, however, is significantly larger in diameter than the opening 27 of the first resistance disk 26.

[0035] The resistance device 25 further comprises a second resistance disk 34, which also has a corresponding track 35 on which the resistance bodies 30 run. However, this track 35 is locally provided with corresponding ramp-shaped contours, onto which the resistance bodies 30 run when the first resistance disk 26 is rotated relative to the fixed second resistance disk 34, so that an axial force is exerted on the first resistance disk 26 and the latter is axially displaced. The second resistance disk 34 also has projections 36 arranged on its outer circumference, which are positioned with the same pitch as the projections 32, wherein the corresponding components of the resistance device 26 have the same outer diameters. In the assembled position, the projections 36 also engage in the grooves 12 for the rotationally fixed arrangement of the second resistance disk 34 in the housing 2.Likewise, the second resistance disc 34 has a central opening 37 which corresponds in diameter to the opening 33.

[0036] Also provided is a further spring device 38 in the form of a disc spring 39, which has a plurality of radially inwardly projecting spring tabs 40, which in the assembled position bear against the underside of the first resistance disc 26. The outer edge 41 of the disc spring 39 is axially supported in the assembled position on a support ring 42, which is received in the groove 11, so that the resistance device 26 can be axially clamped via the disc spring 39, after the resistance device 25 is axially supported on the support ring 26 via the second resistance disc 34.

[0037] Figure 3 shows the assembled position of the freewheel device 1. The housing 2 is shown with its cylindrical housing section 3, which encloses the entire assembly in the circumferential direction. The first disc 4 is formed in one piece with the housing 2, as are the form-locking receptacles 6. The second disc 13 is arranged below the first disc 4, wherein in the example shown, a form-locking element 14 engages in a form-locking receptacle 6 and rests with its leading edge 15 against the wall 16 in a torque-transmitting manner. Since, see Figure 2, fewer form-locking elements 14 are provided than form-locking receptacles 6, the form-locking receptacle 6 shown on the left in the sectional view according to Figure 3 is not occupied by a form-locking element 14. For example, twice as many form-locking receptacles 6 are provided as form-locking elements 14, i.e. the division ratio is 2:1.Also shown in Figure 3 is the spring element 21 in the form of the disc spring 22, which is supported with its edge 23 on the edge flange 18 and is supported with its spring tabs 24 on the second resistance disc 34.

[0038] Also shown is the first support ring 26, on which the resistance device 25 is axially supported via the second resistance disc 34. In Figure 3, the resistance device 25 is followed downwards by the second spring device 38 in the form of the disc spring 39, which is supported with its spring tabs 40 on the first resistance disc 26 and with its edge 41 on the second support 42.

[0039] Figure 3 shows the position in which the positive-locking elements 14 engage in the positive-locking receptacles 6, creating a torque-resistant connection via the edges 15 and the walls 16, so that a torque introduced via the drive element 8, i.e., the pedal crankshaft, is transmitted directly to the housing 2, which in turn is coupled, in a manner not shown in detail, to another output element, such as a sprocket or the like. Naturally, the housing 2 is also coupled to an electric drive (not shown in detail) in the assembled state, via which the bicycle can also be powered.

[0040] Starting from the situation shown in Figure 3, the rider can, on the one hand, apply a torque directly to the housing 2 by pedaling and thus rotating the drive element 8, which is then passed on. In this case, for example, the electric motor is not active. However, if the torque is to be introduced via the electric motor, the drive element 8, i.e. the pedal crankshaft, remains at rest. Since the motor-side torque is applied directly to the housing 2, the housing rotates relative to, for example, the stationary first disc 13, which means that the second disc 13 is also rotated relative to the fixed first disc. During this rotational movement, the first disc 13, with its ramp geometry 17, runs onto the edges of the positive-locking receptacles 6, so that the second disc 13 is pushed axially away from the first disc 4 and pressed against the first disc spring 22, deforming it.As the housing continues to rotate, the positive locking elements 14 slide on the underside of the first disc 4 until they snap into the next positive locking receptacles 6 again, resulting from the spring action via the disc spring 22, upon reaching a defined angle of rotation, etc. This is how the freewheel function is realized.

[0041] If, at the time the user actively wishes to achieve propulsion by pedaling, the positive locking elements 14 are in a position in which a torque-transmitting positive connection between the positive locking elements 14 and the positive locking receptacles 6 is not immediately established, a certain degree of rotation of the second disc 13 would be required until this positive connection is established. Consequently, this angular play must be reduced until torque can be transferred. In order to compensate for this angular play, so that the user does not perceive it as "idle pedaling," the resistance device 25 is integrated, via which a resistance moment is applied immediately upon the start of the active rotational movement of the drive element 8, making rotation more difficult.

[0042] In order to be able to operate both the freewheel and the resistance device synchronously via the drive element 8, the second disc 13 and the first resistance disc 26 are connected in a rotationally fixed manner to the toothed section 9 via their toothed sections 20, 28. This means that even the slightest rotation of the drive element 8 results in a rotation of the second disc 13 and the first resistance disc 26.

[0043] Figure 4 shows a situation in which the second disc 13 has been moved axially away from the first disc 4 against the first disc spring 22 after the form-locking elements 14 are located in the area between two form-locking receptacles 6, i.e., they rest against the underside of the first disc 4, as clearly shown in Figure 4. The resistance device 25 is not actuated. At this moment, no torque is yet applied via the drive element 8. As soon as the driver actuates the drive element 8 via the pedals and rotates it relative to the housing 2, the first disc 13 is rotated accordingly, so that the form-locking elements 14 on the underside of the disc 4 are moved further toward the next form-locking receptacle 6, as shown in the operating position shown in Figure 5. The form-locking element 14 shown in section on the left is clearly about to snap into the corresponding form-locking receptacle 6.

[0044] Simultaneously with the rotation of the second disc 13, the first resistance disc 26 is also rotated relative to the second resistance disc 34. Due to the rotational movement, the resistance bodies 30 run along the ramp-like contours of the second resistance disc 34, which causes them to be pressed axially downwards and thereby inevitably move the first resistance disc 26 axially against the restoring force of the second disc spring 39, which is now also further compressed and builds up a higher restoring force. This is accompanied by increasing axial tension of the resistance device 25, which reaches its maximum when the first resistance disc 26 reaches a maximum axial adjustment position and thus a maximum compression of the second disc spring 39. This maximum tension is achieved as soon as possible after the drive element 8 is turned on.The magnitude of the generated resistance moment, which opposes the rotation of the drive element 8, depends on this strong axial tension of the resistance device 35, which depends on the spring rate of the second disc spring 39. As a result of this tension, the first resistance disc 26 can only be rotated relative to the second resistance disc 34, and of course also to the more or less fixed second disc spring 39, with increased force. This increased rotational resistance can be experienced haptically on the pedals via the drive element 8. This resistance moment remains until the positive-locking elements 14 engage the positive-locking receptacles 6, after which the torque is transferred directly to the housing 2 via this positive-locking connection, and consequently the drive element 8 acts on the drive, so that the driver experiences the corresponding, familiar resistance moment. This situation is shown in Figure 6.It can be seen that the form-locking element 4 shown on the left is completely snapped into the form-locking receptacle 6, its edge 15 is in stop against the wall 16, so that with continued rotation of the second disc 13, the torque is inevitably transmitted directly to the housing 2 via the drive element 8. It can be seen that the first disc spring 22 has been rebounded and the second disc 13 is in contact with the first disc 4. In this situation, which the freewheel device 1 shows immediately after the form-locking elements 14 have snapped into the form-locking receptacle 6, the resistance device 25 is not yet released, i.e. the first resistance disc 26 is still in the axially offset position relative to the second resistance disc 34 and the second disc spring 39 is still tensioned.However, since no further torque is now exerted on the first resistance disc 26 via the drive element 8 after it has been guided directly into the housing 2, there is no further force applied to the first resistance disc 26 or the resistance device 25, so that, ultimately also driven by the restoring force of the second plate spring 39, the resistance bodies 30 can run away from the ramp-like contours again and the first resistance disc 26 is returned to the initial position via the plate spring 39, as described for Figure 3.

[0045] List of reference symbols

[0046] Freewheel device housing housing section first disc opening positive locking receptacle measuring sleeve drive element toothing section retaining groove retaining groove longitudinal groove second disc positive locking element starting edge wall

[0047] Top side geometry support flange opening internal toothing spring device leaf spring edge spring tab

[0048] Resistance device first resistance disc opening toothing section raceway resistance element cage projection opening second resistance disc raceway projection opening spring device disc spring spring tab edge support ring

Claims

Patent claims 1. A freewheel device for an electric drive of a vehicle, comprising a first disc (4) having a plurality of positive-locking receptacles (6), and a second disc (13) having a plurality of positive-locking elements (14), wherein one of the discs (4) is arranged in a rotationally fixed manner and the other disc (13) is arranged rotatably in or on a housing (2), wherein the discs (4, 13) are rotatable relative to one another and, in the process, the positive-locking elements (14) and the positive-locking receptacles (6) are engageable and disengageable relative to one another, wherein the positive-locking elements (14) are in a locked state with the positive-locking receptacles (6) in a locking direction and in a free-wheeling state in a free-wheeling direction, wherein a spring device (21) is provided which axially braces the two discs (4, 13) against one another,wherein the rotatable disc (13) is coupled to a drive element (8) which rotates it and introduces a torque, and wherein a resistance device (25) is provided in the housing (2), which is coupled to the drive element (8) and which, when a torque is introduced, generates a resistance moment counteracting the rotation of the drive element (8).

2. Freewheel device according to claim 1, characterized in that the resistance device (25) has a first resistance disc (26) which is coupled to the drive element (8), and a second resistance disc (34) which is accommodated in the housing (2) in a rotationally fixed manner, as well as resistance bodies (30) arranged between the two resistance discs (26, 34) and resting thereon, via which the resistance moment can be generated when the first resistance disc (26) is rotated relative to the second resistance disc (34).

3. Freewheel device according to claim 2, characterized in that ramp-like contours are provided on one or both resistance discs (26, 34), onto which the resistance bodies (30) run upon rotation of the resistance discs (26, 34).

4. Freewheel device according to one of the preceding claims, characterized in that the resistance device (25) has a further spring device (38) by means of which the resistance discs (26, 34) are axially braced against one another.

5. Freewheel device according to claim 4, characterized in that the first resistance disc (26) is axially movable against a restoring force of the further spring device (38).

6. Freewheel device according to claim 4 or 5, characterized in that the further spring device (38) is a disc spring (39) or a disc spring assembly, which is supported axially on the one hand on the housing (2) and axially on the other hand on the first resistance disc (26).

7. Freewheel device according to one of claims 2 to 6, characterized in that the resistance bodies (30) are balls or rollers guided in a cage (31).

8. Freewheel device according to one of the preceding claims, characterized in that the spring device (21) is a disc spring (22) or a disc spring assembly, which is supported axially on the one hand on the rotatable disc (13) and on the other hand axially on the housing (2) or the second resistance disc (34).

9. Freewheel device according to one of the preceding claims, characterized in that the spring device (21) and the further spring device (38) have different spring hardnesses, wherein preferably the spring device (21) has a lower spring hardness than the further spring device (38).

10. Freewheel device according to one of the preceding claims, characterized in that the drive element (8) is coupled to the rotatable disc (13) and the first resistance disc (26) via a toothed connection.

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