Drive device for a motor vehicle and method for operating such a drive device

Abstract

The invention relates to a drive device for a motor vehicle, comprising a transmission having at least one claw shifting element (10) by means of which at least one gear stage of the transmission can be shifted, and comprising an actuating device (16) for actuating the claw shifting element (10). The claw shifting element (10) has two claw halves (12, 14) that are movable relative to one another along an actuating direction (B) and opposite one another along the actuating direction (B), and three switching states, namely an open state (O), a freewheeling state (F), and a closed state (S). The claw halves (12, 14) can be moved relative to one another along the actuating direction (B) by means of the actuating device (16) between at least one open position (OS) bringing about the open state (O), at least one closed position (SS) bringing about the closed state (S), and at least one freewheeling position (FS) bringing about the freewheeling state (F).

Description

The invention relates to a drive device for a motor vehicle, in particular for a motor vehicle. Furthermore, the invention relates to a method for operating such a drive device.DE 10 2017 111 414 A1 discloses a method for operating a positively acting clutch, wherein the clutch has a first clutch element, a second, axially movable clutch element and a sensor for detecting a movement of the second clutch element into the engaged state of the clutch.DE 10 2016 221 015 A1 discloses a claw clutch for a drive train of a motor vehicle. The claw clutch has a first toothed component designed as a claw body, which can be connected in a positive-locking manner to a second toothed component designed as a claw body for transmitting a torque, in that the first toothed component is arranged so as to be axially movable in order to enter the second toothed component, wherein a blocking diaphragm is inserted between the two toothed components.DE 10 2015 214 266 A1 discloses a torque transmission device for a drive train of a motor vehicle having a separating clutch which has two clutch elements which can be connected to one another in a positively locking manner, and having a free-wheel unit which is arranged in parallel connection with the separating clutch with respect to the torque flow and has two rotary parts which interact via a plurality of free-wheel blocking bodies.DE 10 2012 204 470 A1 discloses a transmission stage for a drive train that can be operated by electric motor. Furthermore, DE 10 2013 011 555 A1 discloses a coupling device for a motor vehicle.It is the object of the present invention to provide a drive device for a motor vehicle and a method for operating such a drive device, so that particularly advantageous operation of the drive device can be realized.This object is achieved by a drive device having the features of claim 1. Advantageous embodiments with expedient developments of the invention are specified in the other claims.A first aspect of the invention relates to a drive device for a motor vehicle, which is also referred to simply as a vehicle and is preferably designed as a motor vehicle, in particular as a passenger vehicle. This means that the motor vehicle has the drive device in its completely produced state and can be driven by means of the drive device. In particular, the drive device can be an electric drive device, by means of which the motor vehicle can be driven electrically, in particular purely. The drive device has a transmission, also referred to as a transmission device, which has at least one claw shifting element. Furthermore, the transmission has at least one gear stage. In particular, it is conceivable that the transmission has at least or exactly two gear stages, namely the previously mentioned gear stage as a first gear stage and a second gear stage. The respective gear stage is also referred to as the respective gear of the transmission. In particular, the gear stages differ from one another in their transmission ratios. By means of the pawl shift, the at least one gear stage of the transmission can be shifted, i.e. selectively engaged or disengaged. If the term gear stage is mentioned below, this is to be understood, unless otherwise stated, as meaning the at least one gear stage which can be selectively engaged or disengaged, that is to say shifted, by means of the claw shifting element. In particular, the respective gear stage can be shifted, and therefore can be selectively engaged or disengaged. In particular, and most particularly whenever the first gear stage is engaged, the second gear stage is designed. In particular, and most preferably whenever the second gear stage is engaged, the first gear stage is designed. The drive device may include, for example, a multi-plate shift element provided in addition to the dog shift element. The claw shifting element and the multi-disk shifting element are collectively also referred to as shifting elements, wherein the at least or exactly two gear stages of the transmission can be shifted by means of the shifting elements, and can therefore be selectively engaged or disengaged. The claw shifting element is a form-locking shifting element, by means of which the at least one gear stage can be selectively disengaged or engaged in a form-locking manner. In contrast, the multi-disk shifting element is a frictionally engaging shifting element.The driving device also includes an operating device for operating the pawl switching element. This means that the claw switching element can be actuated, i.e. switched, by means of the actuating device.The claw switching element has two claw halves that are movable relative to one another, in particular translationally, along an actuation direction and are opposite one another along the actuation direction. In particular, the actuation direction runs along an imaginary straight line. The dog shift element has three shift states, namely, an open state, a free-wheeling state, and a closing state. The claw switching element can thus be switched by means of the actuating device between the switching states, that is to say between the open state, the free-wheeling state and the closed state, in particular in that the claw halves can be moved relative to one another, in particular translationally, along the actuating device by means of the actuating device, and consequently can be moved along the actuating direction and movements of the claw halves which take place relative to one another by means of the actuating device. The claw switching elements can be moved, in particular translationally, by means of the actuating device along the actuating direction relative to one another between at least one open position causing the open state, at least one closed position causing the closed state and at least one free-running position causing the free-running state. That is, when the claw halves are in the open state relative to each other, the claw switching element is in the open state. If the claw halves are in the closed state relative to one another, the claw switching element is thereby in the closed state. If the claw halves are in the free-wheeling position relative to one another, the claw switching element is thereby in the free-wheeling state.The jaw halves are also referred to as halves. One of the claw halves is connected, for example, in particular permanently, in a rotationally fixed manner to a first structural element of the drive device, and the other claw half is connected, for example, in particular permanently, in a rotationally fixed manner to a second structural element of the drive device.The drive device comprises, for example, a housing, wherein, for example, the claw switching element is arranged in the housing. The first component is, for example, a component different from the housing and additionally provided thereto and is rotatable about an axis of rotation relative to the housing. The second component is, for example, the housing, or the second component is a component which is different from the housing and is additionally provided thereto and which can be rotatable about the axis of rotation relative to the housing. In the closed state, the components are connected to one another in a rotationally fixed manner by means of the claw switching element in such a way that relative rotations between the components are prevented both in a first rotational direction extending around the rotational axis and in a second second rotational direction extending around the rotational axis and opposite the first rotational direction, and therefore the first component cannot be rotated relative to the second component either in the first rotational direction or in the second rotational direction around the rotational axis. In the closed state, the components are connected to one another in a rotationally fixed manner in a positive-locking manner by means of the claw switching element. In the open state, the components are decoupled from one another, in particular completely, so that in the open state the components can be rotated relative to one another both in the first rotational direction and in the second rotational direction, namely about the rotational axis. In other words, in the open state, the first component can be rotated relative to the second component about the axis of rotation in both the first direction of rotation and the second direction of rotation. In particular, the components are decoupled from one another in the open state in such a way that no torques can be transmitted between the components via the claw shifting element. In the closed state, however, torques acting about the rotational axis can be transmitted from the first component to the second component and vice versa, both in the first rotational direction and in the second rotational direction. In the free-wheeling state, the dog shift element acts or functions as or as a free-wheeling. This means that in the free-wheeling state the components are connected to one another in a positively fixed manner with respect to the first rotational direction by means of the claw switching element in such a way that relative rotations between the components occurring in the first rotational direction and about the rotational axis are prevented by means of the claw switching element, and therefore the first component cannot be rotated about the rotational axis in the first rotational direction relative to the second component, so that torques acting in the first rotational direction about the rotational axis can be transmitted from the first component to the second component. In the free-wheeling state, however, the claw switching element permits relative rotations between the components about the axis of rotation and occurring in the second direction of rotation, in particular automatically or independently, that is to say without switching the claw switching element, so that in the free-wheeling state the first component is rotatable in the second direction of rotation about the axis of rotation relative to the second component. Since the claw switching element acts or functions as a freewheel in the freewheel state, in the freewheel state, for example, drive forces and / or torques viewed from the first component toward the second component can be transmitted only in the first rotational direction, but not also in the second rotational direction, from the first component to the second component via the claw switching element, since, viewed from the first component and in particular from the second component, the first component is rotatable in the freewheel state about the rotational axis in the second rotational direction relative to the first component. Viewed from the second structural element and toward the first structural element, in the free-wheeling state, the second structural element is rotatable about the axis of rotation in the first direction of rotation relative to the first structural element, wherein rotations of the second structural element about the axis of rotation in the second direction of rotation and relative to the first structural element are prevented in particular in a form-fitting manner by means of the claw switching element. In other words, in the free-wheeling state, the second component cannot be rotated about the rotational axis in the second rotational direction relative to the first component. Thus, in the free-wheeling state, viewed from the second structural element and toward the first structural element, drive forces and / or torques can be transmitted from the second structural element to the first structural element via the claw switching element only in the second rotational direction and not also in the first rotational direction.The respective claw half has respective claws, also referred to as switching claws. In the closed state, the claws of the claw halves cooperate in a positive-locking manner, whereby the claw halves and thus the structural elements are connected to one another in a positive-locking manner, when viewed in the first rotational direction as well as in the second rotational direction. In the open state, a positive interaction of the claws of the claw halves is omitted. In the free-wheeling state, the claws of the claw halves cooperate in a form-fitting manner in such a way that the first structural element cannot be rotated about the axis of rotation in the first direction of rotation relative to the second structural element or the second structural element cannot be rotated about the axis of rotation in the second direction of rotation relative to the first structural element, but the claws of the claw halves allow the first structural element to be rotated about the axis of rotation in the second direction of rotation relative to the second structural element or the second structural element to be rotatable about the axis of rotation in the first direction of rotation relative to the first structural element. The claws of the respective claw half each have exactly one coupling flank and in each case exactly one top surface which is oriented obliquely to the actuating direction and obliquely to the respective coupling flank, and therefore runs. In particular, for example, the respective head surface extends in a respective plane which extends obliquely to the actuation direction. The aforementioned plane is also referred to as a first plane. For example, the head surface extends in a respective second plane, wherein in particular the first plane extends perpendicular to the second plane. The second plane runs, for example, parallel to the actuation direction. The actuation direction coincides with the rotational axis, for example. Thus, for example, the respective claws of the respective claw half form a saw-tooth profile. The head surfaces make it possible that in the free-wheeling state, when the first component is rotated about the axis of rotation in the second direction of rotation relative to the second component or the second component is rotated about the axis of rotation relative to the first component in the first direction of rotation, the head surfaces slide against one another, so that the first component is rotatable about the axis of rotation about the second direction of rotation relative to the second component or the second component is rotatable about the axis of rotation in the first direction of rotation relative to the first component. Due to the oblique head surfaces, the claw switching element can thus act or function as a freewheel in the freewheel state.Furthermore, it is provided that the respective top surface extends starting from the respective coupling flank as far as a respective claw base of the respective claw half.In traction operation of the motor vehicle and in the closed state of the claw shifting element, force and thus torque transmission takes place via the coupling flanks of one of the claw halves and the corresponding coupling flanks of the other claw half. In the traction mode of the motor vehicle, the motor vehicle is driven by means of the drive device. In other words, in the traction mode of the motor vehicle, the drive device, in particular at least one drive motor of the drive device, provides a drive torque by means of which the motor vehicle is driven. The drive motor is, for example, an electric machine. In the free-wheeling state, for example, in the traction mode of the motor vehicle, forces and thus torques can be transmitted from the first structural element to the second structural element in the first rotational direction via the coupling flanks of the claw halves, or forces and thus torques can be transmitted from the second structural element to the first structural element in the second rotational direction via the coupling flanks of the claw halves.Furthermore, it is provided that the actuating device is formed self-locking. This means that the actuating device holds the respective switching state of the claw switching element, in particular the switching state previously switched on, by self-locking of the actuating device and thus automatically or automatically. In other words, the actuating device maintains the claw switching element in the respective switching state of the claw switching element, in particular the switching state previously switched on, without the actuating device being supplied with energy from outside the actuating device. In other words, because the actuating device is designed to be self-locking, activation of the actuating device, and therefore supplying the actuating device with energy from outside the actuating device, is required only for switching the claw switching element, and therefore only for switching the claw switching element from one of the switching states to another of the switching states. In order to keep the claw switching element in the respective switching state by means of the actuating device, there is no supply of energy to the actuating device from outside the actuating device, as a result of which particularly energy-efficient operation of the drive device can be ensured.Through the invention, traction shifts of the transmission can be realized in a particularly advantageous manner. Such a traction shift is understood to mean a shift of the transmission from one of the gear stages into the other gear stage that takes place during traction operation or during traction operation of the motor vehicle, so that in the respective traction shift during traction operation or during traction operation of the motor vehicle one of the gear stages is disengaged and the other gear stage is engaged, thus changing from the initially engaged gear stage to the initially disengaged other gear stage in such a way that the initially engaged one gear stage is disengaged and the initially disengaged other gear stage is engaged.In order to be able to realize a particularly advantageous operation of the drive device, it is provided in one embodiment of the invention that the actuating device is designed as an electromechanical actuating device and has an electric servomotor and at least one restoring spring. The restoring spring is relaxed to a greater extent in the open position compared to the closed position and compared to the free-wheeling position. The restoring spring can be fully relaxed or still partially tensioned in the open position. In the closed position, the restoring spring is tensioned more strongly with respect to the open position and with respect to the free-wheeling position. In the free-wheeling position, the restoring spring is relaxed to a greater extent than the closed position and tensioned to a greater extent than the open position, so that in particular the restoring spring is tensioned in the free-wheeling position, and therefore in the free-wheeling state, but is less severe than in the closed position and more severe than in the open position, in which the restoring spring can be tensioned or else fully relaxed. As a result, the claw shifting element can function or act particularly advantageously as a freewheel in the freewheel state.It has been shown to be particularly advantageous if the claws of a first of the claw halves are formed by a claw switching element of the first claw half, the claw element of which is supported along the actuating direction via the restoring spring on a base element of the first claw half. In particular, the claw element is translationally movable relative to the base element along the actuation direction, so that, for example, by moving the claw element along the actuation direction and in the direction of the base element, the restoring spring is to be tensioned or tensioned. By moving the claw element along the actuation direction, it is away from the base element or the restoring spring is to be relaxed or relaxed. As a result, the free-wheeling state can be realized particularly advantageously, as a result of which particularly advantageous operation of the drive device can be achieved.In a further, particularly advantageous embodiment of the invention, it is provided that the restoring spring, in the free-wheeling position and thus in the free-wheeling state, permits movements of the claw element of the first claw half that take place along the actuating direction and relative to the second claw half and relative to the base element. As a result, the claw switching element can function particularly advantageously as a freewheel in the freewheel state, as a result of which particularly advantageous operation of the drive device can be produced.Since the claw switching element can be switched over between the switching position, the claw switching element is designed as a switchable freewheel or is designed in the manner of a switchable freewheel which, in the closed state, and therefore in the closed position, prevents relative rotations between the claw halves and thus the components that take place both in the first rotational direction and in the second rotational direction, but, in the freewheel state, allows rotations of the first component that take place about the rotational axis relative to the second component or rotations of the second component that take place about the rotational axis in the first rotational direction and relative to the first component. In order to realize this in a particularly advantageous manner, it is provided in a further embodiment of the invention that in the closed position the restoring spring is tensioned so strongly that in the closed position and thus in the closed state, movements of the claw element of the first claw half that take place along the actuation direction and relative to the second claw half and relative to the base element are prevented.A second aspect of the invention relates to a method for operating a drive device according to the first aspect of the invention. Advantages and advantageous configurations of the first aspect of the invention are to be regarded as advantages and advantageous configurations of the second aspect of the invention and vice versa.In order to be able to realize a particularly advantageous operation of the drive device, it is provided in one embodiment of the second aspect of the invention that a traction shift of the transmission is carried out. The traction shift is understood to mean that the transmission is shifted in traction mode or during traction mode of the motor vehicle, whereby, for example, one of the gear stages is disengaged and the other gear stage is engaged, so that the first engaged one gear stage is disengaged and the first disengaged other gear stage is engaged. Preferably, the traction shift of the transmission is carried out in which the claw shift element is in the free-wheeling state at least during a time period during which a torque transfer from the claw shift element to the aforementioned multiplate shift element of the transmission takes place or vice versa. The torque transfer is to be understood, for example, as first transmitting a torque provided, for example, by the aforementioned drive motor via the claw shifting element to at least one vehicle wheel of the motor vehicle, and as this torque is, so to speak, transferred from the claw shifting element to the multi-disk shifting element, so that then the torque is not transmitted from the drive motor to the vehicle wheel via the claw shifting element, but rather via the multi-disk shifting element. This makes it possible, for example, to make fast and jerk-free shifts possible, since the clutch switching element, which is also simply referred to as clutch, is a self-regulating system in the free-wheeling state. The vehicle wheel is a ground contact element of the motor vehicle, which is supportable or supported on a ground via the ground contact element in the vehicle vertical direction of the motor vehicle downwards. If the vehicle is driven along the ground while the motor vehicle is supported on the ground via the ground contact element in the vehicle vertical direction of the motor vehicle downwards, the ground contact element rolls off the ground, in particular directly.In order to be able to operate, in particular shift, the drive device in a particularly advantageous manner, it is provided in a further embodiment of the invention that during the traction shift and in particular when the torque transfer from the claw shift element to or to the disk shift element takes place, the disk shift element is closed in a sliding manner and the claw shift element is switched into its open state, wherein at the beginning of the traction shift the claw shift element is switched into its free-running state and then or thereupon and in particular at one end of the traction shift is switched from the free-running state into the open state, i.e. is transferred. An advantage in this regard is in particular that, in or in such traction gearshifts, there is a no-load state of the claw gearshift element at a gripping point of the multi-disk gearshift element. In this no-load state, the switching claws, particularly the end surfaces which are inclined flanks, slide against each other, and the claw switching element is opened by itself or without torque or opens by itself. This means that in this traction shift, which is designed, for example, as traction upshift, the claw switching element is switched to the free-wheeling state, for example, at the beginning of the traction shift, and is only switched to the open state at the end of the traction shift, in order to avoid an undesired ratcheting, whereby an advantageous noise behavior of the drive device can be realized. After the gripping point and / or a grinding point of plates of the plate shifting element has been reached, which can be seen in particular from a decreasing rotational speed difference of the plates, it is not necessary to wait until the claw shifting element is opened, and is therefore in its open state, before the plate shifting element or its plates can be fully closed. As a result, the activation can be carried out particularly advantageously.A further embodiment is characterized in that the claw shifting element is switched into its free-wheeling state as soon as the traction shift begins. As a result, the torque can be switched in a particularly advantageous manner and the drive device can thus be operated in a particularly advantageous manner.In a further, particularly advantageous embodiment of the invention, it is provided that the claw shifting element is shifted into its open state as soon as a rotational speed difference at the claw shifting element is detected. As a result, the transmission can be shifted particularly advantageously. It has furthermore been found to be particularly advantageous if the claw shifting element is switched into its open state as soon as a pressure signal for a pressure in an actuating element of the multi-plate shifting element is further increased by a gripping pressure. As a result, the traction shift can be carried out particularly advantageously, so that particularly advantageous operation of the drive device can be achieved.Finally, it has been shown to be advantageous if, in the traction shift, in particular when the torque is transferred from the multi-plate shifting element to or to the claw shifting element, the multi-plate shifting element is opened in a sliding manner and the claw shifting element is closed, thus being switched into the closed state, wherein at the beginning of this traction shift, firstly a speed reduction or adaptation to a speed which is less than or equal to a limit speed at which the claw shifting element can be switched into its closed state, whereupon the claw shifting element is switched into its free-running state and then, in particular, at one end of the traction shift, is switched into the closed state. As a result, for example, a tooth-on-tooth position, in particular of the claw shifting element, can be avoided. In addition, excessive shift jerks can be avoided and an excessive torque gap can be avoided, so that a particularly advantageous shift of the transmission can be produced.Further advantages, features and details of the invention will become apparent from the following description of a preferred exemplary embodiment and with reference to the drawing. The features and combinations of features mentioned above in the description and the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures can be used not only in the respectively specified combination but also in other combinations or alone without departing from the scope of the invention.The drawing shows in: FIG. 1 is a schematic and sectional side view of a pawl switching element of a drive device for a motor vehicle; FIG. 2 is a further schematic and sectional side view of the claw shifting element; FIG. 3 is a further schematic and sectional side view of the claw shifting element; FIG. 4 is a diagram for illustrating a method for operating the drive device; and FIG. 5 shows a further diagram for further illustrating the method.In the figures, identical or functionally identical elements are provided with identical reference symbols.FIG. 1 shows a schematic and sectional side view of a claw switching element 10 of a drive device for a motor vehicle, which is also referred to simply as a vehicle. This means that the motor vehicle, which is preferably designed as a motor vehicle, in particular as a passenger vehicle, has the drive device in its completely produced state and can be driven by means of the drive device. In particular, the drive device is an electric drive device, by means of which the motor vehicle can be driven, in particular purely electrically. For this purpose, the drive device has, for example, a drive motor which can be designed as an electric machine. In particular, the drive device has a transmission which can have, for example, at least or exactly two shiftable gear stages, also referred to as gears. A first of the gear stages has a first transmission ratio and a second of the gear stages has a second transmission ratio different from the first transmission ratio, wherein, for example, the second transmission ratio is lower than the first transmission ratio. The gear stages (gears) can be shifted, and can therefore be engaged or disengaged. The drive device, in particular the transmission, can have a multi-disk shifting element provided in addition to the claw shifting element 10.The claw shifting element and the multi-disk shifting element are collectively also referred to as shifting elements, by means of which, for example, the gear stages can be selectively engaged or disengaged.The drive device has, for example, a housing in which the claw switching element 10 can be arranged. By means of the claw shifting element 10, for example, a first component and a second component of the drive device can be selectively connected to one another in a rotationally fixed manner or decoupled from one another. For this purpose, the claw switching element 10 has a first claw half 12 and a second claw half 14. The first claw half 12 is connected, for example, in particular permanently, in a rotationally fixed manner to the first structural element, and the second claw half 14 is connected, for example, in particular permanently, in a rotationally fixed manner to the second structural element. The first structural element and thus the claw half 12 are rotatable relative to the housing, for example, about an axis of rotation D, so that, for example, the first structural element is a structural element provided in addition to the housing and different from the housing. In principle, it would be conceivable for the second component to be a component which is provided in addition to the housing and is different from the housing, so that then, for example, the second component and, with the latter, the claw half 14 can be rotated about the axis of rotation D relative to the housing. It is furthermore conceivable for the second component to be the housing, so that, for example, the first component can be connected to the housing in a rotationally fixed manner by means of the claw switching element 10.The claw halves 12 and 14, which are also simply referred to as halves, are movable in translation relative to one another along an actuation direction B, wherein the claw halves 12 and 14 are opposite one another along the actuation direction B. In the present case, the actuation direction B coincides with the axis of rotation D, wherein the actuation direction B and the axis of rotation D run along an imaginary straight line.The claw shifting element 10 has three shifting states, namely an open state O shown in FIG. 1, a free-running state F shown in FIG. 2 and a closing state S shown in FIG. 3. For this purpose, the drive device has an actuating device 16, which is illustrated particularly schematically in the figures and by means of which the claw switching element 10 can be switched over between the switching states. By means of the actuating device 16, the claw halves 12 and 14 can be moved translationally relative to one another along the actuating direction B between at least one open position causing the open state O, at least one closed position causing the closed state S and at least one free-running position causing the free-running state F. For example, the jaw half 14 can be moved by means of the actuating device 16 relative to the jaw half 12 and, for example, also relative to the components in a translatory manner between the open position OS causing the open state O, the free position FS causing the free state F and the closed position SS causing the closed state S.It can be seen particularly well from FIGS. 1 to 3 that the respective claw half 12, 14 has respective claws 18, 20, also referred to as switching claws, which, for example, at least in the open state O, are situated opposite one another along the actuation direction B. The respective claw 18, 20 has exactly one respective coupling flank K and exactly one respective top surface KF, which runs obliquely to the actuation direction B and obliquely to the respective coupling flank K. In the exemplary embodiment shown in the figures, the respective top surface KF extends in a respective first plane, and the respective coupling flank K extends in a respective second plane. The respective second plane in the present case runs parallel to the actuation direction B, and the respective first plane runs obliquely to the actuation direction B and to the respective second plane. The respective top surface KF extends starting from the respective top surface KF as far as a respective claw base G of the respective claw half 12, 14.The motor vehicle and thus the drive device can be operated in traction mode. In traction mode, the motor vehicle is driven by means of the drive device, in particular by means of the drive motor. This means that in the traction mode the drive motor provides at least one drive torque by means of which the motor vehicle is driven. In the traction mode of the motor vehicle and in the closed state S of the claw shifting element 10, a force transmission is effected, and therefore the drive torque is transmitted between the claw halves 12 and 14 and thus between the components, in particular from the claw half 12 to the claw half 14 and thus from the first component to the second component via the respective coupling flank K of the claw half 12 and the corresponding coupling flank K of the claw half 14.Furthermore, it is provided that the actuating device 16 is designed to be self-locking. This means that, after the actuating device 16 has switched the claw switching element 10 into the respective switching state, the actuating device 16 holds the respective switching state in which the claw switching element 10 is located by self-locking. In other words, after the actuator 16 has switched the dog switching element 10 to one of the switching states, the actuator 16 maintains the dog switching element 10 in the switching state in which the actuator 16 has switched the dog switching element 10 by self-locking, whereby the dog switching element 10 is maintained in the respective switched-on switching state by means of the actuator 16 without the actuator 16 being supplied with power from outside the actuator 16. Thus, the actuating device 16 only needs to be supplied with electrical energy from outside the actuating device 16 in particular when the switching state of the claw switching element 10 is to be changed by means of the actuating device 16, and therefore the claw switching element 10 is switched from one of the switching states to another of the switching states.It can be seen from FIG. 1 that in the open state O the claw halves 12 and 14 and thus the components are decoupled from one another, in particular completely, so that no torque, i.e. torque acting about the axis of rotation D, can be transmitted between the claw halves 12 and 14 and thus between the components. Thus, for example, the claw half 12 and thus the first structural element are rotatable about the axis of rotation D both in a first direction of rotation D 1 extending about the axis of rotation D and in a second direction of rotation D 2 extending about the axis of rotation D and opposite the first direction of rotation relative to the claw half 14 and relative to the second structural element. In particular, it is provided that in the open state O the claw halves 12 and 14 do not cooperate.In the closed state S shown in FIG. 3, the claw halves 12 and 14 cooperate with one another in a form-fitting manner via their claws 18 and 20 in such a way that the claw halves 12 and 14 and thus the structural elements are connected to one another in a form-fitting manner in a rotationally fixed manner. As a result, for example, the claw half 12 and thus the first structural element cannot be rotated about the rotational axis D relative to the claw half 14 and the second structural element either in the first rotational direction D 1 or in the second rotational direction D 2.In the free-wheeling state F shown in FIG. 2, however, the claw switching element 10 acts or functions as a free-wheeling device which allows rotations of the claw half 12 and thus of the first component about the rotational axis D in the second rotational direction D 2 and relative to the claw half 14 and the second component to occur independently or automatically, but prevents rotations of the claw half 12 and the first component about the rotational axis D in the first rotational direction D 1 and relative to the claw half 14 and the second component. This is done in such a way that when the jaw half 12 and thus the first component are rotated about the axis of rotation D in the second direction of rotation D 2 relative to the jaw half 14 and the second component, the top surfaces KF of the jaws 18 and 20 slide against each other.The actuating device 16 is preferably designed as an electromechanical actuating device which has an electric servomotor 22 and a mechanical spring device 24 with restoring springs 26. The respective restoring spring 26 is a mechanical spring and is therefore designed as a respective solid body. In the open position OS, the respective restoring spring 26 is tensioned more strongly with respect to the closed position SS and with respect to the free-wheeling position FS. In the closed position SS, the respective restoring spring 26 is tensioned more strongly with respect to the open position OS and with respect to the free-wheeling position FS. In the free-wheeling position FS, the respective restoring spring 26 is relaxed to a greater extent than the closed position SS and tensioned to a greater extent than the open position OS. It can also be seen that the claws 20 of the claw half 14 are formed by a claw element 28 of the claw half 14, which also has a base element 30. The claw element 28 and thus the claws 20 of the claw half 14 are supported on the base element 30 along the actuation direction B via the restoring springs 26. When the claw member 28 is moved along the base member 30 along the operation direction B, the return springs 26 are biased. If the claw element 28 is moved away from the base element 30 along the actuation direction B, the restoring springs 26 are relaxed or a relaxation of the restoring springs 26 is permitted.It can be seen in particular from FIGS. 1 to 3 that the restoring springs 26 in the free-wheeling position FS, and therefore in the free-wheeling state F, permit movements of the claw element 28 which take place along the actuating direction B and relative to the claw half 12 and relative to the base element 30, as a result of which the head surfaces KF slide against one another when the claw half 12 is rotated about the axis of rotation D in the second direction of rotation D 2 relative to the claw half 14. In the closed position SS, that is to say in the closed state S, however, the restoring springs 26, in particular already, are tensioned so strongly that, in the closed position, movements of the claw element 28 which take place along the actuating direction and away from the claw half 12 and relative to the base element 30 are prevented such that the claw half 12 can be rotated relative to the claw half 14 in the rotational direction D 2 while the head surfaces KF slide against one another. As a result, in the closed state S, the claw half 12 can be rotated relative to the claw half 14 neither in the first rotational direction nor in the second rotational direction about the rotational axis D.FIG. 4 is a diagram for describing a method of operating the driving device. The diagram shown in FIG. 4 has a plurality of sub-diagrams, each having an abscissa A 1, A 2 and A 3 and an ordinate O 1, O 2 and O 3. The time is plotted on the respective abscissa A 1, A 2, A 3. The ordinate O1 shows the switching state of the claw switching element. The ordinate O2 shows a rotational speed and the ordinate O3 shows a torque. A curve V 1 illustrates the shift positions of the claw shift element 10 over time. A curve V 2 illustrates the rotational speed of the claw shifting element 10, in particular of the claw half 12. A curve V 4 illustrates, for example, the rotational speed of the aforementioned multi-disk shifting element or at least or exactly one disk carrier of the multi-disk shifting element, and a curve V 5 illustrates the torque which is transmitted via the multi-disk shifting element.FIG. 4 illustrates a first transmission traction shift, wherein the first transmission traction shift is a traction upshift. During the traction upshift, i.e. during the first traction shift, the first gear initially engaged, and therefore the first gear initially engaged, is disengaged, and the second gear initially disengaged, and therefore the second gear initially disengaged, is engaged. In FIGS. 4 and 5, the first speed and the first speed are denoted by G 1, and the second speed and the second speed are denoted by G 2. In FIG. 4, "G 1" means that the first speed is in gear and the second speed is in gear. In FIG. 4, "G 2" means that the second speed is in gear while the first speed is in gear. In FIG. 4, "G 1-G 2" means a transition phase in which a change is made from the at least engaged first gear to the initially disengaged second gear, thus the initially engaged first gear is disengaged and the initially disengaged second gear is engaged. The transition phase extends from a time t 0 to a time t 2. From the time t 0 to the time t 1, as can be seen from the curves V 3 and V 5, a torque transfer takes place in the present case from the claw shifting element 10 to or to the multi-disk shifting element, since a torque transfer to the claw shifting element 10 is ended and a torque transfer to the multi-disk shifting element is started. It can be seen from the curve V 1 that the claw shifting element 10 is initially in its closed state S while the first gear is engaged. In the transition phase, the claw shifting element 10 is switched from the closed state S to the free-wheeling state F, so that the claw shifting element 10 is in the free-wheeling state F at least during a part of the torque transfer. Starting from the time t 1, the claw shifting element 10 is shifted from the free-wheeling state F into the open state O, so that during at least a part of the torque transfer, the claw shifting element 10 is in the free-wheeling state F. Since the first traction shift is designed as a traction upshift and thus as a shift from the first gear to the second gear, the torque transfer from the claw shifting element 10 to the multi-disk shifting element takes place in the first traction shift. In particular, it is provided that in the first traction shift, the multi-plate shift element, which is initially open, is closed in a sliding manner and the claw shift element 10 is switched into its open state O, wherein at the beginning of the first traction shift, the claw shift element 10 is switched into its free-running state F and then, in particular at one end or towards one end of the traction shift, is switched from the free-running state F into the open state O.In Fig. 5, another diagram is shown with the sub-diagrams described above. In particular, FIG. 5 shows a second traction shift of the drive device, in particular of the transmission. The second traction shift is a traction downshift in which a switch is made from the initially engaged second gear to the initially disengaged first gear. In other words, during the traction downshift, the first engaged second gear is disengaged and the first engaged first gear is engaged. Thus, in FIG. 5, "G 2-G 1" denotes a second transition phase in which the second gear is disengaged and the first gear is engaged. In addition, in the second transition phase, a torque transfer from the multi-plate shifting element to or to the claw shifting element 10 takes place, since in the second traction shift and in particular in the torque transfer taking place in the second traction shift, a torque transfer via the multi-plate shifting element is ended and a torque transfer via the claw shifting element 10 is started. It can be seen in particular that in the second traction shift, the multi-plate shift element is opened in a sliding manner and the claw shift element 10 is switched into its closed state S, wherein at the beginning of the second traction shift, firstly a speed reduction or adaptation to a speed which is less than or equal to a limit speed at which the claw shift element 10 can be switched into its closed state S takes place, whereupon the claw shift element 10 is switched into the free-running state F and then into the closed state S, in particular at one end or towards one end of the second traction shift. The limit rotational speed is reached, for example, 50 revolutions per minute and, for example, at or from the time t 2.With regard to the diagram shown in FIG. 4, the first traction circuit is triggered, for example, at the time t 0 shown in FIG. 4. From the time t 0 to the time t 1, the torque transfer is performed in the first traction shift, and from the time t 1 to the time t 2, a speed adjustment is performed in the first traction shift. With regard to the diagram shown in FIG. 5, the second traction shift is triggered at the time t 0, and the speed adaptation is carried out at the second traction shift from the time t 0 to the time t 1. Starting to the free-wheeling position FS takes place from the time t1 to the time t2, and the limit rotational speed is reached or undershot at or from the time t2 in FIG. 5. At a time t 3, the dog shift element 10 engages and transmits torques, and specifically, is thereafter shifted to the closing state S.

Claims

Drive device for a motor vehicle, having a transmission which has at least one claw shifting element (10), by means of which at least one gear stage of the transmission can be shifted, and having an actuating device (16) for actuating the claw shifting element (10), wherein: - the claw shifting element (10) has two claw halves (12, 14) which can be moved relative to one another along an actuating direction (B) and are opposite one another along the actuating direction (B); - the claw shifting element (10) has three shifting states, namely an open state (O), a free-wheeling state (F) and a closed state (S); the claw halves (12, 14) are movable relative to one another along the actuating direction (B) by means of the actuating device (16) between at least one open position (OS) causing the open state (O), at least one closed position (SS) causing the closed state (S) and at least one free-running position (FS) causing the free-running state (F); claws (18, 20) of the respective claw half (12, 14) each have exactly one coupling flank (K) and each have exactly one top surface (KF), which is oriented obliquely to the actuating direction (B) and obliquely to the respective coupling flank (K); the respective top surface (KF) extends starting from the respective coupling flank (K) as far as a respective claw base (G) of the respective claw half (12, 14); in a traction mode of the motor vehicle and in the closed state (S) of the claw shifting element (10), a force transmission takes place via the coupling flanks (K) of one of the claw halves (12, 14) and the corresponding coupling flanks (K) of the other claw half (14, 12); and the actuating device (16) is designed to be self-locking.Drive device according to Claim 1, characterized in that the actuating device (16) is designed as an electromechanical actuating device and has an electric actuating motor (22) and a restoring spring (26), which: - in the open position (OS) is relaxed to a greater extent than the closed position (SS) and than the free-wheeling position (FS); - in the closed position (SS) is tensioned to a greater extent than the open position (OS) and than the free-wheeling position (FS); and - in the free-wheeling position (FS) is relaxed to a greater extent than the closed position (SS) and is tensioned to a greater extent than the open position (OS).Drive device according to Claim 2, characterized in that the claws (18, 20) of a first of the claw halves (12, 14) are formed by a claw element (28) of the first claw half (12), the claw element (28) of which is supported along the actuating direction (B) via the restoring spring (26) on a base element (30) of the first claw half (12).Drive device according to Claim 3, characterized in that, in the free-wheeling position (FS), the restoring spring (26) permits movements of the claw element (28) of the first claw half (12) which take place along the actuating direction (B) and relative to the second claw half (14) and relative to the base element (30).Drive device according to Claim 3 or 4, characterized in that, in the closed position (SS), the restoring spring (26) is tensioned so strongly that, in the closed position (SS), movements of the claw element (28) of the first claw half (12) which take place along the actuating direction (B) and relative to the second claw half (14) and relative to the base element (30) are prevented.

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