Coupling device for a drive train

Abstract

Coupling device (2) for a drive train (1) of a motor vehicle, comprising a first shaft (3) connectable to or connected with a drive of the drive train (1) and a second shaft (4) connectable to or connected with an output of the drive train (1) and a freewheeling device (5) having a locking element (6), in particular a locking cage, which in a first locking position of the locking element (6) is configured to allow a relative rotation of the first shaft (3) to the second shaft (4) in a first direction of rotation and to couple the first shaft (3) to the second shaft (4) in the second direction of rotation, wherein the freewheeling device (5) in a second locking position of the locking element (6) is configured to allow a relative rotation of the first shaft (3) to the second shaft (4) in a second direction of rotation and to couple the first shaft (3) to the second shaft (4) in the first direction of rotation,wherein the locking element (6) can be set to the first locking position and / or the second locking position without the use of a switching element.

Description

[0001] The invention relates to a coupling device for a drive train of a motor vehicle, comprising a first shaft which is connectable or connected to a drive of the drive train and a second shaft which is connectable or connected to an output of the drive train and a freewheel device having a locking element, in particular a locking cage, which in a first locking position of the locking element is designed to release a relative rotation of the first shaft to the second shaft in a first direction of rotation and to couple the first shaft to the second shaft in the second direction of rotation.

[0002] Such coupling devices for motor vehicle drive trains, which are designed to transmit torque between the first shaft and the second shaft in a first direction of rotation, for example to transfer torque from a drive of the motor vehicle to an output of the motor vehicle, and to release the coupling in a second direction of rotation so that a freewheeling state can be achieved, are generally known from the prior art. For example, such coupling devices are used in the field of secondary drives, for example electric drive axles, in order to decouple the secondary drive from the rest of the drive train in operating states in which drive by the secondary drive is not required, in order to reduce drag losses and the like. The disadvantage of this is that torque transmission in the freewheel device is not possible, so that recuperation or reverse operation is generally not possible.

[0003] For this purpose, switchable freewheel devices are known from the prior art, which can selectively assume the locking position of the locking element and then release this position again. Thus, a locking position can be selectively assumed, for example, when torque is to be transmitted in the desired direction of rotation, or the locking position can be released so that the shafts can rotate freely relative to one another. However, such switchable freewheel devices require active switching elements, for example, actuators, valves, control devices, and the like, which, for example, electromechanically, pneumatically, or hydraulically move switching elements into corresponding positions in order to switch the freewheel device. This increases the effort required to provide the coupling device, particularly with regard to complexity, the number of parts, and the operating strategy.

[0004] The invention is based on the object of providing an improved coupling device for a drive train of a motor vehicle which is less complex.

[0005] The object is achieved by a coupling device having the features of claim 1. Advantageous embodiments are the subject of the subclaims.

[0006] As described above, the invention relates to a coupling device for a drive train of a motor vehicle. The coupling device has a first shaft that is or can be connected to a drive or a drive side of the drive train. For example, the first shaft can be directly or indirectly connected to an output shaft of an electrical machine, in particular an electric motor used as a secondary drive. Furthermore, the coupling device has a second shaft that is or can be connected to an output or an output side of the drive train, for example, to side shafts or a differential. Furthermore, the coupling device has a freewheel device that has a locking element, for example, a so-called "locking cage," which can have finger-like locking struts extending in the axial direction to lock or release pawls or similar freewheel elements.

[0007] The coupling device is fundamentally designed to enable relative rotation of the first shaft to the second shaft in a first rotational direction when the locking element is in a first locking position, and to couple the first shaft to the second shaft in the second rotational direction. In other words, torque transmission in the second rotational direction is enabled when the locking element is in the first locking position, with the two shafts coupled to one another via the coupling device. If the shafts are rotated relative to one another in the first rotational direction, the freewheel device is in the freewheeling state, resulting in decoupling.

[0008] The invention is based on the finding that the freewheel device, in a second locking position of the locking element, is designed to release a relative rotation of the first shaft to the second shaft in a second direction of rotation and to couple the first shaft to the second shaft in the first direction of rotation, wherein the locking element can be set into the first locking position and / or the second locking position without a switching element. In other words, the locking state can be reversed, so that the locking element is moved into the second locking position. In the second locking position, in contrast to the first locking position, torque is transmitted in the first direction of rotation and freewheeling in the second direction of rotation is permitted.

[0009] The movement of the locking element into the locking position or the setting or switching of the locking element into the locking position should not be carried out by an active switching element, but rather without a switching element. This reduces the complexity of the coupling device with regard to actuating the locking element, since no additional actuator, valve, control device, or the like is required to set the locking element. Instead, the locking element is set into the first locking position and / or the second locking position without a switching element.

[0010] The locking element is positioned passively or indirectly, i.e., depending on a specific operating state, for example, a drive device, or the positions of the locking element can be adjusted by specific control of the drive device, i.e., the movement behavior of the first shaft, without the need for an additional actuator or switching mechanism. In principle, the terms "first" and "second" are interchangeable within the scope of this application, for example, "first shaft" or "first locking position."

[0011] In addition to the first locking position and the second locking position, a neutral position can also be provided optionally, whereby with the locking element in the neutral position, the freewheel device is decoupled in both directions of rotation, so that the first shaft and the second shaft can rotate freely relative to each other in both directions of rotation.

[0012] In the coupling device, it can be provided that the locking element is adjustable based on inertia, in particular depending on a speed gradient of the first shaft. In principle, a drive device, in particular an electric machine, can thus be coupled to the first shaft, which is designed to control the speed, i.e. which can regulate a certain speed or can be guided to a certain speed. In particular, a defined speed gradient can be set in order to move the locking element from its current position, for example into the first locking position, the second locking position or the neutral position. For this purpose, the first shaft can be specifically accelerated or braked by the drive device, so that the locking element is moved based on inertia relative to the first shaft, on which the locking element is rotatably arranged, in order to be set into the desired locking position or neutral position in the circumferential direction.

[0013] For example, the locking element can be in the first locking position, with the intention of moving the locking element into the second locking position. For this purpose, a speed gradient is set on the first shaft such that the shaft abruptly changes its current speed, whereby the locking element, which is inert in comparison, is rotated accordingly relative to the first shaft and thus reaches the second locking position. The scenario described is transferable to any transition of the locking element into any locking position or the neutral position and vice versa. It is therefore clear that the setting of the locking element occurs independently of additional switching elements, such as actuators, valves, switching mechanisms and the like, but the position of the locking element is triggered by speed control on the part of the drive device or the first shaft and is set relative to the first shaft due to the inertia of the locking element.

[0014] As described, the locking element is inert relative to the first shaft when performing the adjusting movement. The locking element itself has a certain mass which behaves inertly during such adjusting processes, in particular when the speed of the first shaft changes. In addition, it can be provided that the locking element is coupled to a coupling mass. The coupling mass can be arranged on the first shaft so that it can be rotated as desired, in particular within an angular restriction, for example inside the first shaft or axially spaced from the first shaft, and can be coupled to the locking element in such a way that the coupling mass acts inertly on the locking element or increases the inert mass of the locking element. The same applies to the holding element and the locking strut since these are operatively connected and can therefore also be coupled to the coupling mass. The coupling mass can in particular be a holding plate orhave a retaining element coupled to the locking element. The retaining element can also be integrated into the locking element, or the retaining element, the locking element, and optionally the coupling mass can also be a single component.

[0015] The locking element or its previously described holding element can be arranged on the first shaft so that it can be displaced or rotated by a defined angle of rotation, in particular up to a stop. As described, there is basically a coupling between the locking element and the first shaft, whereby the locking element is not firmly connected to the first shaft, but is mounted on the first shaft so that it can be rotated by the defined angle of rotation. For example, the holding element or the previously described coupling mass has a guide, in particular an engagement element, which engages in a groove or a link on the first shaft. As a result, the locking element basically remains rotatable relative to the first shaft, at least until the engagement element engages in the groove or link at the stop.The groove may provide a stop in both directions in the circumferential direction against which the engagement element can strike in order to limit the angle of rotation of the locking element relative to the first shaft.

[0016] According to a further embodiment of the coupling device, the locking element can be coupled to a locking device having at least two locking positions in which a locking element, in particular spring-actuated, applies a locking force between the locking device and the first shaft. The locking device can, for example, be arranged directly on the locking element, for example on the retaining plate or the coupling mass. The locking device applies the locking force between the locking element and the first shaft, so that an existing locking position, which corresponds in particular to a locking position or neutral position, is maintained until it is actively exited.

[0017] To leave the detent position, the detent force must therefore be overcome. This occurs, as already described, through the inertia of the locking element, specifically through speed control of the drive connected to the first shaft. In principle, more than two detent positions corresponding to the locking positions can be provided, in particular three detent positions, with a first detent position corresponding to the first locking position, a second detent position to the neutral position, and a third detent position to the second locking position. The detent positions can be arranged one after the other in the circumferential direction. In principle, the detent device can be arranged as desired, for example on an axial end surface, wherein it may be preferred for the detent device to be arranged between a radial inner surface of the locking element and a radial outer surface of the first shaft.

[0018] A ball or a pin, for example, can be used as the locking element, which is spring-actuated and subjected to a force against the first shaft or against the locking element. The locking device provides appropriate contours that ensure the locking positions, for example, bevels, ramps, recesses, troughs, and the like. The locking device ensures, in particular, that the locking force maintains the current position of the locking element until it is specifically intended to be left, namely through the described speed control or inertia of the locking element. This prevents the locking element from inadvertently rotating and thus leaving the locked position.

[0019] The described locking element can be movable between a first locking position and a second locking position, in particular by relative rotation between the locking device and the first shaft, in particular above a defined speed gradient. In other words, as already described, a speed gradient is specifically set so that the relative movement between the locking element and the first shaft occurs. This comparatively abrupt speed difference overcomes the locking force, so that the locking element can be moved from the locking position and into at least one further locking position. In this case, the locking element switches, for example, from the first locking position to the second locking position or vice versa, or into the neutral position, so that a different coupling between the first shaft and the second shaft is accordingly created.This can lead to forced synchronization, as the freewheel mechanism couples the first and second shafts in opposite directions of rotation. To support forced synchronization, a torque intervention, particularly a positive or negative one, can be provided by the drive mechanism, and / or a speed control can be provided by the drive mechanism to smooth the synchronization.

[0020] A synchronization system as described above can generally be implemented as a counter-rotation synchronization system, since the movement of the locking element, due to the inertial movement relative to the first shaft, is executed in the opposite direction to the movement of the first shaft, i.e., opposite to the locking direction or in the freewheeling direction. For this purpose, it may be necessary to implement a negative torque intervention to improve synchronization.

[0021] In order to be able to apply a positive torque intervention instead, a transmission element, in particular one that is firmly connected to the first shaft, can be arranged between the locking device and the locking element, which transmission element is designed to transmit a direction of rotation of the locking device in the opposite direction to the locking element.

[0022] In other words, a transmission element is provided between the locking device and the locking element, which is designed to change a direction of rotation. If the locking device is rotated in a first direction of rotation, this rotational movement is translated into a second direction of rotation, which is opposite to the first direction of rotation, due to the coupling of the locking device to the locking element via the transmission element. A gear, a lever, or the like can be used as the transmission element, for example. A bearing point, in particular a pivot point, of the transmission element is located on the first shaft, wherein the transmission element, for example the lever ends or the tooth engagement, are connected to the locking device and the locking element. For example, the locking device can be arranged on one side of the transmission element and the locking element on the other side.The coupling mass can be arranged anywhere on the side of the locking element or the locking device.

[0023] In principle, the arrangement of the first shaft and the second shaft relative to one another is possible in any desired manner. According to one embodiment of the coupling device, the first shaft can be arranged coaxially to the second shaft, wherein the second shaft can in particular surround the first shaft. It is also possible for the first shaft to be arranged adjacent to the second shaft in the axial direction. In the first embodiment, the coupling device, in particular the freewheel device, can be arranged in the radial direction between the first shaft and the second shaft. In the second embodiment, the freewheel device can be arranged between the first shaft and the second shaft in the axial direction. Depending on the available installation space, the first alternative or the second alternative can be implemented.

[0024] As already described, the coupling device can be designed with respect to the locking element using various mechanisms and different freewheel elements. In addition to the described pawls, other freewheel elements or clamping bodies can also be used, for example, rollers. In addition to a coupling device with freewheel elements designed as pawls, a coupling device with clamping rollers or clamping balls is also explained below, for example, to implement a corresponding clamping body freewheel in the coupling device.

[0025] In addition to the described coupling device, the invention relates to a drive train comprising an electric machine and a previously described coupling device. Furthermore, the invention relates to a motor vehicle comprising a previously described drive train and / or a previously described coupling device. The electric machine of the drive train can be connected to the remaining drive train, in particular an output of the drive train, or can be selectively separated, as described above, in particular by means of the coupling device.

[0026] The invention also relates to a method for operating a drive train of a motor vehicle, comprising a coupling device comprising a first shaft connected to a drive of the drive train and a second shaft connected to an output of the drive train and a freewheel device having a locking element, in particular a locking cage, wherein in a first locking position of the locking element a relative rotation of the first shaft to the second shaft in a first direction of rotation is released and the first shaft is coupled to the second shaft in the second direction of rotation and in a second locking position of the locking element a relative rotation of the first shaft to the second shaft in a second direction of rotation is released and the first shaft is coupled to the second shaft in the first direction of rotation, wherein the locking element is placed in the first locking position and / or the second locking position without a switching element.

[0027] All advantages, details, and features described with regard to the coupling device are fully applicable to the drivetrain, the motor vehicle, and the method. The method can be implemented, in particular, with the coupling device, for example, as a component of a described drivetrain or motor vehicle.

[0028] The invention is explained below using exemplary embodiments with reference to the figures. The figures are schematic representations and show: Fig. 1 a schematic representation of a cross section of a coupling device in a first locking position; Fig. 2 a schematic diagram of the coupling device of Fig. 1 in a neutral position; Fig. 3 a schematic diagram of the coupling device of Fig. 1, Fig. 2 in a second locking position; Fig. 4 a schematic diagram of the coupling device of Fig. 1-3 with a coupling mass according to a first embodiment; Fig. 5 a schematic diagram of the coupling device of Fig. 1-3 with a coupling mass according to a second embodiment; Fig. 6 a schematic diagram of a section of a coupling device according to a fourth embodiment; Fig. 7 a schematic diagram of a section of a coupling device in the region of a locking device according to a fifth embodiment in a first locking position; Fig. 8 a schematic diagram of a section of the coupling device of Fig. 7 in a second locking position; Fig. 9 a schematic diagram of a section of a coupling device in the region of a locking device according to a sixth embodiment; Fig. 10 is a schematic diagram of a section of a coupling device in the region of a locking device according to a seventh embodiment; Fig. 11 is a schematic diagram of a section of a coupling device in the region of a locking device according to an eighth embodiment; Fig. 12 is a schematic diagram of a cross section of a coupling device according to a ninth embodiment; Fig. 13 a schematic diagram of the coupling device of Fig. 12 with a coupling mass; Fig. 14 is a schematic diagram of a cross section of a coupling device according to a tenth embodiment; Fig. 15 a schematic diagram of the coupling device of Fig. 14 with a coupling mass; Fig. 16a, Fig. 16b each shows a schematic diagram of a contour of a freewheel device of a coupling device according to Fig. 12-15; Fig. 17 is a schematic diagram of a coupling device according to an eleventh embodiment; Fig. 18 is a schematic diagram of a section of a drive train of a motor vehicle according to a twelfth embodiment; Fig. 19 a schematic diagram of a speed and torque diagram of a counter-rotating synchronization; and Fig. 20 a schematic diagram of a speed and torque diagram of a synchronous synchronization.

[0029] Fig. 1-3 each show a section of a motor vehicle, in particular a drive train 1 with a coupling device 2, wherein a cross-section is shown in the direction of the axis of rotation of the coupling device 2, which, for example, runs centrally. In the embodiment shown, the coupling device 2 has a first shaft 3 and a second shaft 4, which are arranged coaxially around a common axis of rotation. Other arrangements, which, for example, in Fig. 17 are also possible. The description is fully applicable to this.

[0030] Between the first shaft 3 and the second shaft 4, the coupling device 2 has a freewheel device 5 in the radial direction, which provides a locking element 6, which is designed, for example, as a locking cage. The locking element 6 has locking struts 7 that extend in the axial direction parallel to the first shaft 3 and the second shaft 4, respectively, and can act on freewheel elements 8, 8' of the freewheel device 5 to deactivate them.

[0031] In the Fig. 1, the locking element 6 locks a first group of freewheel elements 8, so that a torque transmission is possible via the second freewheel elements 8', which are supported between a first stop on the first shaft 3 and a second stop on the second shaft 4. Alternatively, a reverse arrangement is also possible, in which the freewheel elements 8, 8' are arranged on the second shaft 4, in particular pivotably, and are reset radially inward. If a freewheel element 8, 8' is locked, it is held radially outward in such an embodiment. In other words, the Fig. 1-5, the principle shown with regard to the bearing of the freewheel elements 8, 8' can be reversed and the description otherwise transferred. Purely as an example, four freewheel elements 8, 8' are provided per group, whereby the number is merely exemplary and can be changed as desired. As will be explained below with regard to Fig. 12-16, the type of freewheel elements 8, 8' used or, in principle, the design of the freewheel device 5 or its locking element 6 can be selected as desired. Fig. 1-5, freewheel pawls are used as examples, which can be pushed radially inwards by the locking element 7 in order to release them from the stop or to deactivate them. The use of clamping bodies, as for example in Fig. 12-16 is also possible. The description is therefore fully transferable.

[0032] As described, torque transmission via the second freewheel elements 8' is thus possible, i.e. when the first shaft 3 rotates counterclockwise in the figure. When the first shaft 3 moves or there is a relative movement in which the first shaft 3 is overtaken by the second shaft 4, for example when the second shaft 4 has a higher counterclockwise speed than the first shaft 3, the freewheel device 5 releases the coupling so that the second shaft 4 can overtake the first shaft 3 and the freewheel elements 8' can run freely. Since the first freewheel elements 8 are deactivated by the locking element 6, the first shaft 3 and the second shaft 4 can run freely in this direction of rotation.

[0033] In Fig. 2 shows a schematic representation of a neutral position, which, for example, starts from the position shown in Fig. 1 shown first locking position or the one in Fig. 3. For this purpose, the locking element 6 is moved in the circumferential direction relative to the first shaft 4, so that the locking element 6 deactivates both freewheel elements 8, 8' in the neutral position. In the neutral position, free rotation of the first shaft 3 and the second shaft 4 is thus possible, regardless of the direction of rotation or the relative rotation.

[0034] As described, Fig. 3 the second locking position, in which, inversely to the first locking position of Fig. 1, the second freewheel elements 8' are deactivated, and the first freewheel elements 8 are released. Accordingly, torque transmission from the first shaft 3 in a clockwise direction to the second shaft 4 is possible. If there is a relative rotation between the second shaft 4 and the first shaft 3, in which the second shaft 4 rotates faster in a clockwise direction than the first shaft 3, the second shaft 4 overtakes the first shaft 3 in a corresponding freewheeling state.

[0035] Thus, depending on the position of the locking element 6, it is possible to transmit torque in both directions of rotation and to achieve decoupling in the opposite direction. Optionally, the Fig. 2 shown neutral position can be implemented, which allows freewheeling in both directions.

[0036] The coupling device 2 is designed without a switching element within the scope of this application, which means that no active switching element, for example an actuator, a valve, and the like, is required to set the locking element 6 in the desired locking position or neutral position. Instead, the movement of the locking element 6 is based on inertia, in particular by setting a defined speed gradient on the first shaft 3. Due to the mass of the locking element 6, it behaves inertly with respect to the first shaft 3, on which the locking element 6 is rotatably arranged. If a defined speed gradient, in particular above a specified limit value, is set on the first shaft 3, a relative movement occurs between the locking element 6 and the first shaft 3, since the inert locking element 6 does not follow the first shaft 3 in a rotationally fixed manner. As a result, the locking element 6 can be displaced in the circumferential direction relative to the first shaft 3 in order to Fig. 1-3 positions or stances shown as examples.

[0037] For example, in Fig. 4, Fig. 5 shows a holding element 9 which can act as a coupling mass or can further increase the inertial mass of the locking element 7. The holding element 9 can also be designed as being integrated into the locking element 6. The holding element 9 is firmly connected to the locking element 6 and is coupled to the first shaft 3 via an engagement element 10 which engages in a slotted guide 11 in the first shaft 3, wherein the holding element 9 remains rotatable relative to the first shaft 3 in the circumferential direction. In other words, the slotted guide 11 forms a stop or a stop on both sides in the circumferential direction for the engagement element 10 in order to be able to drive the holding element 9, wherein a relative rotation between the holding element 9 and thus the locking element 6 and the first shaft 3 remains possible for the position of the locking element 6.

[0038] Deviating from the Fig. 4 shown axially adjacent arrangement of the holding element 9 to the first shaft 3 or second shaft 4, a radial integration within the first shaft 3 is also possible, as is the case, for example, in Fig. 5. In particular, a coupling mass 12 is shown here, which is coupled to the holding element 9 and is accommodated radially within the first shaft 3, which is designed as a hollow shaft. This allows the total mass of the locking element 6 to be further increased, so that the inertia of the freewheel device 5 or the locking element 6 can be utilized more effectively to switch the locking element 6.

[0039] Fig. Figure 6 schematically shows a section of a longitudinal section of the coupling device 2, wherein the holding element 9 is clearly connected to the locking struts 7. The freewheel elements 8, 8' are arranged on the outer circumference of the first shaft 3 and can be deactivated or activated depending on the position of the locking element 6. If the freewheel elements 8, 8' are activated, they can engage with the stops on the inner circumference of the second shaft 4 in order to support the first shaft 3 on the second shaft 4, as shown in relation to Fig. 1-3 already described. If the freewheel elements 8, 8' are deactivated, freewheeling is possible. Fig. 6 a locking device 13 is shown, which can be located between the locking struts 7 and the outer surface of the first shaft 4. Possible embodiments of the locking device 13 are described below with reference to Fig. 7-11.

[0040] For ease of illustration, Fig. 7-11, the switching gate or the locking device 13 is projected into the plane. As described, the locking device 13 is usually located between the locking element 6 and the outer circumference of the first shaft 3, so that the Fig. 7-11 are to be understood as curved or circular segment-shaped. Alternatively, a frontal arrangement of the locking device 13 on the first shaft 3 is also possible. The locking device 13 has at least one locking element 14, which is designed, for example, as a ball or pin and is held spring-actuated against a contour of the locking strut 7 or the holding element 9. It is also possible to design the locking device 13 in reverse, so that the contour is implemented in the first shaft 3.

[0041] Purely as an example, Fig. 7 which has already been done in relation to Fig. 1, in which the locking element 6 holds down the freewheel elements 8 with the corresponding locking strut 7. Accordingly, torque transmission through the freewheel elements 8' is possible, or freewheeling by slipping the freewheel elements 8' in the opposite direction of rotation. In this case, the locking device 13 is in a first locking position. In order to transition from the first locking position to the second locking position, a defined speed gradient is set, for example by means of a drive device coupled to the first shaft 3, for example an electric machine, and in particular the electric machine and thus the first shaft 3 are accelerated or braked.

[0042] Due to the inertia of the locking element 6, which does not fully follow the speed gradient of the first shaft 3 due to the lack of a rotationally fixed coupling, the locking force exerted by the return element 15, for example a spring element, on the locking element 14 is overcome, so that a relative rotation between the locking element 6 and the first shaft 3 is possible, in which the locking element 14 overcomes the contour and thus the second locking position, which in Fig. 8. As already described, the locking element 6 or the locking strut 7 switches from the freewheel elements 8 to the freewheel elements 8' and deactivates them. This is particularly possible because, in the described state, the freewheel elements 8' are torque-free and can thus be deactivated.

[0043] During the transition described, when the freewheel elements 8 engage with the corresponding stops on the second shaft 4, a forced synchronization will occur, which can be improved by a targeted torque intervention on the part of the drive device, so that it can be carried out “smootherly”.

[0044] Fig. 9 shows, by way of example, a locking device 13 according to an alternative embodiment, in which the contour has a further locking position between the first locking position and the second locking position, in which the neutral position described above can be assumed. As described, in the neutral position, the locking element 6 can deactivate both freewheel elements 8, 8'. Accordingly, the drive device connected to the first shaft 3 can switch through the individual locking positions using the described speed gradient in order to move the locking element 6 into the desired locking position or neutral position.

[0045] As described, it is possible to carry out a torque intervention in order to improve the synchronization that occurs when changing the active freewheel elements 8, 8'. As previously described, the inertia of the locking element 6 leads to counter-rotation during synchronization, which, as part of a forced synchronization, results in a coupling of the first shaft 3 to the second shaft 4. To improve this, the active group of freewheel elements 8, 8' can first be relieved, for example by reducing the currently set torque on the first shaft 3 or by adjusting the speed below the output speed or above the output speed if the drive device or the system is in recuperation mode. A slight speed difference can be set between the shafts 3, 4 with a slightly positive torque, in particular to overcome the drag torque.This means that if there is a slight speed difference between the first shaft 3 and the second shaft 4, the freewheel device 5 runs freely and does not transmit any torque. A torque surge or a high torque gradient can be applied to the first shaft 3, so that the mass inertia of the switching element 6 overcomes the previously described locking force and the switching element 6 is moved into the desired locking position.

[0046] The previously described counter-rotation synchronization is Fig. 19 schematically shows a diagram of the torque 22 and a speed 23 of a drive device 20 for an embodiment (cf. schematic representation of the drive train 1 in Fig. 18) and an output speed 24 of the coupling device 1 are plotted over time. The individual steps of counter-rotation synchronization will be described using the example diagram.

[0047] In a phase 25, for example, normal operation occurs, in which the drive device 20 introduces torque via the first shaft 3, which is transmitted via the coupling device 1 to the second shaft 4 and thus to the output 21. In a phase 26, the torque 22 of the drive device 20 is reduced or ramped down in order to relieve the load on the freewheel elements 8 (or freewheel elements 8') or clamping bodies 17 that are in transmission.

[0048] Subsequently, in a phase 27, a particularly slight speed difference is set between the first shaft 3 and the second shaft 4. In this case, the torque 22 of the drive device 20 can remain positive, for example, to overcome the drag torques in the drive train 1. Furthermore, in phase 27, the drive device 20 is adjusted, for example, speed-controlled, such that a defined speed difference results between the first shaft 3 and the second shaft 4, for example, less than 25 revolutions / min. In this state, the coupling device 1 no longer transmits any torque.

[0049] In a phase 28, a defined torque impulse can be applied by the drive device 20, resulting in a corresponding speed gradient. Due to the mass inertia of the coupling device 1, in particular the coupling mass 12 or the locking element 6 itself, as described, the locking device 13 is overcome, so that the locking element 6 flips into the opposite position, for example (starting from Fig. 1) the locking strut 7 locks the opposite freewheel element 8' and releases the current freewheel element 8.

[0050] In phase 29, the forced synchronization takes place, since, as described, in phase 28 a change is made by the blocking element 6, for example the Fig. 1 locked freewheel elements 8 are released and the Fig. 1 released freewheel elements 8' are blocked or vice versa. Since the first shaft 3 moves at a lower speed than the second shaft 4, forced synchronization occurs as soon as the now released freewheel elements 8 (or conversely freewheel elements 8') are supported on the stops, whereby the speed difference between the first shaft 3 and the second shaft 4 is reduced. In order to make this process less noticeable for users of the motor vehicle, the first shaft 3 can be deliberately accelerated by the drive device 20 in order to make the speed adjustment "smoother".

[0051] In phase 30, the system is then in synchronization, so that, as shown in phase 31, a torque can be introduced that is opposite to the normal operation or drive state. In particular, in phase 31, compared to the normal operation present in the initial state, i.e. in phase 25, a recuperation mode is possible. As already described several times, the description is also transferable to the reverse change of the operating state, whereby recuperation mode and normal operation can be exchanged accordingly, for example, depending on whether the Fig. 1 shown state and with the in Fig. 3 shown state or vice versa from the one shown in Fig. 3 shown state and with the in Fig. 1 shown state is terminated.

[0052] Fig. 10, Fig. 11 show further embodiments in which the previously described counter-rotation synchronization can be further improved within the framework of a synchronization. For this purpose, a transmission element 16 is arranged between the locking element 6 and the locking device 13 or the holding element 9, which is designed to reverse the direction of rotation. Fig. 10, the transmission element 16 is designed, for example, as a gear whose pivot point is firmly connected to the first shaft 3. Accordingly, the transmission element 16 reverses the direction of rotation of the locking element 6 and the locking device 13 or the holding element 9 relative to each other.

[0053] In the described state, in which the torque surge or the comparatively high speed gradient on the first shaft 3 is regulated, the holding element 9 and any coupling mass 12 present ultimately act as an energy store that seeks to continue the previously executed rotary movement. In doing so, the holding element 9 or the locking device 13 rotates relative to the first shaft 3, which is converted by the transmission element 16 into an opposing movement of the locking element 6. This makes it possible to carry out a uniform or rectified torque intervention, i.e. a torque intervention, in order to improve synchronization upon engagement of the freewheel element 8, 8' to be activated.

[0054] Fig. Figure 11 schematically shows a transmission element 16 designed as a lever. The pivot point of the lever is, as already described, firmly connected to the first shaft 3, with the lever end points each connected to the locking element 6 and the locking device 13 or the holding element 9. The operation of the transmission element 16 is analogous to the transmission element 16 of Fig. 10, so that the preceding description is fully transferable.

[0055] The synchronization, which was previously described in relation to Fig. 10, Fig. 11, is based on an analogue to that already described in Fig. 19 shown diagram described with regard to counter-rotation synchronization, in Fig. 20. The diagram in Fig. 20 can in turn be described using phases 25-31.

[0056] Phase 25, for example, represents normal operation, in which torque flows from the drive device 20 to the output 21 or to the wheels of the motor vehicle to drive the vehicle. In phase 26, the pawl or clamping body currently used to transmit torque is relieved. Since there is no risk of an unwanted switchover, the torque can be reduced quickly.

[0057] In phase 27, as already described, a speed difference is set between the first shaft 3 and the second shaft 4. A significantly higher speed difference can be selected compared to the previously described speed difference, for example, 200 revolutions / min. In this case, the coupling device 1 no longer transmits any torque.

[0058] In phase 28, the coupling device 1 is subsequently switched, namely by a high, positive torque pulse or speed gradient. The magnitude of the torque pulse must be selected in particular such that the counterforce due to the inertia of the locking element 6 or the coupling mass 12 is sufficiently high that the locking device 13 is overcome or a clamping body 17, described below, can leave a (potential) trough 19.

[0059] Since the released freewheel elements 8 (or alternatively freewheel elements 8') only lock in the opposite direction of movement, the first shaft 3 can overtake the second shaft 4. Therefore, there is no need for forced synchronization; instead, there is a "swing over" process, with the first shaft 3 overtaking the second shaft 4 until the speed difference is eliminated. In other words, the speed of the first shaft 3 can be reduced in a speed-controlled manner by the drive device 20 or by "coasting down" until the speed level of the second shaft 4 is reached. Subsequently, the released freewheel elements 8 (or alternatively freewheel elements 8') that are not locked by the locking element 6 engage in phase 30, so that torque can then be transmitted in phase 31, for example, a recuperation torque can be transmitted from the output 21 to the drive device 20.

[0060] Fig. 12 shows an alternative embodiment of a coupling device 2, which basically corresponds to the operation of the coupling device 2 from Fig. 1-11. The preceding description is therefore fully applicable to the following figures. Instead of the previously described locking struts 7, a locking element 6 with clamping bodies 17 is used in this embodiment, which are designed, for example, as rollers, cylinders, or balls. These rest, as already described with regard to the locking struts 7, on an outer circumference of the first shaft 3 and are thus located in the radial direction between the first shaft 3 and the second shaft 4. In the Fig. In the neutral position shown in Figure 12, rotation of the first shaft 3 or the second shaft 4 is permitted in both directions of rotation.

[0061] Fig. 13 again shows a holding element 9, which is coupled to the clamping bodies 17, namely via a return element 18, for example a spring element, which is connected to the first shaft 3 at the rotational axes of the clamping bodies 17. The return elements 18 thus act as return elements and pull the clamping bodies 17 via their shafts into the Fig. 12, Fig. 13 shown rest position or neutral position radially inward. The restoring elements 18 therefore cause a restoring force inward, which ensures that the clamping bodies 17 remain in the (potential) troughs. As before, the holding element 9 is not firmly connected to the first shaft 3, but in this embodiment is only connected to the first shaft 3 via the shafts of the clamping bodies 17. Optionally, as already described above with respect to Fig. 4, Fig. 5, the holding element 9 can in turn be coupled to a coupling mass 12.

[0062] If the first shaft 3 is accelerated or decelerated at a comparatively high speed gradient compared to the second shaft 4, the clamping bodies 17 will run onto the adjacent ramps or contours. The reason for this is again the movement triggered by the inertia of the holding plate 9 and thus of the locking element 6, which comprises the clamping bodies 17. The clamping bodies 17 can move outwards in a radial direction, for example due to a guide in oblong holes, and guided by the contour come into contact with the second shaft 4, so that contact is established between the first shaft 3 and the second shaft 4 and a coupling is established by means of the coupling device 2. This ensures that the coupling is only established in one direction of rotation, in which the clamping bodies 17 couple the first shaft 3 to the second shaft 4. If an opposite rotational movement orRelative rotation occurs, the freewheel device 5 ensures that the first shaft 3 remains rotatable relative to the second shaft 4 and vice versa.

[0063] Fig. 14, Fig. 15 show a Fig. 12, Fig. 13 alternative embodiment, in which the arrangement of the freewheel device 5 remains arranged between the first shaft 3 and the second shaft 4, but the clamping bodies 17 are not arranged on the first shaft 3, but on the second shaft 4. The embodiment according to Fig. 12, Fig. 13 can therefore also be considered as “internal arrangement” and the embodiment according to Fig. 14, Fig. 15 can be referred to as the "outer arrangement." Otherwise, the description is generally transferable. As described, the terms "first shaft" and "second shaft" are also interchangeable, so that in this embodiment, the outer shaft can form the "first shaft."

[0064] Fig. Figure 15 shows the arrangement of the clamping bodies 17 on the holding element 9, again with return elements 18, which, however, act as return elements radially outwards. In other words, the return elements 18 pull the clamping bodies 17 into the Fig. 14, Fig. 15. In this variant, the holding element 9 is coupled to the second shaft 4. For example, in this embodiment, the drive device can be coupled to the second shaft 4, so that the previously described speed control is again possible. As described, in this embodiment, the outer shaft can also be referred to as the "first shaft," since it assumes the speed control.

[0065] Fig. 16a, Fig. 16b show two embodiments of contours along which the clamping bodies 17, for example in the embodiment in Fig. 12-15, are movable. Fig. 16a shows a triangular design of the contours, viewed in cross-section, in which the clamping bodies 17 rest directly against the starting ramps. The radial position of the clamping bodies 17 depends on the restoring force of the restoring elements 18, as well as on the rotational speed, which in turn generates a centrifugal force, and on the rotational acceleration, which is exerted on the clamping bodies 17 due to the inertia of the retaining plate 9 or the optional coupling mass 12. By appropriately selecting the individual components or designing the spring force, ramp angle, and mass, the moment at which frictional connection is established between the first shaft 3 and the second shaft 4, in particular the required speed gradient or the required rotational acceleration, can be precisely adjusted.

[0066] In Fig. 16b, the clamping bodies 17 are located in the rest position or neutral position shown in a recess 19. This makes it possible to define a discontinuous characteristic curve so that initially no relative movement of the clamping bodies 17 occurs even with a speed gradient between the first shaft 3 and the second shaft 4. If a certain speed gradient is exceeded and thus a certain acceleration is caused on the holding element 9 or generally the locking element 6, the clamping bodies 17 are abruptly moved over the edge of the recess 19. Since the described force, which is higher for leaving the recess 19 than the restoring force of the starting ramps of the contour, the clamping bodies 17 are immediately clamped on the contour or the ramps. This makes it possible, in particular, for torque to be transmitted abruptly or suddenly in this embodiment.

[0067] As already described, Fig. 17 shows an alternative embodiment in which the first shaft 3 and the second shaft 4 are not arranged coaxially to one another or nested within one another, but are arranged adjacent to one another in the axial direction. The freewheel device 5 is in this case located in the axial direction between the first shaft 3 and the second shaft 4. However, due to its inertia, the locking element 6 is rotated in the circumferential direction, i.e., around the axis of rotation of the shafts 3, 4, relative to the first shaft 3 or the second shaft 4, in order to achieve a corresponding locking effect or release effect. The preceding description is therefore also completely applicable to the embodiment according to Fig. 17 transferable.

[0068] Fig.Figure 18 shows a schematic overview of the drive train 1, wherein the first shaft 3 is connected, purely by way of example, to a drive device 20, in particular an electric motor, directly to the output shaft or rotor shaft or via a transmission. The second shaft 4 is coupled to an output 21 of the drive train 1, for example, a differential. As can be seen, depending on the state of the coupling device 1, the coupling between the drive device 20 and the output 21 is established or separated, as previously described.

[0069] The method described herein can be carried out with any coupling device 2 from the individual embodiments, wherein all described details can also be implemented within the scope of the method.

[0070] All advantages, details and features shown in the individual embodiments can be combined with one another as desired, are interchangeable and transferable to one another. Reference symbol 1 drivetrain 2 coupling device 3 first wave 4 second wave 5 Freewheel device 6 locking element 7 locking strut 8, 8' freewheel element 9 Holding element 10 engagement element 11 Scenery 12 Coupling mass 13 locking device 14 locking element 15 Reset element 16 Translation element 17 clamping bodies 18 Reset element 19 trough 20 Drive device 21 downforce 22 torque 23 speed 24 Output speed 25-31 phases

Claims

[1] Coupling device (2) for a drive train (1) of a motor vehicle, comprising a first shaft (3) connectable or connected to a drive of the drive train (1) and a second shaft (4) connectable or connected to an output of the drive train (1) and a freewheel device (5) having a locking element (6), in particular a locking cage, which, in a first locking position of the locking element (6), is designed to release a relative rotation of the first shaft (3) to the second shaft (4) in a first direction of rotation and to couple the first shaft (3) to the second shaft (4) in the second direction of rotation, characterized byin that the freewheel device (5) is designed, in a second blocking position of the blocking element (6), to release a relative rotation of the first shaft (3) to the second shaft (4) in a second direction of rotation and to couple the first shaft (3) to the second shaft (4) in the first direction of rotation, wherein the blocking element (6) can be set into the first blocking position and / or the second blocking position without a switching element. [2] Coupling device (2) according to claim 1, characterized by that the locking element (6) is adjustable based on inertia, in particular depending on a speed gradient of the first shaft (3). [3] Coupling device (2) according to claim 1 or 2, characterized by that the locking element (6) is coupled to a coupling mass (12). [4] Coupling device (2) according to one of the preceding claims, characterized bythat the locking element (6) is arranged on the first shaft (3) so as to be displaceable by a defined angle of rotation, in particular up to a stop. [5] Coupling device (2) according to one of the preceding claims, characterized by that the locking element (6) is coupled to a locking device (13) which has at least two locking positions in which a locking element (14), in particular spring-actuated, applies a locking force between the locking device (13) and the first shaft (3). [6] Coupling device (2) according to claim 5, characterized by that the locking element (14) is movable between a first locking position and a second locking position by relative rotation between the locking device (13) and the first shaft (3), in particular above a defined speed gradient. [7] Coupling device (2) according to claim 5 or 6, characterized bythat a transmission element (16), which is in particular firmly connected to the first shaft (3), is arranged between the locking device (13) and the locking element (6), which transmission element is designed to transmit a direction of rotation of the locking device (13) in the opposite direction to the locking element (6). [8] Coupling device (2) according to one of the preceding claims, characterized by that the first shaft (3) is arranged coaxially to the second shaft (4) or that the first shaft (3) is arranged axially adjacent to the second shaft (4). [9] Drive train (1) comprising an electric machine and a coupling device (2) according to one of the preceding claims. [10] Motor vehicle comprising a drive train (1) according to the preceding claim and / or a coupling device (2) according to one of claims 1 to 8. [11] A method for operating a drive train (1) of a motor vehicle, comprising a coupling device (2) comprising a first shaft (3) connected to a drive of the drive train (1) and a second shaft (4) connected to an output of the drive train (1), and a freewheel device (5) having a locking element (6), in particular a locking cage, wherein, in a first locking position of the locking element (6), a relative rotation of the first shaft (3) to the second shaft (4) in a first direction of rotation is released and the first shaft (4) is coupled to the second shaft (4) in the second direction of rotation, and, in a second locking position of the locking element (6), a relative rotation of the first shaft (3) to the second shaft (4) in a second direction of rotation is released and the first shaft (4) is coupled to the second shaft (4) in the first direction of rotation,wherein the locking element (6) is placed in the first locking position and / or the second locking position without a switching element.,

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