Drive device for a vehicle axle

Abstract

The invention relates to a drive device for a vehicle axle, in particular a rear axle, of a two-track vehicle, said drive device comprising an axle differential (15), the input side of which is drivingly connected to a drive unit (EM) and the output sides of which provide output to output shafts (17, 18) leading to the two vehicle wheels, wherein the vehicle axle comprises, for each output shaft (17, 18), a superimposing gearbox (19) that has a multi-plate clutch (7) and enables torque distribution to the vehicle wheels, wherein the vehicle axle has a central multi-plate brake (5) which acts on the vehicle axle and can be used for vehicle braking. According to the invention, the drive device has at least one parking lock (PS1, PS2) for engaging or disengaging a vehicle holding function, the parking lock consisting of: a parking lock wheel (32, 39) formed with external toothing (75); and a pawl (89, 90) that can be engaged with the parking lock wheel.

Description

[0001] Drive device for a vehicle axle

[0002] DESCRIPTION:

[0003] The invention relates to a drive device for a vehicle axle according to the preamble of claim 1.

[0004] Such a drive device for a vehicle axle features an axle differential, which enables a 50 / 50 distribution. Its input side is connected to a drive unit, such as an electric motor, while its output sides drive output shafts leading to the two vehicle wheels. Sports vehicles, in particular, usually feature a torque vectoring system on the vehicle's rear axle. This directs drive torque past the differential directly to the vehicle wheels. This allows the drive torque to be freely distributed on each vehicle axle. In addition to the conventional drive with a differential, such a torque vectoring system also features two superposition gears, two frictionally controlled clutches, two actuators, a control unit, and its own hydraulic system.

[0005] If the vehicle's rear axle is designed without wheel brakes, the rear axle can instead be equipped with a single central multi-disk brake acting on the vehicle axle, allowing vehicle braking to be performed evenly on both sides of the vehicle. The central multi-disk brake can be used to perform vehicle braking as an alternative to or in addition to the multi-disk clutches. Therefore, if the electric motor is unable to recuperate, or only partially capable of recuperation, the multi-disk brake can take over the braking task at least partially or completely. The multi-disk brake can, for example, cause vehicle braking depending on the current recuperation capacity.

[0006] A state-of-the-art parking management system consists of a parking lock integrated into the drive module and two parking brakes located on the rear wheels of the vehicle. Both systems operate independently of each other. This means that if one system fails, the other system takes over the holding function.

[0007] Since the generic drive device on the vehicle rear axle does not have any vehicle wheel brakes, but only a central multi-disk brake, the provision of a parking brake on the vehicle wheel involves a high component expenditure.

[0008] DE 10 2018 133 223 A1 discloses a vehicle axle with electric drive motors in conjunction with a transmission, a torque vectoring unit, and a brake unit. The brake unit comprises an electrohydraulic brake and a parking brake. DE 10 2010 024 147 A1 discloses a drive train of an electric vehicle with a multi-disk clutch. The multi-disk clutch has an integrated parking lock mechanism. DE 10 2022 103 839 B3 discloses a drive device for a vehicle axle. The drive device has an electric motor and a superposition gear with a multi-disk clutch and a multi-disk brake.

[0009] The invention consists in providing a drive device for a vehicle axle in which parking management is possible with reduced component expenditure compared to the prior art.

[0010] The object is solved by the features of claim 1. Preferred developments of the invention are disclosed in the subclaims.

[0011] The invention relates to a drive device for a vehicle axle, in particular the rear axle, of a two-track vehicle. The drive device has an axle differential, the input side of which is connected to a drive unit. The output side of which drives on output shafts leading to the two vehicle wheels. The vehicle axle has a superposition gear with a multi-disk clutch for each output shaft. The superposition gear distributes torque to the vehicle wheels. Furthermore, the vehicle axle is designed without vehicle wheel brakes. Instead, the vehicle axle has precisely one central multi-disk brake acting on the vehicle axle, by means of which vehicle braking can be carried out. According to the characterizing part of claim 1, the drive device has at least one parking lock for engaging or disengaging a vehicle hold function.This consists of a parking lock gear with external teeth and a locking pawl that engages with it. The locking pawl is driven by a multi-plate clutch parking actuator between a release position and a parking lock position, in which the drive mechanism is locked to a transmission housing.

[0012] The locking pawl can be preloaded toward the parking lock position by a spring element. This way, if the multi-plate clutch parking actuator fails, the locking pawl automatically moves toward the parking lock position.

[0013] The multi-plate clutch has an inner plate carrier connected to the output shaft and an outer plate carrier connected to the differential housing of the differential housing, as well as an intermediate plate pack. According to the invention, the inner plate carrier can be designed as a parking lock gear with external teeth that interacts with an inner plate pawl. Similarly, the outer plate carrier can also be designed as a parking lock gear with external teeth that interacts with an outer plate carrier pawl. A common multi-plate clutch parking actuator is preferably assigned to the two pawls, which, with the interposition of a spring element, acts on both the inner plate pawl and the outer plate carrier pawl.For redundancy, the drive device can additionally include a multi-disk brake parking actuator for engaging or disengaging the vehicle hold function. In such a variant, the drive device is expanded with a total of two parking systems.

[0014] One parking system acts on the multi-disk brake via the multi-disk brake parking actuator and applies the required braking force (on a 30% gradient). Even with the multi-disk brake engaged and significantly different friction conditions at the rear wheels, the vehicle can still roll away. To prevent this from happening, both the inner and outer disc carriers of the multi-disk clutch can lock to the transmission housing using two pawls, similar to a parking lock. If the friction at one wheel is insufficient, it will slip. The other wheel can therefore roll down a gradient. This causes the inner disc carrier to twist relative to the housing, allowing the pawl to engage. Now one vehicle wheel and the differential housing are locked, and with them the other vehicle wheel. In this case, a reduced holding force applies for 15% gradients. Both parking systems are driven or controlled separately.

[0015] In the event of a fault (i.e., the multi-plate clutch parking actuator is not functioning), locking the differential is not necessary. It can be assumed that there is sufficient friction at both wheels.

[0016] A core of the invention is that the inner disk carrier (in particular an inner disk of the inner disk carrier) of the multi-disk clutch is designed as a parking lock gear. The outer disk carrier can also be designed as a parking lock gear. Both parking lock gears have gaps in their outer contours, into which a pawl can engage. Both pawls are pressed onto the parking lock gears by two springs (normally closed). A cylinder or a solenoid acts simultaneously on both pawls in such a way that the pawls can be disengaged against the spring force. This is the case during normal ferry operation or when both parking locks need to be released.

[0017] The pawls and parking lock gears are coordinated in such a way that engaging the locks is impossible at speeds above 3 km / h. This function is familiar from modern parking locks.

[0018] Optionally, the cylinder or solenoid can be designed with respect to the lifting force so that a lock can be released under preload (from the slope force). For example, the point of engagement between the parking lock gear and the pawl could be designed differently for the two parking locks. This allows the maximum force points from both parking locks to be positioned so that the two maximums do not add up.

[0019] The invention therefore relates to an overall system consisting of two subsystems, namely the parking locks and the multi-disk brakes. The overall system covers all the requirements of today's systems, both parking locks and parking brakes. Unlike the prior art, the invention requires only two actuators. If one of the two parking systems fails, the other system meets the correspondingly reduced requirements, similar to today's systems.

[0020] Should the braking system fail while driving, the multi-disk brake can act as an emergency brake. If this backup isn't needed, this parking system can be replaced with a conventional parking lock.

[0021] The multi-disk clutch and multi-disk brake each have a hydraulic cylinder controlled by an electronic control unit. This cylinder can be used to apply contact pressure to the multi-disk clutch and multi-disk brake disk packs to perform torque vectoring during normal ferry operation. This directs drive torque past the differential directly to the vehicle wheels. This allows the drive torque to be freely distributed across the vehicle axle. In addition to the conventional drive with differential, such a torque vectoring system also features two superposition gears on each side of the vehicle, two force-locked multi-disk clutches, the two hydraulic cylinders as actuators, a control unit, and its own hydraulic system.

[0022] In contrast, the two actuators according to the invention, namely the multi-disk clutch parking actuator and the multi-disk brake parking actuator, are not hydraulically controlled by the control unit, but rather electrically. When the vehicle hold function is engaged, the multi-disk brake parking actuator locks the multi-disk brake, while the multi-disk clutch parking actuator locks the multi-disk clutch.

[0023] In a first embodiment, the multi-disk brake parking actuator can be implemented as follows: This actuator can have a pressure mechanism integrated into the multi-disk brake, comprising a ball-ramp unit and a preferably self-locking spindle drive. The spindle drive can drive the ball-ramp unit by building up / releasing a contact pressure acting on the multi-disk brake. Due to the self-locking nature of the electrically operated spindle drive, the set contact pressure can be maintained even without power. When the multi-disk brake parking actuator is activated, the hydraulic pressure in the hydraulic cylinder of the multi-disk brake can be depressurized at the same time. Furthermore, when the multi-disk brake parking actuator is activated, the vehicle can be secured on the front axle using the vehicle brakes.

[0024] Embodiments of the invention are described below with reference to the attached figures.

[0025] They show:

[0026] Figures 1 to 4b show different views illustrating the structure and operation of the drive devices according to the invention. Figure 1 shows an electrified vehicle rear axle with an electric motor EM and a transmission 3. The electric motor EM is connected to a high-voltage battery (not shown). Conventional vehicle wheel brakes are omitted from the vehicle rear axle. Instead of such conventional vehicle wheel brakes, the vehicle axle has a central multi-disk brake 5 (described later) and multi-disk clutches 7. The central multi-disk brake 5 effects vehicle braking alternatively or in addition to the multi-disk clutches 7.

[0027] The electric motor EM is connected via its rotor shaft 9, with a countershaft stage 11 interposed, to the input side of an axle differential 15. Its output sides are in driving connection with the vehicle's rear wheels. In Figure 1, the electric motor EM is installed transversely in the vehicle axle. Accordingly, the rotor shaft 9 and the output shafts 17, 18 are axially parallel to one another, leading from the output sides of the axle differential 15 to the vehicle's rear wheels. Likewise, the multi-disk clutches 7 and the multi-disk brake 5 installed in the vehicle axle are axially parallel to one another in the vehicle's transverse direction y.

[0028] The vehicle axle, viewed in the vehicle's transverse direction y, has a superposition gear 19 on each side of the vehicle, with which the electric motor EM can be directly connected to one of the output shafts 17, 18, bypassing the axle differential 15. With the help of the two superposition gears 19, the electric motor EM can therefore drive directly to the vehicle wheels via load paths, bypassing the axle differential 15, in order to perform torque vectoring.

[0029] The intermediate gear stage 11 is connected to an input-side axle differential gear 21. The axle differential gear 21 is connected in a rotationally fixed manner to a rotating differential housing 25. According to Figure 1, the axle differential 15 drives the power in the vehicle's transverse direction y in a 50 / 50 distribution on both sides to the two output shafts 17, 18 leading to the vehicle wheels.

[0030] The two superposition gears 19 are mirror-inverted with respect to a vehicle center longitudinal plane passing through the axle differential 15. Thus, each of the two superposition gears 19 has a gear ratio stage 28 designed in the manner of a planetary gear (but without an external ring gear) having a sun gear 47 on the outside of the vehicle, viewed in the vehicle transverse direction y, which is non-rotatably mounted on the output shaft 17, 18, and a sun gear 29 on the inside of the vehicle, which is rotatably arranged as an idler gear on the output shaft 17, 18. The sun gear 29 on the inside of the vehicle meshes with planet gears 41 on the inside of the vehicle, each of which is non-rotatably mounted on a carrier shaft 43. Each of the carrier shafts 43 has a planet gear 45 on the outside of the vehicle, which meshes with the sun gear 47 on the outside of the vehicle.

[0031] The vehicle-internal sun gear 29 (i.e., the idler gear) sits together with an inner disk carrier 31 of the multi-disk clutch 7 on a hollow shaft through which the output shaft 17, 18 passes. The inner disk carrier 31 of the multi-disk clutch 7 interacts via a disk pack with an outer disk carrier 39, which is non-rotatably connected to the differential housing 25. The disk pack located between the outer disk carrier 39 and the inner disk carrier 31 can be pressurized via an annular piston 63, indicated in Figure 3a. This piston is adjustable by a horizontal stroke using a hydraulic cylinder 49 in order to actuate the multi-disk clutch 7 to a predetermined degree of clutch engagement. The multi-disk clutch 7 is powershiftable and controllable with slip.

[0032] According to Figure 2, the multi-disk brake 57 consists of an inner disc carrier 59 and an outer disc carrier 61 with a disc pack arranged between them. The inner disc carrier 59 is mounted in a rotationally fixed manner on the differential housing 25, while the outer disc carrier 61 is connected in a rotationally fixed manner to the transmission housing wall 55. The disc pack located between the outer disc carrier 61 and the inner disc carrier 59 can be pressurized via an annular piston 63, indicated in Figure 2. This piston can be adjusted by a horizontal stroke by means of a hydraulic cylinder 51 in order to actuate the multi-disk brake 5.

[0033] As further shown in Figure 1, the vehicle's parking management system PM consists of a multi-disk brake parking actuator 57 acting on the multi-disk brake 5 and a multi-disk clutch parking actuator 58 acting only on the left-hand (alternatively only on the right-hand) multi-disk clutch 7. The two actuators 57, 58 provide two independently operating parking systems that are controlled electrically rather than hydraulically by a control unit. When the vehicle hold function is engaged, the actuator 57 acts on the multi-disk brake 5 to apply the required holding force. It should be noted that the vehicle can still roll away if the multi-disk brake parking actuator 57 is actuated alone and if the friction conditions at the rear wheels differ significantly.In order to prevent such rolling away, the left-hand multi-plate clutch 7 and thus the axle differential 15 can also be blocked with the aid of the multi-plate clutch parking actuator 58.

[0034] In Figure 2, the multi-disk brake parking actuator 57 is designed with a pressure mechanism with a ball-ramp unit 65 integrated into the multi-disk brake 5. The disc pack located between the outer disc carrier 61 and the inner disc carrier 59 is pressurized via an annular piston 63, which can be adjusted by a horizontal stroke by means of the hydraulic cylinder 51. On the side axially opposite the annular piston 63, the ball-ramp unit 65 acts on the disc pack. The ball-ramp unit 65 consists of a fixed disc 67 and a rotatable disc 69, between which balls 71 are arranged. The rotatable disc 69 is extended radially outward with a toothing 73, which interacts with a drive spindle (not shown) of the multi-disk brake parking actuator 57.

[0035] As further shown in Figure 3a or 3b, an axially outer, exposed inner plate 32 of the inner plate carrier 31 of the left-hand multi-plate clutch 7 is designed as a parking lock gear with external teeth 75, into which an inner plate pawl 89 can be engaged. Similarly, the outer plate carrier 39 of the left-hand multi-plate clutch 7 is designed as a parking lock gear with external teeth 75, into which an outer plate carrier pawl 90 can be engaged. A common multi-plate clutch parking actuator 58 is assigned to the two pawls 89, 90, which, with the interposition of a spring element 91, 92, acts on both the inner plate pawl 89 and the outer plate carrier pawl 90.The spring element 91, 92 preloads each of the two pawls 89, 90 toward a parking position, so that, particularly in the event of a failure of the multi-plate clutch parking actuator 58, the pawl 89, 90 automatically moves into the parking lock position. In the parking lock position, the pawls 89, 90 can be brought into meshing engagement with the inner and outer plate carriers 31, 39. Furthermore, in the parking lock position, the inner or outer plate carrier 31, 39 can be blocked with a transmission housing wall 55.

[0036] The two multi-disk clutches 7 and the multi-disk brake 5 have a hydraulic cylinder 49, 51 that can be controlled by a control unit. During normal ferry operation, the multi-disk clutch 7 and / or the multi-disk brake 5 can be subjected to contact pressure by means of the hydraulic cylinders 49, 51. However, when the vehicle is parked for an extended period, the hydraulic cylinders 49, 51 cannot guarantee a permanent vehicle-holding function due to the evaporation tendency of the hydraulic pressure acting on the hydraulic cylinders 49, 51. Accordingly, the multi-disk clutch parking actuator 58 and the multi-disk brake parking actuator 57 are not hydraulically controlled by a control unit, but electrically.

[0037] During fault-free operation of the parking management system PM, both the multi-disk brake parking actuator 57 and the multi-disk clutch actuator 58 are actuated. As a result, at least the multi-disk brake 5 applies a holding force to the vehicle, while the two pawls 89, 90 may still be in contact with the upper side of the external toothing 75 of the parking lock gears 32, 39, i.e., they are not yet engaged with the external toothing 75 of the parking lock gears 32, 39.

[0038] The PM parking management system is designed for the following situations during fault-free operation: first, for a parked vehicle with sufficiently high wheel friction values ​​on both sides, in which the multi-disk brake (5) generates sufficient holding force, even without the pawls (89, 90) engaged. The second situation concerns a vehicle parked on a slope with significantly different wheel friction values ​​on both sides, in which the low-friction wheel starts to slip and the high-friction wheel rolls down the slope. In this case, the inner disc 32 rotates until the inner-disk pawl 89 engages. This locks the axle differential 15 and the required residual holding force can be generated on the high-friction wheel. At the same time, the outer disc carrier 39 is held in a rotationally fixed position via the brake 5, and the outer disc carrier pawl 90 remains inoperative.

[0039] In the event that, in fault-free operation, the high-friction vehicle wheel is arranged on the vehicle side equipped with the two parking locks PS1, PS2, the following applies: The high-friction vehicle wheel rolling down the gradient rotates the inner disk carrier 31 with the interposition of the superposition gear (19) and thus the inner disk 32 acting as a parking lock wheel until the inner disk pawl 89 engages.

[0040] Alternatively, if the high-friction vehicle wheel is located on the side of the vehicle opposite the two parking locks PS1 and PS2, the following applies: The high-friction vehicle wheel rolling down the slope rotates the low-friction vehicle wheel due to the differential effect. This causes the inner disk carrier 31 and thus the inner disk 32 acting as the parking lock gear to rotate until the inner disk pawl 89 engages.

[0041] The following describes a fault scenario in which the multi-disk brake parking actuator 57 fails and only the multi-disk clutch actuator 58 is actuated. The actuation of the multi-disk clutch actuator 58 does not automatically mean that the pawls 89, 90 are engaged. Rather, they may not yet be engaged in the external toothing 75 of the parking lock gears 32, 39, but may merely be in contact with the upper surface of the tooth of the external toothing 75 of the parking lock gears 32, 39. In this fault scenario, the parking management PM is designed for a vehicle rolling down a slope. In this vehicle, the two parking lock gears 32, 39 rotate until one of the two pawls 89, 90 engages with the associated parking lock gear 32, 90. This generates a holding force.

[0042] If sufficient holding force is provided after only one of the two pawls 89, 90 has engaged, the other pawl 89, 90 remains disengaged. If one of the vehicle wheels begins to slip after only one pawl 89, 90 has engaged, the other, not yet engaged parking lock gear 32, 39 rotates until the associated pawl 89, 90 engages, thereby generating the remaining required holding force.

[0043] In the embodiment of Figure 2, the multi-disk brake parking actuator 57 is implemented with a ball-ramp unit 65. With such a ball-ramp unit 65, self-locking is only possible with considerable design effort due to the low coefficient of friction between the balls 71 and the ramp-shaped tracks of the stationary disc 67 and the rotatable disc 69.

[0044] With regard to a self-locking mechanism that is easier to implement, reference is made to the exemplary embodiment in Figures 4a and 4b. In Figure 4a, the multi-disk brake parking actuator 57 is essentially structurally identical to that in Figure 2. Reference is therefore made to the description of Figure 2. In contrast to Figure 2, in Figures 5a and 5b, the multi-disk brake parking actuator 57 is not implemented with a ball-ramp unit 65, but with a ramp unit 70. No balls 71 are installed in the ramp unit 70, whereby a much simpler self-locking mechanism can be achieved compared to Figure 2.

[0045] In Figure 4a, the self-locking ramp unit 70 consists of a fixed disc 67 and a coaxial rotatable disc 69. Both the fixed disc 67 and the rotatable disc 69 have ramp-shaped inclined surfaces 72 (Figure 4b) that are in sliding / frictional contact with each other. The rotatable disc 69 is formed with external teeth 73, which are in driving connection with a drive spindle (not shown) of the multi-disk brake parking actuator 57. Depending on the direction of rotation of the rotatable disc 69, pressure builds up or decreases.

[0046] LIST OF REFERENCE SYMBOLS:

[0047] 3 gearboxes

[0048] 5-disk brake

[0049] 7 multi-plate clutch

[0050] 9 Rotor shaft

[0051] 11 countershaft

[0052] 15 axle differential

[0053] 17, 18 Output shafts

[0054] 19 superposition gears

[0055] 21 axle differential gear

[0056] 25 differential housing

[0057] 28 gear ratios

[0058] 29 vehicle-internal sun gear

[0059] 31 Inner plate carrier of the multi-plate clutch

[0060] 32 inner disc designed as a parking lock gear

[0061] 39 Outer plate carrier of the multi-plate clutch

[0062] 41 vehicle-internal planetary gears

[0063] 43 Carrier wave

[0064] 45 vehicle-external planetary carriers

[0065] 47 vehicle outer sun gear

[0066] 49 Hydraulic cylinder of the multi-plate clutch

[0067] 51 Hydraulic cylinder of the multi-disk brake

[0068] 55 Gearbox housing wall

[0069] 57 multi-disc brake parking actuator

[0070] 58 multi-plate clutch parking actuator

[0071] 59 Brake inner disc carrier

[0072] 61 Outer brake disc carrier

[0073] 63 ring pistons

[0074] 65 Ball Ramp Unit

[0075] 67 fixed disc

[0076] 69 rotating writing

[0077] 70 Ramp unit

[0078] 71 Sphere 72 Inclined surfaces

[0079] 73 Gearing

[0080] 75 external teeth for the pawls

[0081] 77 Sliding sleeve 79 Spring element

[0082] 81 , 83 clamping jaws

[0083] 85 mother

[0084] 87 spindle drive

[0085] 89 Inner disc pawl 90 Outer disc carrier pawl

[0086] 91 , 92 spring elements

[0087] EM electric machine

[0088] PM Park Management

[0089] PS1, PS2 parking locks

Claims

PATENT CLAIMS:

1. Drive device for a vehicle axle, in particular a rear axle, of a two-track vehicle, which has an axle differential (15), the input side of which is drivingly connected to a drive unit (EM) and the output sides of which drive to output shafts (17, 18) leading to the two vehicle wheels, wherein the vehicle axle has a superposition gear (19) with a multi-disk clutch (7) for each output shaft (17, 18), with which a torque distribution to the vehicle wheels takes place, wherein the vehicle axle has a central multi-disk brake (5) acting on the vehicle axle, by means of which a vehicle braking can be carried out, characterized in that the drive device for engaging or disengaging a vehicle holding function has at least one parking lock (PS1, PS2), which consists of a parking lock gear (32, 39) formed with external teeth (75) and of a pawl (89, 90) which can be engaged therewith, and that in particular the pawl (89,90) can be driven between a release position and a parking lock position in which the drive device is blocked by a transmission housing wall (55).

2. Drive device according to claim 1, characterized in that the locking pawl (89, 90) is pre-tensioned by means of a spring element (91, 92) in the direction of the engaged parking lock position, so that in particular in the event of a failure of the multi-disk clutch parking actuator (58), the locking pawl (89, 90) automatically moves in the direction of the parking lock position, or that on each of the two vehicle sides, one of the superposition gears (19) with multi-disk clutch (7) is arranged, preferably mirror-inverted with respect to a vehicle center longitudinal plane, and / or that on each vehicle side, the multi-disk clutch (7) has an inner disk carrier (31) which, with the interposition of the Superposition gear (19) is connected to the output shaft (17, 18), has an outer disk carrier (39) connected to a differential housing (25) of the axle differential (15) and an intermediate disk pack, and that the two parking locks (PS1, PS2) are assigned to one of the two multi-disk clutches (7), and that in particular an inner disk (32) of the inner disk carrier (31) is designed as a parking lock gear with external toothing (75), into which an inner disk pawl (89) can be engaged, and / or that in particular the outer disk carrier (39) is designed as a parking lock gear with external toothing (75), into which an outer disk carrier pawl (90) can be engaged, and / or that the inner disk (32) designed as a parking lock gear has a at the axially outer end of the The inner plate is formed in the plate pack.

3. Drive device according to one of the preceding claims, characterized in that a common multi-disk clutch parking actuator (58) is assigned to the two pawls (89, 90), and in particular that the common multi-disk clutch parking actuator (58) acts on both the inner-disk pawl (89) and the outer-disk carrier pawl (90) with the interposition of a spring element (91, 92), and / or that with regard to redundancy, the drive device for engaging or disengaging the vehicle holding function has a multi-disk brake parking actuator (57), with which the multi-disk brake (5) can be actuated.

4. Drive device according to one of the preceding claims, characterized in that the multi-disk clutch (7) and / or the multi-disk brake (5) have a hydraulic cylinder (49, 51) which can be controlled by a control unit, that, in particular during ferry operation, the multi-disk clutch (7) and / or the multi-disk brake (5) can be subjected to a contact pressure by means of the hydraulic cylinders (49, 51), that, in particular, the hydraulic cylinders (49, 51) do not ensure a permanent vehicle holding function when the vehicle is parked due to evaporation tendencies of the hydraulic pressure acting on the hydraulic cylinders (49, 51), and / or that, in particular, the multi-disk brake parking actuator (57) and / or the multi-disk clutch parking actuator (58) can be controlled electrically rather than hydraulically by a control unit, and / or that, in particular, the two actuators (57, 58) can be controlled independently of one another, and / or that, when the vehicle holding function is engaged, both the multi-disk brake (5) is locked by means of the multi-disk brake parking actuator (57) and the multi-disk clutch (7) is locked by means of the two parking locks (PS1, PS2) can be locked.

5. Drive device according to one of claims 2 to 4, characterized in that during error-free operation of the parking management (PM), both the multi-disk brake parking actuator (57) and the multi-disk clutch actuator (58) are actuated, whereby at least the multi-disk brake (5) applies a holding force to the vehicle, while the two pawls (89, 90) are possibly still in contact with the tooth top side of the external toothing (75) of the parking lock wheels (32, 39), ie are not yet engaged in the external toothing (75) of the parking lock wheels (32, 39), and that the parking management (PM) is designed for - a parked vehicle with sufficiently high wheel friction values on both sides, in which the multi-disk brake (5) generates sufficient holding force, even without the pawls (89, 90) being engaged, and - a vehicle parked on a slope with very different wheel friction values on both sides, where the low-friction wheel slips and the high-friction wheel Vehicle wheel rolls down the slope, causing the inner plate (32) to rotate until the inner plate locking pawl (89) engages, so that the axle differential (15) is locked and the required residual holding force can be generated on the high-friction vehicle wheel, while the outer plate carrier (39) is held in a rotationally fixed manner by the brake (5) and the outer plate carrier locking pawl (90) remains inoperative.

6. Drive device according to claim 5, characterized in that in the event that the high-friction vehicle wheel is arranged on the vehicle side equipped with the two parking locks (PS1, PS2), the high-friction vehicle wheel rolling down the gradient rotates the inner disk carrier (31) and thus the inner disk (32) acting as a parking lock gear with the interposition of the superposition gear (19) until the inner disk pawl (89) engages, or in the event that the high-friction vehicle wheel is arranged on the vehicle side opposite the two parking locks (PS1, PS2), the high-friction vehicle wheel rolling down the gradient rotates the low-friction vehicle wheel due to the differential effect, whereby the inner disk carrier (31) and thus the inner disk (32) acting as a parking lock gear rotates until the inner disk pawl (89) clicks into place.

7. Drive device according to one of the preceding claims, characterized in that in the event of a fault, the multi-disk brake parking actuator (57) fails and only the multi-disk clutch actuator (58) is actuated, wherein the two pawls (89, 90) are possibly not yet engaged in the external toothing (75) of the parking lock wheels (32, 39), but are only in contact with the tooth upper side of the external toothing (75) of the parking lock wheels (32, 39), and that in the event of a fault, the parking management (PM) is designed for a vehicle rolling down a slope in which the two Turn the parking lock gears (32, 39) until one of the two pawls (89, 90) engages with the associated parking lock gear (32, 90), thereby generating a holding force.

8. Drive device according to claim 7, characterized in that in the event that after the engagement of only one pawl (89, 90) a sufficient holding force is provided, the other pawl (89, 90) remains disengaged, or in the event that after the engagement of only one pawl (89, 90) one of the vehicle wheels starts to slip, the other, not yet engaged parking lock wheel (32, 39) rotates until the associated pawl (89, 90) engages, whereby the still required residual holding force is generated.

9. Drive device according to one of the preceding claims, characterized in that the multi-disk brake parking actuator (57) has a pressure mechanism integrated in the multi-disk brake (5) with a ball-ramp unit (65) and with a preferably self-locking spindle drive, that the ball-ramp unit (65) consists of a fixed disc (67) and a coaxial rotatable disc (69), between which at least one ball (71) rolls, that the spindle drive drives the rotatable disc (69) of the ball-ramp unit (65) by building up / releasing a contact pressure acting on the multi-disk brake (5), and that in particular the self-locking spindle drive keeps the set contact pressure de-energized.

10. Drive device according to one of claims 1 to 8, characterized in that the multi-disk brake parking actuator (57) has a pressing mechanism integrated in the multi-disk brake (5) with a particularly self-locking ramp unit (70) and a spindle drive, that the ramp unit (70) consists of a fixed disc (67) and a rotatable disc (69) coaxial therewith, that inclined surfaces of the fixed disc (67) and the rotatable disc (69) are in sliding / frictional contact with one another, that the spindle drive drives the rotatable disc (69) of the ramp unit (65) while building up / reducing a contact pressure acting on the multi-disk brake (5), and that a pressure build-up or reduction takes place depending on the direction of rotation of the rotatable disc (69).

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