WO2014169912A1

WO2014169912A1 - Differential gear

Info

Publication number: WO2014169912A1
Application number: PCT/DE2014/200107
Authority: WO
Inventors: Ralph Schimpf; Thorsten Biermann; Franz Kurth; Harald Martini
Original assignee: Schaeffler Technologies Gmbh & Co. Kg
Priority date: 2013-04-16
Filing date: 2014-03-04
Publication date: 2014-10-23
Also published as: DE102013206756A1

Abstract

The invention relates to a differential gear comprising a gear housing, an epicyclic gear casing rotatably mounted about a gear axis in the gear housing, a planet carrier mounted coaxially with the gear axis in the epicyclic gear casing, a braking system with a brake plate package for generating a coupling torque to couple the planet carrier to the epicyclic gear casing, and an actuating mechanism for generating an axial load which is applied to the braking system. According to the invention the actuating mechanism has an axially extendable lifting actuator which is accommodated in the epicyclic gear casing and is rotatably axially supported on the epicyclic gear casing.

Description

Name of the invention

differential gear

Description Field of the invention

The invention relates to a differential gear with a gear housing, a circulation housing which is rotatably mounted in the gear housing about a transmission axis, and a planet carrier sitting in the circulation housing, which is branched by this differential gear applied to the circulation housing drive power and the planet carrier and the circulation housing are selectively frictionally coupled via a coupling device.

Background of the invention

Differential transmissions are generally designed as epicyclic gearboxes and serve predominantly the branching or distribution of an input power supplied via a power input to two drive shafts. Most commonly differential gears are used as so-called. Achsdifferentialgetriebe in automotive. Here, the drive power provided by a drive motor is distributed via the differential gear to the wheel drive shafts of driven wheels. The two leading to the wheels wheel drive shafts are driven in this case, each with equal torque, ie balanced. When driving straight ahead, both wheels rotate at the same speed. When cornering, the speeds of the wheels differ from each other. The axle differential allows this speed difference. The speeds can be set freely, only the average of the two speeds is unchanged. In certain applications, especially in all-wheel drive vehicles, differential gears are used which, when no four-wheel drive is required, allow a switchable interruption of the drive train to drive the vehicle over only one axle and thereby reduce the friction losses of the currently unneeded, otherwise entrained, drive system , A corresponding differential gear is known for example from DE 10 2008 037 885 A1.

Object of the invention

The invention has for its object to provide a differential gear which enables a switchable suspension or bringing about the drive connection between the power input and the two power outputs and is characterized by a cost-effective and robust construction.

Inventive solution

The above object is achieved by a differential gear, with:

a transmission housing,

a circulation housing which is rotatably arranged in the transmission housing about a transmission axis,

a planetary carrier coaxially arranged in the circulation housing to the transmission axis,

a braking device having a brake disk pack for generating a coupling moment coupling the planet carrier to the planetary housing, and

- An actuating mechanism for generating a force acting on the braking device axial force, wherein

- The actuating mechanism comprises an axially expandable Hubaktuator received in the circulation housing and is supported axially in the circulation housing on this. This advantageously makes it possible to provide a differential gear in which the axial forces required to bring about a coupling state of the braking device are guided within the circulating housing and do not have to be removed into the gear housing via the bearing of the circulating housing.

According to a particularly preferred embodiment of the invention, the Hubaktuator is rotatably supported axially in the rotary housing relative to this rotary housing via a first thrust bearing, said first thrust bearing is preferably designed as a cylindrical roller bearing. In addition, the Hubaktuator is preferably axially rotatably supported in the circulation housing and against the braking device via a second thrust bearing. This second thrust bearing can be designed as a cylindrical bearing that is identical to the first thrust bearing. The second thrust bearing can be designed so that the cylindrical rollers roll on a pressure plate, which axially loads the brake disc pack.

The Hubaktuator may be formed as a hydrostatic actuator according to an advantageous embodiment of the invention and in this case comprise an annular piston and an annular chamber, wherein the axial expansion of the actuator is accomplished by applying the annular chamber with a fluid.

As an alternative to the aforementioned embodiment of the invention, it is also possible to design the lifting actuator as a ramp actuator so that it comprises a first ramp disc and a second ramp disc, wherein the first ramp disc can be twisted about the transmission axis relative to the second ramp disc. The twisting of the first ramp disc relative to the second ramp disc is preferably accomplished here by an electromechanical actuating motor, which is stationarily integrated into the transmission housing outside of the circulating housing. The ramp actuator can be designed so that the second ramp disc is rotatably coupled to the transmission housing. The kinematic coupling of the first ram penscheibe with the electric motor is preferably carried out via a bushing portion coaxial with the transmission axis of a bottom portion of the circulation housing and coupled to the electric motor, if necessary, with the interposition of a transmission gear.

The differential gear itself is preferably constructed such that it comprises a first output sun gear, a second output sun gear and a planetary assembly received in the planet carrier, for coupling the two output sun gears in a rotationally movable manner in opposite directions. The planetary arrangement in this case comprises a plurality of planetary orbits, which are rotatable as such about planetary axes, which are aligned parallel to the transmission axis. The braking device and the planet carrier are designed coordinated with one another such that the brake disk pack is located at the radial level of the planetary axles.

The differential gear according to the invention is further advantageously designed such that the brake disk pack is composed of a plurality of brake disks designed as annular disks. These brake discs may be designed as flat sheet steel annular discs, which may be coated with a Reibmaterialbelag. The brake disk pack can be constructed such that it comprises brake disks which are rotationally fixed via an inner peripheral contour but are coupled kinematically in an axially displaceable manner with the planet carrier. Furthermore, the brake disk pack then also comprises brake disks, which are rotationally fixed via an outer peripheral contour but are coupled kinematically in an axially displaceable manner with the circulation housing.

According to a particularly preferred embodiment of the invention, the axial support of the brake disk pack is accomplished by involving a pressure ring element, said pressure ring element is supported on the end faces of the planetary bearing bolts.

The provided for receiving the planet carrier circulation housing is preferably formed as a two-piece pot housing consisting of a first Pot member and a second pot member composed, wherein the first pot member has a radially inwardly extending bottom portion which receives as such the axial force generated by the Hubaktuator.

To the circulation housing, a ring gear is preferably attached and the power input into the circulation housing is accomplished via this crown wheel. In conjunction with this ring gear, an angular gear can be realized. This design is particularly suitable for use as a temporarily switchable rear axle differential. It is also possible, instead of the ring gear there to arrange a spur gear to initiate the drive power.

The internal differential accommodated in the interior of the circulating housing provided here is designed as a spur gear differential with two driven sun gears which can be rotated in opposite directions by means of a planetary arrangement. This spur gear is carried out according to a particularly preferred embodiment of the invention with a teeth to Wildhaber / Novikov. Details of the here on the respective gears preferably realized geometries, as well as to the head and Fußkreisdurchmessern the output sun gears and the attacking them planetary gears are dealt with in more detail in the figure description.

The actuation of the coupling device accommodated in the circulation housing takes place via a ramp sub-unit which is inserted into the circulating housing and acts in this case, preferably via an external, i. outside the circulating housing arranged electromechanical actuator, in particular via an electric motor is actuated.

Brief description of the figures

Further details and features of the invention will become apparent from the following description in conjunction with the drawings. It shows: Figure 1 is an axial sectional view for illustrating the structure of a differential gear according to the invention in which the coupling of the planet carrier is accomplished on a receiving this pot housing via a brake disk pack which is relative to the transmission axis on the web or

Radial level of the Planetenradlagerbolzenachsen extends, wherein the required for bringing about the coupling state a- xiale load of the brake disk pack is accomplished by an axially expandable, inherently stationary Hubaktuator which is received in the circulation housing and rotatably supported therein; a schematic representation to illustrate the structure of the rotatable within the circulating housing Hubaktua- sector.

Detailed description of the figures

The illustration of Figure 1 shows an inventive differential gear. This comprises here a transmission housing G and a circulation housing U which is rotatably mounted in the transmission housing G about a transmission axis X. In the circulation housing U, a planet carrier 3 is received, which in turn is arranged coaxially to the transmission axis X. The differential gear further comprises a first output sun gear 1, a second output sun gear 2 and a received in the planet carrier 3 planetary arrangement P for oppositely drehbewegbaren coupling of the two output sun gears 1, 2. In the differential gear is a brake device BLP which is designed here as Bremslamellenpackung, for generating a coupling moment selectively coupling the planet carrier 3 to the circulating housing U in accordance with an axial force acting on the brake disk pack BLP. Furthermore, the differential gear according to the invention comprises an actuating mechanism 5 for generating those acting on the brake disc pack BLP axial force. The brake disk pack BLP is integrated into the differential gear in such a way that, with a corresponding axial load, it couples the planet carrier 3 to the circulation housing U in a friction-locked manner. By this approach, it is possible to cancel the drive connection between the planet carrier 3 and the circulation housing U by relieving the brake disc pack BLP, or to couple by friction of the brake disc pack BLP the planetary carrier 3 with the circulation housing U frictionally.

The actuating mechanism 5 is designed such that it has an axially expandable Hubaktuator 6 which is received in the circulation housing U and rotatably supported axially in the circulation housing U at this. For this purpose, the lifting actuator 6 is rotatably supported axially in the circulating housing U with respect to this circulating housing U via a first axial bearing AX1. This first axial bearing AX1 is designed here as a cylindrical roller bearing. In addition, the Hubaktuator 6 is rotatably supported axially in the circulation housing U and with respect to the braking device BLP via a second thrust bearing AX2. This second axial bearing AX2 is also designed as a cylindrical roller bearing. The cylindrical rollers of the axial bearing AX2 roll on a pressure plate 4c which axially loads the brake disk pack BLP in the event of actuation.

The Hubaktuator 6 is designed as Rampenaktuator, in particular Kugelrampenaktuator and includes a first ramp disc 6a and a second ramp disc 6b, wherein the first ramp disc 6a relative to the second ramp disc 6b is twistable about the transmission axis X. The second ramp disc 6b is rotatably coupled to the transmission housing G. The twisting of the first ramp disc 6a is accomplished by an electromechanical actuator, not shown here, or other actuator, which is located outside of the circulation housing and is stationarily connected to the transmission housing G. The kinematic coupling of the first ramp disc 6a with the servomotor or actuator takes place via the here shown th collar 6 c, which is formed integrally with the first ramp plate 6 a and extending out of the circulation housing U out.

The differential gear formed here with the inclusion of the planet carrier 3, the planetary arrangement P and the output sun gears 1, 2 is designed as a spur gear with two output sun gears 1, 2. The planetary arrangement P comprises a plurality of planetary planets P1, P2 which are mounted as such on planet pins 6. In the case of the differential gear according to the invention shown here, the brake disk pack BLP and the planetary carrier 3 are configured coordinated with one another such that the brake disk pack BLP is located at the radial or path level of the planetary axes XP parallel to the transmission axis X. By means of this special construction it is achieved that the axial force F acting on the brake disk pack BLP can be removed axially against the circulating housing U, including the planetary pin 6 aligned parallel to the transmission axis X by the planet carrier 3.

The brake disk pack BLP has a set of first ring-like brake disks 4a, which are axially displaceably but rotationally fixedly engaged via an inner edge contour with the planet carrier 3. The brake disk pack BLP has a set of second brake disks 4b, which are axially displaceable but non-rotatably engaged via an outer edge contour with the circulation housing U. These brake plates 4a, 4b are designed as flat sheet steel annular discs and coated with a Reibmaterialbelag.

The axial support of the brake disc pack BLP to the planetary bearing pin 6 takes place with the involvement of a pressure ring element 4d which is supported on the end faces of the planetary bearing pin 6. The planet carrier 3 and the brake disk pack BLP are tuned overall so that the radial distance of the respective planet pin axis XP from the transmission axis X is greater than the inner diameter of a brake disk 4a, 4b and also smaller than the outer diameter of the brake disk 4a, 4b. The provided for receiving the planet carrier 3 circulating housing U is formed as a two-piece pot housing and is composed of a first pot member U1 and a second pot member U2, wherein the first pot member U1 and the second pot member each have a radially inwardly extending bottom portion U1 a, or U2a has.

The aforementioned first and second planetary planets P1, P2 are in direct engagement with each other and thus, as will be explained in more detail below, are coupled to one another in such a manner that they rotate in opposite directions. In this embodiment, a total of three or four planetary planets P1 are provided which are in engagement with the first output sun gear 1. These rotating planetary gears P1 engaged with the first driven sun gear 1 form a first planetary planetary gear set. Furthermore, in this exemplary embodiment, a total of three or four circulating planets P2 are provided, which are in engagement with the second driven sun gear 2. These rotating planetary gears P2 engaged with the second driven sun gear 2 form a second planetary planetary gear set. In each case a circulation planet P1 of the first set is engaged with a circulation planet P2 of the second set. The engagement of the planetary planets P1 of the first set in the circulation planets P2 of the second set takes place in the same gearing plane as the engagement of the planetary planets P1 of the first set in the first output sunshade 1. There may be other numbers of Umlaufplanetenpaaren provided, in particular only two or three, or even five Umlaufplanetenpaare. Furthermore, it is also possible to design and arrange the circulating planets such that they form a closed whole circle by subsequent tooth engagements.

The first output sun gear 1 and the second output sun gear 2 are matched with respect to the tooth geometry such that the top circle of the spur gear 1 a of the first output sun gear 1 is smaller than the Fußkreis the Abtriebssonnenradverzahnung 2a of the second Abtriebssonnenrades 2. The planetary planets P1 of the first set in the range the toothing plane of the first output sun gear 1 into the circulation Planets P2 of the second set. The two Abthebenssonnenräder 1, 2 are thus in the immediate vicinity.

The two Abthebenssonnenräder 1, 2 are formed such that the Abtriebssonnenradverzahnung 1 a of the first output sun gear 1 and the Abriebssonnenradverzahnung 2a of the second driven sun gear 2 have the same numbers of teeth. The circulation planets P1 of the first set and the circulation planets P2 of the second set also have the same number of teeth. About the planetary planets P1, P2 is a symmetrical torque distribution and power split on the output sun gears 1, 2. At the output sun gears 1, 2 collar sections 1 b, 2b are formed. These collar sections 1 b, 2 b are here produced by extrusion molding and provided with an internal toothing 1 c, 2 c. In this internal toothing 1 c, 2 c correspondingly complementarily toothed end portions of Radantriebswellen, or other power transfer components of the respective Radantriebsstranges be inserted. Instead of the internal teeth shown here also other connection geometries for torque transmission and centered recording of corresponding components are possible.

The rotatably attached to the rotary housing U ring gear 7 is driven by a main drive pinion 8. The ring gear 7 and the main drive pinion 8 form an angular gear. The embodiment shown here is thus particularly suitable as an axle differential for a selectively decoupled from the main driveline rear axle. Instead of the torque introduction shown here via a bevel gear, it is also possible to provide the planetary gear U a spur gear which is driven for example via a further spur gear. Such a variant is then particularly suitable for direct attachment to a vehicle transmission.

The planet carrier 3 is seated between a ring element R and the brake disk pack BLP. The axial force support between the ring element R and the brake disk pack BLP takes place here primarily via the planet pins 6 and the planet carrier 3 stiffened by them.

The planet carrier 3 is composed of two carrier shells 3a, 3b and a carrier pin 3c. The carrier shells 3a, 3b are each manufactured as Blechumformteile. These two carrier shells 3a, 3b and the carrier pin 3c are welded together. On the first carrier shell 3a for this purpose webs are formed which bridge the toothing area as such. The first carrier shell 3a forms an inner bore in which an extension of the first output sun gear 1 is rotatably received. The brake disc pack BLP sits on the trunnion 3c. By braking the brake disk pack BLP so that the planet carrier 3 with the circulation housing U can be frictionally coupled. The brake disk pack BLP and the axial load of the same provided adjusting mechanism 5 is designed so that on this brake disk pack BLP in the axially loaded state, the torque applied to the crown gear 7 can be transmitted to the planet carrier 3.

The bearing of the planet carrier 3 in the circulation housing U via a first needle bearing L1 and a second needle bearing L2. The storage of the circulation housing U in the transmission housing G via angular contact ball bearings L3, L4. These angular contact ball bearings L3, L4 also divert the radially and axially directed gear reaction force components engaging on the ring gear 7 into the transmission housing G. The bearing L1 and also the bearing L2 each have no axial forces derived. The main purpose of these bearings L1, L2 is the centering and mounting of the planetary carrier 3 in the circulation housing U.

The operation of the differential gear according to the invention is as follows: About the main drive pinion 8, the ring gear 7 is driven. The ring gear 7 is rotatably fixed to the circulation housing U. Accordingly, the rotary housing U is rotated via the ring gear 7 in rotation. This circulation housing U is arranged concentrically to a transmission axis X and rotatably supported in the transmission housing G via the bearings L3, L4. Together with the circulation housing U, the brake disc rings 4b of the brake disc pack BLP, which are coupled to them in a rotationally fixed manner, are also rotated. The brake disk pack BLP is axially loaded by the pressure ring 4d and the annular plate 4c in accordance with the axial force generated by the adjusting mechanism 5 and thus possibly spent in a coupling state in which the circulation housing U and the planet carrier 3 are frictionally coupled. The adjusting mechanism 5 comprises a Hubaktuator which is axially rotatably supported on both sides in the circulation housing. The lifting actuator comprises a first ramp disk 6a and a second ramp disk 6b. If these two ramp discs 6a, 6b are twisted against each other, they lift axially away from each other, or approach each other axially. The Hubaktuator 6 thus converts a torsion movement in a linear lifting movement in the direction of the transmission axis X. The first ramp disc 6a is supported via the second thrust bearing AX2 on the pressure plate 4c of the brake disc pack BLP. The second ramp disc 6b is supported via the first thrust bearing AX1 at the radially inwardly penetrating bottom portion U1a of the circulating housing U. The actuating force generated by the actuating mechanism 5 acting on the brake disk pack BLP is guided within the circulating housing in the illustrated differential gear and does not engage the bearings L3, L4.

Within the planet carrier 3 there is a power split via the planets P1, P2 on the output sun gears 1, 2. The recorded here in the Umlaufge- housing Umlaufrädergetriebe forms as already mentioned a spur gear. In the embodiment shown here, the output sun gears 1, 2 and the planetary gears P1, P2 of the planetary arrangement P are provided with a teeth to Wildhaber / Novikov. The first output sun gear 1 in this case has a toothing with small head free and concave tooth flank surfaces. The second output sun gear 2 has a toothing with a large head and convex tooth flank surfaces. The tip diameter of the first output sun gear 1 and the theoretical root circle of the second output sun gear 2 correspond approximately to the identical pitch circle. diameter. Both gears 1, 2 have the same number of teeth. The first output sun gear 1 is engaged with the circulation planet P1, the second output sun gear 2 is engaged with the circulation planet P2. The planetary planets P1 have a large tip diameter and form convex tooth flanks. The planetary planets P2 have a small tip diameter and form concave tooth flanks. The planetary planets P1, P2 are engaged in pairs. The intervention takes place in the engagement plane of the first circulation planet P1 in the first output sun gear 1. The first planetary planets P1 have an axial length which essentially corresponds to the axial length of the toothing 1 a of the first output sun gear 1. The second planetary planets P2 have an axial length which substantially corresponds to the sum of the axial lengths of the teeth 1 a, 2 a of both output sun gears 1, 2. The representation according to FIG. 2 once again illustrates the functional field of the lifting actuator 6 incorporated according to the invention into the circulating housing and rotatably mounted in this circulating housing. In the state shown here, the lifting actuator 6 has the shortest axial length. For axial elongation, the first ramp disc 6a is twisted relative to the second ramp disc 6b. The two ramp discs 6a, 6b are supported on rolling elements 6d, which are designed here by way of example as cylindrical rollers 6d. The two ramp discs are axially profiled in the region of the mutually facing end faces and thus cancel each other axially in a relative rotation. Both ramp disks 6a, 6b are rotatably supported axially on the circulation housing U or the brake disk pack BLP via the axial bearings AX1, AX2, which are not closer to each other here. The second ramp disc 6b is rotatably anchored to the transmission housing G. The first ramp disc 6a can be twisted over the here provided with a toothing collar 6c of an actuator which is outside of the circulating housing U. The collar 6c can also be led out laterally from the gearbox G and connected there with a lever, so that the application of the adjusting movement can be effected by a simple encoder acting on that lever, eg a positioning cylinder or a correspondingly dimensioned vacuum unit. From the inner bore of the collar 6c, the wheel drive shaft is then led out as such rotatably engaged in the internal toothing of the second sun gear. Securing the second ramp disc 6b on the gear housing G (not shown here) (see Fig. 1) via a cylindrical collar 6b1 formed either integral with the second ramp disc, or otherwise otherwise torsionally coupled. In this collar 6b1, a slide bearing ring 6b2 is used, which as such superimposes radially on this here recognizable socket portion 6a1, which extends between the first ramp plate 6a and the toothed collar 6c.

The axial, rotatable support of the second ramp disc 6b on the circulating housing U not shown in detail here takes place via the cylindrical roller bearing AX1. This comprises here cylindrical rollers which are guided in a cage AX1 -K and roll on a race AX1 -R. The raceway AX1-R is made as a sheet metal stamped part and designed so that it centers in the circulation housing U, in particular on the radially inwardly penetrating end wall U1 a (see Fig. 1) in the correct position with a slight press fit.

In the installed state of the collar 6b1 rotatably seated in the gear housing G and thus secures the second ramp disc 6b against torsion. If a torque is now introduced into the toothed collar 6c, then the first ramp disc 6a is pivoted relative to the second ramp disc 6b. Due to the axial profiling of the two ramp discs 6a, 6b and the rolling elements 6d inserted between these ramp discs 6a, 6b, the ramp disc arrangement expands axially as indicated by the arrow symbol A1. The corresponding generated actuating forces are transmitted from the inside to the circulation housing via the axial bearing AX1 shown here and to the pressure plate 4c via the second axial bearing AX2. The ramp disk arrangement 6a, 6b is rotatably supported by the two axial bearings AX1, AX2 in relation to the circulation housing U and the components revolving therewith. The actuating forces generated by the ramp disc arrangement and generated in the direction of the transmission axis act within the revolving unit and, due to the two-sided support of the ramp disc arrangement in the circulation housing U out so that they do not have to be removed via the storage of the circulating housing U provided main bearing (L3, 14) and thus have no effect on the load of these bearings.

The adjusting mechanism formed with the inclusion of the ramp discs 6a, 6b is located within the circulating housing U, the actuation of the ramp discs 6a, 6b takes place from the outside here by the first ramp disc 6a applied via the collar 6c with a torque and thus twisted against the second ramp disc becomes.

The actuating mechanism according to the invention rotatably supported on both sides can also have a different construction. The controlled axial expansion of the actuating mechanism can also be achieved by other mechanical concepts, so it is particularly possible to support the two discs 6a, 6b via a threaded structure against each other.

Claims

Claims ifferential gearbox, with:

a transmission housing (G),

a circulation housing (U) which is rotatably arranged in the transmission housing (G) about a transmission axis (X),

- One in the circulation housing (U) to the transmission axis coaxially arranged planet carrier (3),

- A braking device (BLP) with a brake disk pack for generating a planet carrier (3) with the circulation housing (U) coupling coupling torque, and

- An actuating mechanism (5) for generating a force acting on the braking device (BLP) axial force, wherein

- The actuating mechanism (5) has an axially expandable Hubaktuator (6), which is received in the circulation housing (U) and in the circulation housing (U) rotatably supported axially on this.

2. Differential gear according to claim 1, characterized in that the Hubaktuator (6) in the circulation housing (U) relative to this circulation housing (U) via a first thrust bearing (AX1) is rotatably supported axially.

3. Differential gear according to claim 2, characterized in that the first axial bearing (AX1) is designed as a cylindrical roller bearing.

4. differential gear according to at least one of claims 1 to 3, characterized in that the Hubaktuator (6) in the circulation housing (U) relative to the braking device (BLP) via a second thrust bearing (AX2) is rotatably supported axially.

5. differential gear according to claim 4, characterized in that the second axial bearing (AX2) is designed as a cylindrical roller bearing, and that the cylindrical rollers on a pressure plate (4c) roll off which axially loaded the brake disc pack (BLP).

6. differential gear according to at least one of claims 1 to 5, characterized in that the Hubaktuator (6) is designed as a hydrostatic Aktor ator and comprises an annular piston and an annular chamber and the axial expansion of the actuator is accomplished by applying the annular chamber with a fluid ,

7. differential gear according to at least one of claims 1 to 5, characterized in that the Hubaktuator (6) is designed as Rampenaktuator and a first ramp disc (6a) and a second ramp disc (b) and the first ramp disc (6a) relative to the second Ramp disc (6b) about the transmission axis (X) is twistable.

8. Differential gear according to claim 7, characterized in that the twisting of the first ramp disc (6a) is accomplished by a servomotor.

9. Differential gear according to claim 8, characterized in that the second ramp disc (6b) is rotatably coupled to the transmission housing (G).

10. differential gear according to at least one of claims 1 to 9, characterized in that the differential gear comprises a first output sun gear (1), a second output sun gear (2), as well as in the planet carrier (3) recorded planetary arrangement (P), rotatable in opposite directions Coupling of the two output sun gears (1, 2), wherein the planetary arrangement (P) comprises a plurality of planetary orbits (P1, P2), which are rotatable as such about planetary axes (XP), which are aligned parallel to the transmission axis (X), and that the braking device (BLP) and the planet carrier (3) are designed coordinated with each other so that the brake disk pack (BLP) is at the radial level of the planetary axes (XP).