Electric drive device for a motor vehicle, in particular for a motor car

Abstract

Electric drive device (10) for a motor vehicle, comprising: a case (20), an electric machine (12) designed to propel the motor vehicle, which has a rotor (16), a planetary gear set (22) arranged at least partially in the housing (20), which has a first planet gear set (24) with a first sun gear (28) connected to the rotor (16) in a non-rotatable manner, a first planet carrier (30) and a first ring gear (32) and a second planet gear set (26) with a second planet carrier (34) and a second ring gear (36) connected to the first planet carrier (30) in a non-rotatable manner, at least two switching elements (S1, S2), namely a first switching element (S1) and a second switching element (S2), for switching at least two gears, and a differential gear (42) which has a differential input shaft (44) and two output shafts (46, 48), characterized by the fact that: the second planetary gear set (26) has a second sun gear (56), and the second ring gear (36) is non-rotatably connected to the differential input shaft (44), and the second switching element (S2) is designed to lock the second planetary gear set (26).

Description

[0001] The invention relates to an electric drive device for a motor vehicle according to the preamble of claim 1. Furthermore, the invention relates to a motor vehicle, in particular a motor car.

[0002] DE 10 2013 225 519 A1 discloses a planetary gear for a motor vehicle, comprising an input shaft forming a sun gear, a planet carrier carrying one set of planet gears and a second set of planet gears, a first ring gear associated with the first set of planet gears, and a second ring gear associated with the second set of planet gears. A first locking means is also provided for locking the first ring gear. Furthermore, a second locking means is provided for locking the second ring gear.

[0003] A similar transmission concept is disclosed in DE 10 2020 104 727 B3, which also provides two planetary gear sets, wherein the planet carriers of the two planetary gear sets are connected to each other in a rotationally fixed manner, a first ring gear is connected to a housing in a rotationally fixed manner and a second sun gear can be connected to the housing in a rotationally fixed manner by means of a switching element.

[0004] The object of the present invention is to create an electric drive device for a motor vehicle in such a way that a particularly low-loss and compact design can be realized.

[0005] This problem is solved by an electric drive device with the features of claim 1. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0006] A first aspect of the invention relates to an electric drive device for a motor vehicle, in particular for a motor vehicle preferably designed as a passenger car. This means that the motor vehicle, preferably designed as a motor vehicle, in particular as a passenger car, in its fully manufactured state, has the electric drive device and can be driven, in particular purely electrically, by means of the electric drive device. For this purpose, the electric drive device comprises a housing and at least one electric machine by means of which the motor vehicle can be driven, in particular purely electrically. The electric machine has a rotor. For example, the electric machine also has a stator by means of which the rotor can be driven and thereby rotatable about a machine axis of rotation relative to the stator.In particular, the electric machine can provide drive torques via its rotor to propel the motor vehicle. For example, the electric machine, especially its rotor, can drive at least or exactly two vehicle wheels (also simply called wheels) on an axle of the motor vehicle, thus enabling the motor vehicle to be propelled.

[0007] The electric drive device also includes a planetary gear set comprising a first planetary gear set and a second planetary gear set. The first planetary gear set includes a first sun gear, which is permanently and non-rotatably connected to the rotor. The first planetary gear set also includes a first planet carrier, also referred to as the first web, and a first ring gear. The first sun gear, the first planet carrier, and the first ring gear constitute the first gear element of the first planetary gear set. The second planetary gear set includes a second planet carrier, also referred to as the second web. The second planetary gear set also includes a second ring gear. The planetary gear set, and thus the planetary gear sets, are arranged at least partially, and in particular at least predominantly, and thus at least more than halfway or completely, within the housing.The second planet carrier is permanently and rotationally fixed to the first planet carrier. The second planet carrier and the second ring gear are the second gear elements of the second planetary gear set. Particularly when the respective gear element is not rotationally fixed to the housing and is driven, for example, by the application of the respective drive torque or a torque resulting from the respective drive torque, the respective gear element is rotatable about a gear element axis relative to the housing. It is particularly conceivable that the first gear elements are arranged coaxially with each other. Alternatively or additionally, the second gear elements are arranged coaxially with each other.

[0008] The electric drive device also has a first switching element and a second switching element. At least two gear ratios of the electric drive device, in particular the planetary gear, can be switched by means of the switching elements.

[0009] Within the scope of this disclosure, a rotationally fixed connection between two rotatable or rotatably mounted elements means that these two elements are arranged coaxially to each other and connected in such a way that they rotate at the same angular velocity, in particular about an element rotation axis and / or relative to the housing, especially when one of the elements, and thus the other element, is driven. In particular, the respective element can be the respective transmission element. Preferably, the rotor is arranged coaxially to the planetary gear sets, also referred to as planetary sets. For example, the element rotation axis is the aforementioned transmission element rotation axis.The characteristic that elements are permanently connected or coupled to each other in a rotationally fixed manner means that a switching element is not provided which can be switched between a coupling state in which the elements are connected or coupled to each other in a rotationally fixed manner and a decoupling state in which the elements are decoupled from each other and rotatable relative to each other so that no torques can be transmitted between the elements, but rather the elements are always, i.e., permanently, connected or coupled to each other in a rotationally fixed manner.

[0010] The electric drive system also includes a differential gear, which is assigned, for example, to the aforementioned axle and thus, for example, to the vehicle wheels, which can be driven by the electric motor via the rotor. In particular, the vehicle wheels can be driven by the rotor via the differential gear. As is already well known, the differential gear has, for example, the function of allowing different rotational speeds of the vehicle wheels when the vehicle is cornering, such that the outer wheel rotates at a higher speed than the inner wheel, especially while the vehicle wheels are driven by the rotor and thus by the electric motor via the differential gear.

[0011] The differential gear has a differential input shaft through which the respective drive torque, or a torque resulting from the respective drive torque, can be introduced into the differential gear, thereby driving the differential gear and, via it, the wheels. Furthermore, the differential gear comprises two output shafts, which can be driven by the differential input shaft. In particular, the vehicle wheels can be driven by the output shafts, specifically such that a first wheel is driven by the first output shaft and a second wheel is driven by the second output shaft.

[0012] In order to achieve a particularly low-loss and compact design of the electric drive device, the invention provides that the second planetary gear set has a second sun gear, which is a further second transmission element of the second planetary gear set. Furthermore, the invention provides that the second ring gear is permanently and rotationally fixed to the differential input shaft, and that the second switching element is designed to lock the second planetary gear set, thereby enabling advantageous multi-start operation in a particularly low-loss and compact manner.

[0013] For example, the first gear element, if not fixedly connected to the housing, is rotatable about a first gear element axis of rotation relative to the housing, where the first gear element axis of rotation is also referred to as the first planetary gear set axis of rotation. It is conceivable that the second gear element, particularly if not fixedly connected to the housing, is rotatable about a second gear element axis of rotation relative to the gear element, where the second gear element axis of rotation is also referred to as the second planetary gear set axis of rotation. The planetary gear sets can be arranged coaxially, so that the planetary gear set axes of rotation or gear element axes of rotation coincide. However, it is conceivable that the planetary gear sets are arranged disaxially, so that the gear element axes of rotation are parallel to each other and spaced apart.

[0014] Preferably, the rotor is arranged coaxially with at least one of the planetary gear sets, and in particular with both planetary gear sets. In particular, the rotor is rotatable about a machine axis of rotation relative to the stator and, more specifically, relative to the housing, wherein, for example, the stator is fixedly connected to the housing. Since the rotor is preferably arranged coaxially with the planetary gear sets, the machine axis of rotation and the respective axis of rotation of the gear element or planetary gear set coincide. Furthermore, it is preferably provided that the rotor is also arranged coaxially with the output shafts.

[0015] To achieve particularly advantageous drivability in a compact and low-loss manner, one embodiment of the invention provides that the first switching element is designed to connect the second sun gear to the housing in a rotationally fixed manner. This means, in particular, that the first switching element is switchable between a first coupled state and a first disengaged state. In the first coupled state, the second sun gear is connected to the housing in a rotationally fixed manner by means of the first switching element, and thus fixed to the housing in a rotationally fixed position. Therefore, the second sun gear cannot rotate about the axis of rotation of the transmission element relative to the housing, even when the second sun gear is driven.In the first decoupling state, the first switching element releases the second sun gear for rotation relative to the housing about the axis of rotation of the gear element, so that the second sun gear is rotatable or is rotated about the axis of rotation of the gear element relative to the housing, in particular when the second sun gear is driven.

[0016] For example, the first switching element is movable, particularly relative to the housing and / or translationally, between at least one first coupling position that effects the first coupling state and at least one first decoupling position that effects the first decoupling state. Furthermore, it is conceivable that the second switching element is switchable between a second coupling state that locks the planetary gear and a second decoupling state in which the planetary gear is not locked. For example, in the second coupling state, two of the gear elements are rotationally fixed to each other by means of the second switching element. In the second decoupling state, the second switching element releases these two gear elements for a relative rotation with respect to each other, particularly about the axis of rotation of the gear element.For example, the second switching element is movable, in particular translationally and / or relative to the housing, between at least one second coupling position that effects the second coupling state and at least one second decoupling position that effects the second decoupling state.

[0017] It is conceivable that at least one of the switching elements, such as the second switching element, is designed as a positive-locking switching element, such as a jaw coupling, or has a positive-locking switching element, such as a jaw coupling. Furthermore, it is conceivable that at least one of the switching elements, such as the first switching element, is designed as a force-locking or friction-locking switching element, or has such a force-locking or friction-locking switching element, by means of which, for example, one of the transmission elements can be connected to another transmission element or to the housing in a force-locking or friction-locking manner, transmitting torque, and in particular in a rotationally fixed manner. The friction-locking switching element is also referred to as a friction-locking coupling and can, for example, be designed as a multi-plate clutch.The positive-locking switching element is also referred to as a positive-locking coupling and can, for example, be designed as a jaw coupling. The positive-locking switching element is specifically designed to connect two of the transmission elements, or one of the transmission elements and the housing, to each other in a rotationally fixed manner by means of at least one positive locking connection, which is formed, for example, by at least two solid bodies overlapping each other in at least one or both directions of rotation about the axis of rotation of the transmission element.In contrast, the friction-fit switching element can connect two or one of the transmission elements to the housing, particularly exclusively, by friction or frictional forces in a rotationally fixed manner, for example, by connecting at least two friction partners in a torque-transmitting, and in particular rotationally fixed, manner, for example, without the friction partners and the transmission element's axis of rotation overlapping. A friction-fit switching element such as the first switching element is particularly advantageous because it allows for at least a large degree of load-shifting capability, possibly with a certain reduction in traction force, but without interruption of traction force, so that, for example, shifting from a first gear to the second gear and / or vice versa is possible, for example, under load.

[0018] In order to keep losses particularly low, a further embodiment of the invention provides that the second switching element has a claw coupling, so that, for example, the planetary gear can be positively locked by means of the second switching element, in particular in at least or exactly one direction of rotation around the axis of rotation of the gear element.

[0019] It has proven particularly advantageous if the second switching element has a freewheel clutch arranged parallel to the jaw clutch. The freewheel clutch is also simply referred to as a freewheel. Using the freewheel clutch, it is possible, for example, to connect two of the transmission elements, or one of the transmission elements and the housing, in a rotationally fixed manner in a first direction of rotation around the transmission element's axis of rotation. The freewheel clutch allows relative rotation between the transmission elements, or between the transmission element and the housing, in a second direction of rotation around the transmission element's axis of rotation and opposite to the first direction of rotation. This enables a particularly advantageous operation in a way that is especially efficient in terms of weight, cost, and installation space.

[0020] In a further, particularly advantageous embodiment of the invention, the second switching element is designed to connect the second sun gear to the second ring gear in a rotationally fixed manner. This allows for multi-start operation and particularly advantageous maneuverability in a particularly compact and low-loss manner.

[0021] In order to keep costs, installation space requirements and weight particularly low, a further embodiment of the invention provides that the first ring gear is permanently connected to the housing in a rotationally fixed manner.

[0022] In order to keep the installation space requirement particularly small, especially in the axial direction of the planetary gear set and thus along the axis of rotation of the gear element, a further embodiment of the invention provides that the second planetary gear set is arranged axially overlapping with the differential gear set. This means, in particular, that the second planetary gear set is at least partially, and in particular at least predominantly or completely, overlapped or covered by the differential gear set in the radial direction of the second planetary gear set and thus along a direction perpendicular to the axis of rotation of the gear element, for example, from the second sun gear to the second ring gear, especially with regard to the axial extent of the second planetary gear set.

[0023] To enable particularly efficient and space-saving operation of the motor vehicle, a further embodiment of the invention provides that the electric drive device includes a parking lock wheel, which is permanently and rotationally fixed to the second ring gear. The parking lock wheel is, for example, a component of a parking lock that can be activated and deactivated. When the parking lock is activated, the parking lock wheel, and consequently the second ring gear, are prevented from rotating relative to the housing and around the axis of rotation of the transmission element. This prevents, for example, the motor vehicle from rolling away unintentionally, particularly when the motor vehicle is parked on a slope.If the parking lock is deactivated, the parking lock wheel and thus the second ring gear can rotate relative to the housing around the axis of rotation of the transmission element, so that, for example, the vehicle can roll down a slope.

[0024] Finally, to achieve a particularly small installation space requirement, it has proven especially advantageous if, viewed in the axial direction of the planetary gear, the electric machine, the first planetary gear set, the second planetary gear set and the parking lock wheel are arranged in the following order, i.e., consecutively: the electric machine - the first planetary gear set - the second planetary gear set - the parking lock wheel.

[0025] In other words, viewed in the axial direction of the planetary gear set, the first planetary gear set follows the electric machine, the second planetary gear set follows the first planetary gear set, and the parking lock gear follows the second planetary gear set.

[0026] Disclosed or included in the invention is a motor vehicle, preferably designed as a motor car, in particular as a passenger car, which has at least or exactly one electric drive device according to the invention and, in particular, can be driven purely electrically by means of the drive device. Advantages and advantageous embodiments of the electric drive device are to be regarded as advantages and advantageous embodiments of the motor vehicle and vice versa. In particular, the following advantages can be realized by the invention: - loss-optimized and compact design At least one of the switching elements can be designed as a positive-locking switching element or can include a positive-locking switching element and preferably the aforementioned freewheel in order to minimize losses. When converted to a freewheel, this may be located on an unsuitable inner diameter. - low relative speeds in the open-running switching element - The switching elements can be very easily accessible. - Stresses on the switching elements can be kept particularly low. - good gear efficiency, especially in first gear - The rotational speed of the electric machine can be kept low at high speeds, especially due to the multiple turns of the planetary gear.

[0027] For example, the gears, also simply referred to as gears, differ from each other in their ratios, in particular in that the first gear has a lower ratio than the second gear.

[0028] Particularly with regard to kinematic equivalence, which is to be considered included or disclosed in the present case, it may be provided that in a planetary gear set, such as the first planetary gear set and / or the second planetary gear set, a simple planet carrier can be replaced by a double planet carrier, especially if the connections of the two other elements of this planetary gear set are exchanged at the same time. For example, in a planetary gear set, a switching element, for example designed as a brake switching element, especially for fixed connection to the housing, can be replaced by a permanent, fixed connection to the housing, especially if, for example, a switching element is simultaneously installed in a fixed connection of the two other elements of this planetary gear set, or a fixed connection is replaced by a switching element.

[0029] The differential gear is advantageously designed as a bevel gear differential, in particular with a differential cage, wherein the differential cage can be permanently, in particular non-rotatably, connected to the differential input shaft, or wherein the differential cage can form the differential input shaft.

[0030] Further advantages, features, and details of the invention will become apparent from the following description of preferred embodiments and from the drawings. The features and combinations of features mentioned above in the description, as well as those mentioned below in the figure description and / or shown in the figures alone, can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention.

[0031] The drawing shows in: Fig. 1 a schematic representation of a first embodiment of an electric drive device for a motor vehicle; Fig. 2 a schematic representation of a second embodiment of the electric drive device; and Fig. 3 a switching table to illustrate switchable, i.e. selectable and selectable gear ratios of the electric drive device.

[0032] In the figures, identical or functionally equivalent elements are provided with the same reference numerals.

[0033] Fig. Figure 1 shows a schematic representation of a first embodiment of an electric drive device 10 for a motor vehicle. Preferably, the motor vehicle, which is designed in particular as a car and especially as a passenger car, has at least or exactly two axles arranged one behind the other in the longitudinal direction of the vehicle, which are also referred to as vehicle axles. Each axle has at least or exactly two wheels, which are also referred to as vehicle wheels and which are the ground contact elements of the motor vehicle. The respective wheels of each axle are arranged on opposite sides of the motor vehicle in the transverse direction. The motor vehicle can be supported or is supported downwards against a road surface by means of the wheels, which are designed as ground contact elements of the motor vehicle.If the motor vehicle is driven electrically by means of the drive device 10, in particular purely electrically, while the motor vehicle is supported downwards against the road surface in the vertical direction, the wheels roll along the road surface. For example, the drive device 10 is exclusively and thus exactly assigned to one of the axles, so that, for example, only the wheels of the axle to which the drive device 10 is assigned can be driven by means of the drive device 10.

[0034] The drive device 10 comprises an electric machine 12, which has a stator 14 and a rotor 16. The rotor 16 can be driven by means of the stator 14 and is thereby rotatable about a machine axis of rotation 18 relative to the stator 14 and relative to a housing 20 of the electric drive device 10. Via the rotor 16, the electric machine 12 can provide drive torque for driving the wheels of the axle to which the electric machine 12, or the drive device 10, is assigned. The wheels that can be driven by the electric machine 12 via its rotor 16 are also referred to as drive wheels. The drive device 10 also comprises the housing 20, which is shown in a particularly schematic way, wherein the stator 14 is connected to the housing 20, in particular permanently, in a rotationally fixed manner.

[0035] The drive device 10 comprises a planetary gear set 22, which includes a first planetary gear set 24 and a second planetary gear set 26. Preferably, the planetary gear sets 24 and 26 are each at least partially, and in particular at least predominantly, and thus at least more than halfway or completely, arranged in the housing 20, so that the planetary gear set 22 can be at least partially arranged in the housing 20. The first planetary gear set 24 comprises a first sun gear 28, a first planet carrier 30, which is also referred to as the first web, and a first ring gear 32, wherein the sun gear 28, the planet carrier 30, and the ring gear 32 are also referred to as the first gear elements. In particular, if the respective first gear element is not rotationally fixed to the housing 20, the respective first gear element is rotatable about a first gear element axis of rotation relative to the housing 20.

[0036] The second planetary gear set 26 has a second planet carrier 34, also referred to as a second web, and a second ring gear 36. The planet carrier 34 and the ring gear 36 are also referred to as the second gear elements of the second planetary gear set 26. Particularly when the respective second gear element is not rotationally fixed to the housing 20, the respective second gear element is rotatable about a second gear element axis of rotation relative to the housing 20. Since, in the first embodiment, the planetary gear sets 24 and 26 are arranged coaxially with each other, the gear element axes of rotation coincide, and since the rotor 16 or the electric machine 12 is arranged coaxially with the planetary gear sets 24 and 26, the gear element axes of rotation coincide with the machine axis of rotation 18.

[0037] The planetary gear set 24 also includes one or more first planet gears 38. Each first planet gear 38 is rotatably mounted on the first planet carrier 30 and meshes directly with, for example, the sun gear 28 and the ring gear 32. The second planetary gear set 26 includes at least one or more second planet gears 40. Each second planet gear 40 is rotatably mounted on the second planet carrier 34. Each planet gear 40 meshes directly with the ring gear 36.

[0038] The drive device 10, in particular the planetary gear 22, has a first switching element S1 and a second switching element S2. By means of the switching elements S1 and S2, at least or exactly two gear ratios of the drive device 10, in particular of the planetary gear 22, can be switched, that is, engaged and disengaged. In other words, it is conceivable that the electric drive device 10 has at least or exactly two gear ratios, which are represented by the switching elements S1 and S2 and can thus be engaged and disengaged. The first gear ratio is also referred to as first gear 1, and the second gear ratio is also referred to as second gear 2. In particular, the gear ratios differ from each other in their gear ratios, especially in that the gear ratio of first gear 1 is higher than the gear ratio of second gear 2.In other words, the switching elements S1 and S2 are designed to switch at least or exactly two gears.

[0039] The drive device 10 also includes a differential gear 42, which can, for example, be designed as a bevel gear differential. The differential gear 42 has a differential input shaft 44, through which the respective drive torque or a respective torque resulting from the respective drive torque can be introduced into the differential gear 42. This drives the differential input shaft 44, also simply referred to as the input shaft, and thus the differential gear 42. Furthermore, the differential gear 42 comprises two output shafts 46 and 48, which can be driven by the input shaft. This allows the output shafts 46 and 48 to each drive a torque resulting from the input torque. Fig. 1. Provide the torque illustrated by arrows 50, by means of which the wheels of the axle to which the drive device 10 is assigned can be driven. For example, the differential 42 comprises differential gears 52 that mesh with output gears 54 of the differential 42. The output gears 54 are gears that are, in particular, permanently and non-rotatably connected to the output shafts 46 and 48. The differential gears 52 are also gears. Preferably, the rotor 16, which is arranged coaxially with the coaxially arranged planetary gear sets 24, 26, is also arranged coaxially with the output shafts 46 and 48. This means, in particular, that the output shafts 46 and 48 are rotatable about a common output shaft axis of rotation relative to the housing 20, with the machine axis of rotation 18 coinciding with the output shaft axis of rotation.

[0040] Furthermore, it is from Fig. 1. It is evident that the first sun wheel 28 is permanently, and in particular non-rotatably, connected to the rotor 16, and that the second planet carrier 34 is permanently, and in particular non-rotatably, connected to the first planet carrier 30.

[0041] In order to achieve a particularly low-loss and compact design of the drive device 10, the second planetary gear set 26 has a second sun gear 56, wherein the respective planetary gear 40 meshes simultaneously and directly with the ring gear 36 and the sun gear 56. The sun gear 56 is a further second transmission element of the planetary gear set 26. Furthermore, it is provided that the second ring gear 36 is permanently and rotationally fixed to the differential input shaft 44.

[0042] In the first embodiment, the first switching element S1 is designed to connect the second sun gear 56 to the housing 20 in a rotationally fixed manner. Furthermore, in the first embodiment, the first switching element S1 is or has a frictionally or force-fit switching element. The frictionally fitted switching element is, for example, a multi-plate clutch. Thus, it is conceivable that the sun gear 56 can be frictionally and rotationally fixedly connected to the housing 20 by means of the frictionally fitted switching element.

[0043] The second switching element S2 is, for example, a locking switching element by means of which the planetary gear 22 can be locked. In the first embodiment, the second switching element S2 has a positive-locking switching element, in this case designed as a jaw coupling 58, by means of which the direction of rotation to the sun gear 56 around the gear element's rotating bearing can be positively locked and rotationally fixed to the housing 20. Furthermore, in the first embodiment, the switching element S2 has a freewheel clutch 60, also simply referred to as a freewheel, which is arranged or connected in parallel to the jaw coupling 58.

[0044] In the first embodiment, the second switching element S2, also designated K, is configured to connect the second sun gear 56 to the second ring gear 36, thereby enabling, for example, the planetary gear set 26 or the planetary gear set 22 to be locked together. The first switching element S1 is also designated B. Furthermore, in the first embodiment, the second planetary gear set 26 is arranged axially overlapping the differential gear 42. In addition, a parking lock gear 62 of a parking lock 64 is provided, wherein the parking lock gear 62 is, in particular, permanently and rotationally fixed to the second ring gear and thus, in this case, also to the differential input shaft 44.This prevents the ring gear 36 and the differential input shaft 44, and via the latter the output shafts 46 and 48 and thus the drive wheels, from rotating relative to the housing 20 when the parking lock 64 is activated, whereby the parking lock wheel 62 is in particular positively and rotationally fixedly connected to the housing 20, thus securing the motor vehicle against unwanted rolling away, in particular when the motor vehicle is parked on a slope.

[0045] In the first embodiment, the switching element S1 is a friction-fit switching element and thus, for example, a multi-plate clutch, wherein the switching element S1 is particularly free of a positive-locking switching element. Furthermore, it is conceivable that the switching element S2 is free of a friction-fit switching element, in particular because the freewheel is preferably also positively locked or acts in this manner.

[0046] In an embodiment not shown in the figures, it is conceivable that the switching element S2 is a friction-locking switching element, such as a multi-plate clutch, and is free of a positive-locking switching element, so that, for example, the freewheel and the dog clutch 58 can be replaced by, in particular, a friction-locking or force-locking switching element. Furthermore, in an embodiment, it is conceivable that the freewheel is omitted, so that, for example, the switching element S2 comprises only the dog clutch 58 with respect to the freewheel and the dog clutch 58. Thus, it is conceivable that the switching element S2 is designed as a positive-locking switching element, such as the dog clutch 58, and is free of both a freewheel and a friction-locking switching element.Furthermore, in one embodiment, it is conceivable that the claw clutch 58 is omitted, so that the switching element S2 is, for example, a freewheel such as, in particular, the freewheel clutch 60, and thus, for example, with respect to the claw clutch 58 and the freewheel, has only the freewheel. A particular advantage of this embodiment is that the costs can be kept especially low, since no hydraulically or electromechanically controlled switching element is provided. However, compromises could be made with regard to recuperation, because during deceleration and thus during recuperation, the freewheel would be open, thereby allowing a relative rotation between the ring gear 36 and the sun gear 56 about the axis of rotation of the transmission element and relative to the housing 20. The advantage of the one described in... Fig. In the first embodiment shown in Figure 1, in which the switching element S2 has both the freewheel clutch 60 and the dog clutch 58, and in which the switching element S2 has only the freewheel, the advantage is that during a gear change, in particular from first gear 1 to second gear 2, so that the switching element K is, so to speak, a disengaging clutch and the switching element B is a disengaging clutch, especially if dogs or positive-locking switching elements are present, the dog of the switching element K can be opened first, whereby the switching element K is still closed via the freewheel as soon as a torque is transmitted on the switching element B, in particular a braking torque acts on the switching element B, whereby the switching element K then becomes load-free and the freewheel of the switching element K opens automatically and at the correct time.The main reason for this is that a positive-locking switching element, such as a claw coupling, cannot usually be opened, or at least only with considerable inconvenience.

[0047] In order to keep the axial length of the drive device 10 particularly short, the electric machine 12, the first planetary gear set 24, the second planetary gear set 26 and the parking lock wheel 62 are arranged in the following order in the axial direction of the planetary gear 22: the electric machine 12 - the first planetary gear set 24 - the second planetary gear set 26 - the parking lock wheel 62.

[0048] Fig. Figure 2 shows a second embodiment of the drive device 10. In the second embodiment, for example, the switching element S2 is designed as a switching element, in particular a purely friction-fit or force-fit element. Furthermore, the second switching element S2 is designed to connect the second planet carrier 34 to the first planet carrier 30 in a rotationally fixed manner. While in the first embodiment the switching elements S1 and S2 follow both planet gear sets 24 and 26 when viewed axially in the planetary gear set 22, in the second embodiment the switching elements S1 and S2 are arranged between the planet gear sets 24 and 26 when viewed axially in the planetary gear set 22.

[0049] Fig.Figure 3 shows a shift table in which i denotes the gear ratios of gears 1 and 2, Φ the gear spread, and η the gear efficiency in gears 1 and 2. To engage first gear 1, shift element K is closed and shift element B is open. To engage second gear, shift element B is closed and shift element K is open. For example, the gear ratio i of first gear 1 is in a range from 5 to 6 inclusive, particularly from 5 to 5.5 inclusive. For example, the gear ratio i of second gear 2 is in a range from 3 to 4 inclusive, particularly from 3 to 3.5 inclusive. For example, the gear spread is in a range from 1.5 to 2 inclusive.For example, the gearing efficiency in the first gear 1 is at least 98 percent and preferably the gearing efficiency in the second gear 2 is at least 97 percent. Reference symbol list 10 Electric drive device 12 Electric Machine 14 Stator 16 Rotor 18 Machine rotary axis 20 cases 22 planetary gears 24 first planetary gear set 26 second planetary gear set 28 first sun wheel 30 first planetary carrier 32 first ring gear 34 second planetary carrier 36 second ring gear 38 first planetary gear 40 second planetary gear 42 Differential gear 44 Differential input shaft 46 Output shaft 48 Output shaft 50 Arrow 52 Compensating wheel 54 Output gear 56 Second sun wheel 58 Claw coupling 60 Freewheel 62 Parking lock wheel 64 Parking restrictions S1 first switching element S2 second switching element

Claims

Electric drive device (10) for a motor vehicle, comprising: a housing (20), an electric machine (12) designed to drive the motor vehicle, which has a rotor (16), a planetary gear set (22) arranged at least partially in the housing (20), which has a first planet gear set (24) with a first sun gear (28) non-rotatably connected to the rotor (16), a first planet carrier (30) and a first ring gear (32), and a second planet gear set (26) with a second planet carrier (34) non-rotatably connected to the first planet carrier (30) and a second ring gear (36), at least two switching elements (S1, S2), namely a first switching element (S1) and a second switching element (S2), for switching at least two gear ratios, and a differential gear set (42) which has a differential input shaft (44) and two output shafts (46, 48), characterized in thatthat: the second planetary gear set (26) has a second sun gear (56), and the second ring gear (36) is non-rotatably connected to the differential input shaft (44), and the second switching element (S2) is designed to lock the second planetary gear set (26). Electric drive device (10) according to claim 1, characterized in that the first switching element (S1) is designed to connect the second sun gear (56) to the housing (20) in a rotationally fixed manner. Electric drive device (10) according to claim 1 or 2, characterized in that the second switching element (S2) has a claw coupling (58). Electric drive device (10) according to claim 3, characterized in that the second switching element (S2) has a freewheel clutch (60) arranged parallel to the claw clutch (58). Electric drive device (10) according to one of the preceding claims, characterized in that the second switching element (S2) is designed to connect the second sun gear (56) to the second ring gear (36) in a rotationally fixed manner. Electric drive device (10) according to one of the preceding claims, characterized in that the first ring gear (32) is permanently connected to the housing (20) in a rotationally fixed manner. Electric drive device (10) according to one of the preceding claims, characterized in that the second planetary gear set (26) is arranged axially overlapping with the differential gear (42). Electric drive device (10) according to one of the preceding claims, characterized by a parking lock wheel (62) which is non-rotatably connected to the second ring wheel (36). Electric drive device (10) according to claim 8, characterized in that, viewed in the axial direction of the planetary gear (22), the electric machine (12), the first planet gear set (24), the second planet gear set (26) and the parking lock wheel (62) are arranged in the following order: the electric machine (12), the first planet gear set (24), the second planet gear set (26) and the parking lock wheel (62).

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